The effect of chitosan flocculation on clarifying water extract from Stevia rebaudiana Bertoni leaves, prepared by twice repeated water extraction at a solid/liquid ratio of 1:10 (g/mL) followed by pooling and then rotary evaporation concentration of two extracts, was studied. Clarification rate and stevioside loss rate were investigated with respect to different factors. Using orthogonal array design method, the optimal process conditions for chitosan flocculation were determined as follows: ratio between 1% acetic acid solution of chitosan and dried Stevia rebaudiana Bertoni leaves 2:1 (mL/g), 1-fold concentration of pooled extracts from Stevia rebaudiana Bertoni leaves, pH 6.0, flocculation temperature 45 ℃, and flocculation time 4 h. Under these conditions, a clarification rate of 86.63% and a stevioside loss rate of 6.89% were achieved. Chitosan flocculation without the need for special equipment had similar effectiveness to that of membrane separation in clarifying water extract from Stevia rebaudiana Bertoni leaves. Compared with the conventional chemical flocculation, chitosan flocculation could more effectively retain effective ingredients in the water extract and had the advantages of effective flocculation, ready biodegradation, environmental safety and non-secondary contamination.

A two-step steeping process was designed to extract corn starch in the present work. A series of one-factor-at-a-time experiments were done to investigate the effects of steeping time and temperature and acid protease dosage in the second steeping on starch yield. Further, the relationship of starch yield versus the three parameters was modeled based on a Box-Benhnken experimental design and analyzed by response surface methodology. The optimal corn steeping process conditions were identified as steeping at 52 ℃ for 3 h and then steeping at 51 ℃ for 2.25 h in the presence of 700 U/g acid protease. Under the optimal conditions, the predicted starch yield was 65.05%, in good agreement with the experimental value of 64.9%.

Oxidized sweet potato starch was used as the raw material to prepare octenyl succinic anhydride (OSA) modified oxidized sweet potato starch. The effects of OSA amount, pH, temperature and reaction time on degree of substitution (DS) of OSA-modified oxidized sweet potato starch were studied employing response surface analysis. The optimum process conditions determined were as follows: OSA amount 7%, pH 8.40, temperature 40 ℃, and reaction time 10 h. Rapid viscosity analyzer (RVA) analysis showed that the peak viscosity of sweet potato starch decreased after oxidation, and increased after furthermodification with OSA with a positive correlation with DS.

Selenium accumulation in germinating soybean varieties from the Northeast and Jiangsu province was investigated by Na2SeO3 solution soaking-deionizer water spraying method. The results indicated that under the same selenium-enriched conditions (30 mg/L of Na2SeO3 solution, 25 ℃ constant temperature and 6 h soaking time), different varieties of soybean had different selenium tolerance and enrichment capacity. Northeast soybean YH -NJ had the best growth properties and the highest selenium content. With the increase of Na2SeO3 concentration and temperature and the prolongation of soaking time, selenium content in sprouts of soybean YH -NJ increased significantly.

Broken rice and flour from the whitening and polishing of brown rice was extruded, and main factors that affect the contents of soluble solids and soluble sugar in extruded rice flour were investigated. The results indicated that moisture content was the most significant affecting factor, followed by screw speed and extrusion temperature. The optimal moisture content, screw speed and extrusion temperature were determined as 25%, 240 r/min and 140 ℃, respectively. Under the optimal extrusion conditions, the contents of soluble solids and soluble sugar in extruded rice flour were 39.88% and 7.90%, respectively, revealing a 1.53- and 3.64-fold increase compared with those of non-extruded samples. HPLC analysis of soluble sugars in extruded rice flour obtained under the optimal conditions showed that 100 g of samples contained 275.124 mg of fructose, 891.632 mg of glucose, 853.144 mg of sucrose, 516.576 mg of maltose and 353.266 mg of maltotriose.

An L9 (34) orthogonal array design was employed to optimize the extraction of total flavonoids from bayberry (Myrica rubra Sieb. et Zucc.) leaves. The in vitro antioxidant activity of total flavonoids extracted was evaluated by determining their scavenging capacity against hydroxyl radicals and superoxide anions. The optimum extraction conditions were determined as follows: 65% aqueous ethanol solution as extraction solvent at a material/liquid ratio of 1:30 (g/mL) for triple repeated extractions for 1.5 h each time and the extraction rate is 3.34%. Total flavonoids from bayberry leaves could strongly scavenge hydroxyl and superoxide anion free radicals, thus being a powerful natural antioxidant.

Steam distillation extraction was used to simultaneously extract the volatile oil and shikimic acid in star anise. In terms of the yields of volatile oil and shikimic acid, the process conditions material granularity, solid-to-liquid ratio, temperature and extraction time were optimized using one-factor-at-a-time combined with orthogonal array design method to be 80 mesh, 1:15 (g/mL), 150 ℃ and 4 h, respectively. Under the optimal conditions, the volatile yield was 6.69% and the shikimic acid 2.05%.

The individual and combined effects of various natural hydrophilic gums on the suspension stability of fresh sweet corn mix juice were studied. In one-factor-at-a-time experiments, the effects of adding guar gum, flaxseed gum, sodium alginate or xanthan gum on the stability factor of sweet corn mix juice, obtained by determining absorbance before and after centrifugation, were evaluated. Subsequently, response surface methodology was employed to investigate the effect of adding guar gum, flaxseed gum and xanthan gum together on the stability factor of sweet corn mix juice, and the optimal amounts of guar gum, flaxseed gum and xanthan gum were all found to be 0.07%, resulting in a stability factor of 87.91%.

Fructus Psoraleae is one of the most popular raw materials for health products in China. The major bioactive components of Fructus Psoraleae are psoralen and isopsoralen. In the present work, ultra high pressure extraction (UHPE) was used to extract psoralen and isopsoralen from Fructus Psoraleae and compared with the reflux extraction. We found that UHPE resulted in higher yields of psoralen and isopsoralen than the refulx extraction. Using a uniform design, the optimum UHPE conditions including pressure, ethanol concentration, liquid-to-solid raio (mL/g) and extraction time were determined to be 100 MPa, 53%, 90:1 and 3 min for psoralen and 100 MPa, 55%, 90:1 and 3 min for isopsoralen, respectively. UHPE proved to enable normal temperature and rapid extraction of psoralen and isopsoralen, thereby providing an efficient production approach for applying psoralen and isopsoralen in health products and functional products.

The influence of vacuum freeze-drying, vacuum drying and hot-air drying on the inner structure and rehydration quality of Radix Notoginseng (dried roots of Panax notoginseng) was comparatively investigated. Porosity and rehydration rate of dried samples were calculated based on Micro-CT scanning and image reconstruction. All the three drying methods had a highly significant impact on porosity and rehydration rate of dried samples. In terms of inner structure maintenance and rehydration quality, vacuum freeze-drying was superior to the other two methods and more suitable for industrial production.

