The preparation and digestion stability of calcium-chelated cod bone gelatin peptides were investigated in this study. The optimal parameters for chelating cod bone gelatin polypeptides with CaCl2 were obtained by using a 3-factor 3-level Box-Behnken experimental design with response surface methodology as follows: after the gelatin was hydrolyzed at 50 ℃ for 1.5 h, the hydrolysate and CaCl2 were mixed at 50 ℃ at a mass ratio of 8:1 for 1 h and adjusted to pH 5.5. Then, after reaction, the samples were collected by precipitating the calcium-chelated cod bone gelatin polypeptides with pure ethanol, and dehydrated by vacuum freeze drying. The chelating rate was 93.47%. Scanning electron microscope showed that the microstructure of cod bone gelatin polypeptides changed dramatically after chelated with Ca2+, turning from coarse fibers into smooth spherical granules. Fourier transform infrared spectroscopy analysis suggested that after chelated with Ca2+, the spectra of gelatin peptides and its calcium-chelated form changed dramatically, indicating the occurrence of chelating reaction between gelatin peptides and Ca2+. The calcium chelating rate of cod bone gelatin polypeptides decreased from 60.74% to 3.64% after simulated gastric digestion (pH 2.0) for 120 min because H+ competed for the binding sites with Ca2+, causing damage to the calcium-chelated form. The chelating rate increased from 10.74% to 53.38% after 120 min simulated intestinal digestion. However, there was almost 50% of free Ca2+ in the system, suggesting that the chelated structure is sensitive to the gastric environment but remains relatively stable in the intestinal system. The results of this study can provide theoretical support and technical reference for the development of new calcium supplements and for the high-value utilization of aquatic product processing byproducts.

In this study, we investigated the preparation of grass carp surimi with the addition of potato starch by ultrahigh pressure (UHP) processing. The effects of pressure level, holding time and potato starch addition on gel properties of grass carp surimi were examined for optimization of the three factors by response surface methodology. The results showed that gel properties of grass carp surimi were improved significantly by UHP treatment. The gel strength was highest at 300 MPa, and both whiteness and water-holding ability increased with increasing pressure. On the other hand, the changes in gel properties of grass carp surimi were not apparent after treatment for longer than 10 min at 300 MPa. With increasing addition of potato starch, the gel strength of surimi gels was improved significantly, and it reached the maximum at 8% potato starch content. Textural properties of sausages made from the surimi with more than 4% potato starch added were evidently improved. Using one-factor-at-a-time method and response surface methodology, the optimum conditions for the preparation of surimi were found to be addition of 8% potato starch and UHP treatment at 340 MPa for 12 min. Under these conditions, the gel strength was (421.07 ± 19.13) g·cm.

The aim of this research was to determine the synergistic effect of ultra-high pressure and enzymatic treatments on allergen elimination from shelled shrimp (Litopenaeus vannamei). Fresh shrimp were treated by ultra-high pressure alone and in combination with enzymatic digestion after removing head, tail, shell, and digestive tract. The allergenicity of the treated samples was examined by indirect enzyme-linked immunosorbent assay (ELISA). Results showed that the highest percentage of allergen elimination of 45.66% was obtained by single ultra-high pressure treatment under 600 MPa at 40 ℃ for 30 min, and it was increased to 95.27% by combining ultra-high pressure treatment under 200 MPa for 30 min at 40 ℃, enzyme dosage 3 000 U/mg with trypsin hydrolysis. Therefore, the allergenicity of shelled L. vannamei could be eliminated by ultra-high pressure treatment, and better effect could be achieved by combination with enzymatic hydrolysis.

Edible composite films were prepared using corn starch phosphate (CDP) and corn straw cellulose (CSC) as the main ingredients. The effects of CDP to CSC ratio, carboxymethyl cellulose (CMC) concentration, and glycerol (Gly) concentration on the physical properties such as tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP) and transmittance (T) of the edible films were studied. Further, using the comprehensive score for the physical properties as response value, the optimum process conditions were obtained by response surface analysis as follows: CDP and CSC ratio, 8.5:1.5; CMC concentration, 0.8 g/100 mL; and Gly concentration, 1.0 g/100 mL. Under these conditions, the physical properties of edible films were the best overall with a score as high as 0.683, which was increased by 27.14% compared with that of the edible films with no added CSC, and the TS, EAB, WVP and T were 19.75 MPa, 46.89%, 1.167×10-12 g/(cm·s·Pa) and 41.86%, respectively. As observed and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), the surface of the CDP/CSC edible films was smooth, showing a dense structure and good compatibility of the ingredients.

Okras were dried in a vacuum dryer to a moisture content about (5 ± 0.5)% (mf). The drying and quality characteristics of okras were evaluated in terms of moisture content, rehydration ratio, hue angle, total color difference (ΔE) and VC content. In order to achieve faster drying rate along with a high-quality product, the drying conditions, including drying temperature (30 to 70 ℃), system pressure (10 to 50 kPa) and slice thickness (5 to 30 mm) were optimized by response surface methodology based on average drying rate (A-DR) and VC content. Drying models were obtained by the nonlinear fitting of drying curves. In addition, the optimization experiments were carried out based on a second-order central composite rotatable design, and the fuzzy reasoning method was used for sensory evaluation of okra quality under the optimized drying conditions. As a result, moisture content curves of okra during vacuum drying conformed to the Logarithmic model best. Analysis of variance showed that a second-order polynomial model predicted well the experimental data. The drying conditions of 60 ℃ temperature, 18 kPa pressure and 10 mm slice thickness were found optimum for okra vacuum, which resulted in relatively high levels of comprehensive score (0.911), A-DR (1.059 kg/(kg·h)) and VC content (8.315 mg/100 g, md). At the same time, the product dried under the optimum conditions could be accepted by consumers.

Furfural was produced from xylose dehydration catalyzed by high temperature liquid water (HTLW) using toluene as extraction solvent. Important process parameters were optimized by Box-Behnken design using response surface methodology. Furfural yield was used as the response variable. It was demonstrated that initial concentration of xylose had the greatest influence on furfural yield, followed sequentially by toluene dosage, reaction time and temperature and that their optimal levels were determined respectively as 120 g/L, 25 mL, 6 h and 188 ℃ when 20 mL of xylose solution was used. The experimentally measured yield of furfural under these conditions was 68.72%, which basically coincided with the predicted value. Gas chromatography-mass spectrometry (GC-MS) analysis confirmed the product as furfural.

