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Table of Content

15 May 2018, Volume 39 Issue 9
Basic Research
Effect of Whey Protein-Luteolin Complexes on Physical and Oxidative Stability of Emulsions
YUAN Tinglan, ZHU Wenting, CHEN Xianxin, LIU Wenqiang, ZHU Xuemei, XIONG Hua
2018, 39(9):  1-6.  doi:10.7506/spkx1002-6630-201809001
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In this study, heated and native whey protein were separately employed as emulsifiers to prepare oil-in-water (O/W) emulsions using a high-pressure homogenizer. Luteolin at different concentrations (0.00, 0.05, 0.10, 0.20 and 0.40 mg/mL) were added to the emulsions to form whey protein-luteolin complex. Fluorescence spectra, dynamic light scattering spectra, and the contents of protein and luteolin at the interface were determined in order to evaluate the potential influence of the complex as a natural antioxidant on the physical and chemical stability of emulsions. The formation of whey protein-luteolin complex was verified by analysis of fluorescence spectra and fluorescence quenching occurred. Based on the peroxide value (POV) and thiobarbituric acid reactive substance (TBARS) value, whey protein-luteolin complex significantly improved the oxidative stability (P < 0.05), but had no significant effect on the physical stability of emulsions (P > 0.05). The heating treatment could improve the adsorption of luteolin but blocked protein at the interface. However, luteolin content had no significant effect on the adsorption of protein (P > 0.05).
Effect of Acidic Electrolyzed Water on Polyphenoloxidase Activity from Litopenaeus vannamei
SUN Jiangping, ZHAO Li, YU Wenying, XIE Jing, PAN Yingjie, ZHAO Yong
2018, 39(9):  7-12.  doi:10.7506/spkx1002-6630-201809002
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Recently, acidic electrolyzed water (AEW) has been applied in seafood preservation as a novel technology. It is reported that AEW has strong ability to delay the development of melanosis in Litopenaeus vannamei and extend its shelflife. In this paper, polyphenoloxidase (PPO), an essential enzyme for melanosis in Litopenaeus vannamei, was extracted and purified. The effects and kinetics of AEW on purified PPO were then investigated. Based on sodium dodecyl sulfatepolyacrylamide gel electrophoresis, PPO from Litopenaeus vannamei was well purified. Kinetic studies revealed that AEW exhibited inhibitory effects on PPO with a dose-effect relationship. Moreover, AEW showed mixed-type inhibition on PPO with inhibitory constant Ki value of 0.64 mmol/L. In conclusion, this study can provide a theoretical basis for further exploring the mechanism of AEW in food preservation.
Quality Evaluation of Apple Slices during Drying Based on Electrical Properties
TU Peng, BIAN Hongxia
2018, 39(9):  13-18.  doi:10.7506/spkx1002-6630-201809003
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Apple slices were dried in a thermostatically controlled oven at 60 ℃. Changes in eight physicochemical indices and four electrical parameters were determined at different drying times. The experimental results obtained were as follows. As the drying time was increased, moisture content and density were decreased and browning degree was increased; total soluble solid content was decreased with drying time up to 120 min, accompanied by a simultaneous increase in titratable acidity and consequently a decrease in solid/acid ratio, and remained nearly unchanged thereafter. Vitamin C content and firmness were both significantly, negatively and linearly correlated with drying time. Relative permittivity and extracellular resistivity were decreased with drying time, while intracellular resistivity and damping factor showed a wave-shaped trend. Statistical analysis showed that intracellular resistivity and damping factor were inadequate to evaluate the quality change of apples during drying and that relative permittivity and extracellular resistivity had high correlations with firmness, the ratio of total soluble solids to titratable acidity, vitamin C content, browning degree, moisture content and density but were not highly correlated with titratable acidity or total soluble solids. According to the above results, the linear equations were built with relative dielectric constant and extracellular resistivity as independent variables and six physicochemical indices as dependent variables, which would provide a rapid tool to evaluate the quality change of apple slices during drying.
Effects of Garlic Essential Oil and Starter Cultures on Biogenic Amine Accumulation and Microbial Distribution in Smoked Horsemeat Sausages
LI Binbin, ZHANG Yaqing, ZHAO Lili, MAO Shun, LU Shiling
2018, 39(9):  19-25.  doi:10.7506/spkx1002-6630-201809004
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The study examined the effects of garlic essential oil and starter cultures on the accumulation of biogenic amines in smoked horse sausages. Biogenic amines were quantified by high performance liquid chromatography, and the changes of microbial diversity and biogenic amine contents were analyzed by using metagenomics. The results indicated that the combined use of starter cultures and garlic essential oil could reduce the accumulation of cadaverine, putrescine, histamine, tyramine and phenylethylamine and thus had a significant role in controlling the content of biogenic amines. The smoked sausages were rich in microbial species; lactic acid bacteria were the dominant bacteria at the family level throughout the processing of sausages and Staphylococcus was detected in large quantity during the late ripening period.
Low Field Nuclear Magnetic Resonance Analysis of Moisture Distribution and Quality Variation in Boiled Eggs under Different Storage Conditions
DUAN Yunxia, ZHAO Ying, CHI Yujie
2018, 39(9):  26-32.  doi:10.7506/spkx1002-6630-201809005
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In this paper, the changes in moisture content, oxidation condition, texture and color of boiled eggs with and without shell were studied during storage at refrigerator (4 ℃) and room temperature (25 ℃), respectively. The moisture distribution, microstructure change and textural properties were determined using low field nuclear magnetic resonance, scanning electron microscopy and texture analyzer. The effects of protein and fat oxidation on the quality change were studied through carbonyl content and thiobarbituric acid reactive substances content. The results indicated that the moisture content in white and yolk of boiled eggs, especially immobile water content, was decreased during storage (P < 0.05), but the degree of protein and fat oxidation was increased, and shelling treatment was an important factor affecting these changes. At the same time, the hardness and chewiness of boiled egg increased gradually as the storage time was prolonged. The microstructure of egg white gel was denser and the sensory quality was lower than that of freshly boiled egg white gel, but the quality of boiled egg white with shell at refrigerator temperature (4 ℃) changed minimally among all experimental groups. Storage temperature had no significant effect on the color of boiled eggs (P > 0.05), but shelling treatment could change the color of boiled eggs significantly (P < 0.05). On the basis of the above results, the moisture loss and oxidization of boiled eggs were the major reasons for egg quality deterioration. In conclusion, storage at 4 ℃ is recommended for boiled eggs with shell.
Comparison of Bioactive Compounds, Antioxidant Activity and α-Glucosidase Inhibition Activity of Five By-Products from Lotus Seed Production
ZHANG Lu, HUANG Xiangxia, TU Zongcai, ZHAO Yi, WANG Hui, WANG Hao, SHA Xiaomei, ZHANG Shuya
2018, 39(9):  33-38.  doi:10.7506/spkx1002-6630-201809006
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A large amount of lotus receptacle, epicarp, and seed skin are discarded every year without any further utilization. Thus, this study was designed to compare the potentials in high-value utilization of lotus leaf, receptacle, epicarp, seed skin and plumule. The contents of major bioactive compounds in extracts from these materials were measured, and the antioxidant activities and hypoglycemic potential were analyzed with three antioxidant models and α-glucosidase inhibitory assay, respectively. The results indicated that lotus receptacle extract had the highest contents of phenols (232.50 mg GAE/g) and triterpenoids (423.75 mg OAE/g), while the highest content of flavonoids (41.48 mg QuE/g) and condensed tannins (36.13 mg CaE/g) was found in lotus leaf and lotus seed skin extract, respectively. In addition, lotus receptacle extract showed the strongest antioxidant and α-glucosidase inhibition. The 1,1-diphenyl-2-picrylhydrazyl scavenging ability, 2,2’-azino-bis-(3-ethylbenzthiazoline-6-sulphonate) scavenging ability and α-glucosidase inhibition were 2.64, 1.17 and 85 folds higher than that of the positive control, respectively. Furthermore, lotus seed skin extract had the second highest antioxidant ability; the α-glucosidase inhibition of lotus leaf, lotus receptacle, lotus epicarp, and lotus seed skin was higher than that of acarbose. Correlation analysis indicated that phenolics and condensed tannins contributed the most to free radical scavenging and α-glucosidase inhibitory activity, whereas flavonoids contributed the most to reducing power. Thus, lotus receptacle has considerable antioxidant and hypoglycemic activities, and phenolics, flavnoids and condensed tannins are the major bioactive compounds, and therefore it needs to be further investigated for in vivo activity against hyperglycaemia, diabetes and diabetic complication.