One-factor-at-a-time method in combination with response surface analysis based on Box-Behnken experimental design was employed to understand the effect of ClO2 concentration, H2O2 concentration and soaking time on cold sterilization of grass carp meat in terms of total bacterial count and reduction rate. The optimal conditions for maximum bacterial reduction rate were soaking in 157 mg/L ClO2-1.1 g/L H2O2 mixed solution for 6.4 min. Under the optimal conditions, the total bacteria count was reduced from 1.36 × 105 CFU/g to 1.50 × 104 CFU/g and the bacteria reduction was up to 89.01%.

The polyphenols in Tremella aurantialba, Tremella fucitormis and Auricularia aurricula were extracted with 80% acetone, 80% methanol, ethyl acetate and petroleum ether, respectively, and their major components and antioxidant activity were determined using high performance liquid chromatography (HPLC) and in vitro DPPH, hydroxyl and superoxide anion radical scavenging assays, respectively. The results revealed that 80% acetone showed the highest extraction efficiency of ployphenols. Tremella aurantialba, Tremella fucitormis and Auricularia aurricula had similar quercetin content. The contents of rutin and epicatechin were higher in Tremella aurantialba and Tremella fucitormis than those in Auricularia aurricula. Auricularia aurricula contained relatively more chlorogenic acid. All investigated extracts from the three edible mushroom species had a strong ability to scavenge free radicals, especially DPPH and superoxide anion radicals and reduce Fe3+.

The anthocyanidinsins in Loropetalum chinense var. rubrum Yieh leaves were extracted by solvent extraction method and analyzed for their physico-chemical properties. The best extraction conditions were found as follows: 99.5% methanol as extraction solvent at a solid-to-liquid ratio of 1:5 (g/mL) for 2 h extraction at 60 ℃. The pigments were unstable to light and heating but stable to strongly acidic environments and had a different color in slightly acidic and nearly neutral environments. Their tolerance to H2O2 and Na2SO3 was poor and their sensitivity to EDTA and sodium benzoate was high. Glucose and sucrose had little effect on the pigments. Salt, citric acid and some metal ions such as A13+, Ca2+ and Co2+ had hyperchromic effect on them and vitamin C and other metal ions such as Cu2+, Mg2+, Zn2+, Mn2+, K+ and Sn2+ had hypochromic effect. Moreover, Fe2+, Fe3+ and Pb2+ affected the stability of the pigments.

In this paper, artificial neural network (ANN), which can simulate an enzymatic hydrolysis process based on self-learning, was applied to study the optimum conditions for enzymatic preparation of antibacterial peptides from Pinctada fucata muscle with flavourzyme. The hydrolysis of Pinctada fucata muscle by flavourzyme was simulated and optimized using a three-hierarchy ANN structure. The antimicrobial activity of Pinctada fucata muscle hydrolysates was tested by cylinder-plate method. The results demonstrated that the peptide A was obtained after 4 h of hydrolysis under the conditions of pH 7.0, 55 ℃, 7:5 material/liquid ratio and 1.6% enzyme/substrate ratio, which showed the strongest antibacterial activity against Salmonella typhimurium with an inhibition zone diameter of 14.20 mm and an average peptide chain length of 2.6. Four-hour hydrolysis under the conditions of pH 7.0, 55 ℃, 3:2 material/liquid ratio and 1.7% enzyme/substrate ratio generated the peptide B, which had the strongest antibacterial activity against Shigella dysenteriae with an inhibition zone diameter of 23.42 mm and an average peptide chain length of 2.8. The peptide C was obtained under the conditions of pH 6.5, 60 ℃, 7:5 material/liquid ratio, 2.5% enzyme/substrate ratio and 4 h hydrolysis, which displayed the strongest antibacterial activity against L.monocytogenes with an inhibition zone diameter of 16.60 mm and an average peptide chain length of 2.5. The three peptides also had strong antibacterial activity against Escherichia coli and Staphyloccocus aureus with an inhibitory rate ranged of 74.3%－80.8%. The application of ANN for optimizing antibacterial peptides preparation from Pinctada fucata muscle overcomes many shortcomings such as low purity and low extraction efficiency and can therefore provide technical supports for the development and exploitation of antibacterial peptides derived from Pinctada fucata muscle.

In order to improve the solubility of dihydromyricetin in oils, liposoluble dihydromyricetins with different degrees of esterification were synthesized by chemical modification with decanoyl chloride and their solubility and antioxidant property in lard were examined. The results showed that the decanoyl chloride-modified dihydromyricetin had good dispersity in oils and the strongest antioxidant ability when the degree of esterification was 3. At the same concentrations, the antioxidant activity of liposoluble dihydromyricetin with a degree of esterification of 3 was higher than that of dihydromyricetin and BHT. The antioxidant activity of the liposoluble dihydromyricetin at the dosage of 0.05% was similar to that of 0.02% TBHQ.

In this study, the functional and flavor components in antihypertensive Zijuan Pu-erh tea and bitter Kuding tea, which can be added to whole buckwheat tea to compensate their deficiency, were extracted by microwave-assisted organic solvent extraction. The results showed that Zijuan Pu-erh tea samples stored for different times exhibited a significant difference in all investigated functional components except theaflavins (P＜0.05). Nutritional ingredients significantly differed among young leaf Kuding tea, old leaf Kuding tea and their superfine powders (P＜0.05). Orthogonal array based optimizations showed that the optimum extraction conditions of Zijuan Pu-erh tea were 65% ethanol concentration, 540 W microwave output power, 50 s extraction time and 10:1 liquid-to-solid ratio and the resulting extract was rich in anthocyanins (δA = 0.925) and contained 27.709% polyphenol, 0.707% theaflavins (TF), 15% thearubigins(TR), 259.735 mg/g total catechinsand 7.053% caffeine. The optimum extraction conditions of Kuding tea were 55% ethanol concentration, 360 W microwave output power, 120 s extraction time and 25:1 liquid-to-solid ratio, and the extract obtained under the optimum conditions tasted strongly bitter and contained 30.79% flavonidos, 0.699 mg/g chlorophyll, 13.619% tea polyphenol, 4.812% caffeine, and 26.161 mg/g total catechins. Together, these findings demonstrate that both tea extracts can be used to enhance the flavor and function of buckwheat tea.

In this study, the microwave-assisted extraction of polysaccharides from Gracilaria lamaneiformis was optimized by response surface methodology (RSM) and the antioxidant properties of extracted polysaccharides were studied. The results showed that the optimum conditions for polysaccharide extraction were microwave power of 495 W, extraction duration of 17 min, and water-to-material ratio of 100:1. Under the optimum conditions, the extraction yield of polysaccharides was 33.05%. Antioxidant analysis showed that polysaccharides from Gracilaria lamaneiformis could effectively remove DPPH free radicals.

The purpose of this study is to optimize the improvement of foaming properties of albumen protein by papain hydrolysis. Foaming capacity and foam stability were investigated with respect to 4 variables including hydrolysis time, papain dosage, temperature and pH. Two quadratic polynomial regression models describing foaming capacity and foam stability were established based on a Box-Behnken experimental design. According to response surface analysis, the foam stability model was not statistically significant, the foaming capacity model displayed a statistical significance, and the optimum enzymatic modification conditions were hydrolysis time of 45 min, enzyme dosage of 38.2 mg/5 mL of egg white, hydrolysis temperature of 47.5℃, and pH 6.3. Under the optimum conditions, the foaming capacity was up to 2.09, indicating an increase of approximately 140% when compared to non-modified albumen protein.