Objective: To investigate the processing of puffed cereal grains with added Cordyceps militaris by twin-screw extrusion and to explore the effects of addition of C. militaris on the starch pasting characteristics of extruded products. Methods: The flours of five cereal grains, rice, glutinous rice, adlay, red mung bean, and soybean were mixed after adding C. militaris powder and then extruded. Using the one-factor-at-a-time method, moisture content, screw rotation speed, feeding rate and extrusion temperature were selected as independent variables for the optimization experiments which were conducted following an orthogonal array design. The responses were radial expansion rate, degree of gelatinization, moisture content, water-absorbing capacity and solubility index. Optimization of the independent variables was done using range analysis. The starch pasting characteristics of the extruded product were assessed. Results: The optimal processing parameters were determined as follows: material moisture, 16%; screw rotation speed, 180 r/min; extrusion temperature, 80-90-120-140-165 ℃; and feeding rate, 15 r/min. Under these conditions, the radial expansion rate, degree of gelatinization, moisture content, water-absorbing capacity and solubility index were 3.015, 84.32%, 6.11%, 26.65%, and 416.39%, respectively. The rapid visco analyzer (RVA) results revealed that peak viscosity, hold viscosity, final viscosity and setback were reduced significantly in the extruded product after adding C. militaris, while peak time was increased significantly. Conclusions: The extrusion technology was feasible. Moreover, addition of C. militaris could significantly decrease starch pasting characteristics and inhibit starch retrogradation and molecular rearrangement in extruded cereal grains.

This research was conducted to study the effect of glucose oxidase on the browning inhibition and quality of Rosa roxburghii Tratt. juice during processing storage and to explore the conditions for browning inhibition. Using Box-Behnken design combined with response surface methodology, the optimal conditions for browning inhibition were determined as 28 U/L, 38 min and 37 ℃ for enzyme dosage, hydrolysis time and temperature, respectively, yielding a browning index of 0.122 ± 0.001. Under these conditions, glucose oxidase significantly depleted the dissolved oxygen in R. roxburghii Tratt. juice (P < 0.05), decreasing to a level (0.523 mg/L) significantly (P < 0.05) lower than that of the control group (5.991 mg/L), and as a result inhibited the oxidation of R. roxburghii Tratt. juice. Moreover, glucose oxidase treatment could better maintain the VC and amino nitrogen contents of R. roxburghii Tratt. juice, slowed down the formation of the browning intermediate product 5-hydroxymethylfurfural (5-HMF), blocked the increase in browning index (P < 0.01), and effectively inhibited the occurrence of R. roxburghii Tratt. juice browning.

A purified exopolydsaccharide was obtained from the cell-free culture broth of Nostoc flagelliforme cells by concentration, dialysis, deproteinization, alcohol precipitation and sequential column chromatographies on DEAE-52 cellulose and Sephadex-100. By combined use of one-factor-at-a-time method and Box-Behnken response surface methodology, the optimum sulfation conditions for maximum degree of substitution (DS) of sulfate groups in the polydsaccharide (5.05) were obtained as follows: reaction temperature, 71 ℃; reaction time, 3 h; and chlorosulfonic acid-pyridine ratio, 1:7 (V/V). The infrared spectroscopy analysis showed the binding of sulfuric acid groups to the polysaccharide molecule.

α-Linolenic acid was extracted and purified from sacha inchi oil by β-cyclodextrin inclusion complexation under ultrasonic condition where the efficiency of inclusion complexation could be enhanced. The effect of temperature, ultrasonication time and ratio of β-cyclodextrin to a 2:1 (m/m) mixture of mixed fatty acids prepared from sacha inchi oil and absolute ethanol on the α-linolenic acid content (i.e., purity) of purified product was examined by the one-factor-ata- time method. Subsequently, the operating parameters were optimized using response surface methodology (RSM) with Box-Behnken design and experimentally validated. The highest purity of α-linolenic acid of 59.16% was observed when β-cyclodextrin and the mixture of mixed fatty acids and absolute ethanol were mixed together at a mass ratio of 7.4:1 and then ultrasonicated for 73 min at 60 ℃. In this experiment, a new method for the extraction of α-linolenic acid has been established and our approach can provide useful evidence to optimize the extraction of other fatty acids from sacha inchi oil.

In order to achieve efficient utilization of bitter apricot kernel meal (Prunus armeniaca), the effect of blanching on the amygdalin content of bitter apricot kernels with skin, and the optimization of the ultrasonic-assisted extraction of amygdalin from bitter apricot kernel meal left after pressing out oil using response surface methodology was investigated as well as the preparation of highly pure amygdalin from crude extract. The results showed that significant enzyme inactivation and good retention of amygdalin were simultaneously achieved by blanching in a 5-fold volume of boiling water for 10 min, and the relative content of amydalin was (4.72 ± 0.14)% after blanching. The maximum extraction rate of amygdalin of 8.03% was obtained when the extraction was carried out twice using 73% ethanol as extraction solvent at a solvent-to-solid ratio of 8:1 with 20 min ultrasonication. The crude extract obtained was purified by high performance centrifugal partition chromatography (HPCPC), and it turned out that amygdalin with the highest purity of 96.14% was obtained by using the upper organic phase of n-butanol/ethyl acetate/methanol/water (2.5:0.625:0.5:4, V/V) as the stationary phase and the lower aqueous phase of the mixed system as the mobile phase at a centrifugal speed of 900 r/min and at a flow rate of 2.0 mL/min.

Correlation analyses of antioxidant properties were used for selecting an appropriate method for quality evaluation of dried loquat. Arrhenius first order kinetics and difference models were established with drying time and temperature as independent variables versus the contents of flavonoids and total phenols and 2,2’-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid) (ABTS) free radical scavenging capacity. The models were tested by mean error, mean absolute error and root mean square error. Nonlinear programming and evolutionary algorithms were used to minimize the energy consumption. Results showed that flaovonoids, total phenols and antioxidant activity demonstrated a slow upward trend with the loss of water during the drying process of loquat. The Arrhenius difference models improved the accuracy of predictions compared with the first order kinetics models, with determination coefficients of 0.92, 0.90 and 0.93 for flavonoids, total phenols and ABTS free radical scavenging capacity, respectively. Mean error, mean absolute error and root mean square error of validation were between 0.07–0.80, 0.18–1.53 and 0.07–0.59, respectively. The models were found to be valid in terms of precision. Optimal drying time and temperature were (183 ± 1) min and (65 ± 1) ℃, respectively.

The volatile compounds of fermented grains of Chinese Gujinggong liquor were extracted by solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatographyolfactometry (GC-O) by comparison of their retention indices (RI) with those of standards. A total of 148 volatile compounds were identified, with 21 of these being the most important flavor compounds. An internal standard method was used to quantify the 21 compounds and odor activity value (OAV) was used to rank their contributions to the overall aroma of fermented grains. It turned out that hexanoic acid ethyl ester (OAV = 2 817), octanoate (OAV = 534), ethyl butyrate (OAV = 519), and 3-methyl butyl acetate (OAV = 137) made the greatest contributions, followed by ethyl decanoate, butyric acid, ethyl lactate, ethyl phenylacetate, benzenepropanoic acid ethyl ester, benzene ethyl acetate, caproate, 2,3-butanediol, acetic acid, propionic acid and benzyl alcohol.

