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    FOOD SCIENCE 2021 Vol.42
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    Preparation and Antibacterial Activity of Gelatin/Ethyl Cellulose Aerogels Loaded with Zinc Oxide
    PAN Jingjing, ZHANG Chong, LIU Yuyu, ZHANG Hui
    FOOD SCIENCE    2021, 42 (1): 1-7.   DOI: 10.7506/spkx1002-6630-20191214-156
    Abstract497)   HTML122)    PDF(pc) (5066KB)(334)       Save
    Our study aimed to construct gelatin (G)/ethyl cellulose (EC) aerogels and study their three-dimensional microstructures and physical properties. Zinc oxide (ZnO) nanoparticles were loaded into the aerogels and were evaluated for antibacterial activities. A gelatin/ethyl cellulose nanofibrous membrane was prepared by electrospinning and then transformed into the aerogels by freeze-drying. Sodium alginate (SA) and calcium chloride (CaCl2) were added to cross-link the obtained aerogels. The physical properties of the aerogels were analyzed by exploring the morphology, porosity, thermal conductivity, water stability, mechanical properties, and thermal stability. The antibacterial properties were tested using the inhibition zone and turbidimetric methods. The results showed that the aerogel with a gelatin/ethyl cellulose mass ratio of 1:1 cross-linked by SA and CaCl2 presented the best mechanical properties and water stability. The aerogels loaded with ZnO nanoparticles had strong antibacterial activity against Escherichia coli and Staphylococcus aureus, which could be significantly enhanced by ultraviolet irradiation.
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    Preparation of Pineapple Pulp Cellulose Hydrogel and Its Adsorption and Release Characteristics toward Probiotics
    XING Yunyi, HUANG Huihua
    FOOD SCIENCE    2021, 42 (1): 8-14.   DOI: 10.7506/spkx1002-6630-20191120-239
    Abstract359)   HTML69)    PDF(pc) (2950KB)(218)       Save
    Pineapple pulp cellulose hydrogel (PPCH) was prepared by dissolving pineapple pulp cellulose (PPC) in the ionic liquid 1-butyl-3-methylimidazole chloride?(BmimCl), and pH-sensitive hydrogel (PPCH-AA) was prepared from PPC using acrylic acid (AA) as a cross-linker in BmimCl. Their structures and functional properties were characterized and compared with each other. The sustained release behavior of the prepared hydrogels loaded with probiotics in simulated gastric fluid and simulated intestinal fluid was studied. The results showed that the swelling and drug release behavior of the hydrogels were pH-sensitive. The cumulative release of PPCH and PPCH-AA in simulated gastric fluid was 44.11 and 16.7 mg/g in 7 h with release rates of 66.17% and 25.05%, respectively. The cumulative release in simulated intestinal fluid was 59.25 and 58.01 mg/g in 7 h with release rates of 88.87% and 87.02%, respectively. In?conclusion, PPCH-AA?can be used as?a potential delivery?system?for?controlled?release?of?probiotics.
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    Migration Pattern of Lead from Ceramic Food Contact Materials into Acidic Food Simulants
    XIAO Li, DONG Zhanhua, SUN Changjiang, LI Jian
    FOOD SCIENCE    2021, 42 (1): 15-24.   DOI: 10.7506/spkx1002-6630-20191210-113
    Abstract276)   HTML45)    PDF(pc) (6194KB)(138)       Save
    The objective of this study was to explore the migration pattern of the heavy metal lead from a ceramic food contact material into different acidic food simulants at different pH values and temperatures. Migration experiments were carried out by completely immersing the ceramic material in each tested food simulant. The amount of lead released into acetic acid, citric acid and lactic acid solutions was determined by inductively coupled plasma optical emission spectrometry, and its relationship with immersion time, and the temperature, pH and type of acidic food simulant was analyzed. Results showed that the release of lead from the ceramic material was positively with immersion time and temperature and that the average release rate accelerated with increasing temperature. The concentration of lead dissolved in 4% (V/V) acetic acid solution at 20 ℃ was 3.276?mg/L after immersion for 240 h as opposed to 52.413?mg/L at 70 ℃, and the average dissolution rate increased from 0.087? to 1.229? mg/(m2·h) with increasing temperature from 20 to 70 ℃. The dissolution of lead was negatively correlated with the pH of food simulant. The amount of lead dissolved in 4% (V/V) acetic acid solution at pH 2.43 and 20% (V/V) acetic acid solution at pH 1.93 at 20 ℃ was 1.876 and 2.412?mg/L after 24 h of contact with the ceramic material, respectively. Moreover, the dissolution of lead was related to the type of acidic food simulant. Under the same pH conditions, the acidic food simulant with hydroxyl groups dissolved more lead. To sum up, contact time, and the pH, temperature and type of acidic food simulant all affected the dissolution of lead from the ceramic material. The release of lead was linearly correlated with the square root of migration time during the early period and then was linearly correlated with migration time during the middle and late period. The relationship of lead release with the temperature obeyed the Arrhenius law, while the relationship with the pH of acidic food simulant conformed to a logarithmic function.
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    Effects of Dietary Lactic Acid Bacteria on Growth, Meat Quality, Flavor Compounds and Antioxidant Capacity of Sunit Sheep
    DOU Lu, LIU Chang, BA Jimuse, YANG Zhihao, SU Lin, ZHAO Lihua, TIAN Jianjun, GUO Yueying, JIN Ye
    FOOD SCIENCE    2021, 42 (1): 25-32.   DOI: 10.7506/spkx1002-6630-20191217-182
    Abstract315)   HTML43)    PDF(pc) (2717KB)(354)       Save
    To investigate the effects of dietary lactic acid bacteria on the growth, meat quality, flavor compounds and antioxidant capacity of Sunit sheep, 24 lambs were equally allocated into two groups, which were fed a basic diet alone or supplemented with lactic acid bacteria (LAB). The growth performance of lambs, and the numbers of lactic acid bacteria and Escherichia coli in the intestine were evaluated. Following slaughter, Longissimus dorsi muscles were taken to measure meat quality, volatile flavor substances, antioxidant capacity and the expression of antioxidant enzymes genes. The results showed that the number of LAB in the intestinal tract of the LAB supplementation group was significantly higher than that in the control group (P < 0.05), while the number of E. coli was significantly lower than that in the control group (P < 0.05). The addition of LAB increased the average daily mass gain of Sunit sheep (P < 0.05). Shear force, b* value and pH24 h in the LAB group were significantly lower than those in the control group (P < 0.05), while there was no statistical difference in pH45 min or cooked meat rate between the two groups (P > 0.05). LAB could affect the composition and relative contents of flavor compounds in Sunit lamb meat. The relative contents of the major lipid oxidation products octanal, nonanal, decanal, 1-pentanol, 1-hexanol, and 1-heptanol were significantly lower in the LAB group than in the control group (P < 0.05), which indicates that LAB can inhibit excessive lipid oxidation in muscle tissue and impart a well-balance meat flavor. Compared with control group, adding lactic acid bacteria to the diet imparted orange-like, onion-like, rosy and mushroom-like flavors. Catalase (CAT) activity and total antioxidant capacity (T-AOC) in the LAB group were significantly higher than those in the control group (P < 0.05), and the activity of glutathione peroxidase (GPx) was higher than that in the control group without statistical significance (P > 0.05). According to the analysis of antioxidant enzyme gene expression, the expression levels of CAT and GPx genes were significantly higher than those in the control group (P < 0.05), proving that the addition of LAB to the diet could improve the antioxidant capacity of lamb meat. In summary, the dietary addition of LAB can improve the intestinal microbiota in Sunit lambs and meat flavor, and enhance growth performance, meat quality and antioxidant capacity.
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    Acid Resistance in Salmonella typhimurium Induced by Culture in the Presence of Organic Acids
    LI Linqiong, HONG Jing, ZHANG Aijing, WANG Pengjie, GAO Yulong
    FOOD SCIENCE    2021, 42 (1): 33-40.   DOI: 10.7506/spkx1002-6630-20191231-365
    Abstract255)   HTML35)    PDF(pc) (4090KB)(93)       Save
    Objective: To investigate the effect of culture in the presence of organic acids on inducing acid resistance in Salmonella typhimurium CGMCC 1.1190. Methods: The effects of acidification of the culture medium to different pH levels with citric, lactic, acetic or malic acid on the growth, cellular morphology and subsequent acid resistance in medium at pH 2.5 of this microorganism were studied. The Baranyi model was used to fit the growth data of S. typhimurium CGMCC 1.1190 in trypticase soy broth (TSB) acidified with the four organic acids, and the Weibull model was used to fit the inactivation data of stationary-phase cells in medium at pH 2.5. Results: This strain had different tolerances to the four organic acids. Analysis of the inactivation curves showed that all the organic acids could induce increased acid tolerance and their effects decreased in the order of citric acid > lactic acid > acetic acid > malic acid under the same pH condition. For each organic acid, lower pH resulted in stronger acid resistance. The acid resistance parameter δ-value resulting from citric acid was significantly greater than that of the control group (P < 0.05). Furthermore, the cellular morphology of CGMCC 1.1190 cultured in the presence of citric acid was significantly different from that of the control non-acid adapted cells, and the cell aggregation was more obvious with decreasing induction pH. Conclusion: S. typhimurium CGMCC 1.1190 cells exhibited enhanced acid resistance and altered aggregation state upon being cultured in medium acidified with organic acids.
