In this study, we investigated the microbial variations during the processing of traditional salted fish and lactic acid-fermented fish, aiming to provide a theoretical basis for the new processing technology. Illumina MiSeq sequencing was applied to analyze the microbial community diversity in dried-salted fish during different processing stages. The results indicated that the processing system contained highly diverse bacteria, which could be mainly divided into three categories: Bacteroidetes, Firmicutes and Proteobacteria. Enterbacteriaceae, Enterococcactae, Pseudomonadacea and Shewanellaceae were dominant microorganisms in brown-striped mackerel scad (Decapterus maruadsi) during the initial stages of processing while Aeromonadaceae, Bacillaceae, Staphylococcaceae, Comamonadaceae, Enterbacteriaceae, Enterococcaceae, Moraganellaceae and Streptococcaceae were dominant microorganisms in sea bass (Lateolabrax japonicus). The microbial community was homogeneous during the traditional curing process, and the dominant microorganisms identified were Vibrionaceae, Staphylococcaceae, Pseudomonadaceae and Planococcaceae. After inoculation of lactic acid bacteria, the microbial diversity during the fermentation process showed an increasing trend, and lactic acid bacteria became dominant and promoted the growth of the dominant bacteria Exiguobacteracea and Staphylococcaceae; Aeromonadaceae and Lactobacillaceae, which did not appear during the traditional processing, were detected. Microbial community diversity in sea bass during the curing process was significantly higher than that in brown-striped mackerel scad. Microbial community diversity was also increased markedly during the processing of lactic acid-fermented fish.

In order to investigate the changes in the growth state of different yeast species in a mixed culture and the factors affecting their interaction, the effects of initial glucose concentration, pH, and ethanol concentration on the growth of Saccharomyces cerevisiae (Sc) and Pichia fabianii (Pf) when cultured together were investigated, and the differences in the fatty acid composition of both yeasts were also determined by gas chromatography-mass spectrometry (GC-MS). The results showed that Pf had an obvious inhibitory effect on the growth of Sc during their co-culture under normal conditions. At relatively low sugar concentration and low pH, the growth of Sc was more restrained. At an initial glucose concentration of 2%, the Pf/Sc ratio（the ratio of colony numbers) was 28, and the value was 37 at pH 3.5. With increasing concentration of exogenous ethanol, the growth of Pf was more restrained than that of Sc, and Sc became dominant, suggesting it to be more resistant to ethanol than Pf. The Pf/Sc ratio was 0.5 under 12% ethanol stress. The fatty acid composition of Sc mainly consisted of palmitic acid and palmitoleic acid while that of Pf mainly consisted of oleic acid, linoleic acid and linolenic acid. In the mixed culture, the fatty acid composition was dominated by C18 fatty acids, and the linoleic acid and linolenic acid produced by Pf could inhibit the growth of Sc. These results could provide a basis for further research on the interaction of different yeasts in the mixed culture at the transcriptome level and the quality control of fermented products.

This study aimed to construct a histidine protein kinase gene (prcK) deletion mutant of Lactobacillus paracasei HD1.7 for providing an experiment tool for research on the function of the prcK gene. In this research, homologous recombination method was used. Plasmid pKLKRT (including prcK::Tetr) was constructed and used to transform L. paracasei HD1.7 by eletroporation. The prcK::Tetr in place of prcK was integrated into the chromosome of L. paracasei HD1.7 by homologous recombination. One strain that grew only on plates with tetracycline but not on plates with ampicillin was selected. The PCR amplification and endonuclease digestion analysis indicated that plasmid pKLKRT was successfully constructed and introduced into L. paracasei HD1.7. The prcK gene deletion mutant was confirmed by PCR amplification. In conclusion, a prcK gene deletion mutant of L. paracasei HD1.7 has been successfully constructed by homologous recombination, which will lay the basis for understanding the molecular mechanism of the quorum sensing-related genes in L. paracasei HD1.7.

The Suantangzi is a traditional ethnic food with good nutritional properties and unique flavor, which is popular among Manchu people and northeastern Chinese people. The diverse microbes in corn sourdough for Sutangzi play an extremely important role in the development of its nutritional quality. However, the microbial community diversity is still unclear today. This study aimed to study the diversity of the microflora in nine samples of Suantangzi sourdough collected from different regions by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showed that a total of 14 species of fungi were identified from these samples, including Saccharomyces castellii, Geotrichun candidum, Simplicillium lanosoniveum, Rhizochaete sulphurosa, Guehomyces pullulans, Debaryomyces hansenii, Fusarium culmorum, Trichoderma brevicompactum, Oryza lonqistaminata, Geotrichun fraqrans, Galactomyces candidum, Galactomyces geotrichum, Geotrichum sp. and Galactomyces sp. S. castellii was detected in most samples. Based on this observation, S. castellii was predicted to be the dominant fungal species in Suantangzi. Moreover, 4 species of bacteria were also identified, including Bacillus pumilu, Lactobacillus tucceti, Lactobacillus plantarum and Weissella paramesenteroides. Weissella paramesenteroides was supposed to be the dominant species for the widest distribution in the samples.

The key steps for preparing antitumor peptide from enzymatic hydrolysates of Perinereies aibuhitensis were investigated in the present work. The most suitable enzyme preparation was selected and the optimal hydrolysis conditions allowing high inhibition of cancer cell proliferation were determined using one-factor-at-a-time method and orthogonal array design. A fraction containing peptides with molecular weights of 1?3 ku was obtained by ultrafilation of hydrolysates, and it was further purified by sequential ion exchange chromatography, gel filtration chromatography and preparative chromatography. Then, lung cancer A549 cells were used to test the anticaner effect of the purified peptide PAP by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The morphological changes were observed through an inverted microscope, dual acridine orange/ethidium bromide (AO/EB) fluorescent staining and Hoechst fluorescent staining. The results showed that alcalase was found to be the optimal enzyme for the production of anticancer peptide and that the optimal hydrolysis conditions were determined as follows: temperature, 50 ℃; pH value, 11; solid-to-liquid ratio, 1:1; hydrolysis time, 6 h; and enzyme dosage, 300 U/g. The peptide PAP was identified as Ile-Glu-Pro-Gly-Thr-Val-Gly-Met-Met-Phe. Moreover, our results demonstrated that PAP suppressed the proliferation of A549 cells in a time- and dose-dependent manner with morphological features of apoptosis being observed. Therefore, our findings suggest that PAP could inhibit the proliferation of lung cancer A549 cells and induced apoptosis.