This research was intended to characterize the aroma components of five different cooked grains used for Chinese liquor production using solid phase micro-extraction (SPME) combined with gas chromatography-olfactometry-mass spectrometry (GC-O-MS) by NIST database and retention index. A total of 106, 96, 93, 87 and 80 aroma components were identified from cooked sorghum, rice, glutinous rice, wheat and corn, respectively. In addition, GC-olfactometry analysis showed that 26, 20, 20, 15 and 10 odorant compounds were detected in cooked sorghum, rice, glutinous rice, wheat and corn, respectively. The results showed that ethyl caproate, phenethyl alcohol, nonanal, (E)-2-octenal and 2-pentylfuran were the most important aroma-active components, contributing to 0.12%–4.73%, 0.05%–0.55%, 0.06%–1.65%, 0.23%–1.64%, 0.51%–4.82% and 0.06%–1.65% of the total aroma composition, respectively. Cooked sorghum was identified to have the strongest flavor intensity and most diverse composition with the most abundant being esters, aldehydes and ketones among the studied grains. Moreover, terpene was only detected in cooked sorghum. Cooked rice and glutinous rice showed similar aroma composition, both of which were dominated by esters and aldehydes, but cooked wheat and corn produced were less rich in aroma-active compounds with aldehydes being the most predominant. Collectively, the results of the flavor components of the five different cooked grains can provide useful information for selecting raw materials for the production of Chinese liquor.

In order to comparatively analyze the taste compounds and taste characteristics in shiitake mushroom soup and enzymatic hydrolysate, free amino acids and MSG-like components (5’-nucleotides and free amino acids) of shiitake mushroom soup, enzymatic hydrolysate and rehydration liquid were analyzed by an automatic amino acid analyzer and high performance liquid chromatography (HPLC). The equivalent umami concentration (EUC) was calculated with the classical formula. The freshness was evaluated and taste profile was analyzed by electronic tongue. The results indicated that the total content of amino acids in the enzymatic hydrolysate was highest (3 453.98 μg/g), and the ratio of flavor amino acids to total amino acids was similar among the three samples investigated with bitter amino acids being at higher levels. Shiitake mushroom soup contained the highest level of 5’-GMP (967.84 μg/g) while the content of 5’-AMP was the highest in the enzymatic hydrolysate and the rehydration liquid. The EUC of the enzymatic hydrolysate was highest (30.54 g MSG/100 g), suggesting the strongest umami taste. Using electronic tongue and principal component analysis (PCA), the taste of shiitake mushroom soup, enzymatic hydrolysate and rehydration liquid were significantly different from each other with a discrimination index (DI) of 94.

The nutrient contents of loach roe and the fatty acid composition of loach roe oil were determined in this work. Loach roe oil was extracted with n-hexane-isopropanol, and its physicochemical indexes and fatty acid composition were determined and compared with the fat of loach meat, crucian carp roe, sturgeon roe, Rana chensinensis egg and breast milk. The results showed that the moisture content of loach roe was 64.69%, crude protein was 24.49%, crude fat was 5.62%, and ash was 1.56%; the density of loach fish oil was 0.901 4 g/mL, refractive index was 1.463 8, iodine value was 105 g I/100 g, and saponification value was 134 mg KOH/g. Gas chromatography-mass spectrometry (GC-MS) analysis indicated that the unsaturated fatty acid content of loach roe oil was 71.30%, with oleic and linoleic acid accounting for 28.02% and 24.51% of the total amount, respectively. In comparison with loach fish, crucian carp roe and sturgeon roe, the ratio of saturated to monounsaturated to polyunsaturated fatty acids in loach roe oil was roughly the same as that of breast milk fat, which was very close to the golden ratio 1:1:1 of healthy cooking oil, and loach roe and breast milk had almost the same fatty acid composition. Thus, loach roe has great development and utilization potential.

This study aimed to identify and quantify volatile compounds in five different Fenghuang Dancong oolong teas using head space solid-phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Fiftyfive volatile compounds, including alcohols, aldehydes, esters, ketones, alkenes, and alkanes, were identified. Alcohols were the major components, followed by alkene. The major volatile compounds common to these five types of oolong teas were hotrienol, linalool, linaloloxide, D-limonene, β-myrcene, indole, jasmone, nerolidol, benzyl nitrile and σ-cymene. However, their relative contents were different, which are consistent with their aroma patterns.

Headspace solid phase mciroextraction combined with gas chromatography-mass spectrometry (HS-SPME-GCMS) and principal component analysis were used to determine the volatile compounds of “Bashanhong” Toona sinensis at five different developmental stages. Forty-four volatile compounds were detected in fifteen samples. It was indicated that there were significant differences in the species and relative contents of volatile compounds in developing leaves of Toona sinensis. The primary volatile components in tender buds were terpenes, while those during the bud-leaf period and during the juvenile leaf period were sulphur-containing compounds. The relative contents of terpenes and sulphur-containing compounds in mature and old leaves were similar. As the bud-leaf period proceeded to the juvenile leaf period, the species and relative contents of volatile compounds changed quite quickly, which greatly affected the quality stability of fresh and processed tender buds. The volatile compounds which had greater contributions to the aroma characteristics of “Bashanhong” T. sinensis were alcohol, ester, aldehyde and terpene. This research reveals the volatile profile of “Bashanhong” T. sinensis leaves as well as the composition of characteristic aroma compounds at different developmental stages, which could provide useful information for utilization and processing of mature and old leaves of “Bashanhong” T. sinensis.

The main nutritional components, amino acids and minerals in two samples of Xerocomus spadiceus from Linzhi city of Tibet were analyzed, and their nutritional values were evaluated in comparison with those of other boletus such as Boletus edulis, B. aereus and B. speciosus as well as Leccinum crocipodium. The results showed that proteins and crude fibers were the predominant components of X. spadiceus, with a total content of 43.29% and its crude fiber content was 13.73%, which was higher than that of other boletus species and Leccinum crocipodium. X. spadiceus had lower crude fat content with an average of 4.55%. In addition, X. spadiceus possessed a well-balanced amino acid composition with a ratio of essential to total amino acids of 39.10% and a ratio of essential to non-essential amino acids of 0.64, and with umamitaste and medicinal amino acids accounting respectively for 31.80% and 59.33% of the total amino acids. Glutamic acid, aspartic acid, alanine and leucine were the dominant amino acids in X. spadiceus. Methionine and cysteine were the first limiting amino acids. X. spadiceus was rich in minerals, especially potassium, calcium, iron, zinc, and selenium. Moreover, the contents of calcium and selenium in X. spadiceus were higher than in other tested mushrooms. Mercury and lead were not detected and the levels of cadmium and arsenic in X. spadiceus were within the range stipulated in the national standard of China. Therefore, X. spadiceus is a wild edible mushroom high in dietary fiber and protein, low in fat, and rich minerals.

