Objective: To optimize conditions for the preparation of propolis derived flavonoid (PF) liposome. Methods: PF liposomes were prepared by ethanol injection method. One-factor-at-a-time design was used to investigate the effects of five process parameters on encapsulation efficiency. Three main process parameters that influence encapsulation efficiency including lecithin/PF mass ratio, lecithin/cholesterol mass ratio and injection speed were optimized by response surface analysis based on a three-variable, three-level Box-Behnken experimental design. Results: The optimal conditions for preparing PF liposomes were determined as 9.6:1 of lecithin/PF mass ratio, 8.5:1 of lecithin/cholesterol mass ratio and 0.8 mL/min of injection speed. Conclusion: Under these conditions, the actual encapsulation efficiency of PF liposomes was 91.67%, which showed a relative error of 0.086% when compared with the predictive value.

The key stages in the production process that influence the quality of kudzu root slice tea were identified and optimized by one-factor-at-a-time and orthogonal array design method. The results showed that sugar dipping and baking were key to producing kudzu root slice tea. The kudzu root slice tea produced by dipping in 4.0% honey constantly at 65 ℃ for 35 min and then baking at 130 ℃ for 36 min showed the best quality.

The effects of amounts of added glutamine transaminase (TG) and trehalose and raw material water content on texture and sensory properties of pork jerky were explored in the present study. The three process parameters were optimized by response surface methodology for improved hardness, springiness and overall sensory quality score. The results showed that the optimal process conditions for production of pork jerky were as follows: TG and trehalose were added at 3.9 g/kg and 182 g/kg, respectively; the water content of raw pork material was 195 g/kg. Under these conditions, the predicted and actual overall sensory quality scores of pork jerky were 0.989 and 0.981, respectively, suggesting a good agreement with each other. As a result, the proposed mathematical model is valid in predicting the overall sensory quality of pork jerky.

The objective of this study was to optimize the preparation of tea polyphenol liposomes using response surface methodology (RSM). Using one-factor-at-a-time design, four process conditions including tea polyphenol/phosphatidylcholine (TP/PC) mass ratio, cholesterol/phosphatidylcholine (CH/PC) mass ratio, VE/phosphatidylcholine (VE/PC) mass ratio and ethanol volume were identified as main variables that influence encapsulation efficiency. The four process conditions were optimized by response surface analysis based on a four-variable, three-level Box-Behnken experimental design. The results showed that the optimal TP/PC, CH/PC and VE/PC mass ratio were 81:300, 58:300 and 16.7:300, respectively and that 4.5 mL of ethanol was needed. Under these conditions, the encapsulation efficiency of TP liposomes was 78.10%. The TP liposomes obtained showed uniform morphology and irregular oval shape and were distributed in the range of 400－1000 nm.

Reaction conditions for the synthesis of β-Ionol-β-D-glucoside by Koenigs-Knorr method were optimized in this study. The resulting products were characterized and analyzed by thermogravimetry (TG) and pyrolysis-GC/MS. The results indicated that the appropriate conditions for this glucosidation reaction were as follows: 1% freshly prepared SiO2 was added to catalyze a reaction between Br-glucose and β-ionol at a ratio of 1.5:1 in toluene allowed to proceed for 6 h at reflux temperature. FT-IR, ESI-MS and 1H-NMR analyses demonstrated that the products obtained were target products. The glucoside bonds in β-ionol-tetra-O-actyl-β-D-glucoside were broken at around 160 ℃. β-Ionol-tetra-O-actyl-β-D-glucoside and β-ionol-β-D-glucoside and β-ionol-β-D-glucoside could be pyrolyzed into several aromatic compounds such as megastigmatriene, β-ionol, β-ionone, dihydroactinidiolide, dihydroisophorone, isophorone, and 3-oxo-β-ionol. The synthesized β-ionol-β-D-glucoside was stable to heat and could be pyrolyzed into aromatic compounds upon heat, thus holding great promise for applications in the food, tobacco and medicinal industries.

Dual-enzymatic hydrolysis of Sloanea hemsleyana seeds with cellulase and papain was the best way for protein extraction as demonstrated by a comparison of the hydrolysis efficiencies of 6 different enzymes on Sloanea hemsleyana seeds. The effects of simultaneous or stepwise hydrolysis, cellulase/papain ratio, solid/solvent ratio, total enzyme dosage, temperature, hydrolysis time and pH on protein yield were investigated using one-factor-at-a-time design. Further, total enzyme dosage, temperature, hydrolysis time and pH were optimized using quadratic regression universal rotary combination design. The optimal hydrolysis conditions for protein extraction from Sloanea hemsleyana seeds were determined as follows: Sloanea hemsleyana seed meal was suspended in deionized water at a solid/liquid ratio of 1:25, and added simultaneously with cellulase and papain at a ratio of 6:4 until a total enzyme dose of 370 U/g for hydrolysis at pH 7.6, 57 ℃ for 80 min. Under these conditions, the extraction yield of protein from Sloanea hemsleyana seeds was 74.91%.

The extraction of polysaccharides from Schisandra chinensis (Turcz.) Baill leaves (PSL) was optimized using one-factor-at-a-time and orthogonal array design method. Meanwhile, the inhibitory activities of PSL against Staphylococcus aureus, Escherichia coli and Bacillus subtilis were investigated. The results showed that the optimal conditions for PSL extraction were determined as two extraction cycles with distilled water at a solid/solvent ratio of 1:45 (g/mL) at 90 ℃ for 1 h. Under these conditions, the extraction yield of PSL was 9.08%. The PSL obtained could not be effectively deproteinized by Sevag method according to UV spectroscopic analysis and its color was darkened. Meanwhile, IR spectroscopic analysis demonstrated that this PSL possessed common spectral characteristics of polysaccharides and peptide bonds, suggesting that it might be formed by conjugation of polysaccharides with proteins or polypeptides through peptide bonds. Furthermore, the polysaccharide extract possessed inhibitory activities against three bacterial strains under investigation. 

In order to develop a method for the separation of quercetin from ethanol extract from Fructus Forsythiae, the effects of precipitant dose, temperature and stirring time on quercetin yield were explored. The final product was analyzed by HPLC using quercetin standard. The results showed that the adding 0.60 g of sodium carbonate and 1.00 g of zinc acetate and stirring for 40 min provided a quercetin yield of 4.20% from the 60% ethanol extract from 4.00 g of Fructus Forsythiae. The resulting precipitate showed an HPLC profile similar to that of quercetin standard.

The purpose of this study was to optimize the extraction of superoxide dismutase (SOD) from sheep blood by thermal denaturation coupled with CuSO4. Main process conditions that influence SOD specific activity were optimized using one-factor-at-a-time and orthogonal array design. The results showed that thermal denaturation at 65 ℃ for 15 min in the presence of 2.5% CuSO4 in 10 mmol/L aqueous solution and subsequent addition of a 1.25-fold excess of acetone resulted in an SOD specific activity of 2338.9 U/mg. This method was simple, low cost and suitable for industrialized production.

The microwave-assisted extraction of polysaccharides from Panincum miliaceum L. (PPM) was optimized by response surface methodology. One-factor-at-a-time method was used to preliminarily evaluate the effects of microwave treatment time, microwave power and solid/solvent ratio on polysaccharide yield. To investigate their combined effects on the response function, the parameters were used as response variables in a Box-Behnken experimental design and for response surface analysis. The optimal conditions for the extraction of PPM were determined as microwave treatment for 2.7 min at 640 W and 35:1 (mL/g) of solvent/solid ratio. Under these conditions, the actual polysaccharide yield was 9.04%, which showed a relative error of 1.42% compared with the predicted value (9.17%).