Rheological Properties and Gelation Kinetics of Konjac Gum-Xanthan Gum Mixtures
ZENG Ruiqi, LI Weizhou, ZHAO Xin, ZHANG Fusheng, ZHENG Jiong
2018, 39(9):  39-46.  doi:10.7506/spkx1002-6630-201809007
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In order to investigate the synergism between konjac gum and xanthan gum during gelation, we prepared 1% mixed gels with different konjac gum to xanthan gum ratios (2:8, 4:6, 5:5, 6:4, and 8:2) by mass. The rheological properties and gelation kinetics of the mixed system were determined, and the underlying mechanisms were explored. The results showed that the konjac gum-xanthan gum system was pseudoplastic. As the proportion of konjac gum increased, the consistency coefficient K increased and the fluid index n decreased. The dynamic viscoelastic properties were also changed with changing ratio between konjac gum and xanthan gum. When the ratio between konjac gum and xanthan gum was 6:4, the strongest pseudoplasticity and elasticity were observed as indicated by the highest K value and lowest n value. The rate of gelation was greatly affected by the ratio between two gums. Slow gelation rate and poor gel strength were found at a ratio smaller than 6:4. When the ratio was increased to 6:4, the gelation process was accelerated; the SDRa and G’ curves rapidly rose and the gel strength was increased. However, the gelation rate was decreased with further increasing konjac gum/xanthan gum ratio. The kinetic data were well fitted to the Arrhenius equation with a determination coefficient greater than 0.98, indicating an excellent goodness of fit. The activation energy for the gelation process was significantly increased at a 6:4 ratio between konjac gum and xanthan gum (P < 0.05) and it differed in the high- and low-temperature ranges.
Physicochemical Characteristics of Black Seed Coat Powders with Different Particle Sizes of Pepper (Zanthoxylum bungeanum)
YANG Mo, XUE Yuan, REN Lu, LEI Hongjie, XU Huaide
2018, 39(9):  47-52.  doi:10.7506/spkx1002-6630-201809008
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In order to investigate the difference among pepper seed coat powders with different particle sizes for their processing and utilization, the effects of particle size on the color, microstructure, mid-infrared spectrum, adsorption characteristics, bioactives and antioxidant activity of black seed coat powders of pepper (Zanthoxylum bungeanum) were examined. Results showed that superfind grinding significantly reduced the particle size of the coarse powder, brightened the color, disrupted the cell wall, increased the water and oil holding capacity by 33.33% and 44.60%, respectively, and improved the heavy metal ion adsorption capacity. However, it did not alter the structure of functional groups in the powder. The dissolution of polyphenols and flavonoids from the superfine powder were increased by 15.93% and 11.24%, respectively, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging capacity were enhanced significantly as compared with the coarse powder (P < 0.05). Therefore, superfine grindin could significantly improve the dissolution of active substances and effectively increase antioxidant activity, consequently leading to more effective utilization of black seed coat of pepper.
Stability of Phenolic Compounds and Antioxidant Activity of Blueberry Incorporated in Yoghurt during Storage and in Vitro Digestion
ZHAO Yongbo, DU Lingling, LIU Lu, QU Xiuwei, WANG Haixia, CHEN Ping, LI Xiaodong
2018, 39(9):  53-59.  doi:10.7506/spkx1002-6630-201809009
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Changes in the contents of total phenolics, total flavonoids and anthocyanins and antioxidant activity of blueberry incorporated in yoghurt were determined during 21 d of storage at 4 ℃ and digestion in vitro. The antioxidant activity was evaluated by total antioxidant capacity, DPPH radical scavenging and ABTS radical scavenging assays. The results showed that the contents of total phenolic compounds, total flavonoids and anthocyanins, total antioxidant capacity, and DPPH and ABTS radical scavenging activity were 46.14, 41.63, 9.01, 44.51, 59.49 and 61.39 mg/100 g at the beginning of storage, which decreased by 10.20%, 9.86%, 15.54%, 6.52%, 7.23% and 6.03% at the end of storage, respectively. These decreases were smaller than those (1.93%, 3.46%, 0.03%, 3.58%, 4.17% and 4.91%, respectively) observed for blueberry alone indicating that yoghurt decreased the stability of phenolic compounds and had a negative effect on antioxidant activity. A decrease in all these parameters was observed comparing blueberry added to yoghurt with blueberry alone, and after in vitro digestion, the comparison showed a decrease in total flavonoids content and DPPH radical scavenging activity but an increase in the contents of total phenolics and anthocyanins, total antioxidant capacity and ABTS radical scavenging activity, which indicated that simulated gastrointestinal digestion could promote the release of antioxidant substances from blueberry incorporated in yoghurt.
Effect of Heat Treatment on the Secondary Structure and Gel Property of Soybean Protein Isolate
TAO Ruqing, XIA Ning, TENG Jianwen
2018, 39(9):  60-66.  doi:10.7506/spkx1002-6630-201809010
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This study determined the subunit composition and structure, free amino group content, free sulfhydryl content, surface hydrophobicity index and gel strength of soybean protein isolate (SPI). Furthermore, the effect of heat treatment on physicochemical properties, structural characteristics and gel property of SPI was explored. The results showed that with the increase in heat treatment temperature, the subunit dissociation of SPI was aggravated; the β-sheet content decreased significantly, whereas the random coil content increased significantly. The free amino group content, free sulfhydryl content, and surface hydrophobicity tended to increase with elevated temperature from 70 to 95 ℃ when the heat treatment lasted 10 min. In addition, the gel strength of heat induced gel decreased after an initial increase, and its water loss continuously dropped. In the case of heat treatment at 90 ℃, the free amino group content gradually increased, and the free sulfhydryl content and surface hydrophobicity initially increased and thereafter declined with increasing the treatment time from 5 to 60 min; the gel strength and the water loss of heat induced gel increased and declined, respectively. The gel strength and the water loss gradually increased and decreased respectively with the increase in temperature and holding time. To sum up, the optimal conditions to obtain SPI gel should be heat treatment at 90 ℃ for 15 min, and then maintenance at 90 ℃ for 30 min.
Food Engineering
Effect of Ultrasound Treatment on Anthocyanin Stability and Degradation Kinetics
GONG Hui, FU Li, LI Lanqi, CHEN Jianle, LIU Shanshan, CHEN Shiguo, YE Xingqian
2018, 39(9):  67-75.  doi:10.7506/spkx1002-6630-201809011
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In order to better understand anthocyanin (Acy) extraction with ultrasound treatment, the stability of five common Acy compounds was analyzed under different ultrasound conditions (power density, temperature, solvent and pH) in a model system and their degradation kinetics were obtained by a trial-and-error approach. Their degradation products were investigated by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS). Results indicated that the degradation efficiency of Acy under ultrasound treatment declined with increasing temperature. All five Acys had the lowest degradation efficiency in 70% ethanol. The degradation efficiency of Acy decreased initially and then increased with pH in the range of 1-5. The degradation of delphinidin-3-glucose (Dp-3-glu) under ultrasonic treatment was fitted well to the first-order reaction kinetics, while pelargonidin (Pg)-3-glu, malvidin (Mv)-3-glu, peonidin (Pn)-3-glu, and cyanidin (Cy)-3-glu were consistent with the zero-order reaction kinetics. In addition to anthocyanone A, kaempferol, quercetin, syringic acid, ferulic acid and 2,6-dimethoxyphenol were detected in the degradation products of all Pg-3-glu, Mv-3-glu, Pn-3-glu and Cy-3-glu.
Effect of Electrical Stimulation on Horsemeat Tenderness during Postmortem Aging
KONG Lingming, LI Fang, ZHANG Wen, DA Dila·Mai Maiti, YANG Haiyan
2018, 39(9):  76-81.  doi:10.7506/spkx1002-6630-201809012
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Horse carcasses were subjected to different durations of electrical stimulation after slaughter and the cooking loss, shear force, soluble protein concentration (SPC), myofibrillar fragmentation index (MFI), collagen solubility and muscle fiber microstructure in horsemeat were assayed during postmortem aging. The results indicated that electrical stimulation had no significant impact on the cooking loss of horsemeat during aging (P > 0.05). However, within a certain range of electrical stimulation duration, the shear force decreased, whereas SPC, MFI and collagen solubility increased during aging. Under the experimental conditions used in this study, electrical stimulation for 60 s improved the tenderness of horsemeat, but this effect was not enhanced by increasing the treatment time. Electrical stimulation for 60 s decreased the shear force of horsemeat at 14 d of aging by 13.8% and increased SPC and MFI 1.16- and 1.28- fold, respectively as compared with the control. Moreover, this treatment destroyed muscle fiber microstructure. In summary, appropriate electrical stimulation promoted postmortem aging of horsemeat and improved meat tenderness. This study will provide theoretical insights into the mechanism of meat tenderization by electrical stimulation and a theoretical basis for new product development.
Effect of High Pressure Homogenization Pretreatment on Structure and Properties of Cationic Corn Starch
LI Guixiao, DAI Yangyong, HOU Hanxue, ZHANG Hui, LI Xiangyang, WANG Wentao, DONG Haizhou, LIU Chuanfu
2018, 39(9):  82-87.  doi:10.7506/spkx1002-6630-201809013
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In order to investigate the effect of mechanical force during high pressure homogenization on the chemical reactivity of starch, we prepare cationic starch by the wet method from corn starch subjected to 1, 5 and 7 high pressure homogenization cycles (three stages of mechanical action). The structure and properties of cationic starch were examined by scanning electron microscopy, confocal laser scanning microscopy, polarizing microscopy, X-ray diffraction, rapid visco-analyser and differential scanning calorimetry. The results indicated that high pressure homogenization pretreatment destroyed the crystal structure and improved the chemical reaction activity of starch. This phenomenon was the most pronounced at the stage of aggregation and the peak viscosity, light transmittance and chemical reaction activity of cationic starch prepared at this stage were the highest. In addition, the degree of substitution and reaction efficiency were increased by 43.80% and 43.86%, respectively.
