Ethyl-3-methyl-thiopropionate (EMTP) is an important kind of spice. The key factors and conditions for bio-catalytic synthesis of EMTP in non-aqueous system were studied in the paper. The results indicated that the best catalyst in solvent-free medium or normal hexane was Novozym 435. Catalyst dosage, the amount of molecular sieve addition, the number of acetic acid addition, reaction temperature and reaction time were important factors for EMTP synthesis. The optimal preparation conditions, as determined using orthogonal array design method, were 50 mg of Novozym 435, 2 g of molecular sieve, 42 ℃ of reaction temperature, 30 h of reaction time, three times of acetic acid addition with an interval of 2 h, and 150 r/min of shaking speed. The yield of EMTP reached up to 42.4% in solvent-free medium under the optimal conditions.

An affinity chromatography column was prepared by cross-linking of 3-carboxyphenyl ethyldimethyl ammonium (CEA) as a ligand with CNBr-Sepharose-4B and used for an investigation into the optimization of elution conditions for affinity chromatography of acetylcholinesterase (AChE) from the gut of sea cucumber (Stichopus japonica). The appropriate balance system was PBS (0.05 mol/L, pH 7.4) containing 0.3 mol/L NaCl, and the appropriate elution system was PBS (0.05 mol/L, pH 7.4) containing 0.2 mol/L tetraethyl ammonium iodide. Under these conditions, AChE was well adsorbed and separated. Three active bands were separated in the native-PAGE pattern of Preliminarily purified AChE, AChE in the gut of sea cucumber may have different forms and display polymorphism.

Melanin is a kind of complex polymeric phenolic compound, which can be used in the field of medicine, cosmetics, food and electron. In this work, melanin was extracted from apricot kernel skin by alkaline extraction, acid hydrolysis, and repeated precipitation, and one-factor-at-a-time and orthogonal array design methods were used to optimize four extraction conditions including NaOH concentration, extraction temperature, extraction time and material-to-liquid ratio based on melanin yield. Three extraction conditions except extraction time had a highly significant effect on melanin yield (P ＜ 0.01), and could be ranked in descending order of importance as follows: extraction temperature ＞ NaOH concentration ＞ material-to-liquid ratio. The optimal extraction conditions were NaOH concentration of 0.4 mol/L, extraction temperature of 80 ℃, and extraction duration of 6 h, and material-to-liquid ratio of 1:20. Under these conditions, the yield of melanin was 7.2%.

In order to maximize the extraction of protein and fat from pig bones, orthogonal array design method was adopted to optimize the high pressure process of cooking pig bones. The optimal cooking conditions were found as follows: 3 h of cooking at 130 ℃ and a material-to-water ratio of 1:1.5 (mL/g). Under these conditions, the extraction rates of protein and fat were 68.2% and 83.3%, respectively.

Total flavonoids were extracted from Sedum sarmentosum Bunge using ethanol as extraction solvent with the aid of ultrasonic treatment. The effects of the extraction parameters material-to-liquid ratio (g/mL), ethanol concentration, ultrasonic treatment time and extraction temperature on extraction efficiency were explored by one-factor-at-a-time and orthogonal array design methods. The lipid peroxidation inhibitory activity and hydroxyl free radical scavenging activity of total flavonoids extract were evaluated and compared with those of several natural antioxidants. The extraction rate of total flavonoids was up to 1.968% after 40 min of ultrasonic treatment for extraction with 40% ethanol at 80 ℃ and a material-to-liquid ratio of 1:25. The resulting extract revealed obvious scavenging activity on hydroxyl free radicals and antioxidant effect on oil and fat. Under the same conditions, it was superior to citric acid but inferior to vitamin C in terms of antioxidant effect on oil and fat.

Cellulase pretreatment before microwave-assisted extraction of flavonoids from Actinidia arguta stem was optimized by response surface methodology. One-factor-at-a-time experiments were performed to select appropriate levels of enzyme dose, hydrolysis time, temperature and pH. Further, a mathematical model was built and subjected to variance analysis. The optimal cellulase hydrolysis conditions were determined as follows: the optimal enzyme dose was 438 U/g for 64 min of hydrolysis at 49 ℃ and pH 4.7. Under these conditions, the extraction rate of flavonoids was up to 2.89%.

Our present work aimed to investigate the effect temperature control on microwave-assisted extraction of lutein esters. The effect of different levels of microwave power on the time required to heat three different solvents from 10 ℃ to 50 ℃ was explored. Meanwhile, the extraction rate of lutein esters from dried marigold flower powder was investigated with respect to microwave power, extraction time and extraction temperature. In addition, a comparative investigation into the extraction of lutein esters was conducted using one of three different extraction solvents with and without the assistance of microwave treatment at the same temperature. The results obtained showed that solvent media molecules composed of O－H bond revealed rapid warm-up. However, heating power had limited impact on extraction rate of lutein esters. Prolonged extraction time could result in decreased extraction rate. Under the optimal extraction conditions of 1600 W, 20 min and 50, 50 ℃ and 40 ℃, the extraction rates of lutein esters with hexane, ethyl acetate or hydrocarbon furan as the extraction solvent were 83%－95.23%, 81.44%－96.59% and 91.72%－94.40%, respectively. At the same temperature, microwave-assisted extraction greatly improved the extraction rate of lutein esters when compared with solvent extraction alone.

A quadratic orthogonal rotation combination design was used to explore the effects of ethanol concentration, material-to-liquid ratio, extraction time and extraction temperature on extraction rate of anthocyanidin from black mulberry (Morus nigra L.) by ultrasonic-assisted extraction. A regression equation was established using DPS7.05 software. The optimal extraction conditions were found to be 52.46%－55.93% ethanol as extraction solvent at a liquid-to-material ratio of 39.51:1－42.43:1 (mL/g) for 27.77－32.23 min of extraction at 50.18－52.4 ℃. Under these conditions, the extraction rate of anthocyanidin was more than 67%.

Objective: To extract blackberry seed oil from blackberry seeds with supercritical carbon dioxide and determine its fatty acid composition. Methods: Operating parameters that influence the extraction of blackberry seed oil were optimized using an orthogonal array design. The fatty acid composition of blackberry seed oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Results: The optimal extraction conditions were extraction temperature of 35 ℃, extraction pressure of 12 MPa, separation pressure of 12 MPa and separation temperature of 55 ℃. Under thess conditions, the yield of blackberry seed oil was up to 16.10%. The major fatty acids were palmic acid (5.38%), stearic acid (3.53%), oleic acid (13.70%), linoleic acid (60.48%), gamma-linolenic acid (11.16%) and total unsaturated fatty acid (85.34%).

One-factor-at-a-time and central composite designs was used to analyze five crucial variables that influence extraction rate of polysaccharides from Chinese wolfberry fruits by high intensity pulsed electric fields (HPEF) including pH (X1), pulse number (X2), electric field strength (X3), temperature (X4) and material-to-liquid ratio (X5). Based on the experimental data of star point designs, a full quadratic response surface regression model was constructed with SAS 9.1 software and used for ridge analysis of response surfaces. When X1, X2, X3, X4 and X5 were 8.98, 20.49 kV/cm, 10520, 61.76 ℃ and 1:9.43 g/mL, respectively, the highest polysaccharide yield, 13.26%, was obtained. According to response surface predictions, the appropriate levels of X1, X2, X3, X4 and X5 for industrial extraction of polysaccharides from Chinese wolfberries were in the range of 8.50－9.00, 15.00－2.00 kV/cm, 10000－11000, 20－40 ℃ and 1:9－1:10 (g/mL), respectively.