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    Optical Properties of Strawberry Fruit and Their Relationship with Soluble Solids Content and Moisture Content
    XIE Dandan, GUO Wenchuan, GAO Mengjie, LIU Dayang
    FOOD SCIENCE    2021, 42 (1): 41-46.   DOI: 10.7506/spkx1002-6630-20200209-058
    Abstract373)   HTML54)    PDF(pc) (3994KB)(174)       Save
    To understand the optical properties of fruits and their relationships with soluble solids content (SSC) and moisture content, a single integrating sphere system for the measurement of optical properties was established and validated. Furthermore, the absorption coefficient μa and reduced scattering coefficient μ’s of the fruit of the strawberry cultivars ‘Hongyan’, ‘Tianxiang’ and ‘Zhangji’, were measured over the wavelength range of 950–1 650 nm. The relationships of optical properties with SSC and moisture content were analyzed, and partial least squares models to predict SSC and moisture content based on optical properties were established. The results showed that the average relative errors of the system for μa and μ’s were 8.23% and 3.71%, respectively. Over the investigated wavelength range, μa had peaks at 975, 1 197 nm and 1 411 nm, and μ’s generally decreased with increasing wavelength. μa had negative correlation with SSC but positive correlation with moisture content. Moreover, extreme correlation coefficients were observed at the absorption peaks. The models established based on the spectra of μa had the best capability in predicting SSC (rp = 0.815, root mean squares error of prediction (RMSEP) = 1.153%) and moisture content (rp = 0.757, RMSEP = 1.280%), indicating that SSC and moisture content mainly affected the optical absorption property of strawberry fruit, which allowed good prediction of the internal quality of strawberry fruit.
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    Changes in the Structure and in Vitro Enzymatic Digestibility of Starch-Lipid Complexes after Autoclaving Treatment
    QIN Renbing, WANG Shujun, XIANG Fengjuan, WANG Shuo
    FOOD SCIENCE    2021, 42 (1): 47-51.   DOI: 10.7506/spkx1002-6630-20191217-191
    Abstract337)   HTML66)    PDF(pc) (2508KB)(201)       Save
    The effects of autoclaving treatment and retrogradation on the structure and in vitro enzymatic digestibility of complex (HA7-SA) formed between stearic acid (SA) and debranched high amylose starch were investigated. The long-range and short-range molecular orderliness and phase transition temperature of HA7-SA before and after treatment were determined by X-ray diffraction (XRD), laser confocal microscopy-Raman spectroscopy and differential scanning calorimetry. The in vitro enzymatic digestibility was evaluated by in vitro digestion experiments. It was found that autoclaving treatment could significantly decrease the crystallinity of V-type crystal, and increased the crystallinity of B-type crystal, phase transition temperature and short-range molecular orderliness of HA7-SA (P < 0.05). The in vitro enzymatic digestibility and estimated glycemic index (eGI) were significantly decreased after autoclaving treatment. Storage at 4, 25 and 50 ℃ for 24 h after the processing had no significant effect on the structure or in vitro enzymatic digestibility of HA7-SA complex.
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    Effect of Phage vB_SauM_RS on Removal of Milk-Derived Staphylococcus aureus Biofilms
    RUAN Hongri, WANG Yuhui, XU Ruoyang, CHEN Li, JIN Yuqi, WANG Jianfa, SONG Jun, ZHENG Jiasan
    FOOD SCIENCE    2021, 42 (1): 52-58.   DOI: 10.7506/spkx1002-6630-20200105-053
    Abstract230)   HTML39)    PDF(pc) (3864KB)(100)       Save
    Objective: Staphylococcus aureus was used as the host bacterium for isolating a lytic bacteriophage vB_SauM_RS. Its biological characteristics were determined, and its antibacterial effect in milk and its efficiency in removing biofilms were studied. Methods: Bacteriophage and S. aureus were inoculated together into skim milk or whole milk at a ratio of 1:100, which was then kept at 4 or 25 ℃. At different time points, bacterial concentration and phage titer were determined and the phage’s antibacterial effect was evaluated. Then, by crystal violet staining, plate counting method and double-layer agar plate method, bacterial concentration in the biofilm of S. aureus and phage titer were determined at different time points during phage treatment, the effect of the phage on the removal of biofilms formed on the surface of different materials was analyzed, and the changes in the number of bacterial cells in the biofilm before and after being removed were observed by fluorescence microscope. Results: Phage vB_SauM_RS formed clear plaques with halo; transmission electron microscopic (TEM) observation showed that the phage belonged to the Myoviridae family. The optimal multiplicity of infection (MOI) of this phage was 0.01. The one-step growth curve showed that the latent period was 20 min, and the average lysis amount was 39 PFU/cell. The phage was stable at 20–50 ℃ or pH 4.0–11.0. It inhibited the host bacterium, reducing the bacterial concentration in skim milk and whole milk by 1.079 (lg(CFU/mL)) and 1.021 (lg(CFU/mL)) after 24 h incubation at 4 ℃, and by 5.418 (lg(CFU/mL)) and 5.740 (lg(CFU/mL)) after 24 h incubation at 25 ℃, respectively. The results of plate counting and fluorescence microscopic observation showed that this phage had a clear effect on the clearance of bacterial cells in the biofilm, and of biofilms formed on the surface of all tested materials. Conclusion: Phage vB_SauM_RS not only has a good lytic effect on S. aureus in milk, but also can effectively remove the biofilm formed by S. aureus. It is promising as an antibacterial bioagent for preventing and controlling S. aureus.
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    Effect of in Vitro Simulated Digestion on the Structure of Rice Glutelin and the Biological Activity of Hydrolysates
    SHI Jiayi, ZHANG Tai, LIANG Fuqiang
    FOOD SCIENCE    2021, 42 (1): 59-66.   DOI: 10.7506/spkx1002-6630-20200806-082
    Abstract351)   HTML40)    PDF(pc) (3109KB)(208)       Save
    The relationship between rice glutelin structure and the antioxidant activity and angiotensin-converting enzyme (ACE) inhibitory activity of its hydrolysates at different times of in vitro simulated digestion was studied under different hydrolysis time. Endogenous fluorescence spectroscopy and Fourier transform infrared spectroscopy (FTIR) were used to determine the structural changes during glutelin hydrolysis. The biological activity of the hydrolysate was characterized by measuring its antioxidant capacity and ACE inhibitory activity. Quadrupole tandem time-of-flight mass spectrometry was used to identify the most antioxidant and ACE inhibitory components of the hydrolysate. The results showed that the degree of hydrolysis (DH) of glutelin increased rapidly in the first 2 h of digestion, and then tended to level off. After the hydrolysis of glutelin, the maximum absorption wavelength (λmax) was red-shifted, together with an increase in the fluorescence intensity. In addition, the proportion of α-helix structure significantly increased, resulting in decreased antioxidant capacity, while the proportion of β-sheet structure decreased significantly, resulting in increased ACE inhibitory activity (P < 0.05). The hydrolysate of glutelin had the strongest antioxidant capacity at 0.5 h, with half maximal inhibitory concentration (IC50) of (1.113 ± 0.015), (0.518 ± 0.053) and (0.678 ± 0.019) mg/mL for 1,1-diphenyl-2-picrylhydrazyl free radical scavenging, hydroxyl radical scavenging and Fe2+-chelating capacity, respectively. The ACE inhibitory activity first increased, reaching the maximum at 2 h, with an IC50 of (0.693 ± 0.011) mg/mL, and then decreased. The increase in the DH of glutelin reduced the antioxidant capacity, but enhanced the ACE inhibitory activity. The antioxidant capacity of the hydrolysate from 0.5 to 2 h was negatively correlated with the ACE inhibitory activity and then both decreased. The molecular masses of the antioxidant peptides and the ACE inhibitory peptides in the hydrolysate were both below 2 kDa, and VEGGFLFIV was selected as a representative antioxidant peptide. Most of the ACE inhibitory peptides were N-terminal hydrophobic amino acids or basic amino acids. Therefore, optimal functional peptide products with antioxidant or antihypertensive activity can be prepared by controlling the DH during the in vitro digestion of rice glutelin.