Freeze-Thaw Stability of Emulsion System from Ultrasound-Modified Soy Protein Isolate and Soluble Polysaccharide
DING Jian, LI Yang, SHI Borui, SUN Hongbo, QI Baokun, JIANG Lianzhou, SUI Xiaonan
2018, 39(9):  88-94.  doi:10.7506/spkx1002-6630-201809014
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The freeze-thaw stability of composite emulsion systems prepared with ultrasonic-modified soy protein isolate (SPI) and soluble soy polysaccharide (SSP) was studied and correlated with their structural properties. Confocal laser scanning microscopic (CLSM) analysis of the emulsions before and after two freeze-thaw cycles was conducted. Simultaneously, changes in the percentage of solid fat content (SFC) during isothermal crystallization, the amount of emulsified oil and the secondary structure of the emulsifier SPI under different ultrasonic treatments (0, 200, 300, 400, and 500 W) were investigated as well as their relationships with the freeze-thaw stability of the emulsion system. The results showed that the coalescence of droplets in the emulsion system after being subjected to two freeze-thaw cycles decreased with the increase of ultrasonic power. The emulsion with SPI subjected to ultrasonic treatment at 400 W showed the highest stability. The rate of increase in SFC during isothermal crystallization varied among different emulsion systems, but the total SFC was identical in the final balanced emulsions. The amount of emulsified oil also changed. Similarly, different ultrasonic treatments changed the secondary structure of soy protein isolate. The highest random coil structure content in soy protein isolate subjected to 400 W ultrasonic treatment was observed. SPI treated at different ultrasonic powers formed complexes having different structures with SSP, affecting the freeze-thaw stability of emulsions. Therefore, this study indicated that appropriate ultrasonic treatment could improve the conformation and spatial structure of soy protein isolate and promote its binding with soluble polysaccharide molecules, consequently affecting the interfacial structural properties between soy protein isolate and soluble polysaccharide and the freeze-thaw stability of the emulsion system.
Effect of Spray Drying and Freeze Drying on Structural and Functional Properties of Lotus Seed Protein
SHI Wenfang, BAI Rong, Lü Lishuang, LI Jianlin, SHEN Li, ZHANG Li, ZHENG Tiesong
2018, 39(9):  95-101.  doi:10.7506/spkx1002-6630-201809015
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Lotus seed protein was prepared from lotus seeds by alkaline extraction followed by isoelectric precipitation, and then dried by either spray or freeze drying. The resulting protein powders were comparatively evaluated for their structural and functional properties. Our data showed that compared to the freeze-dried lotus seed protein (FLSP), the spray-dried lotus seed protein (SLSP) had greater whiteness and lighter color. Scanning electron microscopy (SEM) showed that the structure of SLSP was folded inwards and wrinkled, being irregularly spherical in shape, whereas FLSP had a big flaky plate-shaped structure. X-ray diffraction analysis showed that both protein powders were non-crystalline. Furthermore, circular dichroism spectra demonstrated that the secondary structure of the dried proteins did not apparently changed except that their regular structure became irregular. SLSP had higher water-holding capacity and foaming properties (P < 0.05), but lower solubility, oil-holding capacity and emulsifying activity than FLSP. Hence, these results indicated that two different drying methods could affect the structural and consequently functional properties of lotus seed protein, implying that the resulting protein powders may have potential applications in different products.
Effect of Drying Methods on Polyphenol Composition and Antioxidant Activities of Figs (Ficus carica L.)
QIN Dandan, ZHANG Shengwan, GUO Meng, GUO Caixia, LI Meiping
2018, 39(9):  102-107.  doi:10.7506/spkx1002-6630-201809016
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The present study aimed to investigate the effects of different drying methods including sun drying, vacuum freeze drying, oven drying, far-infrared drying and vacuum drying on the total polyphenol content, polyphenol composition and antioxidant activities in vitro of figs. The contents of total and individual polyphenol compounds were determined by the Folin-Ciocalteu method and high performance liquid chromatography (HPLC), respectively. In addition, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis-(3-ehtylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacity and reducing power of polyphenols extracted from dried figs were determined and correlated with polyphenol contents. The results showed that the contents of both total and individual polyphenol compounds were significantly affected by the drying methods (P < 0.05) and both the total polyphenol content and the summation of individual polyphenol compounds in vacuum dried figs were the highest. The antioxidant activities of polyphenols extracted from figs were also significantly affected by the drying methods (P < 0.05). Vacuum drying resulted in higher DPPH radical and ABTS+· scavenging capacity and reducing power of polyphenols from dried figs than other drying methods. The antioxidant activity of figs presented a significant correlation with polyphenols including catechin, quercitrin, ferulic acid, and 4-hydroxybenzoic acid (P < 0.05). Based on these results, vacuum drying is the most suitable method for preserving polyphenol compounds and antioxidant activity in figs.
Nutrition & Hygiene
Combined Effect of Methionine Restriction and Collagen Peptides on Lipid Metabolism and Oxidative Stress in High-Fat Diet-Fed Mice
WANG Yanan, ZHANG Jiahong, GUO Haitao, LE Guowei, SHI Yonghui
2018, 39(9):  108-115.  doi:10.7506/spkx1002-6630-201809017
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Purpose: To ascertain the combined effect of methionine restriction (MR) and collagen peptides on lipid metabolism and oxidative stress in high-fat-diet (HFD)-fed mice. Methods: Thirty-six male C57BL/6 mice were randomly and evenly divided into normal diet (ND), high-fat diet (HFD), high-fat with MR diet (MR), and MR diet supplemented with 1% collagen peptides (PMR) groups, respectively. Body weight was measured weekly. At the end of the 22-week feeding period, all mice were sacrificed. Plasma total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and free fatty acids (FFAs) were examined. The concentrations of TG and TC in liver were investigated. The levels of total antioxidant capacity (T-AOC), glutathion peroxidase (GSH-Px), and malondialdehyde (MDA) in liver and plasma were determined. The mRNA expression of fatty acid synthase (FAS), acetyl CoA-carboxylase 1 (ACC-1), sterol regulatory element-binding protein 1c (SREBP1c), cholesterol 7α-hydroxylase 1 (CYP7A1), carnitine palmityl transferase 1 (CPT1) and peroxisome proliferator activated receptor α (PPARα) in liver were assayed by quantitative real time polymerase chain reaction (qPCR). Results: Compared with the HFD group, MR significantly decreased body weight, TG and TC concentrations in liver (P < 0.01), MDA levels in plasma and liver and reactive oxygen species levels in blood and liver (P < 0.01), and down-regulated the expression of FAS (P < 0.01), SREBP1c (P < 0.01) and ACC-1 (P < 0.05) in liver. MR significantly increased GSH-Px and T-AOC activity in liver (P < 0.05) and plasma (P < 0.01), and up-regulated the expression of CYP7A1 (P < 0.01), PPARα (P < 0.01) and CPT1 (P < 0.05) in liver. Compared with the MR group, PMR significantly decreased body weight and TG concentration in liver (P < 0.01) as well as TG and TC concentrations in plasma (P < 0.05), down-regulated the expression of SREBP1c and ACC-1 in liver (P < 0.05), up-regulated the expression of PPARα and CPT1 (P < 0.05), and increased GSH-Px activity in liver (P < 0.05). Conclusion: Dietary methionine restriction can significantly decrease blood and liver lipid accumulation, enhance liver antioxidant capacity in HFD-fed mice and has a synergistic effect when combined with collagen peptides.
Anti-Tumor Activity of Mitissimol D and Its Effect on Apoptosis and Cell Cycle in Vitro
RONG Ruixue, WANG Zhongao, LI Xiaochan, HAN Yuehua, ZHANG Qi, LI Zhipeng, GUO Yunran, CAO Zhiran, WANG Bei
2018, 39(9):  116-120.  doi:10.7506/spkx1002-6630-201809018
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Objective: To investigate the anti-tumor activity of mitissimol D, a novel sesquiterpene compound extracted from Lactarius vellereus, and its effects on cell cycle and apoptosis. Methods: 3-(4,5)-Dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay was used to determine the inhibitory effect of mitissimol D on the proliferation of A549, HCT-8, Bel-7402, SMMC7721 and HeLa cells and to determine the half maximal inhibition concentration (IC50) in comparison with cisplatin as a positive control. A549 cells sensitive to mitissimol D were selected to observe the morphological changes and the changes in cell apoptosis rate and cell cycle. Results: Mitissimol D could effectively inhibit the proliferation of A549, Bel-7402, SMMC7721 and HeLa cells with IC50 (72 h) of 2.46, 19.09, 18.21 and 17.05 μg/mL, respectively. Mitissimol D could cause significant morphological changes of A549 cells, leading to the formation of apoptosomes and it also could induce apoptosis in A549 cells ( 32.14% apoptosis rate at 100 μg/mL after 72 h) and lead to cell block in the S phase. Conclusion: Mitissimol D can significantly inhibit the proliferation of tumor cells from a variety of tissue sources, of which A549 cells are the most sensitive, by interfering with the cell cycle. These findings provide an experimental basis for the development of mitissimol D as a new sesquiterpene compound.