This study aimed to comparatively analyze physiochemical properties, fatty acid composition, VE content and oxidative stability of Carya cathayensis Sarg. oils extracted by cold pressing, supercritical carbon dioxide extraction and organic solvent extraction. They showed considerable variations in acid value, peroxide value, moisture and volatile contents and color but only slight variations in characteristic indices such as iodine value, saponification value, refractive index, relative density were observed. Moreover, these samples had nearly identical fatty acid composition; unsaturated fatty acids were predominant and revealed the highest relative content in the seed oil obtained by supercritical carbon dioxide extraction. The seed oil obtained by organic solvent extraction revealed the highest total VE content, among which, α-vitamin E was predominant. In addition, the seed oils obtained by different extraction techniques exhibited a significant variation in their oxidative stability and the one obtained by organic solvent extraction had the best oxidative stability. In conclusion, cold pressing is the most suitable extraction technique for the extraction of Carya cathayensis Sarg. oil.

This study was undertaken to investigate the sterilization of retort pouches containing staple foods. Variations in central temperature and F value were analyzed under various conditions of sterilization temperature and time. The optimal sterilization process was double peak high temperature sterilization at 80 ℃ for 5 min, 110 ℃ for 5 min, 121 ℃ for 12 min and 125 ℃ for 30 s + 30 s with a peak base temperature of 113 ℃. Under these conditions, the sterilization intensity of retort pouches was attenuated effectively. Moreover, the distillation odor caused by high-temperature sterilization was reduced greatly, and the shelf life was markedly extended. As a result, the quality of staple foods could be obviously improved.

Objective: To optimize the synthesis of Helianthus annuuss polysaccharide-Fe (Ⅲ) complex. Methods: The effects of reaction temperature, pH, reaction time and polysaccharide-trisodium citrate ratio on the yield and Fe content of polysaccharide-Fe (Ⅲ) complex were investigated using one-factor-at-a-time method and an L9(34) orthogonal array design. Results: The optimal synthesis conditions were determined as 3:1 of polysaccharide/trisodium citrate mass ratio and pH 9 for a reaction duration of 3 h at 80 ℃. Under these conditions, the yield of Helianthus annuuss polysaccharide-Fe (Ⅲ) complex was 1.26 g/g. and its Fe content 22.82%. Conclusion: This optimal synthesis process is simple, reliable and suitable for industrial production.

In order to obtain monoglyceride (MAG) with high purity for the synthesis of MLM-type structure lipid, immobilized lipase TL IM from Thermomyces lanuginose was used to catalyze the synthesis of MAG by alcoholysis of rapeseed oil and anhydrous ethanol. The optimal alcoholysis conditions were determined by one-factor-at-a-time and orthogonal array design as follows: rapeseed oil/anhydrous ethanol molar ratio of 1:5, lipase dosage of 7% (m/m, on the basis of the weight of substrates), reaction temperature of 35 ℃ and reaction time of 18 h, resulting in an MAG content of 38.82% in the final products. The purity of the MAG obtained could be increased to 90.76% by a three-stage molecular distillation process.

The fatty acid composition of tea seed oils obtained by organic solvent extraction and supercritical carbon dioxide extraction was analyzed by GC-MS and their main physiochemical properties were measured. After dry-heat treatment at 100 ℃ for different hours, the changes in acid value and peroxide value were also determined. The tea seed oil obtained by supercritical carbon dioxide extraction had higher iodine value and lower peroxide value and acid compared to the tea seed oil obtained by organic solvent extraction. Moreover, the former showed higher unsaturated fatty acid content. However, both tea seed oils exhibited a good antioxidant capacity.

NKA-2 macoporous adsorption resin was the best resin for the separation and purification of crude tannin extract from Galla chinensis as demonstrated by a comparison of the effectiveness of 8 types of macoporous adsorption resin in static adsorption and desorption of tannin. One-factor-at-a-time and orthogonal array design were used to optimize dynamic adsorption and desorption parameters for the purification of the crude tannin extract. The optimal process parameters for maximum tannin yield were determined as follows: 6 BV of 5 mg/mL sample was loaded onto the column at a flow rate of 1 BV/h and after complete adsorption, the column was then eluted with 4 BV of 80% ethanol solution at a flow rate 1 BV/h, yielding a tannin yield of 85.37% and a tannin purity of 62.99%. However, the optimal process parameters for maximum tannin purity were determined as follows: 5 BV of 6 mg/mL sample was loaded onto the column at a flow rate of 2 BV/h and after complete adsorption, the column was then eluted with 4 BV of 80% ethanol solution at a flow rate 3 BV/h, yielding a tannin yield of 76.97% and a tannin purity of 67.78%.

In order to evaluate the separate and joint effects of hot air drying and microwave drying on the rehydration ratio, VC retention and color parameters of spinach, fresh spinach was dried under different hot air temperatures, different microwave powers or their combinations. The results showed that the optimal drying process involved hot air drying at 50 ℃ for a water content of 60% at the transition point and subsequent microwave drying at 540 W. Under these conditions, the drying time was shortened by 40%－50% than that required for hot air drying. Moreover, VC retention was increased by 39.1%－44.3% and total viable count was decreased to 3.59－4.51 (lg(CFU/g)). The resulting product had a water content of 8% (calculated on wet basis). These findings suggest that combined hot air drying and microwave drying can maintain the quality of spinach well and reduce the total viable count to meet the safe range.

Response surface methodology (RSM) was used to optimize the aqueous extraction of camellia seed oil. Quality characteristics of the resultant product were analyzed. The optimum conditions for the extraction of camellia seed oil were determined as follows: camellia seed kernels were dried at 150 ℃, crushed, and added with hot water at a solvent/solid ratio of 3.8:1 (mL/g) for oil extraction at 80.2 ℃, natural pH for 3.4 h. Under these conditions, an oil yield of 69.1% was obtained. All tested physiochemical indexes of the oil obtained met the national standards for grade 2 camellia seed oil. Therefore, aqueous extraction is applicable for the extraction of camellia seed oil.

This study aimed to investigate process conditions for the isolation of casein glycomacropeptide (CGMP) from whey powder by chitosan adsorption. The effects of final pH, final chitosan concentration and adsorption time as well as NaCl concentration and pH for CGMP elution on the efficacy of chitosan for isolating CGMP were explored. The optimum conditions for the isolation of CGMP were determined as follows: chitosan was added to a final concentration of 2 g/L and the pH was adjusted to 4.6 for adsorption of CGMP by chitosan for 60 min; the adsorbed CGMP was then eluted using 2 mol/L NaCl solution alkalified to pH 9; finally the resultant eluate was pooled, desalinate by means of ultrafiltration, concentrated and lyophilized. As a result, CGMP powder was obtained. The results of scale-up experiments showed that the recovery rates of CGMP and sialic acid were 83.3% and 70.64%, respectively and that the CGMP obtained contained 10 mg of sialic acid per gram of sample. This CGMP was composed of a multimer with respective molecular weights of 22 ku and 30 ku as demonstrated by gel electrophoresis analysis.

Based on the concept of clean production and comprehensive resource utilization, a new procedure for the extraction of diosgenin from Dioscorea zingiberensis C. H. Wright rhizomes was proposed. This procedure involved four stages, recovery of starch and cellulose from the raw material, one-step multi-enzymatic hydrolysis, microwave-assisted acidolysis and diosgenin extraction. First, most of the starch and cellulose in Dioscorea zingiberensis C. H. Wright rhizomes were extracted physically. In this process, ultrasonication was introduced to save water. Second, the residual starch and cellulose were further hydrolyzed with added thermostable α-amylase and glucoamylase. Third, diosgenin was released by acidolysis. In this process, microwave heating was used to save acid and shorten the acidolysis time. Finally, a small quantity of solvent was used to extract diosgenin and the extract was refined by re-crystallization. Compared with the traditional single acidolysis procedure, this clean production procedure could save acid by 96.97% and result in an increase in diosgenin yield of 34.56%.