This study was conducted to examine the effects of natural fermentation and pure culture fermentation (with the predominant strains of lactic acid bacteria and yeast isolated from naturally fermented millet) of millet on molecular structure and pasting properties of millet starch, aiming to provide a theoretical foundation for the analysis of the effect and mechanism of pure culture fermentation on the modification of millet starch. Starches were extracted from millet fermented by different starter cultures, and they were examined for differences in granular characteristics, crystallinity, functional groups, molecular mass, and pasting and retrogradation properties. Results were obtained as follows: 1) The starch granules showed marked surface erosion after fermentation with each isolate, but were only slightly affected by natural fermentation. 2) Lactic acid bacterial fermentation yielded a 1.49% increase and a 0.33% decrease in starch crystallinity as compared to natural fermentation and yeast fermentation, respectively. 3) Fermentation did not change the peak positions in the function group region of millet starch, but decreased the characteristic peak intensity; the fingerprint region disappeared after pure culture fermentation. 4). The weight average molecular mass of unfermented millet starch was between 1.5 × 104?5.9 × 105 g/mol, that of the naturally fermented one between 2.1 × 104 ? 5.4 × 105 g/mol, and that of the lactic acid bacteria fermented one between 1.6 × 104?5.3 × 105 g/mol, and that of the yeast fermented one between 1.6 × 104?4.7 × 105 g/mol. 5) After fermentation, the proportions of long-chain amylopectin and amylose decreased, whereas the proportion of short- and middle-chain amylopectin increased. Moreover, after fermentation by the lactic acid bacteria and yeast for 96 h, the gelatinization temperature decreased 0.84 and 1.13 ℃, the enthalpy increased by 1.00 and 0.78 J/g, the setback decreased by 743 and 471 mPa·s as compared with natural fermentation, respectively. It was concluded that the dominant bacteria lactic acid bacteria and yeast in natural fermentation played a major role in changing the molecular structure, and pasting and retrogradation characteristics of millet starch.

This study aimed to screen new probiotics from naturally fermented yak milk. We separated and identified four Enterococcus durans strains by bacterial cultivation, gene sequence alignment and biochemical analysis. These four strains shared 99.4%–99.9% genetic homology by comparison of their 16S rRNA sequences with those of eight other E. durans isolates previously reported and were clustered into a separate branch by phylogenetic analysis. Among these isolates, E. durans SWUN5857 exhibited the most robust resistance to acidic and bile salts and could greatly adhere to intestinal mucus in different segments of the intestinal tract in Kunming mice, especially in lower intestines. Moreover, it inhibited the growth of pathogenic Escherichia coli ((17.0 ± 0.3) mm) and Salmonella ((18.0 ± 0.2) mm), and it was also sensitive to common antibiotics in vitro. Mice gavaged with SWUN5857 for a short term showed a significant body weight gain (P < 0.01) and an increase in immune organ indexes. Besides, this treatment also significantly promoted the animal humoral and cellular immunity level (P < 0.01) and enhanced the secretion of intestinal mucosa SIgA (P < 0.01). In conclusion, E. durans SWUN5857 can successfully adapt to the gastrointestinal condition and improve animal growth performance and immunological function, being, therefore, a promising candidate probiotic.

The killer property Candida albicans LFA418, a wild strain isolated from a winery in Loulan of Northwest China’sXinjiang region. The killer feature and crude killer toxin characteristics of a wild yeast strain Candida albicans isolated from Loulan winery of Xinjiang were studied. The results indicated that Candida albicans LFA418 had a wide spectrum of killering activity against Pichia kluyveri, Saccharomyces bayanus, Lachancea thermotolerans and Candida lusitaniae. The optimal culture conditions to obtain the maximum yield of killer toxins were as follows: inoculums of C. albicans LFA418, 7% (V/V); temperature, 25 ℃, and culture time, 32 h. The activity of crude killer toxins was stable at pH 4.2-4.6 when temperature was -20 ℃ and 4 ℃ and temperature 4-20 ℃ at pH 4.2.

Four different feeding methods for the production of triterpenes by submerged fed-batch fermentation of Ganoderma lucidum G0119 in a 50 L-fermentor were compared. The results showed that glucose feeding during fermentation could obviously promote the mycelical growth of G. lucidum G0119 and the synthesis of triterpenes, and different feeding methods had different influences on the mycelial dry weight and the concentration of triterpenes in the fermentation broth. The highest mycelical dry weight could be obtained by exponential feeding, as well as high concentration of triterpenes. The results showed that the feeding strategy was the best among all tested ones, giving a mycelial dry weight of 17.68 g/L and a triterpene content of 4.58 g/100 g dry mycelium at the end of fermentation, which were significantly increased by 65.70% and 100.88%, respectively, as compared with fed-batch fermentation.

In this study, the protective effect of quercetin on high glucose-induced damage was investigated in Saccharomyces cerevisiae. Compared with the control group, the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were all significantly decreased under high glucose-induced stress (P < 0.05), but intracellular ROS was no obviously changed. After being treated with quercetin, the ROS levels and SOD and CAT activities were dramatically inhibited (P < 0.05), but the POD activity was significantly enhanced in comparison to the control and high glucose groups (P < 0.01). The results showed that POD activity was more sensitive than other indicators in reflecting the resistance to high glucose-induced stress, and quercetin could effectively enhance the antioxidant capacity by regulating POD activity in S. cerevisiae S288c. In addition, high glucose-induced stress resulted in an significant decrease in the expression levels of glycerol-3-phosphate dehydrogenase 2 (GPD2) and sucrose transport protein-encoding genes (SUC2) (P < 0.05), but a significant increase in the expression level of hexose transport-1-encoding gene (HXT1) (P < 0.01), compared with the control. After being treated with quercetin, the expression profiles of GPD2, SUC2, and HXT1 were significantly increased in S. cerevisiae S288c (P < 0.05). However, the expression level of glycerol kinase gene (GUT1) was not changed significantly. These results suggested that quercetin could reduce high glucose-induced damage by regulating the high osmolarity glycerol (HOG) signaling pathway, inulin catabolism pathway and hexose transport pathway to accelerate glucose decomposition. Therefore, we conclude that quercetin plays an important role in protecting S. cerevisiae from damage caused by high glucose-induced stress, and the underlying mechanism may be associated with its antioxidant effect and being involved in the HOG signaling pathway and the glucose decomposition and transport pathways in S. cerevisiae.

This study aimed to establish a classification method for natural plasmids of Lactobacillus plantarum (L. plantarum) by using plasmid replication initiation protein (Rep) as a taxonomic marker. Fifty three plasmids encoding Rep in L. plantarum were divided into six plasmid types by the method of phylogenetic analysis, including five plasmid families and one novel replication type of plasmid. Then, the backbone sequence specific to each plasmid family was further proposed. Finally, a simple and effective classification method and criterion for L. plantarum natural plasmids was established. Compared with the previous classification methods based on plasmid function and incompatibility, this method displayed relatively better practicability and versatility.