Protective Effect of Lactobacillus casei on Acrylamide-Induced Intestinal Injury in Rats
LI Tianjiao, ZHANG Yongjie, WANG Zilong, LIU Ying, LIANG Hui
2018, 39(9):  121-126.  doi:10.7506/spkx1002-6630-201809019
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Objective: To investigate the protective effect of Lactobacillus casei on acrylamide-induced intestinal injury in rats. Methods: Male Wistar rats were randomly divided into following seven groups: control group (normal saline), low-, medium-, and high-dose acrylamide (5, 15, and 30 mg/(kg·d mb)) groups, and Lactobacillus casei [2.1 × 109 CFU/(kg·d mb)] plus low-, medium-, and high-dose acrylamide (5, 15, and 30 mg/(kg·d mb )) groups. The experimental period was 4 weeks. Feces were collected after the last treatment. Twelve hours after fasting, the rats were anesthetized to collect blood samples. The small intestine was obtained for the observation of ultrastructural changes by transmission electron microscope (TEM). Plasma D-lactic acid (D-LA) and diamine oxidase (DAO) concentration were measured by enzymelinked immunosorbent assay. The intestinal microbiota was detected by real-time PCR. Results: The ultrastructural changes observed by TEM showed that the tight junction was swelled; the microvilli, with significantly shortened length (P < 0.05), were loosely arranged in the medium-, and high-dose acrylamide groups. However, the control group did not show abnormal ultrastructure. Abnormal ultrastructural changes were rescued by Lactobacillus casei treatment. The plasma concentration of D-LA and DAO in the medium-, and high-dose acrylamide (15 and 30 mg/kg) groups were significantly elevated (P < 0.05) when compared with the control group. But in the Lactobacillus casei treatment groups, the plasma concentrations of D-LA and DAO were significantly reduced (P < 0.05) when compared with the medium-, and high-dose acrylamide (15 and 30 mg/kg) groups. Compared with the control group, Escherichia coli and Enterococcus faecalis were significantly increased (P < 0.05), and Bifidobacterium and Lactobacillus were significantly decreased (P < 0.05) in the medium-, and high-dose acrylamide (15 and 30 mg/kg) groups. But in the Lactobacillus casei treatment groups, Escherichia coli and Enterococcus faecalis were decreased, and Bifidobacterium and Lactobacillus were increased when compared with the medium-, and highdose acrylamide groups. Conclusion: Lactobacillus casei showed some protective effect on acrylamide-induced intestinal injury in rats. The underlying mechanism may be associated with the protection of intestinal mucosal barrier function and the regulation of the intestinal microbiota.
Inhibition of Boschniakia rossica Polysaccharides on Oxidative Stress-Induced Apoptosis in Vascular Endothelial Cells
CUI Xiangdan, HE Xin, ZHU Jiebo, LIU Liyuan, QUAN Jishu, YIN Xuezhe
2018, 39(9):  127-133.  doi:10.7506/spkx1002-6630-201809020
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Objective: To study the inhibitory effect of Boschniakia rossica polysaccharides (BRPS) on oxidative stressinduced apoptosis in vascular endothelial cells in vitro. Methods: A cellular model was established by treating human umbilical vein endothelial cells with tert-butyl hydroperoxide (tBHP). Cell viability was tested by methylthiazolyldiphenyltetrazolium bromide (MTT) assay, and the levels of malondialdehyde (MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) were measured spectrophotometrically. The reactive oxygen species (ROS) was observed using the fluorescent probe dichlorofluorescein diacetate (DCFH-DA), the mitochondrial membrane potential (ΔΨm) was evaluated by JC-1 staining, and the apoptotic changes were detected by Hoechst staining and TdT-mediated dUTP nick end labeling (TUNEL) assay. The protein expression of Bax, Bcl-2, cytochrome c (Cyt c), truncated Bid (tBid), caspase-3, caspase-8 and caspase-9 were determined by Western blotting. Results: Pretreatment with BRPS significantly increased cell viability, reduced ROS level, inhibited MDA formation, increased SOD activity and GSH level, elevated ΔΨm, and suppressed tBHP induced apoptosis in vascular endothelial cells. Western blotting results showed that BRPS reduced mitochondrial tBid, reduced cytoplasmic Cyt c and Bax/Bcl-2 ratio, and suppressed the activation of caspase-3, caspase-8 and caspase-9 in vascular endothelial cells. Conclusion: BRPS has an inhibitory effect on oxidative stress-induced apoptosis in vascular endothelial cells in vitro, likely through inhibiting mitochondrial apoptosis and death receptor pathways.
Protective Effect of Lactobacillus plantarum Sc52 on LPS-Induced Intestinal Barrier Injury in Mice
HE Zhongmei, LI Tingting, ZHAO Yujuan, DUAN Cuicui, GAO Lei, NIU Chunhua, LUAN Chang, HUANG Cheng, LI Shengyu
2018, 39(9):  134-139.  doi:10.7506/spkx1002-6630-201809021
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Objective: To study the protective effect of Lactobacillus plantarum Sc52 on lipopolysaccharide (LPS)-induced mouse intestinal barrier injury. Methods: Six-week-old male ICR mice were randomly divided into 3 groups. L. plantarum Sc52 was fed to the mice in the experimental group by gavage at a dose of 1010 CFU/d for 14 consecutive days, while the mice in the control and model groups were given an equal volume of normal saline. Then, all mice except those in the control group were intraperitoneally injected with LPS to establish an intestinal barrier injury model. The levels of inflammatory cytokines in serum and intestinal permeability-related parameters were measured by enzyme-linked immunosorbent assay (ELISA). The histopathological changes of the ileum were tested by hematoxylin-eosin staining. The contents of shortchain fatty acids in colonic contents were determined by gas chromatography and the major intestinal bacteria in feces were enumerated by plate counting. The expression of intestinal tight junction protein was examined by Western blot. Results: Intragastric administration of L. plantarum Sc52 could inhibit the increase of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-12 (IL-12) and nitric oxide (NO). In addition, L. plantarum Sc52 could improve intestinal permeability by regulating D-lactic acid and diamine oxidase levels in the serum of mice. Furthermore, after administration of L. plantarum Sc52, the contents of acetic acid and butyric acid in colonic contents were increased, the number of Lactobacilli, Bifidobacterium and other beneficial microorganism were also significantly increased, and the number of harmful bacteria was decreased. Moreover, the expression of tight junction protein in the ileum was up-regulated. Conclusion: L. plantarum Sc52 can effectively protect against intestinal barrier injury caused by LPS in mice.
In Vivo Antioxidant Capacity and Immunoenhancing Activity in Mice of Polysaccharides from Abalone Viscera
WEI Haocheng, SHAO Jie, HE Chuanbo, LI Man, XIONG Hejian
2018, 39(9):  140-144.  doi:10.7506/spkx1002-6630-201809022
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The objective of this work was to explore the in vivo antioxidant capacity of abalone viscera polysaccharides (AVP) and its immunoenhancing activity in mice. An animal model of ethanol-induced oxidative injury and normal mice were used for this experiment. The in vivo antioxidant capacity was evaluated by measuring superoxide dismutase (SOD) activity, and the contents of glutathione (GSH), malondialdehyde (MDA) and protein carbonyl content in liver. The immunoenhancing activity was determined with respect to immune orange indices, cell immunity, humoral immunity and nonspecific immunity. For this purpose, we measured immune organ indices, footpad swelling, hemolysin antibody level and phagocytic index (α). Results showed that AVP exerted good in vivo antioxidant capacity by significantly increasing SOD activity and GSH level (P < 0.05), and reducing the contents of MDA and protein carbonyl (P < 0.05) in the liver of mice with ethanol-induced oxidative injury. Furthermore, AVP enhanced immune function in normal mice by significantly increasing spleen and thymus indices, footpad swelling, serum hemolysin level (P < 0.01) and α value (P < 0.05). Additionally, our data demonstrated that both the antioxidant capacity and immunoenhancing activity of AVP were concentration dependent. This study can provide a theoretical basis for intensive processing and industrial development of abalone viscera.