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    Synergistic Inhibition Mechanism of Reuterin and Catechin against Streptococcus mutans
    WANG Sitong, ZHANG Tong, JIN Man, QU Guoqiang, SUN Xueting, FU Hengfang, LIU Libo, LI Chun
    FOOD SCIENCE    2021, 42 (1): 67-72.   DOI: 10.7506/spkx1002-6630-20191202-032
    Abstract220)   HTML41)    PDF(pc) (4130KB)(78)       Save
    In order to investigate the inhibitory effect of catechin and reuterin (3-hydroxypropionaldehyde (3-HPA)) on the caries pathogen Streptococcus mutans and to dissect the underlying mechanisms, the minimum inhibitory concentrations of reuterin and catechin alone and in combination were determined in the present study. By calculating the fractional inhibitory concentration index (FICI), it was found that catechin (1/8 MIC) and 3-HPA (1/4 MIC) had a synergistic effect when used together. The combination of the two drug resulted in a significant reduction in the contents of biofilm, extracellular polysaccharide (EPS) and organic acid (P < 0.05), more effective than either drug alone. Scanning electron microscopic results showed that the biofilm structure in the combination treatment group significantly changed compared to either individual treatment group, accompanied by a decrease in biofilm thickness and the number of bacterial cells. Collectively, the above results demonstrated that the combination treatment of catechin and 3-HPA could inhibit bacterial aggregation and adhesion, impede bacterial cells from being involved in substrate metabolism, increase acidity and delay biofilm?growth?and?maturation, and thus could be used as a novel antibacterial agent against caries. This study will provide a theoretical basis for the development of natural and safe anti-caries products.
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    Preparation and Stability of Freeze-Dried Polyphenol Extracted from Mulberry Juice Processing Residues
    ZOU Ying, YU Yuanshan, ZOU Bo, CHENG Lina, XIAO Gengsheng, WU Jijun, BU Zhibin, XU Yujuan
    FOOD SCIENCE    2021, 42 (1): 73-78.   DOI: 10.7506/spkx1002-6630-20191121-250
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    Mulberry juice processing residues are a potential source of polyphenols to be used as functional ingredients in foods, but their low stability to oxidation and thermal degradation limits their practical application. In this study, a 70% ethanol extract was prepared from mulberry pomace, a by-product of mulberry juice processing, and freeze-dried with and without cryoprotectants (maltodextrin and/or whey protein, and fermented litchi residues) to obtain seven different powders (P1-P7). Results showed that the total polyphenol content and antioxidant activity of the freeze-dried polyphenol extracts with each cryoprotectant except maltodextrin increased compared with the control group without cryoprotectant, while the (apparent) content of monomeric anthocyanins significantly decreased (P < 0.05). The cryoprotectants affected the extraction efficiency of anthocyanins by encapsulating them, and fermented litchi residues (P5) showed the strongest effect, followed by the mixtures of the freeze-dried extract and maltodextrin at ratios 1:2 (P4) and 1:4 (P7). The contents of total phenols and total anthocyanins, and antioxidant activity in the control group decreased by 19.27%, 18.16% and 11.41%, respectively, after being stored at 25 ℃ for one month. Maltodextrin and whey protein improved the storage stability of the extract, increasing the content of bioactive components and enhancing the antioxidant activity. In the control group, the contents of cyanidin-3-glucoside and cyanidin-3-rutinoside were (11.63 ± 0.13) and (4.14 ± 0.05) mg/g, respectively, which decreased by 26.72% and 16.53% compared with those before storage, respectively. However, the contents of the two main monomeric anthocyanins in the mixtures of the freeze-dried extract and maltodextrin at ratios 1:2 (P4) and 1:4 (P7) did not decrease significantly, indicating their good stability. During in vitro digestion, anthocyanin contents in each group decreased, and the retention rate of anthocyanins in the 1:1:1 freeze-dried extract + maltodextrin + whey protein (P2), 1:2 freeze-dried extract + maltodextrin (P3), and 1:4 freeze-dried extract + maltodextrin (P6) groups increased in contrast to the other groups, indicating improved digestive stability of the polyphenol extract from mulberry pomace.
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    Effect of Superfine Tea Powder on Quality and Starch Digestion Properties of Whole-Wheat Bread
    WANG Yuwan, TU Zheng, YE Yang
    FOOD SCIENCE    2021, 42 (1): 79-85.   DOI: 10.7506/spkx1002-6630-20191204-046
    Abstract344)   HTML62)    PDF(pc) (3830KB)(186)       Save
    The effects of adding different amounts of superfine green tea powder or black tea powder (0.5–2.0 g/100 g of flour) on baking characteristics and antioxidant capacity of whole-wheat bread were studied. Meanwhile, starch digestion properties of whole-wheat bread with different amounts of superfine tea powder were detected by simulated gastrointestinal digestion in vitro. The results indicated that the type and addition amount of tea powder could significantly affect the specific volume, moisture content, color and texture of whole-wheat bread. In addition, the total tea polyphenol content (0.87–1.87 g/100 g), 1,1-diphenyl-2-picrylhydrazy radical scavenging activity (0.45–1.25 g/100 g) and resistant starch content (1.28–17.22 g/100 g) obviously increased with increasing addition level of superfine tea powder. In general, superfine black tea powder at an addition amount of 2.0% could greatly improve the baking and antioxidant properties of whole-wheat bread, and inhibit the starch digestion properties.
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    Changes of Starch and Minerals in Pulp of Plantain Cultivars (Musa spp. AAB) during Postharvest Ripening
    FU Jinfeng, WANG Juan, WANG Lin, SHENG Ou
    FOOD SCIENCE    2021, 42 (1): 86-92.   DOI: 10.7506/spkx1002-6630-20200106-060
    Abstract287)   HTML41)    PDF(pc) (3655KB)(155)       Save
    Objective: To investigate changes in starch and mineral contents of the pulp of two new Plantain (Musa spp. AAB) cultivars resistant to Fusarium wilt, ‘Meishijiao 1 and 2’, during postharvest ripening and to compare them with those of the Cavendish banana cultivar (Musa spp. AAA) ‘Zhongjiao 8’. Methods: The maturity evaluation was carried out using a colorimeter with colorimetric cards, the physical properties of starch were studied by measurement of resistant starch content and optical microscopic observation, and mineral contents were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Results: For freshly harvested fruit, resistance starch accounted for 74.99% and 75.23% of the total starch in ‘Meishijiao 1 and 2’, respectively, which were approximately 26% higher than that in ‘Zhongjiao 8’ (48.64%); during the ripening process, a significant decrease in total starch and resistant starch contents was observed for all three varieties. Starch granules were oblong in the two Plantain cultivars, whereas irregular starch granules were observed in ‘Zhongjiao 8’. The number of starch granules in the flour of the three varieties decreased gradually during ripening. After ripening, the pulp firmness of the Plantain cultivars was greater than that of ‘Zhongjiao 8’, and anthracnose spots in Plantain peel appeared relatively late. The potassium content in the pulp of ‘Zhongjiao 8’ was significantly higher than that of the Plantain cultivars; however, the pulp of Plantain could retain more potassium during ripening. Conclusion: Plantain is promising for deep processing and the development of healthy foods.
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    Effects of Sous-Vide on the Eating Quality and Protein Digestibility of Braised Pork in Brown Sauce
    ZHANG Ze, ZHAO Di, NIAN Yingqun, ZHOU Guanghong, LI Chunbao
    FOOD SCIENCE    2021, 42 (1): 93-100.   DOI: 10.7506/spkx1002-6630-20191130-330
    Abstract1462)   HTML69)    PDF(pc) (3361KB)(241)       Save
    Braised pork in brown sauce is a traditional Chinese dish, but serious protein oxidation occurs during its making. This paper evaluated the feasibility of replacing the traditional process of making braised pork in brown sauce by low-temperature long-time cooking (sous-vide, SV) according to its eating quality and digestibility. Compared with the traditional cooking method, SV significantly increased the moisture content of braised pork in brown sauce and reduced its shear force and cooking loss rate (P < 0.05). Low-field nuclear magnetic resonance indicated that cooking method affected the proportion of immobilized water and consequently physical and chemical attributes. Similar to the traditional cooking process, SV also produced an attractive color. Furthermore, SV significantly improved the L* value of the lean layer (P < 0.05). The in vitro digestion experiments indicated that SV significantly increased the protein digestibility of braised pork in brown sauce when compared with the traditional cooking process (P < 0.05). Taken together, SV is an effective way to prepare traditional Chinese meat products, which is useful to enhance the quality and nutritional value of products.
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    Effects of Heat Treatment Temperature and Time on Thermal Aggregation Behavior of Myofibrillar Proteins from Mirror Carp (Cyprinus carpio)
    CHANG Peng, XIE Yanying, WANG Hao, XIA Xiufang
    FOOD SCIENCE    2021, 42 (1): 101-107.   DOI: 10.7506/spkx1002-6630-20191213-152
    Abstract332)   HTML27)    PDF(pc) (4327KB)(114)       Save
    Effects of heat treatment temperature (30–90 ℃) and time (0–60 min) on the thermal aggregation behavior of myofibrillar proteins (MPs) from mirror carp (Cyprinus carpio) were studied by measuring changes in protein solubility, turbidity, surface hydrophobicity, sulfhydryl content, Fourier transform infrared spectrum and the rupture force of heat-induced MP gels. The results showed that the heat-induced aggregation of MPs strongly depended on temperature. After heat treatment at 30 ℃, the degree of protein denaturation became smaller, and the active sulfhydryl content increased, while the total sulfhydryl content remained unchanged without the formation of any disulfide bonds. In this case, protein aggregation mainly depended on the surface hydrophobic interaction. As heating temperature increased, surface hydrophobicity, β-sheet content, turbidity and the rupture force of heat-induced gels increased, and sulfhydryl content, α-helix content, and solubility decreased. These results corroborated that the increase of temperature could lead to high aggregation ability of proteins. All the tested indexes changed significantly (P < 0.05) during heat treatment from 0 to 15 min and remained stable from 30 min onward. In addition, the highest heat-induced gel strength (1.07 N) was obtained upon heat treatment at 70 ℃ for 30 min. Collectively, the above results suggest that protein thermal aggregation behavior is significantly affected by heat treatment conditions, and it can be regulated by controlling heat treatment condition.