The aim of this study was to optimize technical conditions for ultrasonic-assisted ethanol extraction, cellulase hydrolysis-based extraction and microwave-assisted ethanol extraction of proanthocyanidins from grape seed power using one-factor-at-a-time coupled with orthogonal array design method. Microwave-assisted extraction was found to be the best of the three methods, and the optimal process conditions were ethanol concentration of 80%, material-to-liquid ratio of 1:25 (g/mL), microwave treatment time of 40 s and microwave power of 115 W. Under these conditions, the extraction rate of proanthocyanidins was 10.70%.

One-factor-at-a-time coupled with orthogonal array design method was employed to optimize the extraction of polypehnols from apple. The optimal extraction conditions were determined as follows: 30% ethanol as the extraction solvent at a material/liquid ratio of 1:6, 70 ℃ temperature and 45 min extraction time. Under these conditions, the extraction yield of polyphenols from apple was 9.032 mg/g. The DPPH radical scavenging rate of apple polyphenols extracted was 94.6% and the FRAP 546.4 μmol/L.

Bee pollen is rich in nutrients, most of which are present inside the cells. The development and exploitation of bee pollen is restricted by the existing cell wall. An investigation to cell wall disruption of rape bee pollen by means of protamex hydrolysis was carried out in this study. The optimal cell wall disruption conditions were found to be: pH 8, 48 ℃ and 48 h hydrolysis. Rape bee pollen with protamex treatment under these conditions was observed under SEM (scan electron microscope) and TEM (transmission electron microscope), and the specific surface area, particle size and Zeta potential were characterized. The results obtained collectively indicate the role of protamex hydrolysis in improving the permeability of rape bee pollen cells from different perspectives.

In this study, we immobilized microbial transglutaminase (MTG) onto polypropylene microporous membrane by ozone activation and then evaluated its application to treat soybean whey waste with the purpose to recover proteins and decrease pollution. The results showed that under optimal technological conditions, MTG-conjugated polypropylene microporous membrane recovered 78.4% of proteins from soybean whey waste, and significantly decreased protein and ash contents, COD value and BOD value of soybean whey waste.

Response surface methodology was employed to optimize the supercritical carbon dioxide extraction conditions of tea seed oil. On the basis of one-factor-at-a-time experiments, a mathematical model describing the effects of extraction pressure, extraction temperature, separation temperature and extraction time on oil yield was created using Box-Behnken experimental design and analyzed by response surface methodology. The optimal extraction conditions were found as follows: extraction pressure 29 MPa, extraction temperature 43 ℃, separation temperature 36 ℃, and extraction time 74 min, resulting in an oil yield of 26.13%.

In this study, eggshell membranes were used as the raw material to extract sialic acid based on deproteinization by ethanol precipitation. A four-factor, five-level central composite design combined with multiple regression analysis was employed to mathematically model protein removal rate and sialic acid recovery as a response to ethanol concentration, temperature, heating time and pH, respectively. Ethanol concentration was identified to be the most significant affecting factor, followed by temperature, pH and heating time. The optimal deproteinization conditions were determined to be: ethanol concentration 30%, temperature 80 ℃, heating time 1 h and pH 2. Under these conditions, the removal rate of protein was predicted to be 52.3% and the recovery of sialic acid 82.1%, closely agreeing with the experimental values, respectively. Thus, the created models are reliable.

We here present a novel method to extract non-degraded β-D-glucans from spent yeast cells, mainly based on induced yeast autolysis, hot water extraction, cell wall disruption, defatting and protease hydrolysis. One-factor-at-a-time coupled with orthogonal array design method was applied to the process conditions of induced yeast autolysis and cell wall disruption. The extract obtained under optimized conditions had a total sugar content of 84.9% with an extraction yield of 13.7%. Its purity and yield were both higher than previously reported. Induced yeast autolysis and hot water extraction had a significant effect on β-D-glucan purity and yield. Moreover, protease treatment could further remove protein impurities and increase β-D-glucan purity. The absence of strong acid, strong alkali and oxidant throughout the process helped to protect the physiological activity of products and the environment.

The purpose of this study was to optimize the extraction of cichoric acid from Cichorium lntybus L. by methanol reflux extraction and then establish an HPLC method for determining cichoric acid content in Cichorium lntybus L. One-factor-at-a-time experiments were conducted to understand the effects of reflux temperature, methanol concentration, extraction time and solid-to-liquid ratio on extraction efficiency of cichoric acid. Based on this, an L9 (34) orthogonal array design was employed to optimize extraction efficiency of cichoric acid. The results demonstrated that the optimal conditions for cichoric acid extraction were reflux temperature of 60 ℃, solid-to-liquid ratio of 1:60 (g/mL), methanol concentration of 70%, and reflux duration of 1 h. Under the optimal conditions, the extraction efficiency of cichoric acid was 8.808 mg/g dry basis.

Label-free liquid chromatography-mass spectrometry was employed for proteome profiling of commercial chicken and pork in present study. In addition, the differences in the variety and amounts of small peptides between fresh and cooked samples of both meat species were compared. The results showed that fresh chicken mainly contained ＞ 100 kD proteins with a pI ranging from 6 to 11. Most proteins in chicken soap ranged between 10 kD and 150 kD and revealed a pI of 4－9. Fresh pork also mainly contained 100 kD proteins with an pI ranging from 6 to 11. Most proteins in pork soap were 10－100 kD and had a pI of 3－9. Hence, similarly processed samples of different meat species differed in the proteome, suggesting indexes obtained in proteome profiling can provide a new strategy for meat quality evaluation.

In order to label the botanical and geographical origin of unioral rape honey and discriminate adulterated rape honey, the volatile components in 49 rape honey samples from different geographical origins were analyzed by ultrasonic-assisted extraction, gas chromatography with flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) and fingerprinted. The results indicated that 49 samples investigated could be assigned into 5 groups, with an effective discrimination between raw and commercial rape honeys. Both rape honeys exhibited an obvious difference in their volatile components. We deduce that benzoic acid-4-hydroxy-3,5-dimethoxy-hydrazide has the potential to be used as a marker of botanical origin of rape honey.

The present work was undertaken to analyze the relationships of variations of volatile flavor components with pickling time and salt amount during the pickling of olive for traditional Cantonese-style preserved fruits. The flavor compounds of picked olives derived from different days of pickling with different amounts of salt addition were analyzed by headspace solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Meanwhile, correlation analysis was performed. The results showed that the content of aromatic hydrocarbons in pickled olive was significantly negatively correlated with salt amount, which had a significant positive correlation with alkanes or ketones. Pickling time was significantly negatively correlated with aldehydes, slightly negatively correlated with alkanes and significantly positively correlated with aromatic hydrocarbons. To sum up, partial flavor compounds of pickled olive increases or decreases as the salt addition increases and the pickling time is prolonged; there is a correlation among partial flavor compounds.