To find optimal conditions for the ultrasonic-assisted extraction from polysaccharides from boat-fruited sterculia seeds, ultrasonic power and extraction time and solid/solvent ratio were used as independent variables and polysaccharide yield was used as response function in a three-variable, three-level regression analysis. The optimum conditions for the extraction of polysaccharides were 210 W, 28 min and 1:63 (g/mL). Under these conditions, the yield and purity of crude extract were 28.45% and 60.02%, respectively. This ultrasonic-assisted extraction procedure was stable and applicable for the extraction of polysaccharides from boat-fruited sterculia seeds. Compared with microwave-assisted extraction, this procedure required shorter time, saved water and provided increased crude extract yield and content. 

The extraction of proanthocyanidins from Caryota mitis fruits was optimized by orthogonal array design. The raw material was freeze-dried, comminuted, sieved through an 80-mesh sieve and extracted by solvent extraction technique. The resultant extract was determined by butanol-HCl method for absorbance at 546 nm. The optimum conditions for the extraction of proanthocyanidins were determined as two extraction cycles with 60% ethanol aqueous solution alkalified to pH 9 at a solid/solvent ratio of 1:15 (g/mL) for 2.5 h at 50 ℃. Under these conditions, the extraction rate of proanthocyanidins was 95.18%. In the fifth repeated extraction, the extraction rate of proanthocyanidins was 6.59%. This study demonstrates that Caryota mitis fruits are rich in proanthocyanidins and therefore has great development potential.

The extraction of total flavonoids from stems and leaves of Scutellaria baicalensis Georgi by ethanol extraction was optimized using an L9(34) orthogonal array design. One-factor-at-a-time method was used to investigate the effects of temperature, extraction time, ethanol concentration and solid/solvent ratio on extraction efficiency. The optimum conditions for the extraction of total flavonoids were determined as three extraction cycles with 70% ethanol at a solid/solvent ratio of 1:18 (g/mL), 70 ℃ for 2.0 h each. Under these conditions, the yield and purity of crude total flavonoid extract were 21.02% and 1.39%, respectively.

Response surface methodology was employed to optimize the extraction of proteins from Porphyra yezoensis. The extraction efficiency of proteins was investigated with respect to ultrasonic treatment time, temperature and solid/solvent ratio. The optimum conditions for the extraction of proteins from Porphyra yezoensis were determined as 10 min, 50 ℃ and 10:1 (mg/mL). Under these conditions, the actual extraction efficiency of proteins was 37.6%. The resulting extract was separated by Superdex 200 column chromatography into four fractions and their molecular weights were measured. A pooled sample of fractions 1, 2 and 3, all of which were proteins with a molecular weight larger than 10 ku and obvious free scavenging activity, was analyzed by SDS-PAGE and evaluated for scavenging activities against hydroxyl and DPPH free radicals. The molecular weights of fractions 1, 2 and 3 were 55, 22 ku and 17 ku as measured by SDS-PAGE. Pooled fractions 1, 2 and 3 possessed a marked free radical scavenging activity in a dose-dependent manner. The IC50 values against hydroxyl and DPPH free radicals were 1.481 mg/mL and 0.452 mg/mL, respectively.

In order to obtain optimal conditions for drying Sparassia crispa fruit bodies, four drying methods including low-temperature drying, microwave drying, freeze-vacuum drying and high-temperature drying were individually used to dry Sparassia crispa fruit bodies for understanding of the effects of drying method, temperature and time on the retention of polysaccharides and the removal of water from Sparassia crispa fruit bodies By using orthogonal array design, the optimal low-temperature drying conditions were determined as drying constantly at 50 ℃ for 1.5 h, and the contents of poysaccharides and water in the dried Sparassia crispa fruit bodies were respectively 6.18% and 9.5%; the optimal microwave drying conditions were determined as treatment at medium fire power for 6 min, and the contents of poysaccharides and water in the dried Sparassia crispa fruit bodies were respectively 3.78% and 8.5%. The polysaccharide content of the dried Sparassia crispa fruit bodies obtained by freeze-vacuum drying was as high as 34.80% and the water content was as low as 2.66%. The Sparassia crispa fruit bodies dried at 100 ℃ for 30 min contained 6.05% polysaccharides and 9.2% water. These data demonstrate that freeze-vacuum drying result in the highest retention rate of polysaccharides and the highest removal rate of water from Sparassia crispa fruit bodies.

The purpose of this study is to optimize operating conditions for ultrasonic-assisted extraction of nobiletin from sweet orange residues by response surface methodology. One-factor-at-a-time designs were used to examine the effects of four extraction parameters including ultrasonic power, ultrasonic treatment time, temperature and solid-to-solvent ratio on nobiletin yield. Further a mathematical model for nobiletin yield as a function of the extraction parameters was constructed by regression analysis based on a Box-Behnken design. The mathematical model was statistically significant and its determination coefficient (R2) was 0.9319. Moreover, the linear and quadratic terms had significant effects on nobiletin yield. Optimal extraction conditions were obtained by the use of absolute ethanol at a solid-to-solvent ratio of 1:20 g/mL and ultrasonic treatment for 45 min at 120 W. Under the optimal conditions, the experimental nobiletin yield was 209 μg/g and in good agreement with the predicted value (204 μg/g).

Response surface methodology was employed to optimize conditions for the extraction of polysaccharides from the stems and leaves of wild Gypsophila oldhamiana  Miq. On the basis of single-factor experiments, temperature, time and  solvent-to-solid ratio were selected out of four extraction conditions for a three-level Box-Behnken experimental design. Results showed that optimal extraction conditions were obtained using two extraction cycles at 97 ℃ with distilled water at a solvent-to-solid ratio of 30.5:1 (mL/g) for 3.5 h. Under these conditions, the predicted and experimental extraction yields of polysaccharides were 2.226% and 2.219%, respectively.

Ethyl furoate was synthesized by using HCl to catalyze the reaction between furoic acid and ethanol under microwave irradiation conditions. Using one-factor-at-a-time designs, microwave power, irradiation time and catalyst dose were identified as main variables that influence ethyl furoate yield. These variables were optimized by Box-Behnken experimental design in combination with response surface analysis. The optimal synthesis conditions for ethyl furoate were determined as addition of 1 mL of HCl solution and microwave irradiation at 360 W for 12 min. Under these conditions, the actual reaction yield of ethyl furoate was 83.8%, which was close to the predicted value of 83.7679% with an absolute error of 0.0321%.

Response surface methodology was used to optimize the extraction of crude polysaccharides from Suaeda salsa L. Three extraction parameters including temperature, time and solvent-to-solid ratio were identified as main factors affecting the extraction yield of crude polysaccharides. The extraction parameters were optimized by a three-variable, three-level Box-Bohnken experimental design combined with response surface analysis. The optimal conditions for polysaccharide extraction from Suaeda salsa L. were 3.5 h extraction with hot water (87 ℃) at a solvent/solid ratio of 31.5 mL/g, resulting in an extraction yield of polysaccharides of 2.028%. As demonstrated by comparison with VC and TBHQ, crude polysaccharides from S. salsa L. had excellent reducing power and high abilities to scavenge superoxide anion and hydroxyl free radicals with IC50 values of 0.84 mg/mL and 0.71 mg/mL, respectively. The antioxidant effect of crude polysaccharides from S. salsa L. was lower than that of VC but similar to that of TBHQ.