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    Comparative Study on the Anti-Staphylococcus aureus Mechanism of SP-AP-1 and Iturin A Derived from Fermentation of Spirulina Residue by Bacillus subtilis
    FU Yun, ZHAO Mouming, PANG Yiyang, LIU Xiaoling
    FOOD SCIENCE    2021, 42 (1): 108-114.   DOI: 10.7506/spkx1002-6630-20200103-035
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    The mechanisms of action of the antimicrobial peptides SP-AP-1 and iturin A derived from the fermentation of Spirulina residue by Bacillus subtili were studied by investigating their effects on the cell membrane permeability of Staphylococcus aureus using ultraviolet spectrophotometry, the O-nitrophenyl-β-D-galactopyranoside method and atomic absorption spectrometry, as well as on intracellular protein synthesis and genomic DNA binding using Coomassie brilliant blue, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and agarose gel electrophoresis. Moreover, changes in the secondary structures of the antimicrobial peptides after they exerted their antibacterial effect were investigated by simulating the hydrophobic environment of the cell membrane. The results showed that both SP-AP-1 and iturin A increased the cell membrane permeability of Staphylococcus aureus, thereby resulting in increased intracellular potassium and protein leakage and cell membrane hydrophobicity, with the former being significantly more effective than the latter (P < 0.05). In addition, both antimicrobial peptides could inhibit the synthesis of bacterial proteins, especially those with molecular masses of 17, 20 and 25–35 kDa. Although the two antimicrobial peptides had no significant blocking effect on Staphylococcus aureus genomic DNA, SP-AP-1 darkened the color of genomic DNA bands and competitively bound to DNA with ethidium bromide at increased concentrations, thereby affecting protein expression. This study lays a theoretical foundation for studies on the mechanisms of action of antimicrobial peptides derived from Spirulina residue against Staphylococcus aureus.
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    Effects of Traditional Xinjiang-style Marination on Eating Quality and Heterocyclic Amines Formation in Roast Lamb
    LI Mingyang, NIU Xiyue, XU Qian, REN Xiaopu, PENG Zengqi
    FOOD SCIENCE    2021, 42 (1): 115-123.   DOI: 10.7506/spkx1002-6630-20191130-322
    Abstract315)   HTML33)    PDF(pc) (3328KB)(136)       Save
    To improve the flavor, color and tenderness of roast lamb and reduce the formation of heterocyclic amines (HAs), the present study investigated the effects of different traditional Xinjiang-style marinade ingredients: red chili pepper (H), onion (Y), cumin (Z), and egg white (Q), singly and in combination, on the water content, water-holding capacity (WHC), color, tenderness, texture and HAs content of roast lamb were investigated. The results showed that different marinade ingredients had different impacts on the eating quality of roast lamb. Compared to the other groups, the water content in group Y was significantly reduced (P < 0.05), while the cooking loss rate was significantly increased (P < 0.05). Better WHC and consequent lower cooking loss rate were found in groups Z, HZY and HZYQ in comparison to the other groups (P < 0.05). L* values in all treatment groups except group HZY were significantly higher than in the control group, and b* values were significantly improved in all treatment groups with the exception of group Q, imparting a burnt yellow color to roast lamb. Significantly lower shear forces in groups H, Q, HZY and HZYQ were noted compared to the control group (P < 0.05), indicating improved tenderness of roast lamb. Comparatively, better texture characteristics were observed in groups Q, HZY and HZYQ. The formation of 2-amino-3-methyl-imidazo[4,5-f]-quinoline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP) and 2-amino-9H-pyrido[2,3-b]indole was significantly decreased in all treatment groups (P < 0.05) and onion was the most effective inhibitor against HAs, with the highest inhibition percentage of 53.71%. This study provides a theoretical basis for popularizing the traditional Xinjiang-style lamb marination method.
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    Effect of Secondary Sterilization on Oxidation, Characteristics and Structure of Myofibrillar Protein in Sauced Sheep Tripe during Storage
    HOU Ran, ZHAO Wei, LU Shiling, HAN Ping, LIU Lu, AI Yanwen, DONG Juan
    FOOD SCIENCE    2021, 42 (1): 124-131.   DOI: 10.7506/spkx1002-6630-20191105-052
    Abstract301)   HTML28)    PDF(pc) (3040KB)(71)       Save
    In order to investigate the effects of ultra-high pressure (UHP) and heat treatment on the oxidation, characteristics and structure of myofibrillar protein in sauced sheep tripe, samples were subjected to ultra-high pressure treatment (UHPT) with 400 MPa for 15 min or heat treatment (HT) in water bath at 85 ℃ for 40 min, packaged in vacuum and stored at 4 ℃. An untreated sample was used as a control. The effect of the treatments on myofibrillar protein oxidation and properties was evaluated through measuring carbonyl content, total sulfhydryl content, protein composition, solubility and turbidity. The protein structure was analyzed by ultraviolet absorption spectroscopy, endogenous fluorescence spectroscopy and Raman spectroscopy. The results showed that the carbonyl content of both the treated samples increased faster in the early storage period than did the control, and in general a higher level was observed in the UHPT group in comparison with the HT group. During storage, total sulfhydryl content decreased first and then increased for all groups, and dropped faster in the early storage period in both treatment groups compared with the control group. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that secondary sterilization mainly affected actin and tropomyosin. Both treatments significantly affected the turbidity of myofibrillar protein solution (P < 0.05) with the effect of UHP being weaker. Spectral analysis showed that both treatments transferred tryptophan residues to a non-polar environment, resulting in a decrease in the relative content of α-helix and an increase in the relative content of random coil and folding ratio. The treated protein was transformed from an ordered to a disordered state with the prolongation of storage time. Correlation analysis showed that storage time was significantly correlated with total sulfhydryl content, solubility, and the relative contents of α-helix, and protein oxidation was correlated with protein properties and structure. UHP was more advantageous in preserving the quality of sauced sheep tripe during storage.
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    Effect of Low Voltage Electrostatic Field-Assisted Chilling Storage on Quality of Beef
    HU Feifei, QIAN Shuyi, LI Xia, JIANG Feng, HU Haimei, ZHANG Chunhui
    FOOD SCIENCE    2021, 42 (1): 132-138.   DOI: 10.7506/spkx1002-6630-20200106-071
    Abstract397)   HTML30)    PDF(pc) (4856KB)(130)       Save
    In order to study the effect of low voltage electrostatic field (LVEF)-assisted chilling storage on beef quality, changes in the total bacterial count, total volatile basic nitrogen (TVB-N) content, color, purge loss, cooking loss and shear force of bovine Longissimus dorsi muscles were determined during chilling storage with and without LVEF treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure of muscle tissues. On the 7th day of storage, the total bacterial counts of meat samples subjected to LVEF treatment at 10, 30 and 50 cm away from the electrostatic field generating plate were 5.11, 5.54 and 5.27 (lg(CFU/g)), respectively, which were significantly lower than 6.41 (lg(CFU/g)) observed for the control group (P < 0.05). Compared with the control group, the meat samples in the LVEF groups maintained higher freshness during the whole storage period and had significantly lower TVB-N contents (P < 0.05). Moreover, the meat samples in the LVEF groups exhibited significantly lower purge loss and shear force value (P < 0.05), significantly higher L* and a* values (P < 0.05), higher water-holding capacity and tenderness and a brighter color relative to the control group. SEM and TEM results revealed that the muscle fibers of LVEF-treated meat samples were more densely arranged and the microstructure was better maintained during storage when compared to the control group. In general, LVEF-assisted chilling could effectively prolong the shelf-life of beef and delay its quality deterioration and the effective distance between meat and electrostatic field generating plate was 10–50 cm.