Objective: To establish the HPLC fingerprint of Huangshan Gongju chrysanthemum (Chrysanthemum morifolium Ramat.) for its quality control and evaluation. Method: A total of 28 chrysanthemum samples of different geographical origins were determined by HPLC and evaluated using the Similarity Evaluation System for Chromatographic Fingerprints of Traditional Chinese Medicine to construct a common pattern. Results: Twelve common peaks were identified in the established fingerprints, each of which shared a similarity exceeding 0.96 with the control fingerprint and a similarity below 0.86 with other chrysanthemum varieties. Conclusion: The proposed method is simple, accurate, repeatable and suitable for quality control and evaluation of Huangshan Gongju chrysanthemum.

The volatile flavor compounds of 5 different brands of commercial dry yellow soybean sauces in Beijing were extracted by simultaneous distillation-extraction (SDE) method and analyzed by gas chromatography-mass spectrometry (GC-MS). Totally 69 volatile compounds were identified, including 9 acids, 22 esters, 8 aldehydes, 4 ketones, 3 phenols, 13 herterocylic compounds and 3 sulfur-containing compounds. The common compounds appeared in all five dry yellow soybean sauces were ethyl acetate, ethyl hexadecanoate, ethyl 9-octadecenate, ethyl 9,12-octadecadienoate, ethyl (Z,Z,Z)-9,12,15- octadecatrienoate, 3-methyl butanal, benzeneacetaldehyde, 2-methoxy-4-vinylphenol, 3-(methylthio)-propanal, and furfural,1-(1H-pyrrol-2-yl)-ethanone. These compounds constituted the basic flavor of the five dry yellow soybean sauces, while other flavor compounds were responsible for the unique part of their flavor.

Objective: To determine the chemical components in the volatile oil from rape flowers. Methods: The volatile oil in rape flowers was extracted by steam distillation method, and its chemical components were qualified and quantified by gas chromatography-mass spectrometry (GC-MS). Results: Totally 30 components were found, including 21 identified ones, accounting for 97.40% of total peak area. The major compounds were n-tetracontane (38.14%), n-tetratetracontane (30.24%), allyl isothiocyanate (10.94%), 3-butenyl isothiocyanate (9.56%), β-caryophyllene (1.02%), limonene (1.01%), and allyl thiocyanate (0.75%).

Objective: To determine the composition and contents of amino acids in the whole plant of Rumex dentatus for further study of its nutritional characteristics and food value. Methods: Amino acids were derivatized by 6-aminoquinolyl-N-hydroxysuccinimidyl-carbamate (AQC), and then their derivatives were separated on a Waters 515 HPLC system with a column temperature of 37 ℃ using phosphate buffer as mobile phase A and aqueous acetonitrile as mobile phase B in the gradient elution mode and detected at 248 nm using a UV detector. Results: Totally 17 amino acids were found, and the total content of amino acids in samples was 252.35 mg/g. The correlation coefficients of the calibration curves for 17 amino acids were all above 0.9995 (n = 5). The average spike recoveries of 17 amino acids were between 97.1% and 102.6% with a relative standard deviation (RSD) between 0.3% and 3.26% (n = 3).

Shimadzu 2010 gas chromatograph equipped with DB-WAX capillary column, 37 fatty acid standards and the equivalent chain length (ECL) method were used to identify the fatty acid composition and δ5-unsaturated fatty acids in Pinus armandii kernel. The results indicated that Pinus armandii kernel abundantly contained unsaturated fatty acid (92.83%), mainly linoleic acid (46.12%) and oleic acid (22.68%). Moreover, large amounts of δ5-unsaturated fatty acids were also contained, mainly pinolenic acid (16.11%). The ECL method was found to enable effective identification of δ5-unsaturated fatty acids in Pinus armandii kernel.

Objective: To investigate the prevalence and toxin genes profile of Staphylococcus aureus in infant milk powder and infant rice cereal marketed in Shaanxi province, China. Methods: Totally 367 various samples from 18 regions in Shaanxi province were tested by the national standard method to isolate Staphylococcus aureus; the nuc genes were examined to confirm Staphylococcus aureus status; Staphylococcus aureus enterotoxin genes, exfoliative toxins genes, toxic-shock syndrome toxin-1 gene and Panton-Valentine Leukocidin gene were detected by PCR. Results: Of 367 samples examined, 30 were positive for Staphylococcus aureus, result in a positive rate of 8.17% (30/367), including 11.19% (16/143) milk powder samples and 6.25% (14/224) rice cereal samples. From these positive samples, 29 and 25 strains were isolated from milk powder and rice cereal samples respectively. Among all identified Staphylococcus aureus isolates, 34 strains harbored at least one of the tested toxin genes. The toxins gene profiles detected in S. aureus from infant milk powder samples were pvl, sea, seb, sec, sed, seg, seb＋seg, sec＋seg and seb＋sed＋seg, and their positive rates were 44.82% (13/29), 10.34% (3/29), 13.79% (4/29), 17.24% (5/29), 6.89% (2/29), 41.38% (12/29), 10.34% (3/29), 10.34%(3/29) and 3.45% (1/29) respectively; The toxin gene profiles in S. aureus from infant rice cereal samples were pvl, sea, sec, sed, see, seg, sea＋seg, sec＋seg and sec＋see＋seg, and the positive rates were 36% (9/25), 4% (1/25), 20% (5/25), 4% (1/25), 12% (3/25), 36% (9/25), 4%(1/25), 16% (4/25) and 8% (2/25), respectively. Neither ets,tsst-1, seh, sei nor sej genes were detected in infant milk powder or infant rice cereal. Conclusion: Infant milk powder and infant rice cereal in Shaanxi province were contaminated with S. aureus, some of which contained various toxin genes. The existence of the pathogen in these food products may constitute a potential risk for infants, health.

Objective: To establish an HPLC method for simultaneous determination of five artificial pigments (lemon yellow, amaranth, carmine, sunset yellow and fancy red) in cooked meat products. Methods: Cooked meat products were defatted by petroleum ether, and extracted by ethanol/ammonia/water solution (7:2:1, V/V) with the assistance of ultrasound. The resultant extract was treated using a polyamide SPE cartridge. The pigments were separated on an Eclipse XDB-C18 column (5μm, 4.6 mm × 250 mm) by gradient elution with a mobile phases made up of 0.02 mol/L NH4Ac and methanol, and detected by a DAD detector at alterable wavelength. Results: The established method displayed good linearity with correlation coefficient between 0.9992 and 0.9999. The recoveries of the five pigments ranged between 89.6% and 96.4% with a relative standard deviation (RSD) between 1.24% and 4.11%.Conclusions: This method is sensitive, simple, rapid and accurate, and can be used for simultaneous determination of the five artificial pigments in cooked meat products.

