Lactobacillus casei Fx was isolated from cattle rumen for its ability to transform linoleic acid into c9,t11- conjugated linoleic acid (CLA). Genomic DNA was extracted and a 1 700-bp linoleic acid isomerase (LAI) gene fragment was amplified from the strain by PCR. The gene fragment was purified and cloned into the plasmid pUCm-T-LAI to obtain recombinant plasmid pUCm-T-LAI by TA cloning. The recombinant plasmid and the expression plasmid pET-DsbA were subjected to double enzyme digestion and ligated to the recombinant expression vector pET-DsbA-LAI. After identification by PCR and enzymatic digestion, the recombinant expression vector was transformed into E. coli BL21. The recombinant strain, having LAI activity, possessed the ability to specifically transform linoleic acid into c9,t11-CLA isomer. The results showed that the LAI gene from L. casei Fx was successfully cloned. This work makes it possible to understand the difference among the LAI genes in different rumen bacteria.

One strain of Bacillus amyloliquefacien named LZ-5 was isolated from two wild honey samples collected from different regions. It was found to possess a broad spectrum of antimicrobial activity. Its secondary metabolites had strong antimicrobial activities against some kinds of food spoilage microorganisms, including Bacillus pumilus, Staphyloccocus aureus, Saccharomyces cerevisiae and Aspergillus oryzae. According to its morphological and cultural characteristics, physiological and biochemical properties and 16S rDNA sequence analysis, the strain was identified as Bacillus amyloliquefacien. The main anti-yeast substances produced by it were separated by organic solvent extraction, SephadexLH-20 column chromatography and high performance liquid chromatography. Liquid chromatography-electrospray ionization mass spectrometry was adopted to determine the molecular masses of the substances by comparison with standard compounds. The anti-yeast substances were preliminarily identified as a mixture of iturinA2, iturinA3 and iturinA6.

WRKY proteins are a class of plant-specific transcriptional factors (TFs), which play important roles in plant growth and development, leaf senescence and hormonal signaling. However, their relationship with banana fruit ripening and senescence remains unknown. In the present work, a WRKY TF, termed MaWRKY31, was obtained from banana fruit. Analysis of deduced amino acid sequence and phylogenetic tree revealed that MaWRKY31 contained a typical WRKY domain showing high homology with Arabidopsis thaliana WRKY31, and belonged to the Ⅱb sub-group. Realtime quantitative polymerase chain reaction displayed that MaWRKY31 was induced by ethylene, and up-regulated following banana fruit ripening and senescence. Sub-cellular localization and transcriptional activity analysis revealed that MaWRKY31 was a nuclear protein with transcriptional activation activity. In addition, dual-luciferase transient expression assay demonstrated that MaWRKY31 could activate the promoter activities of the ethylene biosynthetic genes MaACS1 and MaACO1 and the ripening-related gene MaSAG1. Taken together, these results suggest that MaWRKY31 may be involved in banana fruit ripening and senescence, possibly via the regulation of the expression of genes related to ethylene biosynthesis and ripening, which deepens the understanding of the transcriptional regulation mechanism of banana fruit ripening and senescence.

This investigation studied the expression of salt stress-related genes in Lactobacillus plantarum FS5-5, a salt-tolerance strain isolated from naturally fermented miso in northeastern China, at the level of transcription. Results showed that in the logarithmic growth phase, 29 genes were significantly down-regulated, including four ones involved in carbohydrate transport and metabolism, nine ones involved in amino acids transport and metabolism, three ones involved in vitamin metabolism, six ones involved in nucleotide metabolism and seven ones involved in genetic information translation, ribosomal structure and biogenesis. Four genes involved in carbohydrate transport and metabolism were significantly upregulated, which might be closely associated with salt stress resistance of L. plantarum FS5-5. Three genes involved in vitamin metabolism and one gene involved in nucleotide metabolism were selected to be analyzed by real-time fluorescent quantitative polymerase chain reaction and the results showed that the expression of these genes exhibited the same trend in these two methods. The comprehensive analysis of the mechanism of action of L. plantarum FS5-5 to resist salt stress presented in this study which would provide a theoretical basis to improve the tolerance of strains in industrial production.