Objective: A suspension array assay was established for the detection of gentamicin residues and compared with regular enzyme-linked immunosorbent assay (ELISA). Methods: Monoclonal antibody against gentamicin was covalently coupled with polystyrene microspheres with carboxyl groups on their surface by amido bonds to form detection probes. The phycoerythrin (PE)-labeled gentamicin obtained by carbodiimide (EDC) method was allowed to couple with anti-gentamicin monoclonal antibody in an aqueous phase by direct competition method. Then based on the fluorescence signal of the resulting products, a competitive curve for gentamicin was obtained. Meanwhile, a direct ELISA curve for gentamicin was established. Both assays were compared with each other to find variations in detection limit, linear range and spike recovery rate. Results: The IC10 and IC50 of suspension array assay were 0.1 ng/m and 2.8 ng/mL, respectively, and its linear range was 0.1–100 ng/mL; in contrast, the IC10 and IC50 of ELISA assay were 0.27 ng/mL and 1.95 ng/mL, respectively, and its linear range. Each of the assays showed a spike recovery rate varying from 80% to 120% for gentamicin in milk, chicken meat, chicken liver, pork and porcine liver. In addition, suspension array assay had no cross-reactivity with other aminoglycosides, showing a good specificity. Conclusions: Suspension array assay is simple, sensitive and specific and superior to the conventional ELISA assay. As a result, suspension array assay can provide a new technique for the detection of pesticides and veterinary residues.

Near infrared spectroscopy and chemometrics were combined for discriminating non-fermented tea, semi-fermented tea and fermented tea. The original spectra were de-noised by different spectral pretreatment methods, and then principal components extraction from the de-noised spectra was performed for discrimination analysis. Results showed that the best spectral pretreatment method for classification was standard normal transformation coupled with detrended transformation. The original and cross validation correct classification rates were 100% and 94.4%, respectively. In addition, analysis of the contribution rate of near infrared absorption of bonds in different components of tea to the classification demonstrated that the combined stretching vibration of C=O and methyl C－H bands, the stretching vibration of C－H, and the second overtone vibration of C=O band stretch in amino acids or protein played a very key role in the classification of tea.

A capillary electrochromatographic method for the separation and analysis of organic acids in food was proposed using a capillary silica monolithic column. Optimization of experimental parameters that influence separation efficiency was carried out. A capillary silica monolithic C18 column was prepared in our lab for the separation of organic acids using a mobile phase (pH 5.2) consisting of 150 mmol/L sodium dihydrogen phosphate-60 mmol/L borax buffer solution with a final concentration of 5:2 in the mixture and 0.5 mmol/L cetyl trimethyl ammonium bromide. Other experimental conditions were as follows: voltage －6 kV; injection time 10 s; column temperature 25 ℃; and detection wavelength 200 nm. Results showed that the linear range was 10–1000 μg/mL for oxalic acid and fumaric acid, 20–500 μg/mL for succinic acid, 15–1000 μg/mL for tartaric acid and citric acid. The average recovery rates for the organic acids were between 89.8% and 101.1%, with a relative standard deviation (RSD) less than or equal to 6.23% (n = 5). The detection limits of the proposed methods were between 3.0 and 7.5 μg/mL. In conclusion, capillary silica monolithic column is inexpensive, stable to heat and organic solvents, and repeatedly usable. Capillary electrochromatography with capillary silica monolithic column allows simple, rapid and effective separation and analysis of organic acids in food.

Ten batches of raspberry wine from Kashgar and five kinds of counterfeits were analyzed by infrared spectroscopy. The primary absorption peaks in the infrared spectral fingerprints were identified and similarity and cluster analysis were then carried out to find whether the infrared spectral fingerprints of raspberry wine and counterfeits are similar to one another. The results showed that the ten batches of raspberry wine from Kashgar had good similarity. Raspberry wine could be effectively discriminated from counterfeits by similarity and cluster analysis. A good correlation was observed between both chemical measurement methods. As a result, it can be concluded that the developed method is valid method for quality evaluation of raspberry wine.

Solid-phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS) and internal standard method for semi-quantification were used to study the effects of pasteurization and microwave sterilization on aromatic components of seedless ‘Xuegan’ sweet orange juice. The results showed 56, 57 and 53 aromatic compounds were respectively identified from native sweet orange juice, pasteurized sweet orange juice and microwave sterilized sweet orange juice, with respective contents of 1.30, 0.99 mg/g and 0.89 mg/g. Although pasteurized sweet orange juice was richer in total aromatic compounds than microwave sterilized sweet orange, microwave sterilized sweet orange contained more cis-3-hexenol, dodecanal and γ-selinene than pasteurized sweet orange juice but no β-terpineol, responsible for off-odor. Pasteurization and microwave sterilization resulted in a decrease in the total content of esters and hydrocarbons and an increase in ketones.

Clenbuterol is known to be able to inhibit the chemiluminescence generated from the oxidation of luminal by ferricyanatum kalium under alkaline conditions. Based on this principle, an analytical method was developed for the determination of clenbuterol in pork using solid phase extraction and flow injection chemiluminescence. Clenbuterol residue present in pork was extracted into ethyl acetate and cleaned up using a solid-phase extraction cartridge before analysis. The results indicated that the developed method was rapid and sensitive. The limit of detection was 0.026 μg/mL and the linear range was 0.05–1.0 μg/mL. The relative standard deviation (RSD) for 8 repeated determinations was 1.16%. The average recovery rate of clenbuterol in blank pork sample was 91.96%, which was comparable to the results obtained by GC-MS or HPLC.

A method for the determination of melamine in milk and milk products was established by joint use of HPLC-PAD with external standard quantification and UPLC-MS/MS with internal standard quantification. Melamine content of samples was primarily analyzed by HPLC-PAD with external standard quantification, and then confirmed by UPLC-MS/MS and quantified by internal standard method using 13C315N3. Samples were extracted with acetonitrile and then the extract was added with zinc acetate and hydrochloric acid and cleaned up using an MCX solid-phase extraction cartridge prior to UPLC-MS/MS analysis. The limit of quantification of the HPLC-PAD method was 4 mg/kg, while that of the UPLC-MS/MS method was 0.05 mg/kg. The average recovery rates of melamine from milk powder, liquid milk and milk cream across three spike levels as determined by the HPLC-PAD and UPLC-MS/MS methods were 95.7%–102.3% and 91.3%–95.7% (matrix match calibration), respectively, and the relative standard deviations were 1.98%–4.51% and 1.60%–3.27%.

Objective: To develop an HPLC method for determining ferulic acid in Sanliangban medicinal liquor. Methods: At a flow rate of 1.0 mL/min, the prepared analyte was injected at a level of 20 μL for detection at 316 nm. The column temperature was 25 ℃. Efforts were made to determine optimal column type and mobile phase composition. Moreover, the developed HPLC method was investigated in terms of its linear range, recovery rate, precision, reproducibility and stability. Results: Eclipse XDB-C18 column (250 mm × 4.60 mm, 5 μm) was the best column for separation of ferulic acid. Good separation was achieved using a mobile phase made up of acetonitrile and 0.1% phosphoric acid (15:85, V/V). The calibration curve for ferulic acid was linear within the range of 1.15–114.70 μg/mL (R2 = 0.9999). The precision (RSD), reproducibility (RSD), recovery rate and stability (RSD) of this method were 0.4% (n = 6), 1.2% (n = 6 × 2), 99.5% and 0.5% (n = 6 × 2), respectively. The RSD for 8 repeated determinations within 18 h was 1.4%. Conclusion: This method is simple, accurate, specific, reproducible and applicable for quality control of Sanliangban medicinal liquor.

This paper reports a sensitive and specific LC-MS/MS method for the determination of enrofloxacin in soy bean sprout. Samples were extracted with 0.1 mol/L NaOH, cleaned up on a Waters Oasis MAX anion exchange column, and separated by RP HPLC using a mobile phase consisting of acetonitrile and 0.1% formic acid for gradient elution. Enrofloxacin was quantitatively and qualitatively analyzed by ESI-MS/MS in the positive ion scan MRM mode. The method showed a linear range of 1–100 μg/kg and a limit of detection of 0.3 μg/kg. The average spike recovery rates of enrofloxacin in blank sample was 91.6%–94.0% with RSD of 6.6%.