In the current work, the aroma components of marketed navel oranges from five varieties such as Fengjie Newhal navel orange, Fengjie navel orange Fengyuan 72-1, Gannan Newhall navel orange, Changhong navel orange and Beibei Powell navel orange were investigated by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) combined with principal component analysis, and the feasibility of using aroma components for flavor evaluation of orange was explored. The orange varieties presented a large difference in their aroma components. The number of aroma components identified in them was 65, mainly monoterpenes, sesquiterpenes, aldehydes, ketones, alcohols and esters. The first and second principal components were explained as monoterpenes and oxided terpenoid derivatives, respectively. The difference of these aroma components resulted in the unique flavor characteristics of different orange varieties. Therefore, principal component analysis has the potential to be used for aroma quality evaluation of orange.

The volatile constituents of 4 kinds of aromatic rice marketed in Beijing were extracted by steam distillation and analyzed by gas chromatography-mass spectrometry (GC-MS). According to MS spectrum and retention index comparison, 51 compounds were identified, including 31 hydrocarbons, 6 esters, 5 nitrogen-containing compounds, 5 organic acids, 2 aldehydes, 1 acetal and 1 ether. Nineteen compounds shared by four rice were 2,3-dimethyl-2-butene, ethyl acetate, 3-methyl-2-pentene, methylcyclopentane, ethyl i-butyl ether, 2,3-dimethyl-1-pentene, benzene, 2-methylhexane, 2,3-dimethylpentane, 3-methylhexane, cyclohexene, trichloroethylene, hexanal, N,N-dimethylaniline, benzothiazole, tetradecanoic acid, n-hexadecanoic acid, linoleic acid and oleic acid. However, the characteristic compound of aromatic rice, 2-acetyl-1-pyrroline was not found in the extracts.

A polymerase chain reaction (PCR) assay for the detection of Pseudomonas fluorescens in foods was developed in this study. Six pairs of detection primers were designed for the 16－23S rDNA internal transcribed spacer sequence, the gyrB gene and 4 specific genes obtained by bioinformatics, respectively. Primary specificity experiments were used to screen the best primer pair out of them. A PCR amplification system targeting the gyrB gene was constructed and evaluated. The results indicated that the developed assay could specifically detect Pseudomonas fluorescens. The specificity was 14.9 fg/μL for pure DNA, 2.8 × 102 CFU/mL for pure culture and 0.28 CFU/ 25 g for soybean milk with 15 h enrichment.

The volatile components of 37 propoli samples from five provinces (Anhui, Jilin, Hebei, Henan and Gansu) in China were analyzed by headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). A total of 49 compounds were identified including alcohols, esters, aldehydes and terpenoids. The relative contents of the components were analyzed by principal component analysis (PCA). The results showed that propoli samples from different regions could be discriminated by this method. Gansu samples exhibited the largest difference from samples from other four provinces. However, samples from Hebei, Henan and Anhui could not be discriminated.

A high-performance liquid chromatography (HPLC) method was developed for the simultaneous analysis of 5 nitroimidazole multi-residues (metronidazole, dimetridazole, ornidazole, tinidazole and ronidazole) in tilapia muscle tissues. Samples were homogenized and extracted by added sodium chloride, monopotassium phosphate and ethyl acetate. Afterwards, the organic phase was recovered and condensed. Finally, the residue was dissolved in hydrochloric acid/ethyl acetate, defatted by liquid-liquid extraction with added n-hexane, cleaned up on an MCX column by elution with 2% ammonia/methanol, separated chromatographically using acetate buffer solution/acetonitrile (86:14, V/V) as the mobile phase and detected at 320 nm. The results revealed that the limits of detection for 5 nitroimidazoles were all 1.0 μg/kg. The average recoveries for metronidazole, dimetridazole, ornidazole, tinidazole and ronidazole at the spike level of 2.0 μg/kg were 73.3%%, 74.7%, 62.9%, 74.4% and 80.1%, respectively with a RSD of less than 10% (n = 3). This method is simple, sensitive, accurate, precise, and in line with the requirements the Ministry of Agriculture for veterinary drug residue analysis.

The volatile components of fennel bean were extracted by head space solid phase microextraction (HS-SPME) and analyzed by gas chromatography mass spectrometry (GC-MS). The optimum operating conditions for SPME were determined as following: head space adsorption at 55 ℃ for 60 min using a 75 μm Carboxen/PDMS fiber. A total of 38 compounds were identified, representing 86.87% of the total peak area and consisted of 15 hydrocarbons, 13 aldehydes and ketones, 3 alcohols, 3 phenols, 3 ethers and 4 other compounds. The prevailing compounds were 1-methoxy-4-(1-propenyl) benzene (40.75%), nonanal (4.16%), cis-anethole (3.77%), limonene (3.48%), and estragole (2.9%).

The pathogenic viable cells of Vibrio parahaemolyticus in seafood were detected using real-time polymerase chain reaction combined with ethidium bromide monoazide (EMA) dye. For pure culture, there was a negative correlation between the log number of cells and the associated Ct value in the range of 2.2 × 102 to 2.2 × 107 CFU, and the detection sensitivity of single RT-PCR (22 CFU) was slightly higher than that of EMA RT-PCR(2.2×102 CFU). For artificially contaminated oyster samples, similar results were obtained from EMA RT-PCR and plate count method, and slightly lower results from single RT-PCR. Without enrichment, only one positive sample was detected in forty-five seafood samples by EMA RT-PCR with a viable Vibrio parahaemolyticus cell of 114 CFU/g. In conclusion, EMA RT-PCR could provide a rapid, sensitive and accurate way for the quantitative detection of Vibrio parahaemolyticus in seafood.

The essential oil in fresh flowers of wild Chinese chive was extracted by solvent extraction/solvent-assisted flavor evaporation (SE/SAFE) and analyzed by gas chromatography-mass spectrometry (GC-MS) carried out on the non-polar capillary column RTX-5 and the polar capillary column DB-WAX, respectively based on retention index (RI). Totally 47 compounds were identified, including 28 sulfur-containing compounds, 4 aldehydes, 3 alcohols, 3 ketones and 9 hydrocarbons. The major volatiles of fresh flowers of wild Chinese chive were sulfur-containing compounds.

The aim of this study was to analyze the nutritional composition and evaluate the health efficacy of seed kernel essential oil from wild Prinsepia utilis Royle grown in Lijiang region, Yunnan province, China. The routine physicochemical properties, hygiene indexes, amino acid composition, fatty acid composition and mineral elements of the oil were assayed by the internationally recognized methods. The moisture and volatile matter content, refractive index, relative density, iodine value, saponification value, acid value and peroxide value of the oil, identified as a non-volatile oil, were 0.03%, 1.4716(n20), 0.9260(d2020), 45.91, 0.02%, 0.17 mg KOH/g and 1.20 mmol/g, respectively. The total content of 17 amino acids was 46.97%, including 7 essential amino acids (Ile, Leu, Lys, Met, Phe, Thr and Val) with a total content of 13.2%, accounting for 28.1% of total amino acids. The oil was rich in VA (3.257 mg/ 100 g), VD (1.745 mg/ 100 g), VE (8.736 mg/ 100 g) and β-carotene (1.234 mg/100 g). The content of K was the highest of 13 mineral elements tested, reaching 9.8 mg/kg. The content of unsaturated fatty acids was 78.35%, mainly oleic acid and linoleic acid with the same content of 38%. The proportion of saturated to monounsaturated to polysaturated fatty acids was 0.7:1:1, suggesting a well-balanced nutritional structure. Moreover, all indexes tested were in line with the national edible soybean oil standard GB/T 1535－2003 and the Codex-Stan 210. In light of these results, we conclude that seed kernel essential oil from wild Prinsepia utilis Royle grown in Lijiang region is a natural nutritional oil suitable for human consumption.