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    Effect of Microwave and Ultrasonic Treatment on the Color of Anthocyanin-Polyphenol Solid and Liquid Systems
    XU Ye, LI Xuan, BI Jinfeng, GUO Chongting, ZHU Fengmei, WU Xinye
    FOOD SCIENCE    2021, 42 (1): 139-148.   DOI: 10.7506/spkx1002-6630-20191211-115
    Abstract373)   HTML31)    PDF(pc) (6438KB)(102)       Save
    The interaction between anthocyanins and polyphenols can improve color properties of anthocyanins, while the color properties and stability of anthocyanins in solid and liquid systems containing polyphenols are not yet clear. In this paper, in order to clarify the effect and underlying mechanism of microwave and ultrasonic treatment on the color of anthocyanin-polyphenol complexes in the solid and liquid states, the changes in the apparent color, spectral characteristics and anthocyanin composition and contents were examined after the treatments. The results showed that after either treatment, L* value increased, b* value decreased, and a* value did not change remarkably in the solid system. The liquid system showed a remarkable red shift in the absorption spectra, indicating that molecular vibration and cavitation effect have a great impact on the spectral absorption. Meanwhile, in both systems, the content of total anthocyanins increased, together with a decrease in polyphenol content and the conversion of neochlorogenic acid to chlorogenic acid. Multivariate statistical analysis showed significant differences in color properties among the complex systems subjected to microwave and ultrasonic treatment under different conditions, which may be mainly caused by the differences in the contents of protocatechuic acid, catechins and total anthocyanins. For both liquid and solid systems, L*, a* and b* values, absorbance at the maximum absorption wavelength, the contents of total anthocyanins and polyphenols were higher after microwave treatment at 30 W or ultrasonic treatment for 90 min as compared to other treatment conditions, greatly contributing to the color stability of the systems. In summary, microwave and ultrasonic treatments are alternative techniques for improving the stability of anthocyanins.
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    Effects of Different Osmosis Methods on the Dehydration Efficiency and Quality of Mango Fruits
    WANG Juntao, TENG Jianwen, WEI Baoyao, HUANG Li, XIA Ning
    FOOD SCIENCE    2021, 42 (1): 149-156.   DOI: 10.7506/spkx1002-6630-20191110-127
    Abstract288)   HTML34)    PDF(pc) (4762KB)(105)       Save
    Sugar osmotic dehydration is an efficient method for food pre-dehydration. While liquid-state sugar osmotic dehydration (LOD) has been extensively studied, there have been less studies on solid-state sugar osmotic dehydration (SSD). In order to compare the differences between these two osmosis methods, their effects on the dehydration efficiency and quality of mango fruit through mass transfer kinetic analysis using the Fick equation as well as determination of relevant indexes. The results showed that the water diffusion coefficient of SSD30 (sucrose/mango mass ratio = 3:10) increased by 42.11% and 38.96%, respectively, when compared with LOD30 (30% sucrose solution/mango mass ratio = 1:1) and LOD40 (40% sucrose solution/mango mass ratio = 1:1), respectively, the diffusion coefficient of soluble solids by 1.27% and 0.05% respectively, the dehydration efficiency at 48 h by 59.8% and 34.79% respectively, the VC retention rate by 4.54% and 3.99% respectively, and the total phenol retention rate by 2.75% and 24.75% respectively. The amount of waste sugar solution and dissolved non-water substances from SSD30 were minimal. Although the high dehydration efficiency of SSD30 may lead to more severe shrinkage of mangoes, solid-state sugar osmotic dehydration is expected to be promising for reducing the production of waste sugar solution and consequently protecting the environment, as well as improving the dehydration efficiency, reducing the solid gain rate and improving the fidelity in fruit processing.
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    Effect of Ultra-high Pressure on Quality Preservation of Hairtail Fish Balls during Refrigerated Storage
    LUO Huabin, SHENG Zhenzhen, SI Yongli, CHEN Yanting, LIN Lu, GAO Xing, YANG Wenge
    FOOD SCIENCE    2021, 42 (1): 157-162.   DOI: 10.7506/spkx1002-6630-20191202-005
    Abstract427)   HTML41)    PDF(pc) (2818KB)(182)       Save
    To extend the shelf life of hairtail fish balls, this work was undertaken to evaluate the effect of ultra-high pressure (UHP) on the quality preservation of hairtail (Trichiurus haumela) fish balls during refrigerated storage. Hairtail fish balls were treated at 250, 300 or 350 MPa for 5 min. The total bacterial count (TBC), total volatile base nitrogen (TVB-N) content, pH, sensory score, color values, gel strength, and textural parameters of fish balls were measured during refrigerated storage. The results indicated that UHP treatment could significantly decrease the TBC and TVB-N content, and slowed down the increase in pH of fish balls. Furthermore, UHP treatment had no negative effects on the color while maintaining the sensory properties, color values, gel strength, hardness and springiness of fish balls during refrigerated storage. TBC in the control and UHP-treated samples exceeded 105 CFU/g on days 21 and 56, respectively. The sensory score of fish balls in the control group decreased significantly with storage time, off-odor appeared on day 14, and the sensory quality became unacceptable on day 21. There was no significant change in the sensory score of the UHP-treated group within 35 days of storage. The sensory score of the sample treated at 300 MPa for 5 min was still more than 5 on day 49, but became unacceptable on day 56. Overall, the shelf life of fish balls could be extended by approximately 35 days upon UHP treatment at 300 MPa for 5 min, which will provide a basis for the application of UHP to the quality preservation of surimi products.
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    Effect of Ferulic Acid Analogues on Oxidative Stress Induced by Prednisone in Mice
    LIU Ziwei, ZHU Jianjin, CHEN Weiwen, LI Zhefeng
    FOOD SCIENCE    2021, 42 (1): 163-171.   DOI: 10.7506/spkx1002-6630-20191202-028
    Abstract288)   HTML27)    PDF(pc) (5997KB)(65)       Save
    Objective: To evaluate the effect of ferulic acid and its analogues, curcumin and oryzanol, on oxidative stress in mice. Methods: Ninety male ICR mice were randomly divided into six groups: normal, model, ferulic acid, curcumin, oryzanol and positive control (coenzyme Q10) groups. The mice in the normal group were intramuscularly injected with normal saline, while those in the other groups were injected with 40 mg/kg mb of prednisone once every three days for eight weeks to induce oxidative stress. The mice in the normal and model groups were fed a normal diet, and 40 mg of ferulic acid, curcumin, oryzanol and coenzyme Q10 were added to 1 kg of the normal diet for the other four groups, respectively. After feeding for four weeks, behavioral experiments were started: sucrose preference and forced swimming. After feeding for eight weeks, all the mice were sacrificed to collect plasma and liver, heart and muscle tissues and extract mitochondria from heart, liver, and leg muscle tissues for measurement of oxidative stress-related parameters. Results: 1) The body mass of the mice in the ferulic acid group decreased significantly compared with that before being injected with prednisone. The sucrose preference of the mice in the coenzyme Q10 group was significantly higher than that in the model and ferulic acid groups (P < 0.05). The cumulative time of the desperate state for the mice in the curcumin, oryzanol and coenzyme Q10 groups during the forced swimming experiment was significantly shorter than that in the model group (P < 0.05). 2) The contents of hypothalamic corticotropin-releasing hormone (CRH) and pituitary adrenocorticotropic hormone (ACTH) in the ferulic acid, curcumin, oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05). Plasma corticosterone (CROT) levels in the oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05). 3) The contents of malondialdehyde (MDA) in plasma and the tested tissues in the oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05), and the activity of catalase (CAT) was significantly higher than that in the model group (P < 0.05). 4) The total superoxide dismutase (SOD) activity in the tissues and the Mn-SOD activity in muscle mitochondria in the oryzanol and coenzyme Q10 groups were significantly higher than their respective counterparts the model group (P < 0.05). 5) The mitochondrial membrane potential in the oryzanol and coenzyme Q10 groups was significantly higher than that in the model group (P < 0.05). The mitochondrial NADH/NAD+ ratio and acetyl-CoA content in the coenzyme Q10 group were significantly higher than those in the model group (P < 0.05). The above results indicated that under the experimental conditions employed in this study, the anti-oxidative stress and mitochondrial antioxidant capacities of the four drugs increased in the following order: ferulic acid < curcumin < oryzanol < coenzyme Q10. Oryzanol and coenzyme Q10 were significantly more effective in improvinf the activity of antioxidant enzymes in tissues and rescuing the mitochondrial dysfunction caused by oxidative stress. Among these, ferulic acid had the lowest antioxidant capacity and coenzyme Q10 possessed the strongest antioxidant capacity, which was slightly stronger than that of oryzanol. The antioxidant capacity of ferulic acid and its two analogues may be associated with their lipophilicity.
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    Curcumin Enhances the Antioxidant Capacity of Pheochromocytoma (PC12) Cells
    XIAO Baoping, CHEN Lu, ZENG Jun, LIU Jingwen, LI Jian, LI Guiling,
    FOOD SCIENCE    2021, 42 (1): 172-179.   DOI: 10.7506/spkx1002-6630-20200119-246
    Abstract291)   HTML46)    PDF(pc) (2927KB)(137)       Save
    Objective: Lowly and highly differentiated pheochromocytoma (PC12) cells were used to investigate the antioxidant capacity and underlying mechanism of curcumin. Methods: The relative proliferation rate of PC12 cells was measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, and the concentration and duration of curcumin treatment were determined. The effect of curcumin on the total antioxidant capacity (T-AOC) of PC12 cells was detected by 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) cation radical scavenging and ferric ion reducing antioxidant power (FRAP) methods. The level of reactive oxygen species (ROS) was measured by the dichloro-dihydro-fluorescein diacetate assay. The activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined using corresponding commercial kits, and the expression levels of antioxidant enzyme genes were detected by real-time fluorescent quantitative polymerase chain reaction. Results: Upon 10 μmol/L curcumin treatment for 24 h, the relative proliferation rate of lowly differentiated PC12 cells remained unchanged, while it was significantly inhibited in highly differentiated cells (P < 0.05). Treatment with curcumin at all concentrations tested significantly increased the T-AOC of both lowly and highly differentiated PC12 cells (P < 0.01), and reduced ROS level (P < 0.01). Furthermore, the activities and gene expression of SOD, CAT and GSH-Px were enhanced by curcumin. Conclusion: Curcumin can enhance the T-AOC, reduce ROS level, alleviate oxidative stress, and maintain cell homeostasis via increasing the activities and gene expression levels of SOD, CAT and GSH-Px.