A high performance liquid chromatographic method for simultaneous determination of eight kinds of phthalic acid esters (PAEs) in plastic food packaging materials was developed. The contents of PAEs in 27 plastic packaging material samples, assigned to 7 classes were analyzed. All the samples contained DBP, and 44% of them contained DEHP, including one sample found to contain BBP and no other PAEs. These results illustrate that DBP and DEHP are dominantly used as plasticizers in plastic food packaging materials in China at present. The contents of DBP and DEHP were 22.89–267.6 mg/kg and 0.33–899.8 mg/kg in 27 plastic packaging material samples, respectively. PET packaging material and HDPE packaging material were both richer in DEHP.

Volatile odors of chilled tilapia fillets during different storage periods were collected using an electronic nose, and sensory, microbiological and chemical analyses were performed simultaneously. The results showed that the higher the odor concentration of chilled tilapia fillets, the stronger the sensor signal. Moreover, the sensor signals of the odors revealed good responses to their variations in degrees of freshness. Linear discriminant analysis (LDA) was more effective than principal component analysis (PCA) at distinguishing among tilapia fillets with different degrees of freshness, different total viable counts (TVC) and total volatile basic nitrogen (TVBN) contents, suggesting that electronic nose allows quick evaluation of quality deterioration of chilled tilapia fillets. Loading analysis and correlation analysis demonstrated that sensors W2W, W1W, W1S and W2S greatly could make more contribution to discriminating among tilapia fillets with different degrees of freshness and were well correlated with sensory acceptability, TVC or TVBN. Thus, these sensors are potentially useful for further development of fish-specific electronic nose.

Objective：To establish an LC-MS/MS assay for the simultaneous determination of rosmarinic acid, carnosic acid, chlorogenic acid and caffeic acid in rosemary leaves and to optimize conditions for the ultrasonic extraction of these components. Methods: The chromatographic separation was performed on an Agilent Eclipse XDB-C18 column (150 mm × 4.6 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% formic acid in water by gradient elution. The analyztes were monitored by ESI-MS/MS in the negative ion MRM mode. The effects of solvent type, solid/liquid ratio, ultrasonic treatment time, pH and acid type on the extraction of rosmarinic acid, carnosic acid, chlorogenic acid and caffeic acid were investigated. Results: Caffeic acid, chlorogenic acid, rosmarinic acid and carnosic acid showed a good linear relationship over the concentration ranges of 0.0005–0.5, 0.0005–0.5, 0.002–0.2 and 0.01–1 mg/mL, respectively. Under optimal extraction conditions, the contents of rosmarinic acid, carnosic acid, caffeic acid and chlorogenic acid were respectively, 4.07, 14.50, 2.92 mg/g  and 8.49 mg/g as determined by the LC-MS/MS assay. Conclusion: This array allows rapid, sensitive and simultaneous determination of osmarinic acid, carnosic acid, chlorogenic acid and caffeic acid in rosemary leaves. Their optimal extraction conditions have been established.

Chinese propolis is derived mainly from the Populus species and their hybrids. Poplar tree glue has been widely used as counterfeit propolis, but no efficient method is currently available for the detection of counterfeit propolis. In the present study, electronic nose was used to detect the odor differences among 71 propolis and poplar tree glue samples collected from 70 bee farms in 17 provinces in China. Propolis and poplar tree glue was distinguished from each other by principal component analysis (PCA). Comparison with discriminant factor analysis (DFA) showed that the quality of propolis from Gansu province greatly differed from that of propolis from other provinces.

A comprehensive analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of lycopene in dietary supplements. Samples were saponified to remove lipid, followed by vortex-assisted extraction with petroleum ether containing 1 g/100 mL 2,6-di-tert-butyl-4-methylphenol (BHT). The resulting extract was further cleaned up on a neutral alumina solid-phase extraction cartridge. The pooled eluate was determined on LC-MS/MS by atmospheric pressure chemical ionization coupled with a multiple reaction-monitoring (MRM) mode. Lycopene was quantified by external standard method. The limit of detection (LOD) was 10 μg/kg, and the limit of quantification (LOQ) was 100 μg/kg. The average recovery rates of lycopene across six spike levels, 50.0, 100.0, 250.0, 500.0, 2500.0 μg/kg and 5000.0 μg/kg were 88.0%–103.1% with a relative standard deviation less than 15% (n=6). This method is sensitive and provides a new approach for the quantitative analysis and validation of lycopene in dietary supplements. 

The composition of volatile compounds in preserved duck egg yolk and fresh duck egg yolk was analyzed by simultaneous distillation extraction (SDE) and gas chromatography-mass spectrometry (GC-MS). SDE conditions were optimized. Totally 74 volatile flavor compounds were identified in preserved duck egg yolk, which included 11 hydrocarbons, 5 alcohols, 1 ether, 5 aldehydes, 2 ketones, 10 acids, 20 esters, 2 benzenes, 9 sulfurcontaining or heterocyclic compounds and 9 silicides, accounting for 13.248%, 7.337%, 0.499%, 3.882%, 1.478%, 6.604%, 36.273%, 8.127%, 16.602% and 5.781% of the total amount of volatile compounds, respectively. Compared with fresh duck egg yolk, the contents of alcohols, benzenes, and sulfur-containing or heterocyclic compounds in preserved duck egg yolk revealed a significant increase, but the content of ketones exhibited an obvious reduction. These results indicate that the volatile flavor compounds in preserved egg yolk reveal a significant change during the curing process.

Volatile compounds from Dictyophora echinovolvata Zang, Zheng et Hu fruit bodies were extracted by simultaneous distillation extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) with a DB-Wax strong-polar column and a RXT-5 weak-polar column. Totally 74 volatile compounds were identified, including 18 alcohols, 8 aldehydes, 7 acids, 6 ketones, 8 heterocyclic compounds, 5 aromatic compounds and 6 other compounds. Among them the prominent compounds were oxacyclopentadecan-2-one (5.99%), 6,10-dimethyl-5,9-undecadien-2-one (3.06%), 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-ol (2.61%) and benzene acetaldehyde (2.48%). In addition, 10 volatile compounds were identified by gas chromatography-olfactometry, which comprised 1-octen-3-one, 6-methyl-5-hepten-2-one, 2-octenal, 1-(2-furanyl)-ethanone, 5-methyl-2-furancarboxaldehyde, 2-nonenal, caproic acid, cis-geranylacetone, phenylethyl alcohol and 2-acetylpyrrole.

According to the sequence of Cytochrome b in puffer fish published in GenBank, a puffer fish-specific primer pair of HT1-F and HT1-R was designed using Primer Premier 5.00 version for establishing a DNA based method to identify puffer fish species. Partial fragments of Cytochrome b gene in puffer fish samples including 9 major species from 3 genera and 2 unknown puffer fish samples harvested from Fujian province were amplified by PCR. The PCR products confirmed by agarose electrophoresis were used for sequencing. The length of the obtained DNA fragments was 423 bp in all samples. The homology of DNA sequences among these samples was analyzed using DNA MAN software, and a phylogenetic tree among these samples was also established. Eleven samples were divided into 3 groups, 89% of homology rate was observed between groups I and II; 85% of homology rate was observed between two groups and group III. In addition, 2 unknown puffer fish samples were probably from Gastrophysus or Takifugu genus. Collectively, these results provide a reference for the application of DNA sequencing technology to identify puffer fish components and its species present in processed food stuff.