The composition of high-purity procyanidins purified by ADS-17 macroposours resin chromatography from sorghum episperm as a byproduct of sorghum processing was analyzed by electrospray ionization- mass spectroscopy (ESI-MS). Fraction SPC-5 separated from the procyanidins by Toyopearl HW-40 resin chromatography was identified by RP-HPLC-ESI-MS/MS. The high-purity procyanidins were found to be procyanidolic oligomers, including catechin/epicatechin monomers, dimmers, trimers, tetrames, pentamers and hexamers. SPC-5 consisted of 8 trimers and 1 dimmer.

The volatile components of China-Hemp leaves were analyzed by simultaneous distillation extraction (SDE) coupled to gas chromatography-mass spectrometry (GC-MS). The effect of extraction time on extraction efficiency using dichloromethane as the extraction solvent was examined. The results indicated an operating time of 4 h proved optimal for SDE. A total of 44 compounds were identified from China-Hemp leaves, accounting for 86.04%, including 7 ketones (4.67%), 2 hydroxybenzenes (6.13%), 4 aldehydes (3.88%), 8 alcohols (15.35%), 13 hydrocarbons (29.40%) and 8 other compounds (25.64%). The prevailing compounds were caryophyllene oxide (14.36%), caryophyllene (8.08%) and α-caryophyllene(7.05%).

Porphyra haitanensis is an important food resource containing abundant dietary fiber, protein, active substances and trace elements essential for the human body. P. haitanensis is always be harvested for several times during its life cycle. P. haitanensis at the sixth harvest is known as low-value P. haitanensis due to inferior sensory quality, poor palatability and low commercial value. Here, the main nutritional composition and polysaccharide composition of low-value P. haitanensis were analyzed by chemical methods and spectroscopic methods. Compared with high-yield P. haitanensis at the third harvest, low-value P. haitanensis showed a remarkable increase in the contents of crude protein (35.30%), crude fat (0.51%) and crude fiber (5.11%), a dramatic decrease in the contents of total sugar (34.57%) and polysaccharides (20.67%), a similar ash content (10.37%) and a K/Na ratio of 6.3. Hot-water polysaccharide extract from low-value P. haitanensis consisted of a single component with a 28.54 kD molecular weight, which was mainly constituted by galactose (83.12%), 3,6- anhydrogalactose (15.71%) and sulfate group (10.61%). In summary, the results obtained show that low-value P. haitanensis is a high-protein, high-natural dietary fiber, low-fat, low-calory nourishing healthcare food resource.

In this study, the moisture, protein, fat, soluble sugar, ash and VB2 of red glutinous rice planted in Changshu, Xuzhou, Dafeng, Huaian, Shanghai and Henan were determined. Meanwhile, the contents of mineral elements such as Na, Mn, Cu, Zn, Ca, Fe and Mg were assayed by flame atomic absorption spectroscopy, and the contents of 17 common amino acids were analyzed. The results showed that the contents of protein, fat, ash, VB2 and the mineral elements Mg (especially higher, a 1.33-fold increase), Zn, Mn, Fe and Cu of red glutinous rice samples investigated were all higher than those of common rice. The 6 essential amino acids VB2, Leu, Val, Met, Sys, Thr and Lys all exhibited a higher content in the red glutinous rice samples compared with Japonica rice.

A new spectrophotometric method for the determination of chlorine dioxide (ClO2) in tap water was developed based on methyl red (MR) oxidation and discoloration. Wavelength scanning showed that MR had maximal absorption at 518 nm. Under the experiment conditions of c(MR)/c(ClO2) = 6.4, pH 4.0－4.5, 25 ℃ and reaction time of 40 min, a linear equation was obtained as δA518 = －1.7845c(ClO2) +1.5228 (r = 0.992) in the range of 0.0004－0.80 mg/L, the apparent molar absorptivityε = 1.2 × 105 L/(mol ·cm), and the detection of limit 0.0036 mg/L. MR discoloration by ClO2 oxidation was a first-order reaction. The dynamic equation at 25 ℃ was ln[c∞/(c∞－c)] =－0.000689t ＋ 2.263669 with the activation energy Ea = 87.3 kJ/mol and the half-time t1/2 = 16.8 min. The average recoveries for ClO2 in tap water and ClO2 disinfectant were 98.2%－103.2% (n = 5) with a relative standard deviation of 2.43%－3.83%. This method and the recommended standard N,N-diethyl-p-phenylendiamin (DPD) method showed no significant difference (P = 0.05) according to F-test and t-test. Furthermore, satisfying determination results were obtained from this method.

The relationship between fruit quality and active oxygen species metabolism near the epidermis and core of nectarine during postharvest ripening and pathogensis caused by artificial infection with Monilinia fructicola was analyzed. The results indicated that membrane integrity and peroxidase (POD) activities declined, juice rate, lipoxygenase (LOX) activities and H2O2 content increased, while the activities of catalase (CAT), ascorbate peroxidase (APX) and polyphenol oxidase(PPO) increased firstly and then decreased during postharvest ripening and pathogenesis. Partial least squares regression (PLSR) results identified that membrane integrity was significantly negatively correlated with juice rate, H2O2 content or LOX activity but significantly positively correlated with POD activity or APX activity. Pathway coefficient analysis results showed that the activities of APX, POD, LOX and PPO had a negative effect on the content of H2O2, and the order of the effects was APX＞POD＞LOX.

Quality changes in Penaeus vannamei during 0 ℃ storage were studied. The results showed that the contents of total volatile basic nitrogen (TVB-N), sulfhydryl group and various proteins in whole shrimps and shelled shrimps exhibited different regular changes during 0 ℃ storage. TVB-N increased with the increase of storage time, and the increase was faster in whole shrimps. Sulfhydryl groups increased firstly and then decreased and always presented a higher content in whole shrimps compared with shelled shrimps at the same time points. Myofibrillar protein content distinctly decreased, but alkali-soluble protein content showed a substantial increase, and sarcoplasmic protein content little decreased. Therefore, nitrogen-containing materials can represent quality changes of Penaeus vannamei and has a great significance for in-depth study of the quality of Penaeus vannamei.