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    Antithrombotic Effect of Fibrinolytic Enzyme from Lyophyllum ulmarium on Arterial Thrombosis in Rats
    LI Fangfang, WEI Ying, LIU Xue, SHEN Minghua
    FOOD SCIENCE    2021, 42 (1): 180-186.   DOI: 10.7506/spkx1002-6630-20200118-226
    Abstract177)   HTML28)    PDF(pc) (2942KB)(52)       Save
    Objective: To explore the inhibitory effect of the fibrinolytic enzyme from Lyophyllum ulmarium (LUFE) on rat thrombosis. Methods: SD rats were randomly divided into sham operation, model, positive control and low- and high-dose LUFE groups. All groups except the sham operation group were used to establish a ferric chloride (FeCl3)-induced carotid arterial thrombosis model. Before modeling, the rats in the positive control group and the low- and high-dose LUFE groups were administered with 10 mg/kg mb of aspirin and 100 and 400 mg/kg mb of LUFE, respectively, by gavage for 7 days. The changes in thrombus mass and carotid vascular histopathology were observed. The levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), platelet-activating factor (PAF), soluble thrombomodulin (sTM), E-selectin and tissue factor (TF) were detected by enzyme-linked immunosorbent assay. The expression level of CD62P in platelets was detected by flow cytometry. In order to observe the effect of LUFE on platelet function, collagen-induced platelet activation was performed in vitro to observe the effect of LUFE on P-selectin, β-thromboglobulin (β-TG) and platelet membrane glycoprotein IIbIIIa (GPIIbIIIa) levels in platelet-rich plasma. Western blot was used to evaluate the effect of LUFE on the expression levels of phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and p38 mitogen-activated protein kinase (p38 MAPK) in platelets. Results: LUFE significantly reduced thrombus mass and vascular damage, inhibited the increase in serum sTM, E-selectin, TF, TNF-α, IL-6 and PAF levels in the thrombus model rats, and decreased the expression of platelet CD62P. LUFE could in vitro reduce the levels of P-selectin, β-TG and GPIIbIIIa in collagen induced platelet-rich plasma, and down-regulated the phosphorylation levels of platelet PI3K, Akt and p38 MAPK protein. Conclusion: LUFE has an anti-thrombotic effect, and its mechanism may be related to the protection of vascular endothelial cells and the inhibition of platelet activation.
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    Effect of Phloretin on Lifespan of Caenorhabditis elegans
    ZHANG Xiaohan, ZHAO Jiang, HAN Ying, DIAO Cuiru, WANG Hao
    FOOD SCIENCE    2021, 42 (1): 187-196.   DOI: 10.7506/spkx1002-6630-20191206-075
    Abstract299)   HTML36)    PDF(pc) (8165KB)(140)       Save
    Objective: The purpose of this study was to investigate the anti-aging effect of phloretin on Caenorhabditis elegans and the underlying mechanism. Methods: The effect of treatment with different concentrations of phloretin (25, 50 and 75 μg/mL) on the survival rate, motility, pharynx pumping ability, lipofuscin and reactive oxygen species (ROS) levels, and stress resistance (hydrogen peroxide, high temperature, and ultraviolet) of C. elegans was analysed. The mechanism of action of phloretin in prolonging the lifespan of C. elegans was explored by measuring antioxidant enzyme activities and related gene expression levels as well as using mutant C. elegans. Results: Phloretin could significantly promote the longevity of C. elegans, inhibit the decline of its motility, related to senescence, increase stress resistance, enhance free radical scavenging capacity and antioxidant enzyme activities (superoxide dismutase (SOD) and catalase (CAT)), and reduce the accumulation of lipofuscin and the content of malonaldehyde (MDA). Phloretin significantly down-regulated the mRNA expression levels of daf-2 and age-1 (P < 0.05, P < 0.01), but up-regulated the mRNA expression levels of daf-16 and sir-2.1(P < 0.05, P < 0.01). Phloretin failed to prolong the lifespan of the mutants daf-2 (e1370), daf-16 (mu86), and sir-2.1 (ok434), but significantly prolonged the lifespan of the mutant eat-2 (ad1116) (P < 0.05). In addition, phloretin promoted the nuclear localization of DAF-16, and activated the mRNA expression of its downstream target genes sod-3, ctl-1 and hsp-16.2. Conclusion: Phloretin can promote the nuclear localization of DAF-16 through the insulin signaling pathway and the SIR-2.1 signaling pathway, and improve stress resistance and antioxidant capacity, thus prolonging the lifespan of C. elegans.
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    A Food Safety Risk Prewarning Model Using LightGBM Integrated with Fuzzy Hierarchy Partition: A Case Study for Meat Products
    GAO Yanan, WANG Wenqian, WANG Jianxin
    FOOD SCIENCE    2021, 42 (1): 197-207.   DOI: 10.7506/spkx1002-6630-20191210-104
    Abstract279)   HTML31)    PDF(pc) (5456KB)(61)       Save
    In food safety risk management, accurately locating risk points is of critical significance to food safety risk assessment and prewarning, since it helps solve food safety problems from the source. Recently, with the development of informationization in the food industry, a large amount of food safety data accumulated during raw material production, food processing, storage and transportation and, sample inspection urgently need to be developed and utilized. However, there exist lots of deficiencies in the existing food safety risk prewarning system, such as rough risk measurement, low data utilization rate, and high labor cost. Therefore, in this paper, we sorted the food safety data and described the data features for subsequent processing. Meanwhile, in order to take full advantages of the data features of large quantity and high dimension, the combination of prior risk probability and fuzzy hierarchy partition was employed to calculate fuzzy comprehensive risk values based on various attributes for use as the expected output of a predictive model that can predict and validate risk values, generated using light gradient boosting machine (LightGBM) combined with experts’ modification operations. Finally, data on meat products and aquatic products were used to illustrate how to use this method, and its superiority and reasonability were validated. The risk analysis results in this paper, including the risk values and attribute importance distribution, can provide decision makers with valuable information.
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    Characterization of Peptides from Simulated Gastrointestinal Digestion of Ethnic Dairy Products in Yunnan, China
    WEI Guangqiang, SHI Yanan, WAN Changjiang, HUANG Aixiang
    FOOD SCIENCE    2021, 42 (1): 208-214.   DOI: 10.7506/spkx1002-6630-20191129-304
    Abstract313)   HTML33)    PDF(pc) (2352KB)(90)       Save
    Dairy fan, milk pastry and milk residue as traditional ethnic dairy products in Yunnan have a long history, possess distinctive characteristics and are high in protein. This study was implemented to investigate the peptide profiles and free amino acid contents of dairy fan, milk pastry and milk residue by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and an amino acid analyzer based on simulated gastrointestinal digestion, and to analyze potential biological peptides by peptide database searching. The results showed that a total of 221 peptides including five angiotensin converting enzyme inhibitory peptides, four immunoregulatory peptides, three antioxidant peptides, two antithrombotic peptides and one antibacterial peptide were identified from dairy fan, with molecular mass distribution in the range of 500–750 Da. In total 225 peptides including two potential antioxidant peptides were identified from milk pastry, with molecular mass distribution in the range of 750–1 000 Da. In total 222 peptides including two immunoregulatory peptides, two antioxidant peptides and one antithrombotic peptide were identified from milk residue with molecular mass distribution in the range of 750–1 000 Da. The peptides in the three dairy products were mainly derived from β- and α-casein. The contents of free amino acids in dairy fan, milk pastry and milk residue after simulated gastrointestinal digestion were 9.45, 10.7 and 9 g/100 g, respectively, with neutral amino acids being the most abundant, followed by basic and acidic amino acids. This study reveals the biological value of dairy fan, milk pastry and milk residue, and provides a scientific basis for the development of functional dairy products.