Objective: Two most common methods for the determination of condensed tannins in wine: methylcellulose precipitation (MCP) assay and Adams-Harbertson (A-H) protein precipitation assay were compared with each other to find a rapid and accurate method. Methods: Condensed tannins in 32 red and 12 white wine samples from different varieties and different growing regions were determined separately by MCP assay and A-H assay to obtain average condensed tannin content and coefficient of variation. Determination of condensed tannin content in these samples was also carried out using HPLC-MS. In addition, total phenolic content (expressed as absorbance at 280 nm) was spectrometrically determined. Results: Both assays were suitable for the determination of condensed tannins in red wine rather than white wine. The MCP assay, although accurate, did not show a significant variation. The average condensed tannin content measured by the MCP assay was 9.13 times higher than that measured by the A-H assay, and a good linear correlation was observe between both assays (R2 = 0.6029, P＜0.01). Moreover, the MCP assay showed a good linear correlation with HPLC-MS (R2 = 0.7733, P＜0.01) but there was no significant correlation between the A-H assay and HPLC-MS (R2 = 0.4843, P＜0.01). A significant correlation between the content of condensed tannins determined by the MCP assay and the content of total phenols was observed (R2 = 0.9095, P＜0.01), but  the content of condensed tannins determined by the A-H assay and the content of total phenols revealed a poor correlation with each other (R2 = 0.2872, P＜0.01). Conclusion: Both assays can be used to determine condensed tannins in red wine. However, the MCP assay is a better method for the determination of condensed tannins in case that the content of total phenols is determined based on absorbance at 280 nm.

The composition of aroma compounds in mulberry leaf green tea was analyzed by headspace solid-phase micro-extraction and gas chromatography-mass spectrometry (SPME-GC-MS) combined with computer search. The results showed that aldehydes were the most predominant aroma compounds in mulberry leaf green tea. A total of 39 aroma compounds were identified in green tea of mulberry leaves harvested in different seasons, mainly including benzaldehyde, 1-octen-3-ol, 6-methyl-5-hepten-2-one, (E,E)-2,4-heptadienal, 2-ethyl-1-hexanol, nonanal, decanal, 2,6,6-trimethyl-1-cyclohexene-1-carboxaldehyde, 1-methoxy-4-(1-propenyl)-benzene, 6,10-dimethyl-5,9-undecadien-2-one, β-ionone, heptadecan, and so on. However, the components including α-farnesene, β-ocimene, (Z)-3-hexen-1-ol, benzoate, indole, cedrol, naphthalene and its derivative, phytol and hexanal revealed a significant seasonal difference in mulberry leaf green tea. Moreover, some compounds such as hexanal, 2-heptenal and 1-octen-3-ol might be related to beany flavor, which was mixed mulberry green tea aroma.

Immuno-capture PCR (IC-PCR), established by integrating immunological and molecular biological techniques was compared with traditional direct PCR. The sensitivity (104 CFU/mL) of IC-PCR for pure Listeria monocytogenes culture suspensions indicated a 10-fold increase compared with direct PCR (104 CFU/mL). The limit of detection of IC-PCR was 5 × 101 bacteria/PCR reaction system (i.e. 104 CFU/mL), which was 100 times higher than that of direct PCR (5 × 103 bacteria/PCR reaction system, 106 CFU/mL). IC-PCR had high specificity and anti-interference capability for detecting Listeria monocytogenes. Moreover, no cross-reactivity with 18 common foodborne pathogens was observed. Therefore, IC-PCR is a rapid, economical, sensitive and specific so that it can be suitable for rapid diction of Listeria monocytogenes in food safety supervisory agencies and food enterprises.

Corn silk polysaccharides were obtained by water extraction and ethanol precipitation, decolorized, deproteinized and purified by Sephadex G-100 column chromatography. GC-MS analysis showed that the purified polysaccharides consisted of 6 monosaccharides. Among them, glucose was predominant and others were arabinose, galactose, mannose, xylose and lyxose.

The composition of volatile compounds in non-heading Chinese cabbage was analyzed by head space-solid phase microextration and gas chromatography-mass spectrometry (GC-MS). Forty-two, forty-one and thirty-eight compounds were detected in Wuyueman, Jingguan, and Suzhouqing Chinese cabbage varieties, respectively, mainly including aldehydes, ketones, alcohols, nitrile, esters and heterocycles. Moreover, 2-hexenal, 2,4(E,E)-hexadienal, 2,4(E,E)-heptadienal, 2(5H)-furanone, 5-ethyl, 1-penten-3-one, 3-hexen-1-ol, 2-penten-1-ol, benzenepropanenitrile and benzene (2-isothiocyanatoethyl) were the major aroma components in non-heading Chinese cabbage.

Spice liquid was produced from jellyfish protein peptic hydrolysate and glucose through the Maillard reaction. The Maillard reaction products (MRPs) had an appropriate salinity, a distinct delicious taste, a slight sweetness and a harmonious fish-like aroma. To identify and analyze their flavor, the contents of amino acids in the MRPs were analyzed using an automated amino acid analyzer and the contents of volatile compounds in their ether-soluble fraction were determined by GC-MS. The results showed that 17 kinds of free amino acids with a total content of 2.7197 g/dL were detected. The total amount of the ten essential amino acids (including His and Arg) was 48.86% of total amino acids, and the content of tasty amino acids (Asp and Glu) was 17.76%. Glu, Lys, Gly, His and Arg had a significant contribution to the taste of the MRPs. Totally 41 kinds of aroma components were separated and identified, which were composed of 8.71% alkanes, 58.35% alcohols, 13.65% esters, 17.86% acids, 0.42% aldehydes plus ketones, and 3.38% nitrogen-containing compounds plus sulfur-containing compounds. The compounds contributing greatly to the aroma of the spice liquid might be propylene glycol, ethyl acetate, dibutyl phthalate, 4-methyl-5-thiazoleethanol, 3,5-bis(1,1-dimethylethyl)phenol and a small amount of aldehydes and ketones.

In order to establish a loop-mediated isothermal amplification (LAMP) method for rapid diagnosis of Vibrio vulnificus, 4 primers that can recognize the vvhA gene of Vibrio vulnificus were designed and used for LAMP assay. Results showed that this method was highly specific for Vibrio vulnificus. Among 13 amplified strains, Vibrio vulnificus was LAMP positive, and other strains were LAMP negative. Moreover, the detection procedure could be completed within 60 minutes and had a detection limit of 51 CFU/mL. Of 120 seafood samples detected by this method, 37 were positive, which was consistent with the result obtained by the NMKL method (No. 156. 2nd edition. 1997). Compared with the NMKL method, this LAMP method was greatly time saving and lowered instrumental and operational requirements, suggesting good practical applicability.

In this study we report the results of a comparative study on quality characteristics of Chinese wolfberries from 12 different regions of Qinghai province. Chinese wolfberries were determined by national standard methods and previously reported methods for proximate nutritional composition and by pre-column derivatization with DBCEC-Cl and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for amino acid contents. Besides, we measured the contents of polysaccharides and flavonoids. The results show that Chinese wolfberries grown in Qinghai province contained abundant nutrients, a complete range of amino acids with a reasonable blend, relatively high amounts of polysacchadrides and flavonoids, suggesting great development potential.

Objective: To develop a new rapid colloid-gold immunochromatographic assay for the screening of xanthan gum in foods. Methods: The immunochromatographic assay was based on competitive immunoassay. Standard xanthan gum was used to immunize New Zealand rabbits to obtain high titer polyclonal antibodies. Colloid-gold was prepared according to the sodium citrate method, and was then conjugated to polyclonal antibodies. Xanthan gum antigen was coated on nitrocellulose membrane and goat anti-rabbit IgG was coated on control line. Results: The developed colloid-gold immnunochromatographic assay revealed a detection sensitivity of 3 g/kg. Conclusion: A new colloid-gold immunochromatographic strip for the detection of xanthan gum has been successfully developed. This method is highly specific, sensitive, rapid (the detection procedure can be completed in 5 min) and suitable for in situ, rapid, large-scale detection.