Objective: To explore the relationship between the volatile components of different potato varieties and processing temperature and to analyze the differences among different geographical environments. Methods: The volatiles of potato processed at room temperature, 100 and 150 ℃ were detected by electronic nose and the obtained data were analyzed by linear discriminant analysis (LDA). Then headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect and qualitatively and quantitatively analyze the volatile compounds of potato. Results: The electronic nose could sensitively detect the significant difference in volatile composition among two potato growing regions. A total of 54, 62, 75, 71 and 46 volatile compounds were detected in potato samples 1, 2, 3, 4 and 5 by gas chromatorgraphy-mass spectrometry (GC-MS), respectively, mainly including alcohols, hydrocarbons, aldehydes, ketones, esters, furans and other compounds. 2-Pentyl-furan, long-chain alkanes and benzeneacetaldehyde were the characteristic volatile components of potato sample 1,2-pentyl-furan, 2,2,3,3-tetramethyl-butane, 2-octena, benzeneacetal dehyde and oleic acid-3-(octadecyloxy)-propyl ester were the characteristic volatile components of potato sample 2,1-octen-3-ol, 1-butanol- 3-methyl-acetate, toluene, 2-methyl-butanal, benzeneacetaldehyde, formic acid-2-ethylhexyl ester, carbonic acid-isobutyl 2-ethylhexyl ester and 2-pentyl-furan were the characteristic volatile components of potato sample 3,1-octen-3-ol, 3-methylacetate- 1-butanol, carbonic acid-isobutyl 2-ethylhexyl ester, methyl salicylate and 2-pentyl-furan were the characteristic volatile components of potato 4, and 1-octen-3-ol, methyl salicylate, 2-pentyl-furan and 3-methyl-acetate-1-butanol were the characteristic volatile components of potato sample 5. Conclusions: Different potato varieties and different growing regions are different in the main types of volatile components and their relative contents.

Illumina HiSeq high throughput sequencing and the traditional plate culture method were comparatively applied to investigate the structure of bacterial community attached to oyster. Results showed that the dominant bacteria attached to oyster belonged to the Gammaproteobacteria (72.3%) class in the Proteobacteria (77.5%) phylum. At the order level, Vibrionales (49.3%) and Alteromonadales (12.2%) were dominant. At the family level, Vibrionaceae (36.8%), Shewanellaceae (10.3%) and Pseudoalteromonadaceae (7.2%) were dominant. At the genus level, the relative proportions of Vibrio (28.3%), Shewanella (10.3%) and Pseudoalteromonas (7.2%) were high. The results of high throughput sequencing for the top three most dominant genera were consistent with those obtained with the traditional culture method although the proportions of these bacteria were somehow different.

In this study, an electronic nose was used to detect the flavor of Cantonese sausage during processing (0, 12, 24, 36, 42, 48, 54, 60, 72, 96 and 120 h) and storage (0, 2, 4, 6, 8, 12 and 20 weeks). The acid value (AV) and peroxide value (POV) were simultaneously measured to evaluate fat oxidation in Cantonese sausage. The contribution rates of 10 sensors to the flavor of sausages were evaluated through loading analysis, variance analysis and Pearson analysis. The results indicated that as the optimal sensor arrays for monitoring fat oxidation, S4, S6, S7, S8 and S9 for processing and S6, S7, S8 and S9 for storage were selected. Artificial neural network (ANN) models were developed to predict the degree of fat oxidation in Cantonese sausage using electronic nose data. The R2 values of the models based on all sensors for AV and POV prediction during processing were 0.959 and 0.930, respectively, while those were 0.930 and 0.914 based on the optimal sensors, respectively. During storage, all the R2 values were greater than 0.9, except for the POV prediction model based on the optimal sensors with R2 value of 0.805. Therefore, the electronic nose was suitable for evaluating fat oxidation in Cantonese sausages during processing and storage, which could be further applied to guide the commercial production and storage of Cantonese sausage.

In this study, a loop-mediated isothermal amplification (LAMP) assay combined with propidium monoazide (PMA) treatment was developed for the rapid and efficient detection of Staphylococcus aureus with sublethal injury. The sensitivity of PMA-LAMP was investigated by artificially contaminating food samples including frozen dumplings and milk powder with S. aureus. The results showed that a concentration of 3 μg/mL PMA was optimal for completely restraining the amplification of 1.2 × 107 copies/mL of DNA from dead S. aureus which was exposed to a 650 W halogen lamp for 5 min. PMA-LAMP could achieve the specific detection of the unique nuc gene of S. aureus with sublethal injury at a constant temperature of 65 ℃ within 60 min with a sensitivity of 34 CFU/mL. In addition, the PMA-LAMP assay was proved efficient by using it to detect the viable cells in artificially contaminated samples, with a sensitivity of 17 CFU/mL for artificially contaminated milk powder and 1.70 × 102 CFU/mL in artificially contaminated frozen dumplings. It can be concluded that the PMA-LAMP assay can efficiently detect S. aureus with sublethal injury and provide a new technique for detecting S. aureus in food samples.

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed for the extraction of 14 phthalate esters (PAEs) in barley prior to gas chromatography-mass spectrometry (GC-MS) analysis. All barley samples were smashed, sieved with an 80-mesh siever and dissolved in an aqueous solution at pH 2. The PAEs in samples were extracted with acetonitrile and salted out with anhydrous MgSO4 and NaCl. Then, after centrifugation, the supernatant was cleaned up with a C18 sorbent at a solid-to-liquid ratio of 50 mg/g. Moreover, the addition after extraction method was used to evaluate the matrix effects (ME) in the GC-MS analysis of 14 PAEs. As a result, all 14 PAEs exhibited an enhanced matrix effect in barley matrix, with a percentage enhancement in the range of 41.0% to 78.1%. Thus, a matrix-matched curve could be used to eliminate the matrix effects and in turn achieve more accurate quantitation. The recoveries of 14 PAEs in barley matrixes at three spiked levels of 15, 150 and 500 μg/kg ranged from 73.8% to 120.1% with relative standard deviations (RSD) below 10%. The limits of detection (LODs) and limits of quantitation (LOQs) for the PAEs, based on RSN ratio of 3 and 10, ranged from 0.1 to 2.5 μg/kg and from 0.13 to 5.0 μg/kg, respectively. Finally, the 14 PAEs in six barley samples were successfully determined using the proposed method. The results indicated that dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), and bis(2-methoxyethyl) phthalate (DEHP) were present in all the samples examined, but their concentrations were different. The contents of DEP and DEHP detected in all the barley samples were below the maximum residue limit stipulated in the Chinese National Standard (GB 9685—2008).

A fast high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the quantitative determination of T-2 and HT-2 toxins in tilapia, Litopenaeus vannamei and golden scallop. After being homogenized, samples were extracted with 10 mL of neutral ethyl acetate by vibration, and after removing the moisture with sodium sulfate, 5 mL of the upper layer was concentrated with nitrogen blowing, re-dissolved with 1 mL of 0.1% formic acid in methyl alcohol:5 mmol/L ammonium acetate (3:7, V/V), and degreased with hexane. The target compounds were quantified by the matrix-matched external standard method. Under optimized conditions, the lower limits of quantitation (LLOQs) for T-2 and HT-2 toxins in three aquatic products were 2 and 4 μg/kg, respectively. The linear range was 2–100 ng/mL for T-2 toxin and 4–200 ng/mL for HT-2 toxin. The average recoveries for three aquatic samples at three spiked levels ranged from 84.3% to 109.9% for T-2 toxin and 90.9% to 103.2% for HT-2 toxin. The relative standard deviations (RSDs) were in a range of 2.0%–8.7% for T-2 toxin and 2.6%–10.6% for HT-2 toxin (n = 6). The method is simple, rapid, accurate, precise and suitable for the simultaneous detection of T-2 and HT-2 toxins in the three representative aquatic products.