The effects of chives juice soaking under different conditions of soaking time, concentration and soaking way on major physiochemical and physiological parameters of banana during postharvest ripening, such as color, firmness, total soluble solid content, respiration and ethylene release, were probed. The results showed that chives juice could significantly delay the browning of banana peel, which was green-yellow in color on the 6th day, and improve the color saturation. Soaking 20% chives juice for 2 min every 24 h performed for 3 times resulted in a dramatic decrease in banana firmness when compared with the control. No significant difference in total soluble solid content was observed between the treatment group and the control. Ethylene release reached its maximum on the 3rd day and always revealed a higher level in the treatment group when compared with the control. In conclusion, soaking 20% chives juice for 2 min every 24 h performed for 3 times can provide a better way for preserving banana.

Newly harvested rapeseed samples were stored under different temperatures and regularly treated with different concentrations of ozone. Germination percentage, oil content and mold count of treated rapeseed samples were determined once every 10 days during the storage. The control without ozone treatment showed the most substantial reduction in germination percentage. Storage temperature and time as well as ozone concentration had highly significant effect on germination percentage of rapeseed (P ＜ 0.01), with significant interactions. Storage time had the most significant effect on oil content of rapeseed, followed by storage temperature and ozone concentration. All investigated ozone concentrations could effectively inhibit mold growth, especially at high storage temperatures.

Three edible composite coatings, named as M1, M2 and M3, were prepared using chitosan alone or together with cassava starch or corn starch as the coating carrier and acetic acid as the hydrophilous auxiliary agent, respectively, and used to soak mango fruits from cultivar Zihua before shelf-life storage at (20 ± 0.5)℃. The effects of the coatings and distilled water (the control) on the percentage of yellow fruits, yellowing index, the percentage of rotten fruits, respiratory intensity, firmness, weight loss rate, soluble solid content (SSC), VC content and polyphenol oxidase (PPO) activity of coated mango were explored. Coating treatment considerably inhibited the yellowing and rotting of mango, retarded the occurrence of respiration peaks, dramatically decreased the yellowing rate and softness and increased the firmness during the shelf-life. M3 maintained the texture better, effectively delayed the increase of SSC, and retained high VC level, although its inhibitory effect on PPO activity was not significantly different from that of other three treatments. This study indicates that chitosan coating treatment can significantly prevent quality deterioration of mango during the shelf-life, especially when compared with corn starch.

In this study, green-mature bananas were stored at (20 ± 1) ℃ and 85%－90% humidity for 21 days and at the same time exposed continuously to -100 or -200 kV/m high voltage electrostatic fields (HVEF). Respiration intensity, ethylene production, pericarp color, firmness, and the contents of chlorophyll, soluble sugar and starch of the fruits were investigated during the storage period. The results indicated that the occurrence of respiration peaks and ethylene production in banana fruits were accelerated by negative HVEF treatment; the conversion of starch to sugars was faster and began earlier, chlorophyll content was considerably decreased, and the reduction of fruit firmness was lower when compared with the control. Moreover, -200 kV/m HVEF treatment had more desired effect on quality characteristics of green-mature bananas than －100 kV/m HVEF treatment. This study demonstrates that continuous HVEF treatment can promote the postharvest ripening of green-mature bananas, in particular -200 kV/m HVEF treatment group, which ripened 4 days before the control.

Malu grapes were coated with distillated water and 0.1% lysozyme solution alone or mixed solutions containing different concentrations of sodium alginate and 0.1% lysozyme, respectively and then stored at (4 ± 1) ℃. The effects of alginate concentration on sensory quality, decay index, weight loss, hardness, respiration intensity, VC content, soluble solids content and SOD activity of Malu grapes were analyzed during the storage. Malu grapes treated with 1% sodium alginate-0.1% lysozyme showed the best sensory quality. After 25 days, the decay index, weight loss rate, VC content and soluble solids content were 0.17, 9.34%, 3.2 mg/100 g and 12.1%, respectively, and the respiration intensity was significantly lower than those of other treatment groups, suggesting the best fresh-keeping effect of 1% sodium alginate-0.1% lysozyme treatment.

In order to understand the effect of different dosages of ethanol fumigation on the decay, quality and antioxidant activity of Chinese bayberry cultivar Wumei, the fruit was fumigated by different dosages of ethanol at 20 ℃ for 3 h and then stored at 1 ℃ for 8 d. Ethanol fumigation at 500μL/L had the most significant inhibitory effect on decay rate and total aerobic count during the storage period, the loss of total soluble solids and titratable acidity was reduced, and high firmness and VC content was maintained. Moreover, the reduction of total phenolics and anthocyanins contents was distinctly inhibited, the biosynthesis of individual phenolic compounds such as quercetin-3-O-rutinoside and myricetin, as well as the major anthocyanin cyanidin-3-glucoside was induced, and the decrease of DPPH free radical scavenging capacity and reducing power was also inhibited, suggesting the maintenance of high antioxidant activity for Chinese bayberry. These results demonstrate that ethanol fumigation has a promising application prospect in the fresh-keeping of Chinese bayberry.

Freshly harvested Big Five-pointed Star loquat fruits were pre-cooled on the same day and then stored at 3 ℃ and 75%－85% humidity for 30 days. During the storage period, the loquat fruits were treated with ozone for 30 min once a week and sampled every 4 days for the determination for various physiochemical and physiological characteristics. Ozone treatment at the concentration of 100 mg/m3 had some fresh-keeping effect on Big Five-pointed Star loquat fruits. The best fresh-keeping effect was observed by using 150 mg/m3 ozone treatment. Ozone treatment could damage Big Five-pointed Star loquat fruits at the higher concentration of 200 mg/m3.

Cherry tomatoes (Solanum lycopersicum cv. Messina) were used to study the effects of exogenous methyl salicylate (MeSA) on chilling injury and endogenous polyamine level. The results indicated that compared with the control, MeSA treatment inhibited the occurrence of chilling injury in cherry tomato, decreased chilling injury index, decay incidence and electrolyte leakage. The accumulation of endogenous spermidine and spermine levels was significantly promoted in MeSA-treated fruits before cold storage and the levels of putrescine and spermine were increased during storage. These results indicate that the reduced chilling injury in cherry tomatoes after MeSA treatment may be due to an increase in polyamine level.

Fresh-cut apples were treated by high pressure (HP, 25 MPa) argon (Ar) and HP nitrogen (N2), respectively for 1 hour and then stored at 4 ℃ for 14 days. Changes in physiology and quality of the treated samples were determined during the storage period and were compared to those of the non-treated and HP air treated fresh-cut apples. The results showed that HP Ar and HP N2 treatments reduced respiration rate and ethylene production of fresh-cut apples during cold storage, delayed browning and total phenol degradation without influence on titratable acidity or soluble solid content, inhibited microorganism growth of fresh-cut apples, resulting in the fact that the population of psychrotrophs was less than 106 CFU/g and of molds and yeasts less than 104 CFU/g after 14 days of 4 ℃ storage. In conclusion, HP Ar and HP N2 treatments remarkably improve the overall quality of fresh-cut apples stored at 4 ℃ although HP operation has some negative effects on the texture and slightly decreases the firmness of fruits. Moreover, the fresh-keeping effect of HP Ar is better than that of HP N2 treatment.