On the basis of one-factor-at-a-time experiments, Box-Behnken design (BBD) and response surface methodology (RSM) were applied to optimize extraction with 37% HCl and subsequent precipitation with CaCl2 involved in the extraction of L(+)-tartaric acid from Vitis quinquangularis lees. The optimal HCl treatment conditions were 82 ℃ of temperature, 7 min of treatment time and 18% (V/V) of lees-to-HCl. The optimal precipitation conditions were addition of CaCl2 at a ratio of 50 g/L for 2.4 h of precipitation at pH 6.64. Under these conditions, the L(+)-tartaric acid yield from Vitis quinquangularis lees was 41.63 g/L and the actual recovery rate of L(+)-tartaric acid was 87.64%.

Objectives: To investigate optimal conditions for inclusion complex formation between sinomenine and cylcodextrins and determine the inclusion constants and release in vitro of inclusion complexes prepared with different cyclodextrins. Methods: One-factor-at-a-time and orthogonal array design methods were employed for the optimization of inclusion complex formation conditions. The inclusion constants of sinomenine complexes with β-cylcodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD) and γ-cyclodextrin (γ-CD) formed under optimal conditions were determined by the phase solubility method. Moreover, their release in vitro was tested. Results: The optimal conditions for forming sinomenine-cylcodextrins inclusion complexes were 1:1 of sinomenine-to-cylcodextrin molar ratio, 50 ℃ of temperature, and 3 h of reaction duration at pH 7. The inclusion constants of sinomenine-β-CD, sinomenine-HP-β-CD and sinomenine-γ-CD formed under these conditions were calculated as 501.1, 150.0, 600.3 L/mol, respectively. Conclusion: sinomenine and cylcodextrins can form stable inclusion complexes at a molar ratio of 1:1. Various inclusion complexes show remarkable sustained release effect on sinomenine.

Physico-chemical characteristics of juice yield, transmittance, turbidity, soluble solid content, pH, pectin content and anthocyanin content of sour cherry pulp were evaluated after treatment with various commercial pectinases. Ultra AFP was the best enzymes among 7 commercial pectinases. One-factor-at-a-time testing and response surface analysis based on Box-Behnken design were used to determine the optimal conditions for hydrolyzing sour cherry pulp with Ultra AFP. It was indicated that all hydrolysis conditions under investigation significantly influenced juice yield, transmittance and turbidity. Under the optimal hydrolysis conditions: 2.3 h of hydrolysis at 46 ℃ and an enzyme dose of 1.73 mL/kg, the juice yield, transmittance and turbidity of the samples were 86.2%, 90.5% and 2.67 NTU, respectively.

The purpose of the present study was to optimize alkali protein extraction from defatted chickpea using one-factor-at-a-a-time method and response surface methodology. The results showed that all investigated parameters had a notable effect on the extraction yield of chicken protein and could be ranked in decreasing order of importance in their effects as follows: pH ＞liquid-to-material ratio＞extraction time. The optimal extraction parameters were pH 11.0 and 17.7:1 (mL/g) of liquid-to-material ratio for 88.4 min of extraction at 20 ℃, resulting in an extraction yield of 82.33%. The established regression model describing the extraction yield of chicken protein as a function of three extraction parameters was highly significant (R2＝0.9630). The predictive and experimental results were found to be in good agreement. Thus, the model was applicable for the prediction of protein yield.

This study was undertaken to optimize the decolorization of polysaccharides from Morinda officinalis How. using D-900 anion exchange resin. Static and dynamic adsorption experiments were carried out to study the effects of temperature, resin dose, sample loading flow rate and pH on decolorization rate and polysaccharide retention rate. The optimal process parameters were dynamic adsorption at a sample loading flow rate of 1.0 BV/h, sample pH 6.0 and 45 ℃. In conclusion, higher decolorization rate and polysaccharide retention rate could be obtained by using D-900 anion exchange resin

Pectinase and pectinex were used separately to produce kiwifruit juice from kiwi fruit pulp in the current study. To find a better enzymatic pretreatment for the production of kiwifruit juice, one-factor-at-a-time and orthogonal array design methods were used to optimize hydrolysis conditions based on juicr yield, VC preservation rate, changes of juice color and aroma. The results showed that both enzymes could improve the yield of kiwi fruit juice substantially. However, pectinase required more intense hydrolysis conditions and had greater effect on vitamin C content and juice color and aroma compared to pectinex. Mild conditions were required for pectinex treatment, which resulted in better overall quality index of kiwifruit juice. The optimal conditions for pectinex hydrolysis were 2 h of hydrolysis at an enzyme dose of 10000 U/kg and 30 ℃. Under these conditions, the juice yield and vitamin C preservation rate were 0.853 mL/g and 67%, respectively. This study demonstrated that pectinex is more suitable for the production of kiwifruit juice.

Total flavonoids were extracted from geminated brown rice by ultrasound-assisted extraction method using 50% ethanol as extraction solvent. Response surface methodology was employed to optimize the extraction conditions based on extraction rate. A quadratic regression model describing the effects of four process conditions on the extraction rate of total flavonoids was developed using a Box-Behnken experimental design. The response surface analysis showed that the optimal extraction conditions were extraction for 30.5 min at 45.8 ℃ and a material/liquid ratio of 18.9:1 (mL/g) after 11.7 min of ultrasound treatment. Under these conditions, the average extraction rate of total flavonoids was (0.743 ± 0.011) mg/g (n = 5), accounting for 98.5% of the predicted value, 0.754 mg/g. The developed regression model showed excellent goodness of fit.

One-factor-at-a-time method and response surface methodology were used to optimize the microwave-assisted extraction of highly deacetylated chitosan from Chirocephalus diaphanous eggshell. The optimal extraction conditions for achieving maximum degree of deacetylation of chitosan were as follows: microwave treatment time 33.4 min, ethanol soaking time 86 min, NaOH concentration 57.27%. Under these conditions, chitosan with a degree of deacetylation of 84.12% was obtained from Chirocephalus diaphanous eggshell.

The present study was carried out to discover the effect of various manufacturing parameters on color formation in pasteurized sliced ham. One-factor-at-a-time and orthogonal array design methods were employed to investigate the effects of amount of sodium nitrite added in pasteurized sliced ham, total amount of mixed phosphates (sodium tripolyphosphate, sodium pyrophosphate and sodium hexametaphosphate at a mass ratio of 2:2:1), cooking temperature and rolling time＋curing time on the redness and nitrosylhemochromogen content of pasteurized sliced ham. The changes in color parameters, non-heme iron content, sodium nitrite content and pH of 9 orthogonal array runs were measured during 28 d of storage. The results indicated that the optimal manufacturing parameters were determined as follows: sodium nitrite amount 0.05 g/kg, total amount of mixed phosphates 5 g/kg, 16 h of rolling followed by 8 h of curing, and cooking temperature 70 ℃. No interactive effects were found among various manufacturing parameters. The addition of more sodium nitrite in pasteurized sliced ham resulted in increased residue levels. There was no significant correlation between non-heme iron content and color parameters.

One-factor-at-a-time method and response surface methodology were used to optimize the enzymatic extraction of water soluble dietary fiber from apple pomace with cellulase. The highest extraction rate of water soluble dietary fiber, 17.50%, was obtained under the conditions: enzyme dose 0.67%, buffer pH 5.55, hydrolysis time 1.90 h, and temperature 45 ℃.