In this study, a real-time loop-mediated isothermal amplification (Rti-LAMP) assay system was developed for the rapid detection of Salmonella enterica in chicken. It showed that the lowest level of 6 CFU/reaction for pure Salmonella culture could be detected in 45 minutes by the Rti-LAMP targeting the invA gene using Midori Green as nucleic acid dye. Furthermore, 25 g of chicken was artificially with various numbers (CFU) of Salmonella, followed by enrichment culture at 37 ℃ for 4 h and then filtration through Whirl-Pak bag and the bacterial cells were pelleted by centrifugation at 13 000 g. The resulting pellets were suspended in saline and processed for cell lysis and DNA purification. Finally, 2 μL of purified DNA sample was incorporated into 25 μL of Rti-LAMP reactions at 65 ℃ for 60 min. The lowest level of 450 CFU/g of Salmonella was consistently detected by the Rti-LAMP assay. The entire assay could be completed in 7 h. A total of 21 chicken samples purchased from local market were detected by the Rti-LAMP assay using Salmonella culture as positive control. The same one sample was detected positive to Salmonella by the Rti-LAMP assay and the method described in the Chinese national standard. It suggested that the sensitivity and accuracy of the Rti-LAMP assay were comparable to those of the national standard method, and the former took only 7 h, which was highly time-saving compared with the latter.

A new method for the determination of multiple elements in edible mushroom oil with direct injection by inductively coupled plasma mass spectrometry (ICP-MS) was established. Samples were diluted using kerosene, as it has some useful characteristics such as lower saturated vapor pressure and better thermal stability, and thus narrow injector torch and high temperature plasma were used to ensure good determination of the elements with low ionization efficiency and maintain the stability of the plasma torch. The collision reaction cell (CRC) method was adopted to eliminate the background signals caused by polyatomic ion interferences from organic matrix. An optional gas flow of 20% O2 in Ar was added to the carrier gas to prevent carbon build up on the interface cones. The results showed that the limits of detection (LODs) of the method were in the range of 0.018–92.27 ng/g for 26 elements. Its linear correlation was preferable with a correlation coefficient of no less than 0.999 8. The precision expressed as relative standard deviation (RSD, n = 11) was no greater than 4.4%, and the recoveries of the analytes were in the range of 92.60%–106.16%. This method was simple and applicable for the quality control and safety evaluation of inorganic elements in different edible mushroom oils.

A rapid method was developed for the determination of 5 common ethyl esters, ethyl acetate, ethyl butyrate, ethyl lactate, ethyl valerate and ethyl caproate, in liquor without any sample pretreatment using on-line mass spectrometry. Reasonable linearity was achieved for all the analytes over the range of 0.5–20 mg/L with correlation coefficients (R2) greater than 0.99. The recoveries for five ethyl esters at two spiked levels were in the range from 81.1% to 99.7% with relative standard deviations (RSDs) of 4.7%-9.4%. The limits of detection (LODs) of the method ranged from 24 to 312 μg/L. Under optimized conditions, four kinds of distilled spirits marketed in China were analyzed, such as Chinese liquor, brandy, Dry Gin and whiskies. The main ester components and their contents in the same kind of distilled spirit were basically the same while ethyl esters were determined at different levels in Chinese liquor, brandy and whiskies. Meanwhile, the four kinds of distilled spirits could be distinguished accurately using principal component analysis.

Cholesterol, a sterol derived from animal fat, is essential for and possesses important physiological functions in human body. However, unbalanced intake of cholesterol will induce serious cardiovascular and cerebrovascular diseases. A new, rapid and noninvasive method to quantitatively analyze cholesterol in foods of animal origin was developed by near-infrared reflectance spectroscopy (NIRS) within medium wavelength range, and its feasibility was examined. Original spectra of commercially available fresh beef high ribs were collected. The suspicious samples were analyzed and discriminated with Mahalanobis distance and studentized residual, and the outlier samples were determined by twicedetection diagnosis method and removed based on final judgment after secondary partial least squares (PLS) regression analysis. The optimal model for quantitative analysis of cholesterol in fresh beef was established after spectral pretreatment and model optimization. The experiment results indicated that the difference between the predicted values and reference values of the independent test set was not significant (P > 0.05). The overall prediction accuracy could meet the requirements of the Chinese national standard (≤ 10%).

An isotope dilution gas chromatography-tandem mass spectrometry (GC-MS/MS) method was applied to determine 27 phthalate ester residues in pastry. Samples were extracted with a mixture of n-hexane and ethyl acetate (1:1, V/V) and the extract was cleaned up on a C18 column, detected by GC-MS/MS under multiple-reaction monitoring (MRM) mode, and quantified by an isotope internal standard method. The calibration curves of 23 out of 27 phthalate esters tested showed good linearity in the range of 0.05–10 mg/L, while those of di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP) and phthalic acid, bis-dodecyl ester (DLP) were highly linear in the range of 0.1–20 mg/L, all with correlation coefficients greater than 0.99. The limits of detection (LODs) were in the range of 0.000 1–0.009 8 mg/kg and the limits of quantification (LOQs) ranged from 0.000 5–0.032 6 mg/kg. The recoveries of the proposed method for 20 different pastries at spiked levels of 0.1, 0.2 and 2.0 mg/kg were 74.3%–117.5% with relative standard deviations (RSDs) of 2.9%–13.5%. The method is simple and sensitive with a wide linear range, and can be suitable for the determination of phthalate ester residues in pastry.

The formation mechanism of ternary supra-molecular systems composed of aflatoxin M1 (AFM1), β-cyclodextrin or its derivatives (β-CDs) and Hg2+ was studied by measuring the native fluorescence of AFM1 and fluorescence changes of the β-CD-Hg2+-AFM1 system. The fluorescence intensity of the methyl-β-CD-Hg2+-AFM1 ternary supramolecular system in 20% (V/V) aqueous methanol with a molar ratio of Hg2+ to M-β-CD to AFM1 of 6.6 × 104:5.80 × 105:1 could be 4.5 times higher than that of the native fluorescence intensity of AFM1. It was proved that AFM1 entered the cavity of M-β-CD, leading to reduced fluorescence quenching and increased sensitivity of detection by spectroscopic and thermodynamic analyses. Supermolecular inclusion constants and thermodynamic constant were calculated and the superamolecular reaction mechanism was studied preliminarily by the Benesi-Hidebrand equation and Van’t Hoff equation. Good linearity was observed in the AFM1 concentration range of 0.01–2.00 μg/L with a correlation coefficient of 0.999 2 and the detection limit of this method was 0.002 6 μg/L. The method could be used in the rapid detection of AFM1 in dairy products with high sensitivity. It was simple, efficient and economical without interference from most fortified trace minerals except Fe3+ in dairy products.