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    Pediococcus acidilactici AS185 Improves Metabolic Syndrome Induced by a High-Fat and High-Fructose Diet
    ZHANG Lin, GAO Lei, WANG Chao, ZHAO Zijian, DUAN Cuicui, ZHAO Yujuan, YANG Ge, LI Shengyu
    FOOD SCIENCE    2021, 42 (1): 215-221.   DOI: 10.7506/spkx1002-6630-20191202-020
    Abstract389)   HTML34)    PDF(pc) (3603KB)(98)       Save
    Objective: To study the regulatory effect and underlying mechanism of Pediococcus acidilactici AS185 on metabolic syndrome (MS) in mice. Methods: ICR mice were given a high-fat and high-fructose diet once a day for 6 consecutive weeks to establish an MS model, and AS185 was administered by gavage to the animals once a day from week 7 to 14. The body mass, blood glucose, blood lipid and serum inflammatory factors were determined and Western blot was performed to analyze the expression of relevant proteins. Results: The administration of P. acidilactici AS185 could reduce the serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, insulin (INS), fasting blood glucose (FBG), free fatty acid (FFA), C-reactive protein (CRP) and lipopolysaccharide (LPS) in the mouse model. Western blot analysis showed that P. acidilactici AS185 inhibited the activation of nuclear factor (NF)-κB, and the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88), suppressed inflammatory signaling pathways and the expression of inflammatory factors in the high-fat and high-fructose diet-fed mice. Moreover, it activated liver kinase B1 (LKB1) and the expression of adenylate activated protein kinase (AMPK), thereby enhancing the expression of phosphorylated AMPK (p-AMPK) and phosphorylated acetyl-CoA carboxylase (p-ACC), down-regulating the expression of sterol regulatory element-binding protein-1c (SREBP-1c) and finally regulating the lipid metabolism pathway. Conclusion: P. acidilactici AS185 can improve high-fat and high-fructose diet-induced metabolic syndrome in mice by activating the TLR4-MyD88-NF-κB pathway to regulate inflammatory factor levels, and activating the LKB1-AMPK signaling pathway to improve blood lipid disorders.
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    Protective Effect of Tartary Buckwheat Albumin Hydrolysate on High Glucose Induced Insulin Resistance in HepG2 Cells
    FEI Ye, WANG Yong, GONG Shiying, TIAN Yan, WANG Zhuting, LEI Tingwen, ZHANG Lilin, WANG Xilan, LI Hongmei
    FOOD SCIENCE    2021, 42 (1): 222-227.   DOI: 10.7506/spkx1002-6630-20191214-155
    Abstract282)   HTML40)    PDF(pc) (3308KB)(106)       Save
    Objective: To observe the effect of tartary buckwheat (FagoPyrum tataricum Gaertn.) albumin hydrolysate (TBAH) on insulin resistance in HepG2 cells. Methods: TBAH, prepared with alkaline protease, was ultrafiltrated to retain peptides with molecular mass less than 3 kDa. HepG2 cells were induced by high glucose and high insulin for 36 h to establish an insulin resistance model. Then, the cells were cultured with 2.5, 5 and 10 μg/mL TBAH for 24 h. The effect of TBAH on glucose metabolism in HepG2 cells was observed. The effects on oxidative damage indicators nitric oxide (NO), malondialdehyde (MDA), lactic dehydrogenase (LDH), superoxide dismutase (SOD), reactive oxygen species (ROS) and the insulin receptor substrate 1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway in insulin-resistant HepG2 cells were also detected. Results: Compared with the insulin resistance model group, glucose consumption in the TBAH group was significantly increased (P < 0.05) in a dose-dependent manner, while MDA, NO and ROS contents were significantly decreased (P < 0.01, P < 0.05); SOD activity was significantly increased (P < 0.05), whereas LDH activity was significantly decreased (P < 0.05); Phosphorylated IRS-1 protein expression level was decreased (P < 0.05), whereas phosphorylated Akt, PI3K and glucose transporter 4 protein expression levels were significantly increased (P < 0.01). Conclusion: TBAH can improve insulin resistance by inhibiting oxidative stress.
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    Effect of a Mixture of Organic Acids Produced by Propionibacterium acidipropionici with Glycerin as Substrate on the Quality of Prepared Pork Patties during Chilled Storage
    WU Ying, LAI Lixian, ZHANG Wangang
    FOOD SCIENCE    2021, 42 (1): 228-234.   DOI: 10.7506/spkx1002-6630-20191118-207
    Abstract204)   HTML32)    PDF(pc) (2448KB)(56)       Save
    The effects of addition of different amounts (0.2%, 0.3%, 0.4% and 0.5%) of a mixture of organic acids produced by Propionibacterium acidipropionici with glycerin as substrate on the quality of prepared pork patties during refrigerated (4 ℃) storage were studied using samples with no added antioxidant as the control. For this study, we measured the pH, color (L*, a* and b* values), mass loss rate, thiobarbituric acid reactive substances (TBARS) value, total bacterial count and textural characteristics of pork patties on days 1, 4, 7 and 10. The results indicated that adding the organic acid mixture significantly increased the a* value during chilled storage (P < 0.05), being beneficial to improve the color of pork patties, reduced the chewiness, mass loss rate and total colony number (P < 0.05), and inhibited lipid and protein oxidation (P < 0.05). The addition of the organic acids at 0.5% could significantly reduce the hardness of pork patties (P < 0.05), and exerted the strongest inhibitory effect on lipid and protein oxidation as well as microbial growth, thereby greatly improving the quality of prepared pork patties.
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    Quality Analysis of Stored Corn Pancake and Establishment of Shelf-Life Prediction Model
    CAO Yong, ZHANG Suixin, XU Xiuying, ZHAO Chengbin, WU Yuzhu, ZHANG Hao, LIU Jingsheng
    FOOD SCIENCE    2021, 42 (1): 235-242.   DOI: 10.7506/spkx1002-6630-20191202-026
    Abstract315)   HTML26)    PDF(pc) (4873KB)(107)       Save
    The purpose of this study was to investigate the storage quality and shelf-life of tough corn pancakes. Tough pancakes were prepared from a mixture of corn and wheat flours and were stored for up to 14 days. Changes in sensory quality, physicochemical and microbiological indices, texture and starch retrogradation characteristics were measured during the storage period. The key factors affecting the quality change of corn pancakes during storage were discussed, and a shelf-life prediction model for corn pancake was established. The results obtained showed that during storage at 4, 25 and 40 ℃, acid value, peroxide value (POV), the total number of bacterial colonies, enthalpy value and the color parameter b* value increased, while toughness, ductility, the color parameters L* and a* values, and sensory score gradually decreased. According to correlation analysis, the total number of bacterial colonies could be used as a quality indicator to evaluate the storage life of corn pancakes. A kinetic model for the growth of total bacterial colonies under different temperature conditions and a kinetic model with storage temperature as an independent variable were established. The bias factor (Bf) of the developed model was 0.899–1.051, and the accuracy factor (Af) was 1.126–1.281. Further, a shelf-life prediction model for tough corn pancakes was established, and the error between the predicted and actual values was ?4.10%–2.91%, indicating that this model can quickly and reliably predict the shelf-life of corn pancakes. This study will provide technical support and a theoretical basis for the industrial production of corn pancake and related products.
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    Role and Underlying Mechanism of the Ascorbic Acid-Reduced Glutathione Cycle in Scavenging Hydrogen Peroxide in Postharvest Melons Induced by Salicylic Acid
    YANG Qian, FAN Cunfei, WANG Yi, REN Yalin, BI Yang
    FOOD SCIENCE    2021, 42 (1): 243-249.   DOI: 10.7506/spkx1002-6630-20191128-276
    Abstract303)   HTML43)    PDF(pc) (2926KB)(104)       Save
    Objective: To ascertain the role of the ascorbic acid-reduced glutathione (AsA-GSH) cycle in scavenging excessive H2O2 in melons induced by salicylic acid (SA) during postharvest storage. Methods: Melon (cv. Yujinxiang) fruit were soaked in 4 mmol/L SA for 10 min, and stored at ambient temperature. Malondialdehyde (MDA) content and the accumulation level of reactive oxygen species, and the activity of superoxide dismutase (SOD) and catalase (CAT) were determined as well as enzyme activities involved in the AsA-GSH cycle and the contents of substrate and product. Results: SA treatment reduced MDA content, resulting in a 14.6% reduction in MDA content compared with the control group on day 10. SA significantly increased superoxide anion radical production rate and H2O2 content in the fruit (P < 0.05). On day 2 after the treatment, the production rate of superoxide anion radical in the treated group was 1.9 times higher in than that in the control at the same time point, and H2O2 content was 29.7% higher than that in the control on day 6. The chemical increased SOD activity and inhibited CAT activity, suggesting that scavenging of H2O2 is not dependent on the enzymatic system but other systems. Moreover, SA increased the activity of ascorbate peroxidase, glutathione reductase, monodehydroascorbate peroxidase, and dehydroascorbate reductase as well as the contents of ascorbic acid and oxidized glutathione, and decreased the contents of dehydroascorbic acid and reduced glutathione. Conclusion: SA treatment promoted oxygen burst in melons and reduced MDA content. Excessive H2O2 induced by SA was scavenged mainly through the AsA-GSH cycle.