In order to understand the effects of relative humidity on calcification and reactive oxygen species metabolism of Chinese chestnuts, the changes of moisture, calcification index, superoxide anion free radical (O2－ ·) production rate, H2O2 content, SOD and CAT activities, and the content of MDA (malondialdehyde) of Chinese chestnut stored under different levels of relative humidity such as 50%, 70% and 90% and room temperature (25 ℃) were determined. The results showed water loss and calcification index of Chinese chestnuts stored under high relative humidity (90%) were significantly decreased. Meanwhile, O2－ · production rate, H2O2 and MDA content were significantly lower, while SOD and CAT activities of chestnuts were significantly higher as compared with Chinese chestnuts stored under low relative humidity (50%). These findings reveal that high relative humidity (90%) efficiently inhibits the occurrence of calcification, maintains higher reactive oxygen species scavenging activity and decrease lipid peroxidation in Chinese chestnuts during postharvest storage.

Table grape (Vitis vinifera) “ZaNa” was used to investigate the effect of 0.5 or 1.0 μL/L 1-MCP treatment combined with controlled freezing-point temperature (－0.3℃ ± 0.3℃) storage on the postharvest quality and physiology indexes. The results showed that controlled freezing-point temperature storage combined with 1-MCP of both concentrations not only increased the good fruit rate, but also decreased the weight loss rate and stem browning index of grape. The combined treatment inhibited the increase of respiratory intensity and ethylene generation rate of grape cluster and MDA, O2－ ·and H2O2 contents, and LOX activity in grape fruit, and maintained or increased SOD and POD activities of grape fruit. Controlled freezing-point temperature storage combined with 1.0μL/L 1-MCP treatment prolonged the storage life by 20 days compared to general cold storage. In conclusion, proper 1-MCP treatment in combination with controlled freezing-point temperature storage can increase storage postharvest fruit quality and resistance to deterioration and delay fruit senescence.

Post-harvest quality and reactive oxygen species (ROS) metabolism-related enzyme activities were analyzed in postharvest leeks after exposure to a level of 1.7 kJ/m2 UV-C (ultraviolet C) irradiation. This dose of UV-C irradiation significantly inhibited xanthochromia and rotting rate, and slowed the decline of chlorophyll in leeks, with only 19.47% of chlorophyll degraded in multiple UV-C irradiated leeks 8 days after treatment compared with 30.53% in the control. The losses of protein, total phenols and other nutrients were also reduced by the UV-C treatment. The activities of CAT, POD and SOD were higher in UV-C treated leeks than the control. In conclusion, the data obtained suggest that UV-C irradiation is a potential strategy to improve post-harvest quality of stored leeks.

The adsorption and preservative effects of potato microporous starch on high VC Cili pear gravy were investigated by using response surface methodology. The optimal process parameters for the adsorption of Cili pear gravy by potato microporous starch determined in terms of saturated adsorption quantity of VC were triple repeated adsorptions at 39.5 ℃ and a microporous starch/pear gravy ratio of 1:3.6 for 40.2 min each time. Under the optimal conditions, the saturated adsorption quantity of VC was 69.1 mg/g. The optimal drying method for potato microporous starch saturated with adsorbed Cili pear gravy was vacuum freeze drying, and the optimal preservation method vacuum storage in the form of tablets. VC loss (43.70%) on the surface of microporous starch granules was large in the first 9 days, and then VC degradation became slow. The content of VC was 38.8 mg/g after 30 days, exhibiting a loss rate of only 0.43%.

In order to effectively inhibit enzymatic browning in Agaricus bisporus, effects of pH values, temperature, substrate concentration and inhibitors on polyphenol oxidase (PPO) activity from Agaricus bisporus were studied. The results showed that the optimum pH value and temperature for PPO activity from Agaricus bisporus were 6.8 and 15－20℃ using pyrocatechol as substrate. The Michaelis constant of PPO was Km = 0.1072 mol/L. Computational imaging analysis showed that mixture of 0.30 mmol/L sodium sulfite, 0.06% ascorbic acid and 0.05% acetic acid had effective inhibition on enzymatic browning in Agaricus bisporus.

The changes of sensory quality, acid value, peroxide value of crisp peach cookies made using palm oil blend or lard were compared during storage at the same conditions, in order to judge the substitutability of palm oil for lard. It was shown that crisp peach cookies made using palm oil blend exhibited not only the same good sensory quality as ones made using lard, but also better oxidation stability than ones made using lard. This study suggests that palm oil-based shortening can provide a promising substitute for lard in crisp peach cookies.

An indirect enzyme-linked immunosorbent assay (IELISA) was proposed to detect specific antibodies in tartary buckwheat allergenic patients, sera using polystyrene micro-well plate coated with natural tartary buckwheat allergenic proteins and horseradish peroxidase (HRP)-labeled mouse anti-human IgE. Key operations and reaction conditions were optimized. The results showed that the optimal coating antigen concentration, positive serum dilution, HRP-labeled mouse anti-human IgE concentration, blocking time at 37 ℃, reaction time between coating antigen and antibodies in positive sera, and reaction time between positive sera and HRP-labeled mouse anti-human IgE were 100 μg/mL, 1:50, 1:1000, 40 min, 40 min and 40 min, respectively. This method proved highly specific, repeatable and sensitive.

Concentrated peanut protein was extracted from defatted peanut protein powder using aquatic ethanol and then hydrolyzed by bromelain. The hydrolysate obtained, glutamine transaminase (TGase) and wheat flour were used to manufacture noodles. The orthogonal array design method was applied to optimize the formulation of noodles based on sensory evaluation. Noodles based on 8% hydrolyzed peanut protein and 900 U/kg TGase revealed the best quality. The presence of hydrolyzed peanut protein could effectively improve noodle quality and nutritional value.

In this study, NaOH and trypsin were used to hydrolyze cold pressed peanut cake as a byproduct of the cold pressed extraction of peanut oil to obtain peanut protein. Orthogonal array design was employed to optimize the hydrolysis conditions of cold pressed peanut cake for maximum extraction efficiency of protein. The optimal NaOH treatment conditions were pH 9.0, 1:8 material/liquid ratio (g/mL), 8 ℃ extraction temperature, and 2 h extraction time, resulting in an extraction efficiency of 80.68%. The optimal trypsin treatment conditions were 1:50 enzyme/substrate ratio (m/m), 5 g/100 mL substrate concentration, pH 9.0 and 50 ℃ hydrolysis temperature, and the resulting extraction efficiency of protein 96.26%. The optimal conditions for fermentation of hydrolyzed peanut protein obtained using trypsin and desalted whey powder by direct vat set (DVS) lactic-acid bacteria starter for peanut polypeptide beverage with the best taste were hydrolyzed peanut protein amount 2 g/100 mL, desalted whey powder 1 g/100 mL, innoculum amount 1:25 (g/kg), fermentation at 42 ℃ for 5 h, post-aging for at 4 ℃ for 15 h and amount of sucrose addition in fermentation products 9%.