In this study, three functional strains of aroma-producing yeast, highly efficient acid-producing acetobacter and polysaccharide-producing lactic acid bacteria were applied in the enhanced fermentation of Baoning vinegar. Results of enhanced fermentation with single starter cultures showed that compared with the control group, the number and relative contents of volatile compounds in vinegar fermented with aroma-producing yeast were improved by 17.39% and 20.23%, which were 27 and 79.65%, respectively, and the acidity of the samples fermented with acid-producing acetobacter and polysaccharide-producing lactic acid bacteria were increased by 82.75% and 155.75%, which were 3.18% and 4.45%, respectively, along with an increase in organic acid concentration of 23.46%?389.21%. Additionally, the polysacchairde concentration of the vinegar fermented by the third starter culture was up to 1 143.78 mg/L, which was 68.43% higher than that of the control group. Mixed culture fermentation containing 40% yeast, 16% acetic acid bacteria and 44% lactic acid bacteria at an inoculum size of 1% was demonstrated to be optimal for obtaining the best product, which had an acidity of 5.28%, contained 30 volatile compounds and scored 85.65 points in sensory evaluation. This research can provide a theoretical support for improving the flavor and yield of?Baoning vinegar.

This study aimed to obtain lactic acid bacteria (LAB) with high antioxidant activity for meat fermentation. Intact cells, cell-free extracts and fermentation supernatant of 30 LAB isolated from 5 kinds of fermented meat products were evaluated for antioxidant activity by free radical scavenging assays, reducing power assay and linoleic acid peroxidation inhibition assay. According to the meat starters screening standard, eligible strains were identified. The results showed that the 30 strains of LAB had different antioxidant capacities and there were big differences between the antioxidant activities of their intact cells, cell-free extracts and fermentation supernatant. Strains L23, L26 and L28 were screened for excellent antioxidant activity, and L23, reaching the requirement of the meat starters screening standard, could be used as a natural meat starter for the production of fermented meat products. Strain L23 was identified as Weissella hellenica.

In the present study, hairy roots of Stevia rebaudiana were induced by Agrobacterium rhizogenes ACCC10060, and then cultured to produce chlorogenic acids. Furthermore, the effect of methyl jasmonate on the synthesis of chlorogenic acids was also investigated. Leaf explants of Stevia rebaudiana were infected with Agrobacterium rhizogenes ACCC10060, and then co-cultured for inducing hairy roots. After 14 days, hairy roots grew out. The PCR analysis results indicated that the rolB and rolC genes of Ri plasmid in Agrobacterium rhizogenes were successfully transferred into the hairy root genome, which confirmed that the tested induced roots were hairy roots. Compared with B5 and WPM liquid medium, MS was more suitable for hairy root growth and the accumulation of chlorogenic acids. After 35-day culture, the dry weight of hairy roots increased about 30 times, and the maximum contents of chlorogenic acid, 3,5-dicaffeylquinic acid, and 4,5-dicaffeylquinic acid were 3.47, 11.47 and 3.04 mg/g, respectively. Methyl jasmonate solutions at 15, 45 and 100 μmol/L were added into the medium, respectively as an inducer for higher production of chlorogenic acids after three weeks of culture. Both biomass and chlorogenic acid content were increased when the hairy roots were treated with methyl jasmonate for 1, 2, 4 and 8 days respectively. The optimal concentration of methyl jasmonate was 45 μmol/L for chlorogenic acid production. The total yield of chlorogenic acids was increased to 2.68 folds as compared to that of the control group (P < 0.01). These results suggested that Stevia rebaudiana hairy roots could be used to produce chlorogenic acids and that methyl jasmonate treatment could significantly increase chlorogenic acid production.

The aim of this study was to investigate the influence of medium components on γ-aminobutyric acid (GABA) enrichment during soybean sprouting and further to optimize the variables by response surface methodology (RSM). Furthermore, the mechanism of GABA accumulation in germinated soybean under low salt stress was also preliminarily investigated. The results demonstrated that soybean germination in the optimized medium containing 1.0 mg/mL sodium glutamate (MSG), 2.0 mmol/L pyridoxal phosphate (PLP), 2.0 mmol/L CaCl2 and 100 mmol/L NaCl yielded accumulation of a high level of GABA, (269.93 ± 4.73) mg/100 g dry weight, which was around 11 times higher compared with ungerminated soybeans (control). With increasing concentration of NaCl and extending stress time, glutamine acid decarboxylase activity and GABA content of sprouted soybean increased. Correlation analysis indicated that there was a significantly positive correlation between the GABA content of sprouted soybean and sprout length, glutamine acid decarboxylase activity, free amino acids content or soluble protein content. The germination of soybeans was restrained, the GAD activity was enhanced, and the contents of free amino acid and soluble protein were increased under low salt stress. Finally, GABA was accumulated at a high level.

A carotenoid cleavage enzyme with HPLC grade purity of 95.6% was obtained from Staphylococcus pasteuri (S. pasteuri) TS-82 by using anion-exchange chromatography, preparative high performance liquid chromatography (PHPLC), and superdex peptide chromatography together. The purified enzyme had a specific activity of 125 U/g with 466-fold purification and 2.39% recovery. Its molecular weight was 655.093 D as identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI/MS). Enzymatic characterization indicated that the purified enzyme had optimal temperature of 60 ℃ for degrading C40 carotenoids and 50 ℃ for degrading β-apo-8?ˉ-carotenal, and it maintained stable activity at 50 ℃. The optimum pH value was 3.0 for degrading all investigated substrates. The Km and vmax values indicated that the enzyme showed the highest affinity towards zeaxanthin, followed by astaxanthin, β-carotene, canthaxanthin, and β-apo-8?ˉ-carotenal in a decreasing order. The metal ions Al3+ and Fe3+ were identified as potent activators for the purified enzyme, whereas Fe2+ as a potent inhibitor. H2O2 was able to increase the enzyme activity in degrading β-carotene at levels of 0-16 mmol/L. Alcohol at low concentration (4%–16%) did not inhibit the activity of the enzyme. In conclusion, the enzyme showed great acid resistance and thermostability, which makes it stable in wine environment and provides a basis for industrial application.

A fungal strain producing blue pigment, named F10, was isolated from a wild pine in southern Jiangxi, and it was identified as a member of the genus Pseudofusicoccum in the family Botryosphaeria by using ITS rDNA sequence homology comparison as well as morphological traits. We studied the stability of blue pigment when exposed to different solvents, pH values, temperatures illumination intensities, metal ions, oxidizers and reductants. The data showed that the pigment was sensitive to pH, metal ions, and reductants but not light, temperature or oxidants. We speculated that pH, metal ions, and reductants might change the structure of the pigment. Analysis of the basic chemical structure by high performance liquid chromatography-mass spectrometry (HPLC-MS) and infrared spectroscopy (IR) revealed that the pigment was aromatic carboxylic acid compounds.