The purpose of this study was to optimize the processing parameter for fluorescence labeling of oxidized muscle proteins from large yellow croaker (Pseudosciaena crocea) with luorescein-5-thiosemicarbazide (FTSC), and further to establish a two-dimensional gel electrophoresis (2-DE) system for oxidized muscle proteins. The results showed that the optimized electrophoresis process was as follow. The protein sample was prepared by liquid nitrogen milling and using a lysis buffer containing 8 mol/L urea, 2 mol/L thiourea, 4% CHAPS, 65 mmol/L DTT and 0.2% carrier ampholyte, and then the oxidized protein was labeled with FTSC (20 mmol/L in DMSO) for 3 h at 40 ℃ in the dark, and washed five times with ethanol/ethyl acetate (1:1). The sample was loaded onto immobilized pH gradient (IPG) gel strip (pH 5–8), and separated by isoelectric focusing (active rehydration for 14 h at 50 V; desalting for 2 h at 500 V, 1.5 h at 1 000 V and 1 h at 4 000 V; voltage for 0.5 h at 6 000 V at first and then for 1 h at 10 000 V; focusing for 80 000 vhr at 10 000 V; finally balancing for 10 h at 500 V). After isoelectric focusing, the IPG strip was transferred and the proteins were separated by 12% SDS-PAGE. Finally, 2-DE maps for the oxidized and whole muscle proteins with high resolution and even distribution were obtained by direct scanning using a fluorescence image scanner and scanning after silver staining. This study would provide a foundation for the separation and identification of oxidized muscle proteins, and further for the clarification of protein oxidation mechanism by two-dimensional gel electrophoresis and proteomics technology.

This study aimed to elucidate the intracellular mechanism of action of antimicrobial peptide F1 on Staphylococcus aureus. The binding of the genomic DNA of S. aureus to antimicrobial peptide F1 was investigated with gel retardation, and the competitive intercalation of F1 and ethidium bromide (EB) into the genomic DNA were analyzed by fluorescence spectroscopy. The influence of F1 on the synthesis of protein in S. aureus was determined by Coomassie brilliant blue method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The inhibition of β-galactosidase and nonspecific esterase activities of S. aureus cells by the antibacterial peptide was measured using o-nitrophenyl β-D-galactopyranosiden (ONPG) and di-O-acetylfluorescein (FDA), respectively. Finally, the changes in the cell cycle of S. aureus after being treated by F1 were monitored with flow cytometry. The results showed that F1 bound with DNA and could weaken the fluorescence intensity of EB-DNA complex, hindering the expression of genetic information of S. aureus. Besides, the protein biosynthesis of S. aureus was also inhibited, which was further proven by the measured activities of two intracellular enzymes, β-galactosidase and non-specific esterase. Therefore, F1 could lead to the aberration of the intracellular enzyme system and metabolic pathways of S. aureus, and block the DNA synthesis phase of the cell cycle of S. aureus.

This study aimed to investigate the process of biofilm formation of Hafnia alvei Ha-01, and to examine the influences of different culture conditions (carbon source, pH, NaCl concentration, and adhesive material) on the number of viable cells in biofilm formed by Hafnia alvei and its growth properties by the ultrasonic plate method and scanning electron microscopy (SEM), and we also assessed the relationship between exogenous N-acyl-homoserine lactone (C6-HSL) as a quorum-sensing (QS) signal molecule and the biofilm formation of Hafnia alvei. The results indicated that the biofilm formation of strain Ha-01 was closely related to incubation time. The biofilm formation ability of Ha-01 varied depending on carbon source, and when xylose was used as carbon source, its biofilm formation ability reached the strongest level of 7.51 (lg (CFU/cm2)), which was increased by 10.28% as compared with that in LB medium. The biofilm formation ability of Ha-01 was stronger under neutral conditions, with the viable cell count reaching 7.77 (lg (CFU/cm2)). At a NaCl concentration of 2%, the biofilm formation was the highest, reaching 7.18 (lg (CFU/cm2)). The biofilm formation ability of Ha-01 on different material surfaces was deceased in the order of Al, Zn, and glass. The numbers of viable cells on these materials were 7.22, 6.48, and 6.11 (lg (CFU/cm2)), respectively. The biofilm formation ability became stronger with the increase of exogenous C6-HSL. In conclusion, culture conditions could affect the biofilm formation of Hafnia alvei, which could be regulated by AHLs.