The bound volatile aroma compounds of wild Cili pear juice were extracted by chromatographic separation on an Amberlite XAD-2 column followed by microwave-assisted acid hydrolysis (acid hydrolysis first under microwave treatment and then in a 40 ℃ water bath) and analyzed by GC-MS. One-factor-at-a-time and orthogonal array design methods were used for the optimization of microwave-assisted acid hydrolysis conditions. The most types of bound volatile aroma compounds were extracted when the water phase fraction obtained from Amberlite XAD-2 column chromatographic separation was adjusted to pH 1 with 1 mol/L HCl solution, treated by microwave for 3 min at 800 W and then kept in a 40 ℃ water bath for 36 h. Octanoic acid was identified as the most abundant compound, followed by n-hexadecanoic acid, 4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexen-1-one, 4-(5-hydroxy-2,6,6-trimethyl-1-cyclohexen-1-yl)-3-buten-2-one, 2,4-bis(1,1-dimethylethyl)-phenol, etc. Under the same conditions of pH and water bath temperature, microwave-assisted acid hydrolysis was more effective in releasing bound volatile aroma compounds from wild Cili pear juice than single acid hydrolysis for a longer time.

Surface and internal temperatures, water vapor pressure and oil adsorption rate changes in different stages were measured during the deep-frying and cooling processes of cylindrical potato strips. It was found that continuous water vapor escape from the porous shell layer could prevent oil from entering potato strips during the deep-frying process. During the cooling process, over 70% of oil was absorbed into the porous shell layer, providing an impetus for oil absorption-The difference in water vapor pressure between the inside and outside of the shell layer was very sensitive to ambient pressure. Cooling of fried potato strips was studied in different vacuum environments. The results obtained showed that under an absolute pressure of 80 kPa, the total oil absorption rate was decreased from 40% to 13.6%, suggesting that vacuum environments could reduce the water vapor pressure difference between the inside and outside of the shell layer, effectively promote the detachment of adherent oil droplets from the surface, impeding their absorption into the structure of fried potato strips and therefore reducing oil uptake.

Three methods, ultra high pressure (UHP) treatment, UHP treatment followed by papain hydrolysis and concurrent UHP treatment and papain hydrolysis, were developed for eliminating allergens in water soluble protein extracted from Litopenaeus vannamei. One-factor-at-a-time and orthogonal array design methods were used to optimize the operating conditions. The effectiveness of the methods was examined by indirect enzyme-linked immunosorbent assay (ELISA). The optimal UHP treatment was performed under 150 MPa and for 35 min at 45 ℃ when used alone, and the OD492 nm of antigen-antibody reaction was 0.1997. When used before papain hydrolysis, the optimal UHP treatment was performed under 350 MPa for 20 min at 45 ℃, and the OD492 nm of antigen-antibody reaction was 0.0492. When used concurrently with papain hydrolysis, the optimal UHP treatment was performed under 300 MPa for 35 min at 45 ℃, and the OD492 nm of antigen-antibody reaction was 0.05. These results demonstrate that UHP treatment followed by papain hydrolysis and their concurrent action were more effective in eliminating allergens in Litopenaeus vannamei. Therefore UHP has eliminating effect on allergens in Litopenaeus vannamei.

Objectives: To investigate the relationship between color values and antioxidant activity of mung bean clear soup (MBCS) and the effects of water type, granule sugar, table salt and sodium bicarbonate on them. Methods: Phenolic contents (total phenols, total flavonoids and condensed tannins), pH value, color values (L*, a* and b*) and antioxidant properties (DPPH free radical scavenging ability and FRAP value) of MBCS during cooking were tested and the correlations among these parameters were analyzed. Results: The color values and antioxidant activities of MBCS increased with increasing amount of dissolved phenols. Deionized water resulted in increased phenolic contents and antioxidant activity of MBCS compared to tap water. The antioxidant activities of MBCS were decreased by addition of sodium bicarbonate or granule sugar but increased by addition of salt. There was a strong correlation between the b* and antioxidant activities of MBCS. Conclusion: Phenols mainly contribute to the color and antioxidant activities of MBCS and influences the pH. Slightly acidic water is favorable for the preparation of green MBCS with strong antioxidant activity.

This paper reports the optimization of process conditions for the ultrasonic-assisted extraction of oil from Chirocephalus diaphanous by one-factor-at-a-time and orthogonal array design methods. Ethyl acetate was found to be the most suitable solvent for Chirocephalus diaphanous oil among 5 solvents under investigation. The optimal extraction conditions were determined as 150 W of ultrasonic power, 1:10 of material/liquid ratio (g/mL), 40 min of extraction time, and 60 ℃ of extraction temperature. Under these conditions, the oil yield was 84.83%. The ultrasonic-assisted extraction method had the advantages of time-saving extraction and better oil quality over the traditional solvent extraction method.

One factor-at-a-time and orthogonal array design methods were used to determine the optimal operating conditions for water extraction of proanthocyanidins from cinnamon (CPAs). Nine types of macroporous adsorption resin were compared for their effectiveness in adsorbing and desorbing CPAs. Meanwhile, the in vitro inhibitory effect of CPAs on the formation of advanced glycation end products (AGEs) was tested. The optimal extraction conditions were found to be 2 h of extraction at 60 ℃ with acidic water at pH 5.0 (adjusted with sodium acetate-acetic acid buffe) at a liquid/solid ratio of 14:1 (mL/g). Under these conditions, the extraction rate of CPAs was 14.27 mg/g. LSA-21 resin was the most effective in purifying CPAs. CPAs had strong inhibitory activity on the formation of AGEs with an IC50 of 45.93μg/mL, which was higher than that of the positive control aminoguanidimine.

The effects of carboxymethyl cellulose sodium (CMC) vacuum infusion and hot-air drying on rehydration properties and texture after rehydration of nata de coco were investigated by one-factor-at-a-time method and response surface methodology. The results indicated that the rehydration rate of dried nata de coco could be improved by CMC vacuum infusion. The main factors that influence rehydration properties were CMC concentration, nata de coco-to-CMC ratio, drying temperature and vacuum infusion time. The optimal processing conditions were nata de coco/0.9% CMC ratio of 1:2 (m/V), vacuum infusion for 4.5 h at -0.08 MPa, and hot-air drying at 60 ℃。

Yellow-orange light was obtained from sunlight using a yellow filter film and used to wither Dancong tea and its aromatic components were analyzed by gas chromatography-mass spectroscopy (GC-MS) to explore the effect of withering with yellow-orange light on aromatic components. The composition and contents of aroma substances were tested before and after withering. Meanwhile, the change trend of its major components related to taste was also investigated. The results showed that semi-made tea obtained through withering with yellow-orange light had more varieties and higher contents of aroma substances and a stronger aroma.

Six mineral elements and 18 amino acids in soft tissues of wild and farmed swan mussels (Anodonta woodiana) respectively collected from Meilianghu natural water of Taihu Lake and Nanquan aquaculture farm of Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and liquid chromatography (LC), respectively. Although 6 mineral elements and 18 amino acids in swan mussels from two different habitats were ranked in a similar order of their content, significant differences in the contents of some mineral elements and a few amino acids were observed among habitats. The levels of mineral elements such as Ca, Na, Mg, Sr and Se, especially for Mg and Sr in wild swan mussels were significantly higher than those in farmed swan mussels. However, the content of K in farmed mussels was significantly higher than that in wild mussels. Moreover, wild and farmed swan mussels revealed basically similar amino acid composition, and 17 amino acids showed no significant difference in their content, but farmed swan mussels contained significantly more taurine. The contents of essential amino acids in farmed mussels and wild swan mussels were 37.65% and 36.75%, and the ratios of essential amino acids to total amino acids were 60.38% and 58.11%, respectively.