Objective: To investigate dynamic changes in the microbial community structure during the fermentation of Zizhong Dongjian, a Chinese traditional fermented vegetable product, by polymerase chain reaction-denatured gradient gel electrophoresis (PCR-DGGE). Methods: Four samples of Dongjian with different fermentation times were collected from Zizhong, Sichuan province. Total bacterial DNA was extracted from the samples, and nested PCR was applied to amplify the V3 region of 16S rDNA for identification based on DGGE fingerprints. Meanwhile, the dominant bands were cloned, selected and sequenced, and a phylogenetic tree was constructed. Results: During the fermentation process of Dongjian, rich bacterial diversity was observed and the microbial community structure was changed greatly. The similarity of bacterial community between Dongjian samples with different fermentation times ranged from 9% to 67%. Among them, samples fermented for two and three years exhibited the highest similarity to each other, up to 67%. Furthermore, the bacteria involved in the fermentation process of Dongjian were mainly divided into 3 categories: Firmicutes, Proteobacteria, and unculturable bacteria. Among these, Firmicutes was the most dominant species followed by Proteobacteria, which accounted for 53% and 37% of the total population, respectively, while unculturable bacteria accounted for only 10%. Conclusions: DGGE fingerprint can provide a comprehensive and true reflection of dynamic changes in the microbial diversity of Dongjian during fermentation. Meanwhile, it also provides a theoretical basis for the production process for Dongjian and the formation of flavor substances.

The anthocyanins from leaves of the tea cultivar ‘Zijuan’ were separated and purified by sequential column chromatography using MCI gel CHP 20P resin (75–150 μm) and SephadexTM LH-20, through gradient elution with 5% acid-methanol and 5% acid-water. A total of 6 anthocyanins were separated from the purified extract, which were analyzed by high performance liquid chromatography (HPLC), thin layer chromatography (TLC) and HPLC-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that the anthocyanins were identified as delphinidin 3-O-β-D-galactoside, cyanidin 3-O-β-D-galactoside, delphinidin 3-O-β-D-(6-(Z)-p-coumaroyl)galactopyranoside, cyanidin 3-O-β-D-(6-(Z)-p-coumaroyl)galactopyranoside, delphinidin 3-O-β-D-(6-(E)-p-coumaroyl)galactopyranoside and cyanidin 3-O-β-D-(6-(E)-p-coumaroyl)galactopyranoside.

The essential oils of Cinnamomum camphora L. Presl from three different origins obtained by hydrodistillation were analyzed by purge and trap thermal desorption-gas chromatography-mass spectrometry (P&T-TD-GC-MS), and their inhibitory activity against plant pathogenic fungi was comparatively assessed. A total of 22, 20 and 16 volatile components were detected in the essential oils of C. camphora grown in Jiangxi, Anhui and Guangxi provinces, respectively. The major components identified with a relative content of more than 1% were β-myrcene, β-caryophyllene and linalool. Furthermore, the essential oil of C. camphora from Guangxi province was also analyzed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 44 components were identified in the essential oil of C. camphora from Guangxi province, dominated by alcohols and terpenes. In the antifungal assay, the leaf oil from Guangxi province showed strong antifungal activities against Colletotrichum gloeosporioides, Botrytis cinerea, and Fusarium graminearum with half maximal?inhibitory concentration (IC50) values of 31.74, 35.79 and 38.02 mg/L (after 48 h of treatment), respectively. Linalool was found to be a significant contributor to the antifungal activity. Overall, the essential oil of C. camphora might have the potential to be developed into a natural antimicrobial agent that can be used in the preservation of fruits and vegetables.

The differences in the chemical and aroma profiles of moderately and entirely fermented apple vinegar were investigated. The total phenols content, and organic acid and aroma profiles were determined and analyzed using Folin-Ciocalteu colorimetry and high performance liquid chromatography (HPLC), respectively. The volatile aroma components were extracted by headspace solid-phase microextraction (HS-SPME) and identified by gas chromatography-mass spectrometry (GC-MS). The total phenols content in the moderately fermented sample was 21% higher than that in the entirely fermented one. The organic acids species in two vinegar samples were exactly the same, but their contents were different. The moderately fermented vinegar contained higher levels of tartaric acid, citric acid and fumaric acid while the entirely fermented one contained higher levels of pyruvic acid, malic acid, α-ketoglutaric acid, lactic acid, acetic acid and succinic acid. The moderate fermentation could provide the vinegar with more abundant aroma-active compounds. A total of 37 volatile compounds were detected, including citronellol, nerol, butanoic acid ethyl ester, 4-methyl-3-hexyl acetate ester, and 2-methylbutyl acetate, which were also detected in the apple juice. The moderate fermentation method could be an effective way to develop apple vinegar with high quality because of its protective effects on total phenols and aroma compounds.

Different varieties of flat-European hazelnuts have different contents of nutrients, especially oil content, fatty acid composition, and α-vitamin E content. This study was designed to compare the diversity of 8 flat-European hybrid varieties of hazelnuts. Oil contents were determined with Soxhlet extraction. Fatty acids were analyzed by gas chromatography and colorimetry. Cluster analysis was applied for discrimination among these varieties. The results showed that there were significant differences in the contents of nutrients among 8 varieties. The mean oil content was 56.36% ranging from 52.92% to 59.24%. Monounsaturated, polyunsaturated, and saturated fatty acids averagely accounted for 72.54%, 16.11%, and 7.85% of the total fatty acids, respectively; oleic acid, the most abundant fatty acid, represented about 72.29%. The contents of linoleic acid and oleic acid were more than 85%. α-VE content ranged from 113.42 to 285.16 μg/g. The eight varieties were clustered into four groups: varieties 4#, 5#, 6#, and 7# in group 1, 8# in group 2, 2# and 3# in group 3, and 1# in group 4. The first three principal components accounted for 43.384 % (PC1), 34.436% (PC2) and 12.606% (PC3) of the total variation, respectively.

In this study, we examined the effects of different organic solvents on the extraction efficiency and composition of organic sulfur-containing compounds from tillering onion. The organic sulfur-containing compounds were extracted by dichloromethane and ethyl acetate and n-hexane, respectively, and then analyzed by headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS). The optimum extraction conditions with dichloromethane as the extraction solvent were determined to be 4 h extraction at a ratio of material to liquid of 1:4 (g/mL) with stirring at 250 r/min, leading to a yield of (0.413 3 ± 0.007)%, which was higher than those obtained with ethyl acetate and n-hexane as the extraction solvent, (0.273 3 ± 0.011)% and (0.288 9 ± 0.009)%, respectively. A total of 45 components were extracted by the three solvents and 9 organic sulfur-containing compounds were detected in each solvent extract, among which, thiophenes and thioethers were predominant. In addition, 12, 3 and 8 unique organic sulfur-containing compounds were extracted by methylene chloride, ethyl acetate, and n-hexane.