The organic pollutants were investigated by gas chromatography-mass spectrometry (GC-MS) using NAGINATATM software and the health risks associated with dietary exposure to them were assessed in 34 samples of 4 kinds of edible oils, soybean oil, sunflower oil, rapeseed oil and corn oil. The results showed that 14 to 80 organic pollutants were found in the investigated oils with their total concentrations varying from 1.44 to 54.77 mg/kg. Moreover, among these pollutants, the total amounts of pesticide residues, synthetic intermediates and others (polycyclic aromatic hydrocarbons, phthalic acid esters, etc) were in the range of 0.16–36.005, 0.095–9.78 and 0.045–19.725 mg/kg, respectively. According to the Chinese national standards GB 2763—2014 and GB 2762—2012, dietary exposure assessments for some organic pollutants were carried out. It was found that the risk level at which people were exposed to the organic pollutants in edible oils chronically could be accepted. Moreover, much attention should be given to dieldrin and 3,5-dimethylphenomethylcarbamate (XMC) due to their high exposure level at 3.35%–90% and 4.50%–87.25%, respectively.

The secondary contaminant of di-(2-ethylhexyl) phthalate (DEHP) during tea infusion and sample preparation was investigated and controlled in this study. The aim of this research was to evaluate the transfer rate of DEHP during tea infusion using isotope DEHP-D4 simulation and gas chromatography-tandem mass spectrometry (GC-MS/MS). Serious secondary contaminant of DEHP could occur in the reagents and vessels used and the process of rotary evaporation, amounting to 13%–400%. Transfer rate of DEHP-D4 was found in the range of 4.5%–11.9%, which was related with tea category, brewing method and number of brewing cycles, but not with the concentration of DEHP-D4 spiked in tea. This finding is helpful for the risk assessment of DEHP and the formulation of maximum residue limit of DEHP in tea.

The speciation of arsenic in Lentinus edodes was analyzed using ultrasonic-assisted extraction (UAE) combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Six arsenic compounds were extracted ultrasonically from the samples using 0.3 mol/L acetic acid solution as extraction solvent. The chromatographic separation was performed on a Hamiton PRP-X100 anion exchange column using a mixture of 25 mmol/L ammonium dihydrogen phosphate and water as the mobile phase. Under the optimized conditions, there were good linear relationships in the range of 0–50 μg/L for six arsenic compounds, with correlation coefficients all above 0.998 0. The limit of detection (LODs) of six arsenic species (AsC, AsB, DMA, MMA, AsIII, and AsV) were between 0.31 and 0.59 μg/L. The precision of the method, expressed as relative standard deviation (RSD), was less than 5%. The recoveries of AsC, AsB, AsIII, DMA, MMA, and AsV were in the range of 94.30%–102.75%. Speciation analysis could accurately determine six arsenic species in L. edodes. Inorganic arsenic was the main species in L. edodes, which was in the range of 48.68%–64.25%. This method was simple, rapid, sensitive and accurate, and could meet the requirements for the quantitative analysis of arsenic speciation in plant materials.

A double depuration-gas chromatography (DDGC) method was developed for the simultaneous determination of residues of hexachlorocyclohexanes (BHCs), dichlorodiphenyltrichloroethanes (DDTs) and indicator polychlorinated biphenyls (PCBs) in eggs and egg products. Samples were extracted with acetonitrile followed by double purification with concentrated sulfuric acid and calcined hydrotalcite. Then the analytes were analyzed by GC and quantified with an external standard method. Results showed that compared with the traditional sulfonation method, more thorough extraction and higher purification efficiency of the target analytes with less interferences were achieved by double-purification with concentrated sulfuric acid and calcined hydrotalcite. Good linearities were obtained for four BHCs, two DDTs, and seven PCBs with correlation coefficients greater than 0.999 in the range of 10–200 μg/L. The limits of detection (LODs) (RSN = 3) and limits of quantitation (LOQs) (RSN =10) of the GC method were 1.12–3.89 and 3.73–12.97 μg/kg, respectively. The recoveries of these analytes from liquid egg, preserved eggs and salted eggs ranged from 78.04% to 105.05%, with relative standard deviation (RSD) ranging from 1.28% to 7.55% at three spiked levels of 10, 20, and 100 μg/kg. The method was simple, rapid, accurate and sensitive, and it was suitable for rapid detection of PCBs, BHCs and DDTs residues in eggs and egg products.

This research was done to improve the objectivity of quality evaluation of dried aquatic products and to establish a reliable evaluation model based on electronic nose. Salted silver carp dried under different drying conditions by a heat-pump dryer were detected by electronic nose and measured for total volatile basic nitrogen (TVB-N). Principal component analysis (PCA) combined with statistical pattern recognition and partial least squares (PLS) regression analysis was used to identify TVB-N values of dried silver carp. The results showed the electronic nose had different responses to the TVB-N values of the silver carp dried under different conditions. The recognition rates of training set and testing set based on the K nearest neighbor (KNN) analysis model were over 90%. The correlation coefficients of the PLS model for training set (containing 30 samples) and testing set (containing 15 samples) were 0.913 5 and 0.933, respectively. The root mean square error of cross validation (RMSECV) was 3.67, and the root mean square error of prediction (RMSEP) was 3.26. Results showed that the predictions of the PLS model based on TVB-N could provide greater accuracy in identifying fish dried under different conditions. In conclusion, as an intelligent instrument for the analysis and identification of olfactory signals, electronic nose is a potential objective tool for evaluating the quality of dried fish.

Purpose: To develop a rapid detection kit for Enterobacter sakazakii contamination in milk powder. Methods: A double-antibody sandwich ELISA assay was developed using two monoclonal antibodies against E. sakazakii as the capture antibody and detection antibody, respectively. A test kit that could show a color reaction within 2 h was developed through the optimization of the ELISA reaction. Results: The optimum working concentration of the capture antibody was 10 μg/mL and the optimum dilution of the detection antibody was 1:5 000. The limit of detection (LOD) of the kit was 104 CFU/mL and a linear relationship between OD450 nm values and the lg values of E. sakazakii concentration was observed in the range of 104–108 CFU/mL. In specificity test, three reference strains of E. sakazakii could be detected by the kit whereas other nine strains of common foodborne pathogens were detected as negative. The LOD of the kit was substantially improved to 1 CFU/mL of the original bacterial content after pre-incubation of model samples in broth for 8 h. Both the intra-assay and inter-assay coefficients of variation of the kit were lower than 6%. It could be stored at room temperature for at least six months. Conclusions: The established double-antibody sandwich ELISA kit is suitable for the rapid detection of E. sakazakii in milk powder with high sensitivity, high specificity, high precision and strong stability.