In order to establish a simple and fast assay for the detection of estradiol in foods, estradiol hapten was synthesized and identified by nuclear magnetic resonance (NMR) and infrared spectroscopy. The hapten was activated by DCC/NHS ester method and covalently coupled to carrier proteins (bovine serum albumin and ovalbumin). Polyclonal antibodies were obtained from immunized rabbits. The optimal reaction conditions of indirect competitive enzyme-linked immunosorbent assay (icELISA) were established. The IC50 and LOD of the developed method were 3.9 ng/mL and 0.3 ng/mL, respectively. The cross-reactivity with one of 8 structural analogues of estradiol was less than 1.21%. High sensitivity and specificity will contribute to the development of commercial ELISA kits for the detection of estradiol in foods.

A new resonance light scattering (RLS) method for the determination of trace iodine was developed based on the principle of I (Ⅴ) reacting with excessive potassium iodide and cetylpyridimium bromide to form an ion-associated complex (1:1) in the presence of 0.03 mol/L H3PO4, thus resulting in an obvious enhancement of RLS. Reaction conditions including acidity, reagents dosage, reaction temperature and reaction time were optimized. An excellent linear relationship between the enhanced RLS intensity and I (Ⅴ) concentration was achieved in the range of 0.02－0.4 μg/mL with the maximum RLS peak wavelength at 469 nm. The detection limit was 0.033μg/L. The method was applied to the determination of iodine in refined sea salt, laver and kelp samples. The results were in good agreement with those obtained by iodimetry. The relative standard deviation was 0.7%－1.2% (n＝5), and the recovery rate was 98.4%－101.5%.

The released aroma components of Actinidia arguta (Sieb. et Zucc) fruits grown in Qianshan Mountain were extracted by solid-phase microextraction (SPME), separated and identified by gas chromatography-mass spectrometry (GC-MS). The changes in hardness and soluble solid content of Actinidia arguta were also analyzed during storage at 20 ℃. The results showed that the hardness of freshly picked fruits was 6.6 kg/cm2 and dropped to 0.95 kg/cm2 on the 10th day, soluble solid content rose from 8.50% to 11.45%. After 2, 4, 6, 8 days and 10 days of storage, 6, 12, 15, 15 kinds and 15 kinds of aroma components were identified. A total of 22 compounds were identified from Actinidia arguta, and the major aroma components are terpinolene, β-pinene, p-cymene, D-limonene and α-pinene.

An ion chromatographic method has been developed for the determination of sucrose, glucose and fructose in two kinds of fruits and two kinds of drinks. The analytes were separated on a METROSEP CARB 1 (150 mm × 4.0 mm) anion exchange column using 30.0 mmol/L NaOH as mobile phase at flow rate of 1.0 mL/min and detected with a pulsed amperometric detector. The total time it took to separate the sugars was 25 min. The linear ranges of sucrose, glucose and fructose were 1.0－50.0 mg/L. The detection limits for sucrose, glucose and fructose were 0.085, 0.126 mg/L and 1.072 mg/L (20μL injection, and the quantitative analysis was based on the peak areas), respectively. The RSDs of peak areas for five consecutive determinations of 8 mg/L sucrose, glucose and fructose were 6.09%, 2.90% and 3.03%, respectively. The RSDs of retention time were 2.49%, 1.78% and 1.79%, respectively. The recovery rates for the sugars across three spike levels were in the range of 83.4%－126.6%. Satisfactory results were achieved for the determinations of sucrose, glucose and fructose by the method. Meanwhile, the method was simple, accurate, fast, effective and applicable for the quality control of fruits and drinks.

Crude oil was squeezed from Swida wilsoniana fruits grown in Yudu county, Jiangxi province and refined. The fatty acid composition and physicochemical properties of refined oil were analyzed. The most predominant fatty acids in Swida wilsoniana fruit oil were linoleic acid (34.69%), oleic acid (34.47%) and plamtic acid (22.37%). Crude oil had a very dark color (77Y＋12R＋8.7B), high acid value (15.3 mg KOH/g) and high peroxide value (76.9 meq/kg), but it was greatly improved after refining. Several nutrients (carbohydrates, water, β-carotene, tocopherols, nicotinic acid and thiamine) and minerals (potassium, sodium, magnesium and phosphorus) were detected in crude oil. The refining process could result in significant reduction in the contents of carbohydrates, water, β-carotene, sodium, magnesium and phosphorus although the content of vitamin E did not exhibit an obvious change. Moreover, nicotinic acid, thiamine and potassium were undetectable in refined oil.

Objective: To establish a new method for the determination of sulfur-containing amino acids in milk powder by reverse-phase high performance liquid chromatography (HPLC). Methods: Milk powder was subjected to acid hydrolysis or oxidation and subsequent hydrolysis. The optimal hydrolysis conditions and chromatographic separation conditions were investigated. Results: The detection limits of the method for methionine and (Cys)2 were 0.7μmol/L and 0.3μmol/L, respectively, and the linear ranges were both 10－300μmol/L with correlation coefficients of 0.9993 and 0.9992, respectively. In addition, no significant difference was observed between the results of methionine content obtained with acid hydrolysis and oxidation and subsequent hydrolysis, which were both 0.43 g/100 g, whereas the (Cys)2 contents were 0.06 g/100 g and 0.15 g/100 g, respectively, showing a significant difference. Conclusion: Both acid hydrolysis and oxidation followed by hydrolysis can be used for the detection of methionine in milk powder, but only the latter is suitable for the detection of (Cys)2.

In order to explore the applicability of FT-NIR technique for rapid and non-destructive evaluation of apple quality in terms of titratable acidity (TA), pH and solid soluble content (SSC), NIR spectra in the wavelength range of 12000 to 8000 cm-1 were acquired from 40 samples including Fuji and Pink Lady apples during the storage period of 30 days. Universal mathematical models of TA, pH and SSC for both apple varieties were established using partial least square (PLS) regression. The results showed that a stable model of TA was developed in the wavelength range of 7502 to 4247 cm-1. The coefficient of correlation (R2) of calibration and root mean square error of estimation (RMSEE) were 0.9231 and 0.0263%, respectively. Meanwhile, the coefficient of correlation of prediction (R2) and the root mean square error of cross-validation (RMSECV) were 0.9071 and 0.0266%, respectively. In addition, a stable model of pH was achieved by PLS＋FD model based on NIR spectra in the wavelength range of 11995 to 4247 cm-1. The R2 of calibration and RMSEE were 0.9263 and 0.0700, respectively, and the R2 of prediction and RMSECV were 0.9113 and 0.0772, respectively. A good model of SSC was obtained by min-max normalization pretreatment in the wavelength range of 6102 to 5446 cm-1. The R2 of calibration and RMSEE were 0.9212 and 0.3570%, respectively, and the R2 of prediction and RMSECV were 0.9130 and 0.370%, respectively. The models of TA, pH and SSC were stable in evaluating the quality of Fuji and Pink Lady apples and could meet the requirements for rapid and non-destructive evaluation of fruit quality.

A high performance anion exchange chromatographic-pulse amperometric detection method was established to determine glucose, sucrose and lactose in milk powder. The separation column used was METROSEP CARB 1 (150 mm × 4.0 mm) anion exchange column, and the mobile phase was 37 mmol/L NaOH. Citric acid was used to precipitate proteins from milk. The linear ranges of glucose, sucrose and lactose were 1－40, 1－50 mg/L and 1－50 mg/L with correlation coefficients of 0.9966, 0.9968 and 0.9985, respectively, and the detection limits were 0.014, 0.091 mg/L and 0.083 mg/L. The precision relative standard deviations of precision for 5 replicate determinations were in the range of 1.10%－4.96%. The recovery rates for glucose, sucrose and lactose in 4 different commercial samples were 90.13%－104.83%. The method was suitable for rapid determination of glucose, sucrose and lactose in milk powder, thanks to its short analysis time and simple pretreatment.