Ultrasound-assisted blanching combined with ascorbic acid (UBA) was applied in the pretreatment of carrots for the purpose of inhibiting enzymatic browning in this study. The optimization of processing parameters for the inactivation of peroxidase (POD) and polyphenol oxidase (PPO) was done by the combined use of one-factor-at-a-time method and response surface methodology. The combined method was compared with individual blanching and ascorbic acid soaking in terms of their effect on carrot quality. The optimized processing parameters were 0.29 W/mL, 3 min, 60 ℃ and 1% for ultrasonic power density, irradiation time, temperature and ascorbic acid concentration, respectively. In addition to ensuring the inactivation of both enzymes, UBA treatment was able to greatly increase ascorbic acid content in carrot while maximally maintaining the integrity of the cell structure than could the separate treatments. Hence, UBA was a mild and efficient pretreatment method.

In this study, the deproteinization and structural characterization of the polysaccharides extracted from Dendrobium officinale Kimura et Migo grown in Huoshan county of Anhui province were investigated. Three protein removal methods: the Sevage method, enzymatic hydrolysis and their combination were comparatively evaluated in terms of protein removal and polysaccharide loss rates. The combined method was found to have the highest deproteinization efficiency, yielding 81.58% protein removal and 15.63% polysaccharide loss. After purification of the polysaccharides by successive DEAE-cellulose-52 and Sephadex G-100 column chromatography, an active fraction named as DOPA-1 was obtained. By using UV spectroscopy and high performance liquid chromatography (HPLC), the polysaccharide DOPA-1 was confirmed to be homogeneous. Moreover, DOPA-1 was mainly composed of mannose, glucose and galactose as revealed by GC analysis, with a molar ratio of 1:0.42:0.27. IR spectroscopy and Cango red test indicated that DOPA-1 contained β-D-mannopyranose and possessed a triple-helix conformation.

In the current study, xylooligosaccharides (XOS) were prepared by catalytic hydrolysis of beech wood xylan using carbon-based solid acid catalyst (AC-SO3H). The effects of reaction time, temperature and catalyst dosage on the yield of XOS were investigated. Using orthogonal array design, the optimal hydrolysis conditions were determined as 0.5 g of xylan, 0.2 g of AC-SO3H, and reaction time 3 h at 140 ℃. Under these conditions, the effect of different catalysts, namely, AC-SO3H, M-AC-SO3H and S-AC-SO3H, on XOS yield was investigated. The results showed that the highest yield of XOS of 66.60% was obtained by using AC-SO3H.

In this paper, Ni-Ag/SBA-15 catalyst was used to catalyze the hydrogenation of soybean oil in supercritical CO2. The optimum conditions were determined as follows: CO2 pressure, 8.0 MPa; hydrogen partial pressure, 3.40 MPa; hydrogenation temperature, 100 ℃; the amount of catalyst, 0.20%; stirring speed, 300 r/min, and hydrogenation time, 90 min, giving a product with an iodine value of 86.0 g I2/100 g, and a trans fatty acid (TFA) content of 11.7%. Using hydrogenation kinetic equation and MATLAB software program, the reaction rate and selectivity for supercritical CO2 hydrogenation of soybean oil were investigated. Compared with conventional hydrogenation, the hydrogenation rate in supercritical CO2 was higher, and the hydrogenation selectivity for linolenic acid and linoleic acid were better. At the same time, the TFA and stearic acid contents of hydrogenated soybean oil products were 11.7% and 9.4% in supercritical CO2, which were lower than that from conventional hydrogenation.

The removal of phenol from wood vinegar prepared from wild jujube seed shell by using emulsion liquid membrane was studied in this work. Kerosene was used as solvent to prepare emulsion liquid membrane. The effects of processing conditions including kind and concentration of surfactant, concentration of liquid carrier (tributylphosphate, TBP), internal phase concentration and volume ratio of oil phase to internal phase on the stability of the emulsion and the removal of phenol from wood vinegar were investigated and these variables were optimized by response surface methodology for improved removal rate of phenol. The use of 8% (V/V) surfactant T154 and 3% (V/V) TBP, an internal phase concentration (NaOH) of 0.6 mol/L, a volume ratio of oil phase to internal phase of 5:4 (V/V) and emulsification for 20 min with stirring at 4 500 r/min were found to be optimal for good emulsion stability. Under these conditions, the removal rate of phenol from wood vinegar solution was 55.31%.

The high hydrostatic pressure extraction of anthocyanins from blueberry pomace was investigated with a focus on the mechanism by which high hydrostatic pressure (HHP) enhances the extraction of anthocyanins by affecting physical properties of the extraction solvent (a mixture of 37% HCl and 66% ethanol (1:99, V/V)). The results showed that HHP processing could affect physical properties of the extraction solvent including maximum absorption wavelength, pH value, conductivity, infrared absorption and chemical shift caused by the intermolecular hydrogen bonding between ethanol and water. With increasing pressure, the hydrogen bonding between ethanol and water became more stable. A significant correlation was found between the extraction yield of anthocyanins and infrared absorption and chemical shift from the intermolecular hydrogen bonding. In conclusion, HHP treatment could the intermolecular hydrogen bonding and therefore physical properties of the extraction solvent, leading to increased extraction yield of anthocyanins from blueberry pomace.

The present work was done to optimize the process conditions for cold-air drying (CAD) of pickled Apostichopus japonicus by the combined use of one-factor-at-a-time method (OFAT) and response surface methodology (RSM). The response variable was the weighted average of sensory scores and dehydration rate. A comparison of CAD, vacuum freeze drying (VFD), hot-air drying (HAD) and vacuum microwave drying (VMD) was performed in terms of the quality of dried products. Results?showed that?the optimal cold-air drying conditions were determined as follows: vacuum desalination time, 4.2 h; drying temperature, 19 ℃; and wind speed, 1.70 m/s, resulting in a weighted average of 0.77. With respect to nutrient retention, VFD and CAD were?better than HAD and VMD. In terms of heat?shrinkage, the drying methods were in the decreasing order of HAD, VMD, CAD and VFD with only a marginal difference being observed between CAD and VFD, while they followed the decreasing order of CAD, VFD, HAD and VMD in terms of rehydration rate. In terms of textural characteristics, CAD and VFD were better than HAD and VMD. These?results?showed?that CAD was more practical in industrial production.