An HPLC method was presented to determine adenosine content in Armillaria mellea fermentation broth. The chromatographic separation was performed on an Agilent Zorbax Eclipse XDB C18 (4.6 mm × 150 mm, 5 µm) column using a mobile phase consisting of acetonitrile and deionized water (10:90, V/V) at a flow rate of 0.5 mL/min. The column temperature was 30 ℃. Adenosine was detected at 259 nm. The HPLC method showed a linear range of 0.05－0.25 mg/mL and a correlation coefficient of 0.99964. The precision (RSD) for 5 repeated determinations was 1.26%, the stability (RSD) for 7 repeated determinations was 1.29%, and the repeatability (RSD) for 5 repeated determinations analysis was 1.76%. The average recovery across three spike levels was 99.82% (n = 3). This method was accurate, reliable, rapid and suitable for analysis of adenosine in Armillaria mellea fermentation broth.

In this study, an improved sample pretreatment method was used to analyze the composition of free and protein-bound amino acids in fresh scales of lily from Lanzhou. A total of 18 protein-bound amino acids and 20 free amino acids were identified and their contents were determined. The results show that the dominant protein-bound amino acids in Lanzhou grown lily were arginine, glutamic acid, aspartic acid, leucine, glycine, serine, lysine, proline and valine. Arginine and glutamic acid revealed the highest level among 18 protein-bound amino acids. Moreover, arginine was also a major free amino acid in lily scales.

In hydrochloric acid medium, Se (Ⅳ) powerfully catalyzes the oxidation of methylene blue by potassium bromate, causing methylene blue to fade. Based on this, a new catalytic kinetic spectrophotometric method was developed in this study for determining trace Se (Ⅳ). Under given conditions, the linear range for Se (Ⅳ) determination was 0–0.6 μg/50 mL. The limit of detection of the developed method was 3.63×10-10 g/mL. This method allowed the determination of Se (Ⅳ) content in original and infused tea so that the leach rates of Se (Ⅳ) from Tieguanyin, Green tea and Black tea in hot water could be calculated from both measured values as being 24.7%, 25.3% and 22.7%, respectively.

Inductively coupled plasma mass spectrometry (ICP-MS) with smart heater pre-digestion and microwave digestion was applied to determine lead, cadmium, chromium, copper and zinc in kelp. We compared the results obtained for the contents of the five metal elements by an external standard method and an internal standard method. The results indicate that the internal standard method was better and exhibited a linear range of 0－50 μg/L for each metal element (r ＞ 0.9998) with a RSD less than 5%. The limits of detection for these metal elements were 0.3－1.9 μg/kg. It allowed simple, rapid, sensitive and accurate determination of heavy metal elements in kelp.

A solid-phase extraction coupled with gas chromatography method was developed for the determination of nitrophenol residues in fruits and vegetables. Samples were extracted with methanol-water-H3PO4. The crude extract was purified on HLB solid-phase extraction column, derivatized with acetic anhydride, and re-extracted with n-hexane. The derivatives were determined and confirmed by gas chromatography-election capture detector (GC-ECD). The established method was linear in the range of 0.01–1.0 mg/L. The limit of quantification (LOQ) was 0.01 mg/kg. The recovery rates were in the range of 81.0%–106.6% across three spiked levels (0.01, 0.02 mg/kg and 0.05 mg/kg) in six fruits and vegetables (strawberry, apple, tomato, potato, spinach and aubergine), and the relative standard deviations (RSD) were in the range of 3.9%–8.1%. This method is reliable, stable and suitable for the determination of nitrophenol residue in fruits and vegetables.

In this study, a universal predictive model for decay index based on ethanol content in strawberry was proposed. Based on this universal model, a separate predictive model for strawberry cultivars Fengxiang and Hongyan harvested at two different time points was developed and validated. The analysis of variance of the model parameters (slopes and intercepts) of different predictive models showed a significant difference between both cultivars but no significant difference between both harvest time points for the same cultivar, suggesting that the predictive models were affected by cultivar rather than harvest time. The relative errors of these four predictive models observed when validated using independent experimental data were 8.82%, 4.72%, 14.64% and 10.35%, respectively, indicating high prediction accuracy. Thus, different strawberry cultivars and different harvest times had high adaptability to the predictive models. In conclusion, predictive modeling can provide a theoretical basis for non-destructive real-time measurement of fruit quality using gas sensor array.  

This study was conducted to investigate the effect of cold acclimation combined with ice-temperature storage (CACITS) on the quality of broccolis. Physicochemical indexes and nutritional components of broccolis were detected every 14 days during storage. The results show that the contents of VC and chlorophyll in broccoli were decreased more significantly by cold acclimation combined with ice-temperature storage than ice-temperature storage alone and ordinary cold storage; moreover, cold acclimation combined with ice-temperature storage could reduce respiratory intensity and ethylene generation rate in broccolis, increase peroxidase (POD) and catalase (CAT) activities, inhibit polyphenol oxidase (PPO) activity and delay the increase of relative electric conductivity. As a result, it can be concluded that cold acclimation combined with ice-temperature storage is better for the quality of of broccolis than ice-temperature storage alone.

This study was designed to establish a predictive model for the shelf-life of chilled pork with specific spoilageoorganisms. Pork leg muscles were washed with 80 ℃ sterile water, inoculated with Aeromonas spp., seal-packaged, and stored at 0, 4, 7, 15 or 20 ℃. The values of pH, TVBN and TBA and total viable count were determined during storage at the different temperatures. Besides, sensory evaluation was carried out. The resulting data were analyzed with the software Origin 8.0. The results show that the growth dynamics of A. spp. in chilled pork could be well fitted with a modified Gompertz model.  Temperature effect on maximum specific growth rate and lag phase was described by the root-mean-squares (B?lehrádek) model as a good linear relationship with R2 values of 0.93 and 0.95, respectively. At the end of organoleptic shelf life, the average logarithmic value (lg NS) of A. spp. number (CFU/g) in pork samples stored at 0, 4, 7, 15 or 20 ℃ was (6.33 ± 0.14)(lg (CFU/g)), and the average value of lg Nmax was(7.36 ± 0.21)(lg(CFU/g)). A shelf life (SL) model for chilled pork stored at 0–20 ℃ was established as follows: SL = [1/(0.026T－0.00048)2]－[(7.36－lgN0)/2.718 × (0.0102T + 0.148)2] × {ln[－ln(6.33－lgN0)/(7.36－lgN0)]－1}. The model was validated by observing the actual shelf-life of pork at 8 ℃ and 12 ℃. The relative errors between the actual and predicted shelf-lives at 8 ℃ and 12 ℃ were both below 10%, suggesting that the predictive model was effective in predicting the shelf-life of chilled pork stored at 0–20 ℃.

“Guiqi” mangoes were coated with calcium bentonite or sodium bentonite and stored at ambient temperature (28–33 ℃). Physicochemical and physiological indexes were measured during the storage, including decay index, weight loss rate, respiration intensity, soluble sugar content, titritable acidity, soluble solids, membrane permeability, protopectin and soluble pectin. The results show both calcium bentonite and sodium bentonite could significantly decrease decay index and water loss, restrain the appearance of peak values of respiration intensity, soluble sugar content and soluble solids content, retard the decrease of titritable acidity, slow down the degradation speed of pectin, and maintain cell membrane functionality well. Furthermore, sodium bentonite was more effective in preserving mango than calcium bentonite.