Gene Chip Analysis of the Regulatory Effect of Enzymatic Hydrolysate of Sea Cucumber (Acaudina molpadioides) on Glucose and Lipid Metabolism in Diabetic Mice
DONG Lisha, LI Yanyan, ZHANG Hongyan, CUI Chenxi, HAN Jiaojiao, WANG Zhaoyang, SI Kaixue, ZHOU Jun, SU Xiurong
2018, 39(9):  145-153.  doi:10.7506/spkx1002-6630-201809023
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Objective: In other to provide a theoretical basis to make better use of Acaudina molpadioides, we studied the regulatory effect of an enzymatic hydrolysate of A. molpadioide on glucose and lipid metabolism in mice with diabetic nephropathy. Methods: db/db diabetic mice were fed normally for 10 weeks and subsequently administered with different doses of the hydrolysate for 12 weeks. Urine glucose (UG), fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), glycosylated serum protein (GSP), fasting insulin (FIN) and serum lipid levels were examined at regular intervals during the administration period. Using gene chip technology, the expression levels of related genes in the kidney were measured and compared between different groups and the results were validated using real-time quantitative polymerase chain reaction (qRT-PCR). Results: Compared with the model group, the hydrolysate at all doses significantly decreased UG, FBG, HbA1c and GSP (P < 0.05), improved oral glucose tolerance, significantly lowered serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) (P < 0.05), and increased high density lipoprotein cholesterol (HDL-C). In addition, we identified 81 differentially expressed genes, including 54 up-regulated and 27 down-regulated genes. The expression levels measured by qRT-PCR of 11 selected genes were consistent with the results of gene chip test. Conclusion: The enzymatic hydrolysate from Acaudina molpadioide can significantly control glucose and lipid metabolism in db/db diabetic mice (P < 0.05), and the underlying mechanism may be related to slc2A4 expression level.
Protection and Underlying Mechanism of Astaxanthin against Hydrogen Peroxide-Induced Oxidative Stress in PC-3 Cells
NI Xiaofeng, YU Haining, WANG Shanshan, ZHANG Chengcheng, SHEN Shengrong
2018, 39(9):  154-162.  doi:10.7506/spkx1002-6630-201809024
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Objective: To investigate the protective effect and underlying mechanism of astaxanthin on oxidative stress induced by hydrogen peroxide in PC-3 cells. Methods: A cellular model of oxidative stress was established by inducing PC-3 cells with H2O2, and pretreatment of PC-3 cells was conducted using astaxanthin at different concentrations. Then, the changes in cell viability, apoptosis, reactive oxygen species (ROS) levels, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), cleaved caspase-3 expression and the mitogen-activated protein kinases-nuclear factor erythroid-2-related factor 2-heme oxygenase 1 (MAPK-Nrf2-HO-1) signaling pathway were investigated. Results: Astaxanthin at 20 μmol/L significantly increased cell viability, decreased the accumulation of intracellular ROS, and inhibited the decrease of Bcl-2/Bax ratio and the activation of caspase-3, consequently reducing the apoptosis rate from 51.4% to 14.8%. Our further study showed that astaxanthin could promote the phosphorylation of Nrf2 and the expression of HO-1 in a concentration dependent manner. Pretreatment with extracellular signal-regulated protein kinase (ERK) inhibitor U0126 and Akt inhibitor LY294002 decreased Nrf2 expression by inhibiting ERK and PI3K/Akt (phosphoinositide 3-kinase/protein kinase B) pathways, suggesting that the up-regulation of HO-1 expression was mediated by the upstream ERK and PI3K/Akt signaling pathways. Cell viability decreased significantly when the ERK signaling pathway was inhibited, while inhibition of the c-Jun N-terminal kinase (JNK) and p38 MAPK signaling pathways did not affect the protective effect of astaxanthin, which demonstrated that astaxanthin could improve cell viability through the ERK signaling pathway, but not the JNK or p38 MAPK signaling pathway. Conclusion: Astaxanthin can effectively attenuate hydrogen peroxide-induced oxidative stress and maintain the normal physiological activity of PC-3 cells.
Protective Effect of Konjac Powder on Acute Alcoholic Gastric Mucosal Injury and Chronic Alcoholic Intestinal Injury in Mice
SHEN Jiujun, DENG Liling, SHUAI Tiangang, REN Wang, DENG Li, ZHONG Geng
2018, 39(9):  163-169.  doi:10.7506/spkx1002-6630-201809025
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Objective: This work was designed to investigate the effect of konjac powder on acute gastric mucosal injury and chronic intestinal injury in mice in order to provide a theoretical basis for the development of natural food products against alcoholic organ damage. Methods: A mouse model of acute gastric mucosal injury and chronic intestinal injury was established by gavaging 56% (alcohol content by volume) Erguotou liquor, and then the mice were gavaged with different doses of konjac powder suspended in water. In addition, normal control and model groups were established in the experiment. The following indicators were measured: gastric mucosal ulcer index, the contents of SOD, MDA, NO and PGE2 in gastric tissue, the levels of free ammonia and short-chain fatty acids (SCFA) in cecum contents, and the intestinal microflora. Meanwhile, histopathological evaluation of the gastric mucosa and intestinal tissue was conducted. Results: Compared with the model group, gastric ulcer indexes in the middle-dose and high-dose treatment groups were reduced by 25.42% and 28.18%, while MDA levels were reduced by 38.07% and 47.32%, respectively. The levels of SOD, NO, PGE2, Bifidobacterium and Lactobacillus in the two dose groups were significantly increased; free ammonia and enterococcus in cecum contents were significantly decreased, whereas the levels of acetic acid, butyric acid and valproic acid were increased. Moreover, the pathological changes of the gastric mucosa and intestine were significantly improved. Conclusion: Konjac powder can execute a protective effect against alcoholic gastric mucosal injury and chronic alcoholic intestinal injury presumably by reducing gastric mucosal lipid peroxidation, increasing the antioxidant capacity of gastric mucosa, improving the intestinal microenvironment, and enhancing gastrointestinal mucosal barrier function.
Effect of Lutein on the Inflammatory Response of Carotid Atherosclerotic Plaques
LIU Yang, CHEN Mingjun, SONG Xiang, LIU Hongbin
2018, 39(9):  170-175.  doi:10.7506/spkx1002-6630-201809026
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Objective: To investigate the effect of lutein on the inflammatory response of carotid atherosclerotic plaques. Methods: Totally 169 consecutive carotid atherosclerosis patients from the General Hospital of PLA were recruited, and randomly divided into placebo (starch capsule, at once-daily dose), low-dose (20 mg/d), middle-dose (40 mg/d), and highdose lutein (60 mg/d) groups. Each patient was subjected to the collection of venous blood sample and positron emission tomography-computed tomography (PET-CT) examination within 1 week of the trial and after the end of the medication. The medication period was 12 months. Routine blood examination, blood biochemical indexes, inflammatory factors and drug concentration were detected in two blood samples of each patient. The carotid plaque was examined by PET-CT, and target-to-background ratio (TBR) was calculated to reflect the degree of plaque inflammatory response. Results: The serum concentrations of lutein in three treatment groups at low, medium and high doses were increased when compared with those at the beginning of the trial. Compared with the placebo group and the baseline level, the patients from the treatment groups had a significant decrease in TBR. The higher dose resulted in a greater decrease of TBR. Conclusion: Lutein can reduce the inflammatory response of carotid atherosclerotic plaques and have a definitely preventive effect on the occurrence of cardiovascular and cerebrovascular events.
Packaging & Storage
Effect of Transportation Vibration on Different Grades of Road on Antioxidant System of Hami Melons (Cucumis melo var. saccharinus) during Storage
ZHOU Ran, ZENG Yuanyuan
2018, 39(9):  176-181.  doi:10.7506/spkx1002-6630-201809027
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The effects of transportation on different grades of roads on the antioxidant system of Hami melon are different. The transportation vibration environment of a semi-trailer on expressway, arterial road (AR), secondary roads (SR), and tertiary roads (TR) were simulated in this experiment. The respiration rate, decay index, total phenolics content, VC content, ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities ferric reducing antioxidant power (FRAP) capacity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity of different road vibration treatments and control treatment without vibration during storage at room temperature (23 ℃) for 28 days were compared. The results showed that the total phenolics and VC contents, APX, SOD, CAT and POD activities, FRAP and DPPH radical scavenging capacity of Hami melon under different grades of road vibration were lower than those of the control group at day 28 of storage, and SR and TR caused significantly higher respiration rate and greater damage to the antioxidant system of Hami melon than expressway and AR (P < 0.05), which indicated that vibration can increase respiration rate and reduce the activity of various enzymes and antioxidants in the antioxidant protection system during the storage of cantaloupe, accelerating cell membrane lipid oxidation, destroying the integrity of the cell membrane, and finally accelerating the senescence and spoilage of melons. The effect of transportation vibration on SR and TR was more obvious.