This study aimed to investigate the effect of different tenderizers, ultrasonic power, irradiation time, pork water content, tenderizer dosage, tenderization temperature, time and pH on pork tenderness. Fig leaf protease was a significantly better tenderizer than papain, and various enzymes were more effective when used in combination than when used individually. In addition, enzymes were better tenderizers than inorganic compounds. Ultrasonic treatment could facilitate the tenderization of pork by combinations of fig leaf protease and other tenderizers, reducing the tenderization time by one-third. Using one-factor-at-a-time method and orthogonal array design, the optimal tenderization conditions were determined to be ultrasonic irradiation at 240 W for 5 min and tenderization at 50 ℃ and pH 7.5 for 60 min with 4.0 g of a tenderizer combination containing fig leaf protease per 100 g of meat, yielding a soft, juicy and elastic product with improved mouth feeling and excellent tenderness.

The goal of this study was the accumulation of γ-aminobutyric acid (GABA) in fermented chicken sausage produced using lactic acid bacteria. Firstly, the optimal fermentation strains was selected. Then, the effects of addition of L-glutamate (L-Glu), VB6 and CaCl2 on the GABA content of chicken sausage were investigated, and their amounts were optimized using Box-Behnken experimental design. The results showed that among three different sources of lactic acid bacteria, the GABA-producing abilities of lactic acid bacteria from yogurt and pickles were weaker, both of which gave yields lower than 10 mg/100 g, which was significantly (P < 0.05) lower than that of Enterococcus durans (62.14 mg/100 g). The addition of L-Glu, VB6 and CaCl2 at levels of 7.75, 6.73 and 8.35 mg/100 g, respectively was found to be optimal, yielding a GABA content of 68.32 mg/100 g, which was significantly higher than that of the samples without these additives (1.10-fold increase) and that of unfermented sausage (around 10-fold increase). Analysis of variance suggested that the regression model could quite exactly predict GABA accumulation in chicken sausage. All of the three additives had significant effects on the GABA content of chicken sausage (P < 0.01). The interaction effects between L-Glu and VB6, and between L-Glu and CaCl2 were significant (P < 0.05) on GABA accumulation in chicken sausage.

This study was aimed to establish a rapid method for the identification of adulterated meat and meat products. Five pairs of species-specific primers, yielding amplicons having significantly different melting temperatures (Tm), were designed targeting the mitochondrial COXⅠ gene of pig and bovine, the 16S rRNA gene of sheep, goat, dog, fox and raccoon, and the 12S rRNA gene of chicken and duck, respectively. The established multiplex RT-PCR-melting curve analysis method was evaluated in term of specificity and sensitivity and was applied in the detection of commercial meat products. The method showed a good speci?city and sensitivity, and was able to detect 0.001–1 ng of DNA from single species and 0.1 ng of DNA form mixed species. Thus, it can be used to test both raw and processed meat products.

A surface plasmon resonance (SPR) biosensor system was developed for the determination of estradiol (E2) using an indirect competition method without labeling in real time. In the indirect competition method, the antigen (E2-BSA) was immobilized on the sensor chip surface and competed with E2 in samples for binding with the antibodies. Then the SPR response decreased in the presence of E2, which prevented the coupling of antibodies and E2-BSA, and so the SPR response was inversely proportional to E2 concentration. Assay parameters, including antibody concentration and number of regenerations, were optimized and E2-spiked milk samples were detected by this method. A linear relationship was obtained between inhibition percentage and common logarithmic value of E2 concentration over the range of 15.63 to 500 ng/mL and the limit of detection (LOD) was 11.13 ng/mL. The present study demonstrated a simple and general strategy for label-free detection of various small molecules.

Au@PVP core-shell nanoparticles were prepared by the hydrothermal method. Benzidine molecules were absorbed onto the surface of Au@PVP core-shell nanoparticles through the hydrogen bonding interaction between benzidine and polyvinylpyrrolidone (PVP). Benzidine molecules could be highly sensitively detected by the electromagnetic enhancement effect of the inner-core Au nanoparticles under the optimal excitation wavelength and the appropriate pH value. The limit of detection (LOD) was 10-9 mol/L, which was nearly 103 times lower than the limit of detection of the gas chromatography (GC) method for surface drinking water described in the Environment Quality Standards for Surface Water.

In this paper, a rapid label-free method to analyze the immune response to allergens by using a portable surface plasmon resonance (SPR) biochip was presented. Shrimp hemocyanin, monoclonal antibody against shrimp hemocyanin, and ascites fluid containing the monoclonal antibody were immobilized onto the surface of the biochip as probes, respectively. The biochip was then used to detect the immune response between shrimp hemocyanin and the corresponding monoclonal antibody. The kinetics of the reaction was analyzed, and the standard curve was constructed. Eight different batches of samples and seven different batches of unpurified ascites were detected on the same chip. This method allowed real-time, label-free, low-cost, environment-friendly and easy-to-control detections. It was suitable for real-time and continuous detection and rapid screening of a large number of samples. The developed portable SPR biochip detection system can be widely applicable to real-time rapid detection and quality control in factories, markets, supermarkets and other fields. It can also be applied in the clinical detection of allergen-specific antibody in serum of patients.

Objective: Different procures for viral concentration and RNA extraction from fruits and vegetables were proposed taking into account the difference in surface structure between both materials and they were used to develop a sensitive and rapid real-time fluorescent reverse transcription-polymerase chain reaction (RT-PCR) for the quantitative detection of astrovirus in fruits and vegetables using the primers and probes designed according to published sequences. Methods: A standard curve for quantitative detection of astrovirus was constructed by plotting the cycle threshold (Ct value) versus the starting concentration of 10-fold serially diluted cRNA. Then the method for norovirus and hepatitis A virus RNA extraction from fruits and vegetables described in the standard ISO/TS 15216-2:2013 was applied to detect astrovirus. The viral recovery rate, sensitivity and reproducibility of the assay were evaluated by using artificially contaminated cabbage and strawberry samples. Finally, 60 fruit and vegetable samples were tested to demonstrate the feasibility of this method. Results: The amplification efficiency of the real-time fluorescent RT-PCR was 95.9%, with a limit of detection (LOD) of 5.6 copies per reaction. The viral recovery rate of artificially contaminated cabbage samples was 0.94%?9.63%, compared to only 1.03% for the strawberries. Analysis of the artificially contaminated samples containing the same viral levels demonstrated high reproducibility with a coefficient of variation (CV) of less than 2%. Additionally, one strawberry sample collected from a retail market in Beijing was shown to be astrovirus-positive, and the detection rate was 1.67%. Conclusion: The developed method is rapid, efficient and sensitive for quantitative detection of astrovirus in fruits and vegetables, and will be a useful tool for routine screening and risk assessment of foodborne viruses.