A liquid chromatography tandem mass spectrometric (LC-MS/MS) method was established for simultaneous determination of albendazole and its metabolites including albendazole sulfone, albendazole sulfoxide and albendazole-2-aminosulfone in meat. Samples were extracted with acetonitrile and cleaned by liquid-liquid extraction. The separation of analytes was performed on an XDB-C18 column with acetonitrile and 0.1% formic acid solution as the mobile phase. The external standard calibration curve was used for quantification. The LOD of albendazole and its metabolites was 0.010 mg/kg. A good linear relationship between peak area and concentration in the range of 0.010－0.050 mg/kg for albendazole and its metabolites was achieved with a correlation coefficient of more than 0.99. The spiked recovery rates and relative standard deviations (RSDs) were 82.3%－97.6% and 4.9%－12.9%, respectively. The method was simple, fast, accurate, convenient, and applicable for qualitative and quantitative determination of albendazole and its metabolites.

In order to establish a new rapid method for determining bisphenol A (BPA) in nursing bottles, cut pieces of nursing bottles were extracted with high-purity water under ultrasonic assistance, and the extracted analyte was enriched by solid phase extraction and determined using a uminol-H2O2-Cr chemiluminescence system. The esults showed that the chemiluminescence system was inhibited by BPA. An excellent linear relationship was observed in the range of 2.0 × 10-9 －1.0 × 10-5 mol/L. The detection limit was 4.6 × 10-10 mol/L. The average spike recoveries of BPA in 5 types of commercial samples were in the range of 95.4%－106.8%, and the relative standard deviations for 7 parallel determinations were all less than 4%. The method had the advantages of sensitivity, simplicity, rapidity, low cost and accuracy over the Chinese national standard method, thus being worth promoting and popularizing.

A reversed-phase high performance liquid chromatographic method with solid-phase extraction was proposed for the residue dynamic analysis of imazalil in rambutan. The analyte was separated on a Shim-pack VP-ODS (150 mm × 4.6 mm, 5μm) using a mobile phased composed of a mixture at a volume ratio of 75:25 of methanol and acidic Na2H2PO4 solution approximately at pH 5 (adjusted with 85% phosphoric acid) at a flow rate of 0.85 mL/min, and detected at 229 nm. The injection amount was 20 μL. An excellent linearity of imazalil in the range of 15.0－960.0 μg/L was achieved (r ＝0.9994). The detection limit was 5.0 μg/L. The average spike recovery rates were in the range of 86.4%－104.5% with relative standard deviation of 0.84%－2.87%. The method was fast, simple, and applicable for the determination of imazalil residue in rambutan.

An electric nose was used to evaluate the quality of black pepper duck breast during storage. The sensory index, microbial parameters and TVB-N of black pepper duck breast were analyzed. The results showed that microbial parameters and TVB-N could not accurately reflect the quality of a sample. However, slight odor change could be sensitively identified by electric nose so that it can be used to identify and judge the quality of meat products as a fast, effective detection strategy.

Staphylococcal enterotoxin (SE) is an important pathogenic factor for human food-borne diseases. Based on a couple of monoclonal antibodies with high sensitivity and affinity, a rapid, sensitive, specific DAS-ELISA method for the quantitative detection of SE was established. The linear regression equation was y＝4.074x－1.1888 (R2＝0.9892). The detection limit was 0.307 μg/mL. The average recovery rates for SE in skim milk powder were 103%－107% with relative standard deviation (RSD) of less than 10%. In addition, the method was also successfully used for monitoring the dynamic change of SE secretion in culture supernatants of Staphylococcus aureus isolates, indicating that it can be used not only for the detection of enterotoxin-producing strains but also for monitoring the secretion of SE. Moreover, the positive rates of the method for the detection of SE in fresh milk and porcine lymphoid samples were 51.7% and 59.1%, respectively. The total coincidence rate between the results obtained by the method and imported kit was 92.5%. Therefore, the method was sensitive and efficient and could provide an effective technical support for monitoring food-borne pollution.

Beef hydrolysate was prepared with flavorzyme and used to further prepare sauced beef essence via simulated Maillard reaction with both amino acids and reducing sugars. Sauced beef essence was formed after the reaction in solution, which was yellowish-brown and had a full meaty taste and a persistent aftertaste. The essence was analyzed by simultaneous distillation extraction and gas chromatography-mass spectrometry. A total of 64 kinds of volatile compounds were identified. Benzaldehyde, benzeneacetaldehyde, γ-terpinene, 1-methoxy-4-(1-propenyl)-benzene, and 5-methyl-2-thiophenecarboxaldehyde were the compounds responsible for the characteristic flavor of sauced beef essence.

The gyrB gene, which encodes the B subunit protein of DNA gyrase, is a single copy gene and has conserved regions for PCR primers. A pair of specific primers target to the gyrB gene of V. parahaemolyticus was designed, and a SYBR green I-based real-time PCR for V. parahaemolyticus detection was established. The PCR primers could amplify 285-bp gene fragment from chromosomal DNA of V. parahaemolyticus, and no positive reaction was detected in 8 other pathogenic bacteria using conventional PCR. In addition, the results of melting curve analysis showed only a specific peak with a melting temperature (Tm) of 90 ℃, and no primer-dimers peak was observed. These findings indicated that the PCR primers had high specificity. Both geometric growth and plateau phases were observed in PCR amplification curves. Analysis of standard curves revealed excellent correlation between the number of copies (in the range of 2.06 × 108 to 2.06 × 103) and PCR threshold cycle (Ct) with a correlation coefficient of 0.992 (R2 ＝0.992). It took only 4－5 h (from nucleic acid extraction to analysis of results) to detect samples by the method. Therefore, SYBR green-based I real-time PCR had the advantages of higher sensitivity and ease of operation over traditional methods and could be used for inspection and quarantine of import and export commodities, food safety detection, and diagnostic studies and molecular epidemic survey of aquatic animal diseases caused by V. parahaemolyticus.

A high performance liquid chromatographic method was established for the determination of hydroxyproline in fishery products with pre-column derivatization. Samples were hydrolyzed with hydrochloric acid before pre-column derivatization with dansyl chloride. The analyze was separated using a C18 column and detected using a UV detector. Good separation was achieved for hydroxyproline and other amino acids. The linear range was 0.5－20 μg/mL (r ＞ 0.9999). The detection limit was 0.5 μg/mL. The average spike recovery rates were 80.2%－103% with a RSD of 3.2%－5.6%. The method was sensitive, accurate and suitable for the determination of hydroxyproline in fishery products.

Derivatization reaction is very important for the determination of sec-butylamine. For the purpose of establishing a gas chromatography-electron capture detection (GC-ECD) method for determining sec-butylamine, the optimal derivatization reaction conditions were studied by response surface methodology. Based on the results of one-factor-at-a-time experiments, a central composite design was used to investigate the pairwise interaction effects of reaction time, temperature and derivatization reagent (acetonitrile containing 0.05μL/mL pentafluorobenzaldehyde) amount on sec-butylamine recovery. The optimal derivative temperature, derivative duration and derivatization reagent amount were found to be 22.42 ℃, 31.72 min and 1.25 mL, respectively.