Release of Cinnamaldehyde from Active Chitosan Composite Packaging Films and Its Application in Quality Preservation of Fresh Pork
ZENG Shaofu, HU Changying, KUANG Hengfeng, HUANG Cheng, WU Yumei
2018, 39(9):  182-189.  doi:10.7506/spkx1002-6630-201809028
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Cinnamaldehyde-chitosan (CIN-CS) composite films with different initial concentrations (0.5%, 1.0%, 1.5% and 2.0% (V/V)) of CIN were prepared. The thermal stability of these films was increased by increasing concentration of cinnamaldehyde. The release of cinnamaldehyde from these films into headspace and fatty food stimulants such as isooctane at 4, 25 and 40 ℃ was studied using gas chromatography-mass spectrometry. The efficacy of 2.0% CIN-CS film versus blank control and pure CS film in preserving the quality of fresh pork during storage at 4 ℃ was evaluated with respect to pH, total bacterial count, total volatile basic nitrogen (TVB-N) and sensory evaluation. Our results indicated that CIN addition improved the thermal stability of the CS films. The release of CIN from 2.0% CIN-CS increased with time and temperature, reaching 59.22% when equilibrium was attained at 40 ℃. The release rate of CIN into isooctane decreased with increasing CIN concentration, whereas it increased with increasing temperature. When applied on fresh pork, the 2.0% CIN-CS film showed a significant decrease in pH, TVB-N and total bacterial count as well as better sensory evaluation compared with the pure CS film and the blank control (P < 0.05). The shelf life of 2.0% CIN-CS film packaged pork was 7 d, while that of the blank group was 4 d.
Postharvest Benzothiadiazole Treatment Promotes Wound Healing in Pear Fruits
ZHANG Jingrong, WANG Bin, JIANG Hong, WANG Yi, LI Xue, SI Min, LI Yongcai, BI Yang
2018, 39(9):  190-195.  doi:10.7506/spkx1002-6630-201809029
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Objective: To investigate the promotion effect of postharvest benzothiadiazole (BTH) treatment on wound healing in harvested pear fruits, and to explore the role of phenylpropane metabolism and antioxidant enzymes in wound healing. Methods: The pear cultivar ‘Yuluxiang’ was tested in this study. After being subjected to artificial wounding, the fruits were treated with BTH at 100 g/L and then kept under dark condition at ambient temperature (20–25 ℃) and relative humidity (RH) of 80%–85% for wound healing. The healing efficiency was evaluated by determining weight loss rate and incidence in inoculated fruits, and the BTH treatment and control groups were compared for differences in the activities of phenylalanine ammonialyase (PAL), superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) and the contents of total phenolics, flavonoids and lignin during wound healing. Results: BTH treatment had no significant effect on fruit weight loss. During wound healing, the incidence of both the treated and control fruits decreased without any significant difference between them (P < 0.05). These findings indicated BTH treatment decreased the incidence of postharvest disease. BTH treatment also significantly increased PAL, SOD, POD and PPO activities. In addition, BTH treatment effectively promoted the accumulation of total phenols, flavonoids and lignin. The correlation analysis showed that disease incidence was significantly negatively related to PAL activity as well as total phenolic and flavonoid contents and highly significantly negatively related to POD and PPO activity in treated fruits. Conclusion: BTH treatment promotes wound healing in harvested pear fruits. Phenylpropane metabolism, POD and PPO play an important role in wounding healing.
Effect of Storage Temperature on Chilling Injury and Quality of Jiashi Melon
AN Ruili, WANG Bin, WEI Changqing, DU Hongfeng, TANG Fengxian, SHAN Chunhui
2018, 39(9):  196-201.  doi:10.7506/spkx1002-6630-201809030
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The purpose of this study was to investigate the effects of different storage temperatures on chilling injury and fruit quality in Jiashi melon. Changes in decay incidence, weight loss percentage, chilling injury index, hardness, and the activities of fatty acid desaturases (FADs), lipoxygenase (LOX) and adenosine triphosphatase (ATPase) were determined during storage at 0.5, 3.0 and 21.0 ℃, respectively. The results indicated that the occurrence of chilling injury in Jiashi melon was correlated with storage temperature and duration. Jiashi melon was highly vulnerable to chilling injury at 3.0 and 0.5 ℃, but chilling injury appeared relatively late at 0.5 ℃. A lower storage temperature delayed fruit decay, maintained higher activities of FADs and ATPase, inhibited the increase in LOX activity, and enhanced cold resistance in Jiashi melon. While chilling injury did not occur at 21.0 ℃, both weight loss percentage and decay incidence were relatively higher. Based on the above indicators, Jiashi melon had better quality when stored at 0.5 ℃.
Application of Sorbic Acid Nanoparticles in Improving the Quality and Shelf-Life of Chilled Pork
WANG Jiayi, WANG Qian, DING Wu
2018, 39(9):  202-206.  doi:10.7506/spkx1002-6630-201809031
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Sorbic acid nanoparticles (SAN), an edible coating made from chitosan, sorbic acid and sodium tripolyphosphate by ionic gelation process, were investigated for their antimicrobial and antioxidant effects on chilled pork in comparison with chitosan nanoparticles, potassium sorbate and blank control. Results showed that the changes in total volatile basic nitrogen (TVB-N), pH and thiobarbituric acid (TBA) value were effectively controlled by SAN. The total numbers of bacteria, and molds and yeasts in chilled pork samples treated with SAN was significantly lower (P < 0.05) than those in the blank control group during the whole storage period, and those in the chitosan nanoparticle group at the late stage of storage. At 7 days of storage, a value (redness) in chilled pork treated with SAN was significantly higher (P < 0.05) than the other groups. Compared with the blank control, SAN extended the shelf life of chilled pork by 5 days. Thus it can be concluded that SAN could inhibit microbial growth and lipid oxidation and prolong the shelf life of chilled pork.
Effects of 1-Methylcyclopropene Combined with ξ-Polylysine on Quality and Volatile Components of Fuji Apples during Shelf Life after Cold Storage
YAN Tingcai, QIN Hua, ZHANG Peng, TIAN Shiping, LI Jiangkuo, LI Boqiang
2018, 39(9):  207-214.  doi:10.7506/spkx1002-6630-201809032
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Fuji apples were treated with 1-Methylcyclopropene (1-MCP) (1 μL/L) immediately after being harvested, and then stored in a precise temperature-controlled refrigerator (?(0.5 ± 0.3)℃) for 10 months. Thereafter, they were transferred to ambient temperature and sprayed with ξ-polylysine at different concentrations (500, 1 000 and 1 500 mg/L). Our purpose was to investigate the effect of 1-MCP combined with ξ-polylysine on the quality of apples during shelf life. The volatile constituents of different treatments were analyzed by headspace solid phase microextraction gas combined with gas chromatographymass spectrometry (HS-SPME-GC-MS). The results showed that 1-MCP combined with ξ-polylysine treatments effectively maintained fruit firmness and slowed down the decrease in the contents of soluble solids, titratable acid and VC in apples when compared with the untreated control and the best effect was observed at an ξ-polylysine concentration of 1 000 mg/L. The main volatile substances identified included hexanol, hexanal, trans-2-hexenal, 2-methylbutyl acetate. The relative content of aldehydes in the CK group increased first, then decreased, and finally was lower at the end than at the beginning of shelf life. The treatment with ξ-polylysine at 1 000 and 1 500 mg/L showed an upward trend; 1-MCP treatment alone resulted in an initial decrease followed by an increase in the relative content of aldehydes, whereas the opposite was observed for the 500 mg/L ξ-polylysine group. The latter two groups showed a higher relative content of aldehydes at the end than at the beginning of shelf life. The relative contents of esters in the CK, 1 000 and 1 500 mg/L treatment groups showed an upward trend. The 500 mg/L treatment group tended to decrease initially and then increased, while the single 1-MCP treatment group showed the opposite trend. The relative content of alcohols in the 1-MCP and 1 500 mg/L ξ-polylysine groups decreased first and then increased, and the CK and 500 mg/L treatment groups and the 1 000 mg/L treatment group showed an increasing and decreasing trend, respectively. During the shelf life, the relative content of aldehydes in the 1 000 mg/L treatment group was always highest, and this treatment could effectively mitigate the decrease in the relative contents of the main flavoractive compounds 2-methyl butyl acetate and 2-methyl-1-butanol. 1-MCP combined with ξ-polylysine treatment could maintain the quality and flavor of apples and ξ-polylysine was most effective when used at 1 000 mg/L.
Control and Mechanism of Postharvest Diseases in Citrus Fruits by Benzothiadiazole Treatment
LIU Xiaojia, XUE Yaobi, ZHOU Yahan, YAO Shixiang, DENG Lili, ZENG Kaifang
2018, 39(9):  215-223.  doi:10.7506/spkx1002-6630-201809033
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(Fengqi Navel) orange fruits (Citrus sinensis L. Osbeck) were used as experimental subjects to evaluate the efficacy of different concentrations of benzothiadiazole (BTH) in controlling lesion diameters and disease incidence in citrus fruits inoculated with Penicillium italicum, Penicillium digitatum and Colletotrichum gloeosporides separately in the same and different wounds. At the same time, the optimum concentration of BTH to control these diseases was determined. The effects of BTH wound inoculation and dipping treatment on endogenous salicylic acid (SA) content and disease resistance-related enzymes activities in citrus peel were also investigated. The results indicated that BTH treatment at three concentrations (0.25, 0.50, 1.00 mmol/L) could reduce lesion diameters of citrus fruits inoculated with three pathogens and the best effect was observed at 0.50 mmol/L. All these three treatments controlled disease incidence at the early stage of disease, but the effect was marginal at the late stage. By comparison, BTH at 0.50 mmol/L was most effective. BTH wound inoculation at the optimum concentration could increase the content of endogenous SA in the peel. BTH dipping treatment had no significant effect on the content of endogenous free SA in the peel, but could promote the accumulation of endogenous bound SA content. Both BTH treatments could increase the activities of β-1,3-glucanase (GLU), chitinase (CHI), phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO) in the peel. Therefore, BTH could be effective in inducing postharvest disease resistance in citrus fruits.