In this paper, a duplex droplet digital polymerase chain reaction (ddPCR) method was developed to detect the content of unauthorized genetically modified (GM) maize event VCO-01981-5 based on a QX100 ddPCR platform. Towards this goal, PCR primers and TaqMan probes were designed based on the maize endogenous gene hmg and VCO-01981-5 event specific boundary sequences, and the probes were labeled with different chromophores so that the two targets could be detected in one single droplet. Analysis of the specificity of the method showed that both endogenous gene hmg and foreign sequence could be detected only in event VCO-01981-5. Moreover, the sensitivity, linearity and accuracy were evaluated and it was found that when relative standard deviation (RSD) was 25% or less, 5 copies of boundary sequences and 4 copies of gene hmg could be quantitatively detected, and the quantitative results (target copy) were highly correlated with the amount of DNA template up to 50 ng (R2 ≥ 0.99), with an average error of less than 10%. All the above results indicated that the established method in this study was very specific, stable, accurate and sensitive, and had a wide quantitative range in quantitative analysis of GM maize VCO-01981-5. Therefore, this method can be applied practically in quantitatively determining this GM maize event in imported and exported agricultural product and foods. Besides, this reported method can be used as a reference to establish a quantitative method for the detection of other GM maize events and GM events of other plants.

A quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) method was proposed to determine 20 polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) in vegetables. Samples were extracted with acidified acetonitrile, salted?out with anhydrous magnesium sulfate and sodium?chloride and cleaned with C18 modified silica gel and primary secondary amine (PSA), and the analytes were detected by GC-MS/MS under the selective reaction monitoring (SRM) mode and quantified by an external standard method. The calibration curves of monobromobiphenyl, dibromobiphenyl, tribromobiphenyl, terabromobiphenyl, pentabromobiphenyl and exabromobiphenyl as well as the corresponding PBDEs showed good linearity in the range of 0.05–5.0 mg/L, heptabromobiphenyl and octabromobiphenyl as well as the corresponding PBDEs showed good linearity in the range of 0.1–5.0 mg/L, nonabromobiphenyl and decabromobiphenyl as well as and the corresponding PBDEs showed good linearity in the range of 0.2–5.0 mg/L, with correlation coefficients of greater than 0.99. The limits of detection (LODs) were 0.30–17.67 ng/kg. With the proposed method, the recoveries in 3 different vegetables at spiked levels of 0.25, 0.5 and 2.5 mg/kg were 70.5%–118.9% with relative standard deviations (RSDs) of 1.3%–11.2%. The proposed method is simple and sensitive with good reproducibility and recovery, and thus can be suitable for the determination of PBBs and PBDEs in vegetables.

An extraction method based on an aqueous two-phase system consisting of the hydrophilic ionic liquid [C4MIM]BF4 and the inorganic salt (NH4)2SO4 for the simultaneous determination of six chlorophenols in red wine by high performance liquid chromatography (HPLC) was established. The extraction efficiency and enrichment factor were found to be influenced by the types and concentrations of salts and ionic liquids, as well as pH value, and these parameters were investigated to determine the optimal conditions for extracting chlorophenols. Under the optimal conditions, the linear ranges of six chlorophenols were 20–200 μg/L with correlation coefficients (R2) of 0.999, and the limits of detection (LODs) were in the range of 3.68–12.16 μg/L. This method was successfully applied to analyze six chlorophenols in real red wine samples with spiked recoveries ranging from 87.73% to 103.44% and relative standard deviation (RSD) ranging from 0.33% to 6.35%. This method is simple, rapid, environmentally friendly and efficient.

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with solid phase microextraction method was established for the simultaneous determination of 72 veterinary drugs including sulfanilamide, quinolone, glucocorticoid, macrolides, beta-agonist, steroid hormone, tetracycline, penicillin, chloramphenicol and beta-lactam in pork, fish and shrimp samples. Samples were extracted by 80% (V/V) acetonitrile in water, followed by cleanup of the extracts through a Prime HLB solid phase extraction column directly without activation. Separation was performed on a C18 column and the eluates were detected by multiple reaction monitoring scanning with electronic spray ionization. An external standard method was applied for quantification. The limits of quantitation (LOQ) for 72 veterinary drugs were in the range of 0.5 to 5 μg/kg. Recoveries from different food matrices were from 75.6% to 122.3% with relative standard deviations between 0.6% and 10.7%. This method was significantly efficient in the determination of multiple veterinary drugs and suitable for rapid multiresidual analysis of veterinary drugs in handling of food safety emergencies.

Objective: Aiming at the development of an immunochromatographic method based on dyed latex beads for the detection of clenbuterol (CLB) in swine urine. Methods: Dyed latex beads were conjugated with anti-CLB antibody and vacuum freeze-dried. CLB-bovine serum albumin (CLB-BSA) conjugate and goat anti-mouse IgG antibodies were coated onto nitrocellulose membranes to establish test and control lines, respectively. The test was carried out by placing swine urine into the sample well and mixed with dyed latex beads. After incubation, the optical density was measured by a microplate reader. Results: After optimizing the physical and chemical parameters, the best surfacant was Tween-20, 300 nm dyed latex beads were chosen, and the incubation time was 9 minutes. The limit of detection (LOD) was 0.013 ng/mL. The recoveries from spiked swine urine varied from 97.8% to 106.0%, with relative standard deviation of less than 9.6%. Conclusion: A sensitive and accurate method for the detection of CLB was successfully developed in this paper.

Butter and cream are natural food products containing partially saturated animal fat while margarine and non-dairy whip topping contain refined and preternaturally saturated vegetable oils. Thus, butter and cream are more expensive than margarine and non-dairy whip topping. In the food industry, margarine is widely used as butter while non-dairy whip topping is used as cream. In order to find an analytical tool to differentiate butter (cream) from margarine (non-dairy whip topping), we used 1H nuclear magnetic resonance (1H-NMR) to analyze the compositions of extracts (CDCl3) of the four species. We found that the levels of cholesterol, butyrate, 1-penten and conjugated linoleic acid were higher, while total unsaturated fatty acid and linoleic acid were lower in the butter than in the margarine. Cholesterol, butyrate, linoleic acid, linoleic acid, 1-penten, conjugated linoleic acid, and total unsaturated fatty acid were higher while total saturated fatty acid was lower in the cream than in the non-dairy whip topping. All these differences were significant (P < 0.05). Partial least squares discriminant analysis (PLS-DA) was used to find the characteristic components in each group, and the results for fatty acids were consistent with those obtained with gas chromatography (GC). Conclusively, an identification method for butter (cream) and margarine (non-dairy whip topping) based on 1H-NMR metabolomics has been established for the first time, which can provide an analytical method for the quality identification and control of butter (cream).