A multi-residue method for the simultaneous determination of 86 pesticide residues in jasmine tea was developed based on optimized quick, easy, cheap, effective, rugged, and safe (QuEChERS) with an improved cleanup procedure using optimized sorbent mixture by gas chromatography-tandem mass spectrometry (GC-MS/MS). Samples were extracted with acetonitrile, and the extracts were cleaned up by liquid-liquid extraction with saturated sodium chloride aqueous solution. Then, the organic phase was transferred into a cylinder filled with a hybrid adsorbent and an organic membrane filter for cleanup and filtration and determinated by GC-MS/MS with an external standard method. The linear range of the developed method was from 5 to 400 μg/kg with correlation coefficients (r2) of more than 0.98. The limits of quantification (LOQs) for the tested pesticides were determinated to be in the range between 0.1 and 8.0 μg/kg. The recoveries of 91.8% of the 86 pesticides at the spiked levels of 80 μg/kg ranged from 70.1% to 116.0%, with relative standard deviations (RSDs) between 1.9% and 11.4% for all the pesticides.

A method for the determination of bongkrekic acid (BKA) in foods was developed using mixed-mode weak anion exchange (WAX) solid phase extraction (SPE) combined with high performance liquid phase chromatography with diode array detection (HPLC-DAD). BKA was separated on a C18 column using a mobile phase consisting of acetonitrile, methanol and 1% acetic acid aqueous solution (10:62:28, V/V). There was a good linearity between the peak area of the analyte and its concentration in the range of 0.1–40 mg/L with a correlation coefficient of more than 0.999. The extraction solvent and conditions were investigated and optimized, and six SPE catridges were compared for their purification efficiencies. The best efficiency was achieved when samples were ultrasonically extracted with 80% acetonitrile in water for 30 min and the extract was cleaned up by WAX solid phase extraction. The limit of detection (LOD) of the method was 0.03 mg/kg. The mean recoveries of BKA from spiked samples were 83.3%–95.6% with relative standard deviation (RSD) less than 5% (n = 6). Compared with the standard method, this method is more accurate and sensitive with higher recovery, requires a simpler and quicker pretreatment and thus, can be used for the determination of BKA in various food samples.

An analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLCMS/ MS) was developed for the determination of eugenol in fish and farming water samples. Fish samples were extracted with n-hexane and the extract was cleaned up by solid phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge. Water samples were directly concentrated and purified with HLB cartridge. Eugenol was quantitated with an internal standard method in the multiple reaction monitoring mode using negative electrospray ionization within 4 min. The calibration curve for the analyte was linear (R2 > 0.996) in the range of 1 to 200 μg/L. The recoveries of the drug from fish and farming water samples were 88.6%–106% and 89.2%–96.5%, respectively with relative standard deviations (RSDs) of 7.82%–11.90% and 5.18%–7.83%. The limits of quantity (LOQs) were 2.5 μg/kg in fish and 0.05 μg/L in water, respectively.

A new approach for the determination of methyl-3-quinoxaline-2-carboxylic acid (MQCA) residue in fish and shrimp samples by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) based on immunoaffinity column (IAC) purification was developed. MQCA was extracted from samples with 2 mol/L hydrochloric acid and adjusted with water to pH 7–8. After being cleaned up and concentrated by immunoaffinity column, the analyte was analyzed by UPLC-MS/MS with electrospray ionization in positive ion mode (ESI+) using multiple reaction monitoring (MRM) and quantitatively determined by an external standard method. The separation was performed on an ACQUITY UPLC BEH C18 column with a gradient system consisting of 0.1% formic acid (V/V) and methanol as the mobile phase. Good linearity in response was obtained in the concentration range of 1.0–50.0 ng/mL with correlation coefficients larger than 0.995. The limit of quantification (LOQ) was 1.0 μg/kg. The average recoveries of MQCA at spiked concentrations of 1.0, 5.0, and 20.0 μg/kg ranged from 74.2% to 86.5% with relative standard deviations (n = 5) less than 10%. The method is simple, fast, sensitive and reliable, and suitable for the determination of MQCA residue in fish and shrimp samples.

The effects of oleocellosis induced by orange oil on the membrane lipid metabolism of Navel orange at low ripening stage (nearly ripe) were studied based on collapse index, discoloration index and cell membrane-related substances. Results showed that oil treatment could induce oleocellosis in Navel orange and the severity of oleocellosis increased as time prolonged. Orange oil exerted phototoxic effects on the fruit peel; the cell membrane system was involved in the response of the fruit to oleocellosis. Oil treatment increased phospholipase D (PLD) activity, decreased phosphatidylcholine (PC) and phosphatidylinositol (PI) and enhanced phosphatidic acid (PA) contents, indicating that the severity of cell membrane degradation increased as oleocellosis developed. Lipoxygenase (LOX) activity was also enhanced by oil treatment during the early storage period, thereby leading to the decrease of unsaturated/saturated fatty acid ratio and the accumulation of reactive oxygen species (ROS). Malondialdehyde (MDA) and electrolyte leakage were increased due to the increased contents of hydrogen peroxide (H2O2) and superoxide anion (O2 ?·) during the whole storage. Cell membrane damage contributed to the occurrence of oleocellosis and led to the increase of oleocellosis severity during storage. This study could provide a theoretical reference for exploring the mechanisms and control strategies of oleocellosis.

This study attempted to elucidate the bacterial spoilage mechanism of salmon during cold chain storage and transport at 4 ℃. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), the traditional identification method and PCR were adopted to analyze the microflora changes in salmon during cold chain storage and transport at 4 ℃ and identify the specific spoilage organisms by testing the spoilage abilities of the dominant strains with yield factors. DGGE fingerprint showed that the diversity of bacterial species decreased during the cold storage of salmon, but the brightness of bands for Pseudomonas spp. and Shewanella spp. increased, which indicated that both strains became the predominant bacteria during the storage. Five dominant spoilage bacteria, Carnobacterium maltaromaticum LMA28, Pseudomonas syringae pv. syringae B728a, Pseudomonas fluorescens SBW25, Carnobacterium sp. WN1359 and Shewanella baltica OS678, were isolated and identified at the end of storage. After separately inoculating the 5 dominate spoilage organisms into sterilized salmon and refrigerating them for a certain period of time, their yield factors of TVB-N were 1.26 × 10-7, 1.25 × 10-7, 1.36 × 10-7, 1.08 × 10-7 and 1.03 × 10-7 mg TVB-N/CFU, respectively. These results showed that P. fluorescens SBW25 has the strongest spoilage ability for salmon, followed by C. maltaromaticum LMA28, P. syringae pv. syringae B728a, Carnobacterium sp. WN1359 and S. baltica OS678 successively.