Effect of Radish Seed Protein Extract on Quality of Tray-Packaged Sturgeon Fillets Stored at 4 ℃
LI Jun, LI Pinglan, GAO Liang, WANG Shun, GUI Meng
2018, 39(9):  224-231.  doi:10.7506/spkx1002-6630-201809034
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The objective of this paper was to investigate the efficacy of radish seed protein extract (RSPE) in preserving the freshness of cold stored surgeon fillets. The antibacterial activity of RSPE against nine sturgeon spoilage bacteria was studied. Sturgeon fillets were treated with 64 (T1), 32 (T2) and 2 AU/mL (T3) RSPE solutions, respectively, and sterile saline solution was used as control. All samples were analyzed periodically for microbial counts (total viable counts (TVC), Enterobacteriaceae, Pseudomonas, Aeromonas and Psychrotrophs), Physicochemical properties (pH, color, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and biogenic amines) and sensory characteristics. The results showed that the growth of nine sturgeon spoilage strains was inhibited by RSPE with inhibition zones larger than 17.5 mm in diameter. The shelf-lives of the control, T1, T2 and T3 groups determined by microbiological analysis were 7, 11, 9 and 7 d, respectively. Meanwhile, the accumulation of TVB-N, TBA and biogenic amines were significantly and concentrationdependently inhibited by RSPE as compared with the control. The results of sensory evaluation were consistent with the microbiological and physicochemical results. As a consequence, RSPE could effectively inhibit the growth of spoilage bacteria in sturgeon and reduce the spoilage rate of sturgeon during cold storage. Therefore, it has the potential to be used as a novel biological preservative for chilled sturgeon fillets.
Impact of Precooling Time on Quality and Physio-Biochemical Characteristics of Common Bean (Phaseolus vulgaris L.) and Cowpea (Vigna sinensis) under Controlled Atmosphere Storage Conditions
WANG Libin, LIN Chen, LUO Haibo, JIN Changhai, YU Zhifang, QIAN Chunlu
2018, 39(9):  232-238.  doi:10.7506/spkx1002-6630-201809035
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In order to explore the impact of precooling time on their quality and physio-biochemical characteristics, freshly harvested common bean (Phaseolus vulgaris L.) and cowpea (Vigna sinensis) were placed at room temperature ((20.5 ± 4.5) ℃) with a relative humidity of 72% for 0, 6 and 12 h, respectively, and precooled to 9.0 ℃ before 15 d controlled atmosphere storage (gas composition: 3% O2 + 1% CO2 + 96% N2, temperature: (9.0 ± 0.5) ℃, humidity: (80 ± 5)%) followed by 2 d stimulated shelf life at room temperature (temperature: (24.5 ± 4.5) ℃; humidity: (65 ± 2)%). Samples were collected for quality and physio-biochemical analysis after controlled atmosphere storage and shelf life. Results showed that compared with those precooled after 6 and 12 h at room temperature, P. vulgaris L. and V. sinensis precooled immediately after harvest possessed higher sensory evaluation score and higher contents of reducing sugar and chlorophyll as well as lower mass loss rate, respiration intensity, spot index and cellulose content after controlled atmosphere storage and shelf life. Meanwhile, immediate precooling maintained high activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and cellulose (CEL), and low levels of respiration intensity (RI), superoxide anion (O2-·) production rate, hydrogen peroxide (H2O2) and malondialdehyde (MDA). Therefore, immediate precooling could delay the senescence of P. vulgaris L. and V. sinensis during controlled atmosphere storage and shelf life and maintain high quality by improving antioxidant status and reducing oxidative stress.
Effects of Different Storage Methods on Quality of Rosa roxburghii Fruits from Lhasa
LI Yuanhui
2018, 39(9):  239-243.  doi:10.7506/spkx1002-6630-201809036
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In this study, the effects of different storage methods on the fruit quality of Rosa raxburghii from Lhasa area, China were investigated. Fruits were stored at room temperature (RT), room temperature with modified atmosphere packaging (RT + MAP), low temperature ((1.0 ± 0.5) ℃) (LT), and low temperature ((1.0 ± 0.5) ℃) with MAP (LT + MAP), respectively. The changes of fruit firmness, soluble solids content (TSS), titratable acidity (TA) content, vitamin C content, superoxide dismutase (SOD) activity, weight loss and decay incidence during postharvest storage were determined. The results showed that the amount of vitamin C in fruits was decreased by 69.55%, 25.91%, 41.93% and 14.47% for the RT, RT + MAP, LT and LT + MAP groups, respectively, and SOD activity by 47.99%, 24.96%, 33.98%, and 14.32%, respectively, after 6 d storage. Fruit decay occurred only in the RT + MAP group (1.78% decay incidence). The fruit quality of the LT + MAP treatment was the best since it delayed the decrease of fruit firmness, TSS, TA and fruit weight loss during postharvest storage when compared to other treatments.
Ripening Characteristics of ‘Hongyang’ Kiwifruits Following Postharvest Ethylene Treatment
YUAN Sha, LI Huajia, ZHU Yongqing, LI Ke, YUAN Huaiyu, XU Rui, ZHONG Yang, ZHOU Yan, HU Qiuhui
2018, 39(9):  244-251.  doi:10.7506/spkx1002-6630-201809037
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‘Hongyang’ kiwifruits harvested at different maturities were treated with exogenous ethylene. Fruit quality parameters were measured at different times after the treatment. Our aim was to determine the appropriate harvest time for the ‘Hongyang’ cultivar. Furthermore, the influence of ethylene concentration and temperature on the ripening process was investigated. The results showed that ripened and softened fruits could be accepted by consumers only when kiwifruits reached a certain degree of maturity (dry matter content greater than 17%), allowing for earlier harvesting and marketing. Softening of ‘Hongyang’ kiwifruits was completed in 3–5 days when treated with ethylene at 25–100 μL/L treatment (20 ℃), and there was no significant difference in soluble solid content (SSC) or titratable acidity (TA) between different concentration treatments. Temperature was an important factor that affects the ripening. At higher temperature (20 ℃), ethylene could significantly shorten the softening process.
Effect of Chitosan Combined with Hypochlorite on Storage Quality of Beibei 447 Sweet Orange (Citrus sinensis L. Osbeck cv. Jincheng)
LIU Mi, ZHANG Yu, ZHAO Xin
2018, 39(9):  252-257.  doi:10.7506/spkx1002-6630-201809038
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In order to investigate the effect of chitosan combined with hypochlorite on the storage quality of citrus fruits (the Beibei 447 cultivar of Citrus sinensis L. Osbeck cv. Jincheng), we used chitosan alone and in combination with either sodium hypochlorite or calcium hypochlorite to coat the fruits, respectively. Then, the contents of soluble solids, total sugar, total acid, VC, total flavonoids and total phenolics were analyzed every five days during storage. It was found that chitosan was good for maintaining fruit quality and the treated fruits maintained high contents of VC, total phenols and total sugar during storage. In addition, chitosan combined with hypochlorite coating was significantly more effective than chitosan alone and the best effect was obtained using 0.01 g/mL chitosan + 200 mg/L Ca(ClO)2, effectively delaying the deterioration process. The results of this study suggest that chitosan combined with hypochlorite has the potential to maintain the quality and extend the post-harvest storage life of Beibei 447 sweet orange.
Reviews
Advances in Understanding the Interaction between Flavonoids and Other Compounds
LANG Yuxi, MA Yan, LI Bin, YAN Tingcai, ZHANG Qi, CHOU Shurui, LIN Yang, WANG Yuehua, MENG Xianjun
2018, 39(9):  258-264.  doi:10.7506/spkx1002-6630-201809039
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Flavonoids are a wide variety of secondary plant metabolites with complex structures that widely exist in plant roots, stems, leaves, flowers and fruits. These compounds have attracted much attention due to their greatly positive effects on human health, such as anticancer, antibacterial, anti-viral, anti-inflammatory and anti-allergic. Researchers have verified their various biological activities in vivo and in vitro. However, flavonoids usually coexist with other compounds in plants, such as carbohydrate, protein, lipid and acid, and interact with these compounds inside the body when ingested together. Therefore, the functions of flavonoids have a close relationship with other compounds. The interaction between flavonoids and other compounds together with the underlying mechanisms and the outcome is reviewed in this paper.