A time-resolved fluroimmunoassay (TRFIA) for the determination of ciprofloxacin (CPF) in an indirect competitive immunoassay mode was developed and applied. CPF-OVA was coated by physical adsorption onto a microtitre plate, and CPF standard or sample was competed with CPF-OVA for limited anti-CPF antibody, which was traced using europium-labeled goat anti rabbit IgG. The effects of experimental conditions including CPF-OVA concentration, buffer type, and reaction time on the sensitivity of TRFIA were explored. Under optimal conditions, the method revealed a detection limit of 0.5 μg/L, an IC50 of 4.32μg/L and a linear range (IC20－IC80) of 1.13－28.85 μg/L. The spike recovery rates of CPF in honey and milk at three spike levels were in the range of 80.66%－100.30% and 76.30%－95.22%, respectively, and the intra-batch and inter-batch coefficients of variation were 7.42% and 10.92%, respectively. The method was sensitive, specific, stable and suitable to be used for high-throughput determination of CPF residues.

A new analytical method was developed for the determination of brilliant blue in food by high performance liquid chromatography (HPLC). It was preliminarily confirmed that the presence of brilliant blue in food was mixtures of its three isomers. Sample extracts were purified by polyamide column chromatography and separated on an Inertsil ODS-SP C18 (150 mm × 4.6 mm, 5 μm) column using a mobile phase made up of methanol and 0.02 mol/L ammonium acetate solution. The detection wavelength was set as 629 nm. The spike recovery rates across three spike levels were in the range of 91.1%－94.7%. The method was simple and accurate.

Fourier transform infrared spectroscopy (FT-IR) combined with soft independent modeling of class analogy (SIMCA) method was applied for tracing the geographical origin of glutinous rice. PCA (principal component analysis) models were built by the method of cross-validation based on such pre-treatments as nine-point Savitzky-Golay smoothing, baseline correction and Standard Normal Variate (SNV) normalization in the region of 3000－2800 cm-1 and 1760－1700 cm-1. Identification of glutinous rice from seven origins was performed by identification rate and rejection rate. Under the significance level of α＝0.05, the identification rates of predicted samples were 100% except for the glutinous rice (80%) from Hanzhong, Shaanxi province; the rejection rates were 100% except for glutinous rice from Wuxue, Hubei province (83%) and Hangzhou, Zhejiang province (97%). Thus, the combination of FT-IR and SIMCA is an effective and efficient strategy for identifying the geographic original of glutinous rice.

Colloidal gold immunochromatographic assay (GICA) and gas chromatography (GC) was separately used for the analysis of chloramphenicol (CAP) residues in creatural products. Samples were spiked with 0.3, 0.5μg/kg and 1.5μg/kg CAP and determined by the methods. CAP residues at concentrations above 0.5μg/kg could be detected by GICA. The average recovery rates of GC were 78.1%, 85.3% and 88.3%, respectively with relative standard deviation (RSD) of 5.3%－9.0% and the detection limit was 0.3μg/kg. Three positive samples and other 105 samples analyzed by GICA were confirmed by GC and no false positive and negative samples were observed. Therefore, GICA is a rapid, accurate, reproducible and suitable to be used for rapid in situ screening of CAP residues in food products of animal origin, while GC is sensitive and suitable to be used for quantification of positive samples.

A method for the determination of folic acid in food by ultra performance liquid chromatography-mass spectrometry/mass spectrometry (UPLC-MS/MS) has been established. Sample extract was separated on Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) using a mobile phase consisting of acetonitrile and 0.1% formic acid (5:95, V/V) at a flow rate of 0.25 mL/min, and analyzed by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in a positive-ion selective reaction monitoring (SRM) mode at a collision energy of 14 eV using m/z 442.3, m/z 295.1 and m/z 176.0 as the parent, quantitative and qualitative ions, respectively. The column temperature and the injection volume were set as 40 ℃ and 2 μL, respectively. The average blank spike recoveries for 4 replicate determinations across three spike levels were in the range of 80.7%－89.7% with RSD of 2.90%－3.85%. The limit of detection was 1 ng/mL. An excellent linear relationship was achieved in the range of 0.001－1.000 μg/mL. The method was characterized by simple operation, time saving and high sensitivity.

Objective: To establish a novel method for determining the contents of polybrominated diphenyl ethers (BDE-47 and BDE-99) in drinking water by solid phase extraction (SPE) or solid phase micro extraction (SPME) combined with gas chromatography (GC). Methods: In the SPE-GC method, 100 mL of water sample was purified by LC-C18 SPE column chromatography through elution with hexane. The eluent was evaporated to dryness in water bath at 80℃, and the remaining residue was re-dissolved with isooctane and made up to 1 mL. Finally, 1μL of the solution was injected into GC for the determination. The limits of detection (LOD) for BDE-47 and BDE-99 were 0.0008μg/L and 0.0009μg/L (RSN= 6), respectively, the regression equations showed good linearity with a correlation coefficient of 0.9996 and 0.9997, respectively, and the RSDs for 6 replicate determinations were in the range of 1.0%－4.9% and 0.96%－4.4%, respectively. In the SPME-GC method, 10 mL of water sample was placed into a 15-mL SPME bottle and adsorbed by solid-phase micro-extraction for 25 min at 40 ℃ with a rotation speed of 1150 r/min. Then, the fiber was air-dried, immediately followed by GC analysis. The LODs of the SPME-GC method for BDE-47 and BDE-99 were 0.0000μg/L and 0.0044μg/L (RSN = 6), respectively, the linear correlation coefficients were 0.9996 and 09992, respectively, and the RSDs for 6 replicate determinations varied in the range of 6.7%－11.4% and 6.0%－10.1%, respectively. Results: BDE-47 and BDE-99 were undetected in 52 samples randomly collected from a certain city. Conclusion: Both analytical methods are characterized by simplicity, rapidity, high precision, good accuracy and satisfactory recovery rate.

A fuzzy mathematical comprehensive evaluation method was applied for the sensory analysis of chicken. According to the evaluation results from consumers, the sensory quality of chicken was determined. The results showed that the evaluation scores for the appearance, color, smell, taste of chicken soup after heating were 0.171, 0.323, 0.206 and 0.300, respectively. The comprehensive value could more objectively reflect the grade and traits of chicken. Therefore, the fuzzy mathematical method is a simple and effective method for identifying the sensory quality of chicken.

Based on the topological theory and self-MATLAB program, Kier’s molecular connectivity indices (mXtv) and electro-negativity distance vector (Mt) were calculated for 41 volatile compounds in Chuliang Longan as identified by GC-MS. A five-element regression model of quantitative structure-retention relationship (QSRR) for retention index (RI) as a function of mXtv and Mt was constructed using leaps-and-bounds regression (LBR). The traditional correlation coefficient (R2) and the cross-validation correlation coefficient (Q2) of leave-one-out (LOO) were 0.981 and 0.976, respectively. The robustness of the regression model was validated by Jackknife method, and the results showed that the R2 was between 0.975 and 0.986. The present study demonstrates that the model is highly reliable and has favorable predictive ability, and can better elucidate the change rule of GC-MS retention indices for organic components.

In order to simultaneously determine the aromatic composition and odor characteristics of Xihu Longjing tea by as chromatography (GC)-mass spectrometer (MS) and GC-olfactometry, volatile aromatic components were extracted from Xihu Longjing tea infusion in-tube extraction and direct thermal desorption (ITEX). It was confirmed that the compounds responsible for the characteristic aroma of Xihu Longjing tea were dimethyl sulfide, 2-(methylthio) propionaldehyde, 3-ethyl- 2,5-dimethylpyrazine, linalool, α-terpineol, geraniol and cis-jasmone.