The purpose of this study was to establish a high performance liquid chromatography (HPLC) method for the qualitative and quantitative detection of histamine in Suanzharou, a unique and traditional fermented meat product of the Tujia nationality in southeastern Chongqing. 1,7-Heptanediamine was used as an internal standard substance. Dansyl chloride was used as a derivatization agent. The chromatographic separation was accomplished using an Agilent C18 column as stationary phase and a mixture of 70% methanol and 30% ultra pure water as mobile phase, and the UV detector was set at 254 nm. The analyte was extracted with 0.4 mol/L HClO4 solution and analyzed by HPLC. Results showed that the peaks for 1,7-heptanediamine and histamine dihydrochloride appeared at 4.335 min and 7.723 min, respectively, and an acceptable separation was achieved. The proposed method showed a good linearity between the ratio of peak area (histamine dihydrochloride and 1,7-heptanediamine) and the mass concentration of histamine. The recovery of spiked samples was between 98.5%–102.2%, the instrumental limit of detection (LOD) was 0.50 mg/L and the limit of quantitation (LOQ) was 1.00 mg/L. The precision expressed as relative standard deviation (RSD) was 1.0%. The histamine content of 10 real samples was detected to be in the range of 19.68–44.15 mg/kg, with significant differences existing among these samples (P < 0.05). In conclusion, this method is reliable for the detection of histamine in Suanzharou with high sensitivity and precision.

In this paper, a novel disposable centrifugal microfludic chip with pre-storage biochemical reagents was developed for the rapid detection of pesticide residues in agricultural products, which was based on the principle of enzyme inhibition and photometric analysis. The microfludic chip was integrated with sampling, enzyme inhibition, color development and detection chamber. By coupling with a portable detection device developed in our laboratory, the microfludic chip could provide a simple, easy-to-use, low-cost and sensitive approach for rapid detection of organophosphate and carbamate pesticides on site. Results indicated that the microfluidic chip could achieve an automatic detection process with the advantages of less consumption of reagents (reduction by one-twentieth) and satisfied accuracy compared with the traditional pesticide residue detector. Furthermore, the microfluidic chip was proved to be a powerful tool for screening pesticide residues in the case of high-throughput requirement. The microfluidic chip was superior to the traditional pesticide residue detector in term of detection sensitivity, reproducibility and measurement accuracy. The microfluidic chip coupled with self-made detection device is particularly suitable for on-site, rapid and high-throughput screening of pesticide residues by nonprofessionals.

The aim of study was to develop a novel method using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to determine 34 components, which are categorized into 6 kinds of plastic additives including antioxidant, plasticizer, ultraviolet light absorber, colorant, surfactant and fire retardant, in highland barley liquor. Samples were diluted with water to a 20% alcohol content, and extracted with acetonitrile under salting-out conditions. The UPLC system was equipped with a Waters HSS T3 C18 analytical column (2.1 mm × 150 mm, 1.7 μm) utilizing methanol-0.1% ammonium acetate as mobile phase in gradient elution mode with a ?ow rate of 0.2 mL/min. An electrospray ionization ion source under positive ion mode (ESI+) for multiple reaction monitoring analysis was used, and quantification was performed by an external standard method. The calibration curves exhibited a good linearity in wide concentration ranges with correlation coefficients of over 0.99 for all analytes. The average recoveries from spiked highland barley liquor at two concentrations ranged from 71.2% to 106.7% with relative standard deviations (RSDs) from 4.2% to 15.4%. The limits of detection (LODs) were between 5 and 50 μg/L. A total of fifteen kinds of plastic additives were found in 12 batches of samples. Therefore, the new method allowed simultaneous determination of different kinds of plastic additives that differ widely in physicochemical properties. It is a promising method for the identi?cation and quantitation of plastic additive compounds in liquor.

In this study, a colorimetric probe was devised and synthesized by coupling a salicylaldehyde moiety, which acts as a recognition unit, to the naphthalimido diazonium salt (a signal unit) through an azo bond for the detection of cyanide. After reacting with cyanide, the absorption bands of the probe shifted from 404 to 505 nm and the color changed rapidly from yellow to red. The probe allowed ratiometric detection of cyanide in aqueous solution with a linear range of 0.5–40.0 μmol/L and a limit of detection (LOD) of 0.13 μmol/L, which is much lower than the maximum contaminant level (1.9 μmol/L) for cyanide in drinking water set by the World Health Organization. The probe also displayed excellent selectivity for CN- rather than other anions including F?, Cl?, Br?, I?, SCN?, AcO?, S2?, H2PO4?, N3? and NO3?. The method developed in this study gave the same results as those from the national standard method in real sample detection. In addition, the probe was successfully used to prepare test strips, which can be used to monitor cyanide conveniently, and the discernible concentration of cyanide can be as low as 5.0 μmol/L.

A simple, rapid and sensitive method for the simultaneous determination of 18 kinds of glucocorticoids in milk was developed by the quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in the multiple reaction monitoring (MRM) mode. Milk samples were extracted with acidified acetonitrile, and salted out by adding sodium chloride anhydrous sodium magnesium sulfate. After purification with PSA and C18 as the adsorbent, the supernatant was analyzed by HPLC-MS/MS. The matrix effect in the method was in the range of 0.81–0.96, the limits of detection (LODs) were in the range of 0.1–0.3 μg/kg and the limits of quantification (LOQs) for the analytes were in range of 0.3–1.1 μg/kg. The method exhibited a good linear relationship in the range of 0.5–100 ng/mL, with a correlation coefficient (R2) of higher than 0.993 6, and recoveries were between 73.7% and 98.6% at three spiked levels with relative standard deviations (n = 5) of 4.9%–12.9%. This method was simple, accurate, reliable, and suitable for the rapid detection of glucocorticoids in bulk serum samples.

Peanut products are susceptible to changes in temperature and relative humidity (RH) during storage. Peanuts are easily infected by hazardous fungal species, producing a variety of potent mycotoxins. This study aimed to develop a method for the rapid detection of moldy peanuts. Firstly, clean and fresh peanut kernels were sterilized and inoculated individually with five common hazardous fungal species. Then, the samples were stored at 26 ℃ and 80% RH for 9 days. During this period, spectral information of the peanut samples in the wave number range of 4 000 to 600 cm-1 were collected using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The spectral changes of peanut samples infected with different fungal species were analyzed by loading analysis. A quantitative model to predict contamination levels of hazardous fungi in peanut samples was developed by partial least squares regression (PLSR). The results showed that the spectral alterations for the samples were clearly fluctuated during different storage periods. The PLSR model could predict the total number of colonies of single and multiple strains in fungus-infected peanut samples with good?accuracy. Especially, the model provided better prediction of Aspergillus ochraceus 3.6486 infection with a coefficient of determination for the prediction set (Rp2) of 0.915 7, a root mean-square error of cross-validation (RMSECV) of 0.208 0 (lg (CFU/g)) and a residual predictive deviation (RPD) of 2.52. The Rp2, RMSECV and RPD values of the prediction model for total fungal species were 0.780 3, 0.358 0 (lg (CFU/g)) and 1.76, respectively. These findings demonstrated that ATR-FTIR could be used as a reliable analytical method for rapid determination of fungal contamination levels in peanuts during storage.