Progress in Microencapsulation of Functional Food Ingredients by Complex Coacervation Method
WANG Ying, ZHAO Meng, HUANG Xue, FANG Yapeng
2018, 39(9):  265-271.  doi:10.7506/spkx1002-6630-201809040
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Complex coacervation is an emerging technology for microencapsulation, which has attracted increasing attention from food researchers. This review elucidates the environmental factors influencing complex coacervation. Herein we summarize recent advances in the application of complex coacervation in the microencapsulation of lipid-soluble functional ingredients such as functional oil, essential oil, fat-soluble vitamins and fat-soluble antioxidants, and hydrophilic ingredients such as probiotics, enzyme, water-soluble vitamin, sweetener and bitter peptide.
Research and Application of Big Data-Based Co-Regulation Model in Food Safety Governance
TAO Guangcan, TAN Hong, SONG Yufeng, LIN Dan
2018, 39(9):  272-279.  doi:10.7506/spkx1002-6630-201809041
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This paper is aimed to construct a food safety and nutrition information collection and analysis platform with new internet technologies including big data to improve the analytic capacity and the data-mining capability, and thereby to provide more accurate and comprehensive food safety and nutrition information for government agencies, food companies, guilds, inspection organizations, consumers, and social media. Based on big data features of food safety in Guizhou province, a cloud computing and big data-based service platform composed of four layers was proposed which integrates data acquisition, analysis and application. The “food safety cloud” (www.fsnip.com) based on the proposed method has attained relatively significant achievements such as promoting data connectivity, improving the work efficiency, and reducing the cost of food safety governance. Thus, the platform can improve the efficiency of food safety governance.
Progress in Space Nutrition and Food for Long-Term Human Space Flight
DONG Haisheng, ZHAO Wei, ZANG Peng, YU Yanbo, CAO Ping, HE Chunjiang, CHEN Bin
2018, 39(9):  280-285.  doi:10.7506/spkx1002-6630-201809042
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Physiological adaptive changes may occur in astronauts under the particular space environmental conditions such as microgravity, noise, vibration, and hermetic cabin during long-term manned space flight. Space nutrition supply is an important research issue for mankind to explore space, especially in the case of long-term manned space flight. This paper reviews recent progress in research on space nutrition in the United States, Russia and other countries for long-term manned space flight activities such as space station, manned lunar landing and manned Mars exploration. Compared with mid- and short-term manned space flight mission, space nutrition for long-term manned space flight is more focused on improving nutritional balance, resource recycling, healthcare function and sensory acceptance.
Progress in Research on the Biosynthesis Pathway and Metabolic Regulation of Phenolic Acids
GAO Yuan, MA Shuai, DAI Min, WANG Meng, FENG Xiaoyuan
2018, 39(9):  286-293.  doi:10.7506/spkx1002-6630-201809043
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Phenolic acids, a class of plant secondary metabolites, are widely present in plants and have several bioactivities such as antioxidant, anti-inflammatory, anticancer, antibacterial, and immune-enhancing activities. In recent years, many studies have demonstrated that phenolic acids are closely related to plant development, induced resistance, food quality, and human health. The isolation, identification and biosynthesis pathway of phenolic acids have been investigated widely. Herein, the biosynthesis and metabolic regulation of phenolic acids, the influence of induced resistance on phenolic content, the relationship between phenolic acids and food quality, and the applications of metabolomics in studies on plant phenolics are reviewed, so as to provide a useful basis for the exploitation of phenolic acids in fruits and vegetables.
Progress in Research on Mycotoxins Contamination, Toxicity, Biosynthesis and Regulatory Factors of Mycotoxins in Fruits
SHEN Youming, NIE Jiyun, LI Zhixia, LI Haifei, WU Yonglong, ZHANG Jianyi
2018, 39(9):  294-304.  doi:10.7506/spkx1002-6630-201809044
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Mycotoxins are an important detrimental factor for fruit quality. The presence of some mycotoxins in fruits such as patulin, Alternaria toxins, ochratoxin A and aflatoxins is an issue of major concern nowadays. Current studies are focused on the formation, transformation, control and elimination of mycotoxins to ensure the safety and quality of fruits. The aim of this review is to survey mycotoxins contamination, producers, toxicity and toxicology, encoding genes, biosynthetic mechanisms and influencing factors.
Legislation of Genetically Modified Food Labeling in America and Its Enlightenment to China
GUO Guihuan, JI Jinyan
2018, 39(9):  305-309.  doi:10.7506/spkx1002-6630-201809045
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On July 7, 2016, the President Obama signed the Act 764 for enforcing National Bioengineered Food Disclosure Standards, which indicates a major change in the labeling system of genetically modified food (GMF) in the United States of America (USA): from the voluntary labeling system to the mandatory labeling system. This Act requires the companies to provide information on GMF, in order to protect the consumer’s right to know. At the same time, the disclosure standard is a product-oriented standard and allows the application of a variety of forms to disclose information, including the two-dimensional code, thereby facilitating manufacturers to fulfill their obligations. To a certain extent, the USA mandatory GMF labeling system balances the interests of consumers and producers. This GMF labeling system can provide valuable information for China to perfect its GMF labeling system.
Progress in Analytical Methods for Major Chemical Contaminants Affecting Tea Quality and Safety
LIU Tengfei, DONG Minghui, YANG Daifeng, ZHANG Cunzheng, GU Junrong, XU Deliang
2018, 39(9):  310-325.  doi:10.7506/spkx1002-6630-201809046
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Tea is one of the most popular drinks in the world, which is widely consumed for its special aroma, and medicinal and health-promoting properties. With the rapid development of modern industry and the wide application of chemical fertilizers and pesticides, the problems of environmental pollution and ecological damage have gained extensive attention. Pesticide residues, heavy metals and mycotoxins are the major chemical contaminants in tea. Tea quality and safety have attracted a great deal of interest because such contaminants can be readily accumulated and threaten the life and health of humans, thus leading to economic losses. Due to their potential health risk for consumers, many studies have focused on the detection of these contaminants. This paper reviews published sample pretreatments and analytical methods for the detection of pesticide residues, heavy metals and mycotoxins in tea samples. The advantages and disadvantages of these methods are discussed, and future trends are presented as well. This review is expected to provide useful information for future studies of such contaminants in tea.
Analysis and Application of Microbial Volatile Organic Compounds in Agricultural Products
JIN Jing, XIE Shunping, JI Houwei, ZOU Ximei, ZHANG Li, LIU Jian
2018, 39(9):  326-332.  doi:10.7506/spkx1002-6630-201809047
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This review outlines the analytic methods for the determination of microbial volatile organic compounds (MVOCs) and their applications in agricultural products. The methods used for MVOCs capture, instrumental detection and data analysis are summarized. The focus of this review is on the applications of MVOCs in the detection of microbial contaminants in agricultural products, the quality control of fermented foods and the exploration and utilization of microbial resources.
Precision Prebiotics: Progress and Trends
WU Shaohui, WEI Yuanan, WU Jiayi, ZHENG Huiling, HUO Jinhong
2018, 39(9):  333-340.  doi:10.7506/spkx1002-6630-201809048
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Prebiotics play a significant role in regulating the intestinal microbiota. Increasing amounts of research data, clinical trial results, and widespread reports have documented the beneficial effects of prebiotics in the prevention and interventional treatment of chronic metabolic and immune diseases, such as irritable bowel syndrome, diabetes, and obesity. Taking into consideration of the development trend of precise nutrition, it is foreseeable that prebiotics will have a significant impact on the emerging industry of microbiota (or microecological) health care. This paper reviews the latest research findings and presents a functional paradigm of prebiotic action with focus on the evolving concept of prebiotics. A better understanding of the physiological mechanisms involved can help to define and develop the concept of ‘precision prebiotics’ that represents an outgrowth of precise nutrition. This highlights the necessity of studying the properties, components, and structures of prebiotics and exploring the relationship among prebiotic composition, bacterial species and physiological functions. Moreover, ascertaining the mechanism of action of prebiotics at the molecular level of cell biology will help with personalized prebiotic formulation and nutritional intake plan that enhance and ensure the health of each individual.
Legal Regulation of Occupational Anti-Counterfeiting in the Field of Food
YIN Hongqiang
2018, 39(9):  341-346.  doi:10.7506/spkx1002-6630-201809049
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With the increase of profit-making occupational anti-counterfeiting cases reported, all social circles are arguing about this social phenomenon. Starting with the applicability of punitive damage system, this article summarizes the institutional evolution of China’s food law on occupational anti-counterfeiting. At the same time, given the current condition of China, the causes of food safety accidents are interpreted from the perspective of sociology. This review justifies supporting occupational anti-counterfeiting in the field of food safety based on special policy considerations. In addition, the negative effects of occupational anti-counterfeiting are elucidated with respect to the conditions for the applicability of punitive damage system, the definition of food safety standards, food mislabeling and malicious prosecution in an effort to make the best use of the strengths and avoid the weaknesses of occupational anti-counterfeiting and consequently help to purify the food market.