This study aimed to solve the problem of fast aging of rice during storage in plum rain season environment. High-quality rice of the ‘Nanjing 9108’ cultivar was packaged with a nano-antibacterial material prepared in our laboratory or a normal material (control) and stored in a simulated plum rain season environment (38 ℃ and 92% RH). Samples were withdrawn every 7 days for the measurement of α, β-amylase, catalase and lipase activities, fatty acid and total acid contents, the cross-sectional microscopic structure of rice endosperm and starch pasting properties. The results showed that nano-packaging led to a slower decline in α, β-amylase and catalase activities of rice compared with normal packaging. In addition, nano-packaging delayed the time to reach the lipase activity peak by two weeks and simultaneously mitigated the accumulation of fatty acids and total acid. More importantly, there was no evident difference in the cross-sectional microscopic structure of rice endosperm between nano-packaging and fresh rice, implying that nano-packaging could retard rice aging. Moreover, starch pasting characteristics of nano-packaged rice significantly differed from those of normally packaged rice. This study confirmed that the nano-packaging could retard rice aging in high temperature and humidity environment, inhibit the changes in related enzyme activities and chemical components, and consequently maintain the storage quality of rice.

To extend the shelf life of fresh-cut Agaricus bisporus, the effects of different time periods of hot air pretreatment at 40 ℃ and 85% relative humidity (RH) on physiological and biochemical indices of fresh-cut A. bisporus during cold storage (4 ℃, RH 85%) were investigated. Results showed that hot air pretreatment for 5–10 min significantly reduced the activities of peroxidase and polyphenol oxidase, increased phenylalanine ammonialyase activity and total phenol content, inhibited superoxide anion generation rate, and markedly enhanced superoxide dismutase activity and ascorbate content, slowed down the decline in ascorbate peroxidase activity of fresh-cut A. bisporus. The results suggest that appropriate hot air treatment can inhibit enzymatic browning and reactive oxygen species metabolism of fresh-cut A. bisporus, and finally slow down senescence. The correlation analysis showed that the browning of fresh-cut A. bisporus was caused by enzymatic browning and non-enzymatic browning, and hot air treatment can delay the occurrence of browning by inhibiting the enzymatic browning.

The effects of individual and combined treatments with 1-methylcyclopropene (1-MCP) at 5 μL/L and tebuconazole at two different concentrations on brown rot control, color and firmness of postharvest “Qingcui” plum fruits during storage were studied in order to explore the possible application of 1-MCP combined with tebuconazole for postharvest preservation of “Qingcui” plum fruits. The results showed that tebuconazole at two concentrations alone and combined with 1-MCP could effectively control the occurrence of brown rot on normal fruits and wounded and inoculated fruits during storage at 20 and 0 ℃, while 1-MCP treatment alone had no such effect on wounded and inoculated plum fruits during storage at room temperature. But it was effective in inhibiting brown rot inoculated in wounds on plum fruits stored at low temperature and also effective against natural incidence at room temperature and low temperature. The combination of 1-MCP with 27.0 mg/L tebuconazole was the most effective against brown rot on plum fruits. At the same time, 1-MCP treatment alone and combined with tebuconazole at two concentrations rather than tebuconazole alone could effectively inhibit the progression of fruit yellowing and softening. The tebuconazole residues of plum fruits subjected to 13.5 mg/L tebuconazole treatment and 1-MCP combined with tebuconazole at 13.5 and 27.0 mg/L were below the maximum residue limit stipulated in the Chinese national standard.

This study aimed to improve the functional properties of frozen whole egg (FWE) for the purpose of developing FEW-based food products for special dietary use. The changes in the functional and physicochemical properties of FWE with NaCl added at 0.5%, 1%, 2% and 4% during six months of frozen storage were researched. With this aim, fresh liquid whole egg was added with NaCl, stirred thoroughly and quick-frozen before frozen storage. The results showed that the surface hydrophobicity of FWE was increased with increasing storage time and NaCl content. Total sulfhydryl content and surface sulfhydryl content were decreased with the extension of storage time, but they displayed irregular changes with NaCl content. Solubility was gradually decreased during storage time, and in terms of solubility, FWE with 1% and 2% NaCl added were better than the blank group significantly. The foaming capacity of FWE exhibited an overall decreasing trend, while the foam stability was changed reversely. The foaming capacity of FWE was significantly improved by adding 2% NaCl, and after frozen storage for 60–180 days, it was higher than that of the quick-frozen samples without NaCl addition and without storage and that of the fresh samples. Simultaneously, gel hardness and water holding capacity rose in the early storage period and then continuously declined. Moreover, gelling properties of FWE were obviously improved by adding 1% NaCl, and after 30 days of storage, they were higher than those of fresh egg and FWE without storage or NaCl addition. Therefore, we concluded that the functional properties of FWE could be effectively improved by adding an appropriate amount of NaCl, which can provided a theoretical guidance for the development of FEW-based food products for special dietary use.

A nano-SiO2 modified polyvinylidene chloride (PVDC) composite coating was prepared by the blending method and its effect on the quality changes of salted duck egg was examined. The results showed that different coatings could significantly reduce quality deterioration such as increased weight loss, volatile base nitrogen (TVB-N), and total bacterial counts (P < 0.05) compared with the control group. The nano-SiO2 modified PVDC coating was significantly more effective in inhibiting the increase in weight loss and total bacterial counts and the accumulation of TVB-N and free fatty acids, as well as pH changes in egg yolk and albumen than other coatings (P < 0.05). The nano-SiO2 modified PVDC coating could significantly inhibit the growth of total bacterial counts (P < 0.05) and preserve the sensory quality of salted duck eggs (P < 0.05), prolonging the shelf life by 70 days at 28 ℃ and 70% relative humidity in comparison with the control group. This study can provide evidence supporting the application of PVDC composite coatings in the preservation of salted duck eggs.

To elucidate the possible mechanism by which 6-benzylaminopurine (6-BA) regulates the senescence of broccoli, the effects of 30 mg/L 6-BA on the endogenous 6-BA content, total chlorophyll content, total bacterial account, ethylene production, the expression of senescence-related genes, the activities and gene expression of the ethylene-forming enzymes in broccoli were investigated. The results showed that 6-BA treatment could significantly alleviate the degradation of total chlorophyll and inhibit the increase in total bacterial count in broccoli. The endogenous 6-BA content of control broccoli continuously decreased with the extent of storage time, while exogenous 6-BA treatment maintained higher endogenous 6-BA content at the later stage of storage. The endogenous 6-BA content in both the control and 6-BA treatment groups decreased after cooking. Additionally, 6-BA treatment down-regulated the expressions of chlorophyllase gene (2BoCLH2), cysteine protease gene (5BoCP5), proline rich protein gene (BoLSC810), and retarded the decline in the expression of chlorophyll a/b binding protein 1 (BoCAB1). Moreover, 6-BA treatment significantly suppressed ethylene production in broccoli, which might be associated with decreased activity of ethylene synthase and down-regulated expression of BoACS1 and BoACS2. These results suggested that exogenous 6-BA maintained higher endogenous 6-BA level at the later period of storage, thereby inhibited ethylene production, and finally slowed down the senescence of broccoli.