The present study aimed to evaluate the fresh-keeping effect of two types of edible multi-purpose preservative films (prepared mainly with chotisan and sodium alginate in the presence and absence of clove oil) on fresh-cut ‘Miben’ pumpkin. Fresh-cut ‘Miben’ pumpkin was coated with different films, and then stored at low temperature. Textural properties, ethylene production, and MDA content in fresh-cut pumpkin were determined during storage period. The results indicate that the two types of edible preservative films could obviously maintain textural properties, reduce MDA accumulation, and delay ethylene production in fresh-cut pumpkin. The edible film consisting of chotisan, sodium alginate and clove oil was more effective in maintain storage quality of fresh-cut pumpkin and prolonging its shelf-life.

In order to explore the effect of nitric oxide on its storage quality, green asparagus was immersed in 0.2 mmol/L sodium nitroprusside (SNP) for 5 min before cold storage and chlorophyll, vitamin C, total sugar and total flavonoid contents as well as membrane permeability and antioxidant activity in nitric oxide (NO)-treated green asparagus were measured every four days during 20 days of cold storage. Meanwhile, the effect of NO treatment on comprehensive quality of green asparagus was also evaluated by principal component analysis. The results show that NO treatment could attenuate the decrease of chlorophyll, vitamin C, total sugar and total flavonoid contents, inhibit the increase of lignin content and membrane permeability, and enhance total antioxidant activity of postharvest green asparagus. Principal component analysis revealed that the comprehensive quality of NO-treated green asparagus exhibited a sharp decrease after 12 days of storage, while NO treatment could prolong the shelf life of green asparagus by 4 days. Therefore, NO treatment can be a promising method for maintaining the quality of postharvest green asparagus.

In order to explore the effect of repeated freeze-thaw cycles on their quality, color parameters, cooking loss, water-holding capacity, shearing force and TBARS of frozen surimis of grass carp and common carp were determined during 4 repeated freeze-thaw cycles. More freeze-thaw cycles could result in a significant increase (P＜0.05) in cooking loss of grass carp and common carp surimi and a significant reduction (P＜0.05) in water-holding capacity but no significant difference between both fish species was observed. The shearing force of grass carp surimi was inversely proportional to the number of freeze-thaw cycles. The first freeze-thaw cycle caused denaturation and contraction of protein in common carp surimi and resulted in an increase in its shearing force, whereas the parameter declined with increasing number of freeze-thaw cycles. Repeated freeze-thaw cycles aggravated lipid oxidation in surimi from both fish species. As a result, significantly increased TBARS (P＜0.05) was observed and a significant difference  (P＜0.05) was also between both fish species. After the fourth freeze-thaw cycle, surimi from both carp species lost their original color.

The change of TVB-N in fresh grass carp packaged with packaging materials with different O2 permeability under vacuum package or air package was investigated during storage different temperatures: 8 ℃ and 20 ℃. The results show that TVB-N increment (Y) and storage time (t) followed the equation: Y=AtB. In this equation, A was affected by package mode and storage temperature rather than O2 permeability, but B was affected by all the three conditions and expressed as a function of O2 permeability (Q) using the equation: , where a and b were dependent on package mode and storage temperature, d was dependent on storage temperature and O2 permeability rather than package mode.

This study was designed to examine the effect of 1-methylcyclo-propene (1-MCP) treatment on the contents of chlorophyll, amino acids and soluble solids, hardness and appearance of okra pods stored at 9 ℃. 1-MCP treatment did not delay the decrease of chlorophyll content during the first 2 days of storage rather than during the following 3 days. Total amino acid content in 1-MCP treated okra pods declined slowly, and the slowest decline was observed in okra pods treated with 200 nL/L 1-MCP. Soluble solid content initially rose and then declined in 200 nL/L 1-MCP treatment group and control group. Compared with control group, 200 nL/L 1-MCP treatment could effectively inhibit the reduction of soluble solids. Moreover, 1-MCP treatment was effective in inhibiting the decline of fruit harness so that storage quality of okra pods could be maintained better.

The aim of the present study was to explore the effect of Maillard reaction products (MRPs) from xylose and glycine on antioxidant activity and color of fresh pork. The results indicate that MRPs from xylose and glycine resulted in a marked decrease in MDA content and an increase in T-AOC value in pork. The MRPs resulting from Maillard reaction for 24 h and 48 h were the most effective in reducing MDA content, and those resulting from Maillard reaction for 72 h and 96 h were the most effective in increasing T-AOC value. Meanwhile, all MRPs tested could remarkably improve the L* value and a* value of pork.

To investigate the effect of different food wrapping films on storage quality of mushroom (Pleurotus nebrodensis), single mushroom was packaged with polyethylene (PE) film or punched polyamide (PA) film with various aperture or thickness and stored at 0 ℃ for 60 days. Sensory evaluation, O2 and CO2 volume fractions in the packaging bag, vitamin C content, soluble protein content, PPO activity, and total phenol content were analyzed every 15 days during storage. The results show that mushrooms stored under the conditions: 0 ℃, 60%–70% relative humidity, 20% CO2 and 4% O2 had better sensory quality and higher contents of nutrients (2.7 mg/g vitamin C and 0.87 mg/g soluble protein).

In this study, an integrative array kit for rapid simultaneous determination of protein content and acidity in raw milk was developed based on formaldehyde titration and acid-base titration. The kit was composed of 4 regents. The results obtained with it, highly stable, were completely consistent with those obtained by the Kjeldahl method and acid-base titration. After 540 d of sealed dry storage, its performance remained good. This kit may be also available for the determination of protein content in sterilized milk and yogurt.

Seven different brands of sweet sauces were evaluated using electronic tongue with cross-type sensors, and four physicochemical indices including total acid value, amino nitrogen value, salt content and reducing sugar content of these sweet sauces were also determined. The acquired data were analyzed by principal component analysis (PCA) and canonical correlation analysis (CCA). Results demonstrate that electronic tongue technique was very effective in discriminating 7 different sweet sauce brands according to overall taste evaluation. Moreover, an obvious correlation between physiochemical indices and sensor response signals was observed. Accordingly, electronic tongue technique can be hopefully applied for online production monitoring of sweet sauce so as to ensure consistency and objectivity in quality evaluation.

The respective amounts of sodium diacetate, sodium lactate and potassium sorbate added together to high-moisture roasted shrimp were optimized using a three-variable quadratic orthogonal rotation combination design. Aerobic plate count of high-moisture roasted shrimp with preservative treatments after 10 d of storage was used as response dependent variable. The results show that in decreasing order, the antimicrobial effects of the preservatives were sodium lactate, potassium sorbate and sodium diacetate. There were no significant interaction effects among them. The optimum amounts of sodium diacetate, sodium lactate and potassium sorbate added to high-moisture roasted shrimp were 0.44, 22.60 g/kg and 0.55 g/kg, respectively, resulting in minimum logarithmic aerobic plate count of 2.26 (lg(CFU/g)) as predicted by the developed regression model, that is, the aerobic plate count is 180 CFU/g. The relative error between the predicted logarithmic aerobic plate count and its actual counterpart was 3.55%, suggesting that this regression model was reliable.

Orthogonal array design was used to optimize conditions for the fermentation and germination of brown rice for separate use for the production rice tea. The results show that both fermentation and germination were conducive to increasing the contents of free amino acids, reducing sugar and γ-aminobutyric acid (GABA) in rice tea, improving its quality. The optimal fermentation conditions were fermented rice (resulting from 24 h natural fermentation of rice and water) : pineapple juice (1:1.5, V/V) as fermentation starter, 35 ℃ of fermentation temperature and 18 h of fermentation time. The rice tea obtained had maximum free amino acid content, a strong aroma, a genuine taste of rice and a clear orange colour. The optimal germination conditions were calcium lactate at 0.5 mmol/L as glutamate decarboxylase activator, pH 5.5–6, 35 ℃ of germination temperature and 24 h of germination time. The resulting rice tea had maximum contents of reducing sugar and GABA, a clear colour and a lingering aftertaste.