A matrix solid phase dispersion (MSPD) and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed for the simultaneous determination of alprazolam, midazolam, triazolam, estazolam, oxazeoam, diazepam, nitrazepam, clonazepam, carbamazepin, lidocaine, phenobarbita, amobarbital and secobarbita residues in meat. Sample extract was cleaned up using an MSPD kit before UPLC-MS/MS. The analytes were monitored under multi-reaction monitoring (MRM) mode and quantified by an external standard method. The chromatographic separation was achieved on a BEH C18 column using a mobile phase composed of 10 mmol/L ammonium acetate and methanol through gradient elution. The results showed that the limits of detection for 13 sedatives ranged between 0.05 and 3 μg/kg. The average spike recoveries for the sedatives in a blank pork sample at three spike levels were 77.4%－100.2% with relative standard deviation (RSD) of 1.3%－14.8% (n ＝3). The method was simple, rapid, sensitive, accurate and applicable for the determination of 13 sedative residues in meat.

The volatile aroma components of pomelo peel tea, pomelo peel and green tea were comparatively analyzed by headspace-GC-MS in order to discover the originals and causes of volatile aroma components in pomelo peel tea. It was shown that limonene and myrcene were the major components of three samples. This indicates that limonene and myrcene are not new aroma components transferred from pomelo peel to green tea and not the specific aroma substances of three samples. Several oxygen-containing compounds that can differentiate green tea and pomelo peel were detected in pomelo peel tea, accounting for approximately 5% of the total volatile compounds. The percentage of oxygen-containing compounds was higher than that obtained using simultaneous distillation extraction. The difference may come from the oxidation of alkenes caused by long-term repeated extraction at high temperature during the simultaneous distillation extraction process. However, headspace extraction requires mild reaction conditions, yielding aroma components similar to those released under natural conditions.

In this study, the quality and aroma components of Jincheng oranges during the periods of growth and development were evaluated by solid-phase micro-extraction (SPME) coupled to GC-MS. The results showed that 76 aroma volatile compounds were identified during the growth and development periods. Meanwhile, 40, 41, 36, 38 and 39 aroma volatile compounds were detected during five development periods, respectively, which were aldehydes, alcohols, esters and terpenes. The relative contents and number of aldehydes increased at first and then decreased. In contrast, esters kept an increasing trend during the whole development process. The contents of soluble solids, vitamin C and reducing sugar exhibited an increasing trend during the period of development although titratable acid showed an initial decrease followed by an increase.

The essential nutrients of 43 hazelnut varieties including Corylus heterophylla, Corylus avellanas and their hybrids were analyzed. Hazelnut kernel contained 3.87%－9.51% water, 0.92%－2.03% starch, 12.66%－19.09% sugars in total, 29.22－68.57 mg/g protein, and 53.80%－63.33% fat content. All the nutrients of Corylus avellana are significantly different with those in Corylus heterophylla and hybrid hazelnuts. The contents of starch and total sugar in Corylus heterophylla and hybrid hazelnuts were significantly different. Three groups of hazelnuts were ranked in decreasing order of as follows: hybrid hazelnuts ＞ Corylus heterophylla ＞Corylus avellanas by water content, Corylus avellanas ＞ hybrid hazelnuts ＞ Corylus heterophylla by starch content, hybrid hazelnuts ＞ Corylus avellanas ＞ Corylus heterophylla by total sugar content, Corylus avellanas ＞ Corylus heterophylla ＞ hybrid hazelnuts by soluble protein content, and Corylus avellanas ＞ hybrid hazelnuts ＞ Corylus heterophylla by fat content.

Soybean isoflavones are a group of important functional components in Douchi such as genistein and daidzein. The content of soybean isoflavone in Yongchuan Douchi during the traditional fermentation process was determined by high performance liquid chromatography (HPLC) in this study. The results showed that the content of soybean isoflavone revealed a gradual decrease from 3117 to 1754 mg/kg during the fermentation process. The content of aglycone exhibited a dramatic increase from 3.2% to 95.7% while the content of glucosides presented a considerable drop.

In order to explore the effect of rapid chilling on the edible quality of rabbit meat, Longissimus dorsi meat samples from twenty-four rabbits were subjected to two different treatments, namely rapid chilling and conventional chilling, and quality indices of chilled rabbit meat were then measured. The results showed that rapid chilling ((－12 ± 1 )℃, 30 min), accelerated the declining rate of carcass temperature, attenuated the drop of pH, improved the color of rabbit meat, enhanced water-holding capacity and retarded lipid oxidation within seven days of aging period when compared with the conventional chilling treatment ((0 ± 4) ℃, 24 h). However, the rapid chilling treatment did not exhibit significant effect on shearing stress of rabbit meat.

Fresh-cut Muscat grapes were treated in hot water at 40, 45 ℃ and 50 ℃ for 6 min, respectively in order to explore the impact of heat treatment on the antioxidant activity, physiological and biochemical changes and quality of fresh-cut Muscat grapes during storage at (0 ± 0.5 )℃. The results showed that the antioxidant activity of grape treated with hot water was far lower than CK after 7 days of storage. In addition, the treatments at 45 ℃ or 40 ℃ for 6 min decreased the content of total phenols during the whole storage period, and the treatment at 45 ℃ for 6 min also inhibited the decrease of vitamin C and the increase of disease incidence and MDA content. Although no significant impact on titratable acid was observed, heat treatment, especially at 45 ℃ for 6 min, greatly increased POD activity.

In this study, the effect of relative humidity on water evaporation loss of spinach during storage period was investigated. During 44 h of storage at 5 ℃ and a relative humidity of 99%, the water loss rates of single spinach and bound spinach were 41.32% and 23.32%, respectively. In addition, under the same temperature and storage period and different relative humidity levels: 99%, 80% and 40%, the water loss rates of single spinach were 66.70%, 54.60% and 41.32%, respectively. Moreover, a correlation between water loss rate and relative humidity was established. These results showed that during the early part of the storage period, spinach revealed higher relative humidity and lower water loss rate. However, with increasing storage time, water loss rates were basically the same under various relative humidity levels.

In order to explore the injury status of peach varieties during low-temperature storage and shelf-life period, 15 peach varieties were analyzed for hardness, juice yield, relative conductivity, ethylene production, flesh color and sensory evaluation during 0 ℃ storage and 3 days of shelf-life period at 20 ℃ . The results showed that hardness, juice yield, relative conductivity of different peach varieties revealed a significant change during low-temperature storage. The peak of ethylene production was observed at different time points. Nectarine 75 , Jintong 7 , Ruipan 4 , Jingyu and Huayu peach fruits had no flesh browning; however, other varieties had various flesh browning after 30 days of storage. The flesh browning of Lvhua 9 was observed at the beginning of storage, but the flesh browning of all other varieties became more obvious with the increase of storage time. After the shelf-life period at 20 ℃ , the varieties except nectarine 75 and Jintong 7 revealed hardness change at different degrees or rebound at different storage periods. Meanwhile, the yield of juice and relative conductivity of different varieties were also different. In conclusion, different peach varieties have different sensitivity to low temperature. Nectarine 75 and Jintong 7 reveal the least sensitivity to low temperature among 15 peach varieties, but Okubo , Ruipan 3 , Ruipan 4 , Wan 24 , Jingyu , Huayu , Jingyan and Yanhong varieties are sensitive to low temperature. Dadong , Lvhua 9 , Gaofeng , Bixia and Zhonghuashoutao varieties reveal the most sensitive to low temperature and chilling injury.

To analyze the effect of system-2 ethylene on the activities of catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) during exposure to cold stress, anti-sense ACS2, wild-type Lichun and ethephon-treated anti-sense ACS2 tomato fruits were used to the models of non-system-2 ethylene synthesis, normal system-2 ethylene synthesis and compensative system-2 ethylene synthesis, respectively. It was indicated that wild-type Lichun and ethephon-treated anti-sense ACS2 tomato fruits decreased chilling injury index, inhibited the increase of electrolyte leakage and increased the average activities of CAT, APX and SOD compared with native anti-sense ACS2 tomato fruits. The increase of POD activity was inhibited in wild-type Lichun but induced in ethephon-treated anti-sense ACS2. From these results, it can be concluded that system-2 ethylene can improve the cold resistance of tomato during exposure to cold stress by increasing CAT, APX and SOD activities and regulating POD activity.