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    Effect of Preharvest 1-Methylcyclopene Application on Superficial Scald and Antioxidant Capacity of ‘Bartlett’ Pears during Shelf Life
    LI Yingli, ZHANG Shaoying, DONG Yu
    FOOD SCIENCE    2021, 42 (1): 250-256.   DOI: 10.7506/spkx1002-6630-20191202-006
    Abstract253)   HTML31)    PDF(pc) (3815KB)(96)       Save
    This study determined the effect of preharvest 1-methylcyclopene (1-MCP) treatment on superficial scald and related antioxidants and antioxidant enzymes in ‘Bartlett’ pears during shelf life, so as to take measures to controll incidence of superficial scald. Results showed that spraying 300 mg/L 1-MCP at 15 d before harvest reduced superficial scald index, retarded the onset of superficial scald, and extended storage life by 1 month as compared to the control group (distilled water treatment). 1-MCP treatment inhibited respiration and ethylene production rates, reduced the contents of α-farnesene and conjugated trienols (CTols) in peel and delayed the peak of ethylene production. In addition, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and the contents of anthocyanins, total flavonoids, and total polyphenols were significantly increased at the middle and late stage of storage in 1-MCP treated fruit. 1-MCP inhibited the loss of ascorbate peroxidase (APX) and catalase (CAT) activities, improved peroxidase (POD) activity in the late stage of storage, and reduced membrane lipid peroxidation and the accumulation of malondialdehyde (MDA).
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    Effect of Ascorbic Acid Combined with Modified Atmosphere Packaging on Storage Quality and Antioxidant Activity of Lingwuchangzao Jujube Fruit
    LIU Hui, ZHANG Jinglin, LIU Jiechao, ZHANG Guangdi, FANG Haitian, ZHANG Qiang, JIAO Zhonggao
    FOOD SCIENCE    2021, 42 (1): 257-263.   DOI: 10.7506/spkx1002-6630-20191219-232
    Abstract366)   HTML37)    PDF(pc) (2721KB)(122)       Save
    Objective: To explore the synergetic effect of exogenous ascorbic acid (AsA) combined with modified atmosphere packaging (MAP) on the storage quality of Lingwuchangzao jujube fruit. Methods: Postharvest jujube fruit were soaked in 0.3 g/100 mL AsA solution and then packaged in polyethylene bags or 0.03 mm thick low-density polyethylene (LDPE) bags with modified atmosphere in them. Changes in the physicochemical characteristics and antioxidant capacity of the fruit were investigated during subsequent cold storage. Results: The preservation effect of AsA combined with MAP was better than that of either alone. MAP in LDPE bags combined with AsA significantly delayed the decrease in fruit firmness and the content of titratable acid (P < 0.05), suppressed the increase in respiration rate and relative conductivity, maintained the contents of AsA, flavonoids and polyphenols, and improve antioxidant capacity. Conclusion: The combination of MAP and AsA can effectively improve the storage quality and prolong the storage period of Lingwuchangzao jujubes, and the best preservation effect can be achieved using 0.3 g/100 mL AsA combined with MAP in 0.03 mm thick LDPE bags.
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    Effect of Storage Temperature on the Quality of Flammulina velutipes and Shelf Life Predictive Modeling
    NIU Yaoxing, WANG Ting, BI Yang, ZHANG Yu, LIU Hong, YUN Jianmin
    FOOD SCIENCE    2021, 42 (1): 264-271.   DOI: 10.7506/spkx1002-6630-20200103-029
    Abstract326)   HTML34)    PDF(pc) (3914KB)(169)       Save
    In order to study the quality change of Flammulina velutipes during postharvest storage and to quickly predict the shelf life, we kept the mushroom under three temperature conditions simulating those occurring during storage and circulation (4, 15 and 25 ℃). The sensory and physicochemical qualities of the samples were evaluated at regular intervals. The first-order kinetic model combined with the Arrhenius equation was used to establish shelf life prediction models based on quality indexes. The prediction accuracy of these models were verified and evaluated. The results showed that low temperature could remarkably slow down the spoilage and extend the shelf life of postharvest F. velutipes. More specifically, low temperature inhibited the mass loss, browning and the increase in malondialdehyde content, slowed down the decline in soluble solid content and maintained high free proline content. The shelf life prediction models based on mass loss rate, disease index, browning degree, and soluble solid content all exhibited high accuracy with determination coefficients R2 higher than 0.90. The relative errors between the predicted and actual values were less than 10%. Particularly, soluble solid content was a more accurate indicator to predict the shelf life. Therefore, the established models can quickly and reliably predict the remaining shelf life of F. velutipes, which will provide a practical guidance to control the storage and circulation conditions in real time so as to extend the shelf life of F. velutipes.
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    Biocontrol of Blue and Green Molds and Induction of Disease Resistance in Citrus Fruit by Bioactive Substances from Gymnopus sp. 0612-9
    HE Tian, CUI Chaoyu, ZHENG Xianneng, LONG Haozhi, HUO Guanghua
    FOOD SCIENCE    2021, 42 (1): 272-278.   DOI: 10.7506/spkx1002-6630-20191205-064
    Abstract222)   HTML21)    PDF(pc) (5091KB)(80)       Save
    This study was undertaken in order to investigate the biocontrol effect of the ethyl acetate extract of the fermentation broth of Gymnopus sp. 0612-9 (GSFE) on blue and green molds in ‘Nanfeng’ citrus and to evaluate the efficacy in inducing disease resistance. Citrus fruit were pre-treated with different concentrations (0, 0.25, 0.55 and 5.50 mg/mL) of GSFE, and then artificially wounded and inoculated with spore suspensions of blue and green molds. Subsequently, the infection rate was quantified and changes in peel defense enzyme activities were measured regularly. The results indicated that the infection rate and disease index were both significantly reduced by GSFE treatment at all concentrations tested when compared with the control group, being the most effective at a concentration of 5.50 mg/mL. Moreover, the activities of phenylalanine ammonialyase, superoxide dismutase, peroxidase were enhanced remarkably by GSFE treatment. GSFE increased significantly the contents of total phenolics and total flavonoids, decreased the accumulation of malondialdehyde (MDA) and lipoxygenase (LOX) activity, and reduced membrane lipid peroxidation, thereby improving disease resistance. This study provides an idea for the development of GSFE as a postharvest citrus preservative.
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    Progress in Methods for Improving the Emulsification Properties of Polysaccharides, Structure-Activity Relationship and Its Application in Foods
    ZHANG Manli, WANG Qiang, CHEN Bingyu, LIU Hongzhi
    FOOD SCIENCE    2021, 42 (1): 279-284.   DOI: 10.7506/spkx1002-6630-20200105-052
    Abstract373)   HTML46)    PDF(pc) (1765KB)(181)       Save
    Polysaccharides have attracted more and more attention because of their biological activity and multiple functional characteristics. However, only a few amphiphilic polysaccharides can act as an emulsifier, which seriously restricts their application in various fields. In this paper, the physical, chemical and biological methods commonly used for improving the emulsification properties of polysaccharides are summarized. Next, it discusses the effect of polysaccharide structure on its emulsification properties and the current status of its application in foods, and analyzes the existing problems in this field. Finally, an outlook on future trends is given. Hopefully, this review will provide a theoretical rationale for improving the emulsification properties of polysaccharides to broaden their scope of application.
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    Microbial Spoilage and Formation and Detection of Volatile Odor Compounds in Packaged Chilled Meat: A Review
    YANG Xiaoyin, ZHANG Yimin, LIANG Rongrong, ZHU Lixian, LUO Xin
    FOOD SCIENCE    2021, 42 (1): 285-293.   DOI: 10.7506/spkx1002-6630-20200207-046
    Abstract449)   HTML42)    PDF(pc) (2317KB)(288)       Save
    Consumers always use spoilage odor emitted from meat as an important indicator to judge the freshness of meat. The microbiota and microbial metabolic pathways in chilled meat vary under different packaging conditions, leading to the release of volatile odor compounds during storage, which directly determines the off-odors and spoilage degree of chilled meat. Thus, qualitative and quantitative analysis of volatile organic compounds in packaged meat is significant for understanding the process of meat spoilage. In this article, we review microbial community succession and the changes of typical volatile compounds in chilled beef, pork and lamb, as well as tray packaged, vacuum packaged, and modified atmosphere packaged poultry meat, with a special focus on the dominant microbial populations that produce spoilage odors under specific packaging conditions. The formation mechanisms of these off-odors are discussed based on substrate utilization and metabolic pathways, and the existing methods for their detection are also summarized. We expect this review will provide some useful information for controlling the formation of spoilage odors in meat products and monitoring the shelf-life of packaged chilled meat using volatile biomarkers.
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    Application of Cryoprotectants in the Frozen Storage of Meat and Aquatic Products: A Review
    LI Minhan, LI Hongjun, LI Shaobo, YU Sijie, HE Zhifei
    FOOD SCIENCE    2021, 42 (1): 294-301.   DOI: 10.7506/spkx1002-6630-20191230-361
    Abstract402)   HTML46)    PDF(pc) (2244KB)(554)       Save
    As one of the major methods to store meat and aquatic products, freezing can significantly extend product shelf life. However, freezing also has an adverse impact on product quality, reducing eating quality. Being able to slow down the quality deterioration of meat and aquatic products during the freezing process and improve the consumer acceptability of frozen products, cryoprotectants have recently attracted great attention. This paper outlines the mechanisms of action of carbohydrates, proteins, salts and polyphenols as cryoprotectants, and it also summarizes the current status of the application of cryoprotectants in meat and aquatic products. Furthermore, an outlook on future directions in this field is presented. Hopefully, this review will provide a theoretical basis for the industrial application of cryoprotectants in meat and aquatic products to maintain their quality.
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