Post-harvest plum fruits (Prunus salicina cv. Black amber) were treated with 1-methylcyclopropene (1-MCP) and then stored at 0 ℃ for 28, 67 or 96 d before shelf-life storage for 9 d at 20 ℃ to deal with the effect of 1-MCP on non-volatile components in plum during cold storage and subsequent shelf life was investigated using multivariate analysis. One-way analysis of variance (one way-ANOVA) showed that the levels of sucrose and malic acid decreased gradually, D-fructose level decreased at first and then increased in plum fruit during cold storage, whereas the peaks of other components productions were detected on day 67 of cold storage. In contrast, non-volatiles in plum fruit reached their peaks on at the end of the shelf life after 96 d of cold storage. Principal component analysis (PCA) showed that the contents of various components in plum fruits stored for 67 d at 0 ℃ decreased at the end of the shelf life compared with those at the beginning, while plum fruits after 96 d of storage at 0 ℃ showed an opposite change during the subsequent shelf-life storage. Because of 1-MCP treatment, the peaks of sugars and acids in plum fruits stored for 67 d and for 96 d significantly dropped during the shelf life, and the metabolic rates of these substances slowed down, the nutritional quality was maintained, and fruit deterioration was delayed. Partial least squares regression (PLSR) and path analysis showed that D-fructose was significantly and positively correlated with sensory sweetness/sourness ratio, and was a major direct or indirect factor. Malic acid correlated significantly and positively with sensory sourness or soluble solids content (SSC), while D-glucose had an indirect impact on SSC. Sorbitol was significantly and negatively correlated with pH value.

In order to understand their preservation effects of Penaeus vannamei, sensory characteristics, pH, total volatile basic nitrogen (TVB-N), total bacteria count (TBC) and trimethylamine (TMA) were measured on Penaeus vannamei treated with ε-polylysine, chitosan or phytic acid during cold storage at (4 ± 1) ℃. The results showed that the shelf life of Penaeus vannamei was prolonged averagely by 2－4 d due to treatment withε-polylysine, chitosan or phytic acid compared with control samples. The sensory quality could be maintained well due to treatment with 0.08% phytic acid solution. However, ε-polylysine was more effective in reducing the TBC and TMA of Penaeus vannamei.

Packaging materials with good barrier properties can effectively extend the shelf life of meat. Chilled meat with modified atmosphere packaging (MAP) has different shelf lives because of the complexity of gas ratio and the diversity of packaging materials. In our present study, chilled pork was packaged under high-oxygen MAP (35% CO2 and 65% O2) using three materials with different levels of barrier property (high, medium and low) and determined for total bacterial count (TBC), coliform count, color, TVB-N, drip loss and pH during cold storage in order to observe the effect of packaging materials on the shelf life and quality of chilled pork. The results showed that the total plate count of meat packaged with high barrier material (PET/CPE film) after 10 days of storage exceeded food safety standards. The pH was at freshness grade 2 during storage. The TBC of meat packaged with medium barrier material (PE/PA film) did not exceed 6 lg(CFU/g) during the shelf life, the color was maintained well, the sensory quality was relatively better, but the drip loss was higher. Low barrier material (PA/CPP film) resulted in the biggest change in the TBC of chilled meat, which reached 6.46 lg(CFU/g) on the 13th d, and meanwhile the color, odor and overall acceptability were poor. Therefore, PE/PA film can provide a better barrier material for meat preservation under high-oxygen MAP.

The effect of modified atmosphere packaging (MAP) with systems consisting of 10% O2 and different concentrations of CO2 (10%－50%) on major quality and physiological indices of fresh-cut iceberg lettuce stored at 4 ℃ was investigated. The results showed that high CO2 concentrations could increase the membrane permeability of iceberg lettuce. Significantly, 10% O2 ＋30% CO2 inhibited the activities of PPO, POD and CAT, delayed tissue aging and browning, and maintained the contents of chlorophyll, vitamin C and sugar content well. The sensory evaluation results showed that the fresh-cut iceberg lettuce exposed to 10% O2 ＋30% CO2 still had commercial value after 15 days of storage.

The effect of 1-MCP treatment on the aroma composition of kiwifruits (A.chinensis cv. Hongyang) during cold storage was investigated by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Totally 92 kind of aroma components were detected, including alcohols, aldehydes, esters, ketones and hydrocarbons. The varieties of alcohols, aldehydes, esters and ketones revealed an initial increase and a final decrease. The change trend of ketone and alcohols contents was similar with that of the varieties. The relative content of ketones in 1-MCP-treated kiwifruits was obviously lower than that in the control, and the relative content of alcohols was higher than that in the control during the later stage of storage. The relative content of aldehydes revealed an increase trend and hydrocarbons revealed a decrease trend during the storage. The changes in the varieties of aroma components in kiwifruits were not always consistent with those in their contents during the whole storage period. The varieties and relative contents of aromatic compounds in the control and 1-MCP-treated kiwifruits had significant differences during the storage period. 1-MCP treatment could inhibit the production of esters in kiwifruits during the whole storage period and also result in the accumulation of alcohols and aldehydes in the later stage of storage, thus affecting the sensory quality of kiwifruits.

Chitosan, nisin and lysozyme were used to develop an antibacterial formula for braised whole chicken. In order to find the optimal formula, response surface methodology was employed to optimize antibacterial rate as a function of the levels of added ingredients based on a regression model. The best antibacterial effect was observed when 0.36% chitosan, 0.038% nisin and 0.05% lysozyme were added to braised whole chicken, resulting in an antibacterial rate of 95.4% after 3 d of storage at room temperature. Moreover, the experimental data could be well fitted with the established regression model.

In this study, cocoa butter substitute/peanut bonbons were made with peanut sugar as the core and cocoa butter substitute as the main coating material. Response surface methodology was used to optimize the ingredient composition of bonbon core and coating based on a central composite design. According the results of significance analysis of various variables and their interactions, the optimal bonbon core was composed of sugar, starch syrup, peanut powder and lard at a mass ratio of 3.33:4.02:7.24:1, and the optimal bonbon coating was composed of 30% sugar, 0.5% emulsifier, and cocoa butter substitute:cocoa powder at a mass ratio of 8:1, 1.4 mm in thickness, and formed at 50 ℃.

The retrogradation of mung bean starch in ice cream during frozen storage leads to an unpleasant starchy taste. In this study, mung bean starch was treated withα-amylase and the effects of various hydrolysis conditions on retrogradation properties of mung bean starch were investigated using orthogonal array design method. After proper treatment with α-amylase, the unique taste of mung bean was still maintained, and mung bean starch showed high water-holding capacity, good gelatinization properties and significantly lower retrogradation degree compared with native mung bean starch. The optimal hydrolysis conditions were pH 6.5, α-amylase dosage 0.0008% and 70 ℃ for a hydrolysis duration of 8 min. Different levels of enzymatic hydrolysate of mung bean starch, CMC-Na, gelatin, glycerin monostearate (GMS) were added together for manufacturing ice cream and these ingredients were found to have different effects on the swelling rate, melting resistance and taste of ice cream. Ice cream with enzymatic hydrolysate of mung bean starch, CMC-Na, gelatin and GMS added at 60%, 0.1%, 0.1% and 0.15%, respectively showed notably improved taste.