This study aimed to explore the effect of N-glycosylation on enzymatic characteristics of hyperthermoacidophilic α-amylase ApkA for the purpose of establishing the basis of the development of genetically engineered yeast. Based on the amino acid sequence analysis of ApkA, a signal peptide deleted mutant ApkAds and a double site mutant ApkAdsD182N/ G373S containing two potential N-glycosylation sites were constructed and expressed in Pichia pastoris GS115. The recombinant α-amylases ApkAds and ApkAdsD182N/G373S were expressed at high levels and secreted into the culture medium. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the molecular weights of ApkAds and ApkAdsD182N/G373S were about 45 and 55 kD, respectively. Compared with ApkAds, the mutant ApkAdsD182N/G373S showed optimal pH of 5.5–6.0 instead of 6.5. The mutant ApkAdsD182N/G373S was more stable under acidic conditions. Its optimal temperature was 100 ℃ compared with 90 ℃ for ApkAds . When incubated at 90 ℃, ApkAds and ApkAdsD182N/G373S exhibited half-lives of 5 and 5.5 h, respectively. After incubated at 100 ℃ for 10 min, the residual activities of ApkAds and ApkAdsD182N/G373S were 32.03% and 49.04%, respectively. These results suggest that N-glycosylation moderately increases enzymatic activity and stability under acidic conditions, optimal temperature, and thermostability of ApkA, and the mutant ApkAdsD182N/G373S is ideal for starch liquefication.

In this study, we evaluate the quality and antioxidant activity of raw sauce produced by high-salt liquid-state fermentation of rice dregs with mixed starter cultures. The results showed that all four rice sauces fermented by different mixed starters reached the quality requirements of the Chinese national standard GB 18186-2000 for first-grade soy sauce. The sauce fermented by soy sauce koji containing Aspergillus oryzae and Aspergillus niger plus Zygosaccharomyces rouxii (S4) contained 41.81 g/L total free amino acids. The rice sauces had higher contents of total amino acids, essential amino acids, flavor amino acids and antioxidant amino acids than soy sauce fermented by Aspergillus oryzae (S5). The antioxidant activity of the rice sauces fermented by soy sauce koji containing Aspergillus oryzae alone (S3) and both Aspergillus species (S4) plus Zygosaccharomyces rouxii was higher than that of their counterparts (S1 and S2) obtained without the use of Zygosaccharomyces rouxii. S3 was found to have the strongest antioxidant activity, showing a 175.42- and 2.16-fold increase in hydroxyl and DPPH radical scavenging capacity compared with VC, respectively. The antioxidant activity of rice sauce was strongly influenced by fermentation temperature, reaching a peak at 35 and 50 ℃. In conclusion, the quality and antioxidant activity of rice sauce fermented with mixed cultures could be considerably improved compared with single culture fermentation, which is greatly attributed to Zygosaccharomyces rouxii.

Owing to its role as an important source for astaxanthin accumulation, Haematococcus pluvialis has gained more and more attention in recent years. In this research, we examined the effects of butyl hydroxyanisole (BHA) at different concentrations on the astaxanthin production under unfavorable conditions during the logarithmic growth phase of H. pluvialis LUGU. The results demonstrated that 2 mg/L BHA was optimal for maximum astaxanthin production, which reached 29.03 mg/g, 2.03 times higher than that of the control (14.30 mg/g). Moreover, under the same condition of BHA induction, initial algal cells with different growth status also had a great influence on astaxanthin synthesis. The accumulation of astaxanthin in the algal cells in the late exponential growth phase (14 d) reached the highest level of 29.3 mg/g, which was 2.93, 1.01 and 1.73 times higher those in the early and middle exponential, and stationary growth phases, respectively. qRT-PCR analysis shows that the transcriptional levels of phytoene synthase (psy) gene induced by 2 mg/L BHA was 9.2 times higher that of control. These findings showed that appropriate concentration of BHA could not only increase the transcription of psy gene, but also could obviously promote intracellular astaxanthin accumulation in microalgae, providing an effective strategy for the industrialization of astaxanthin.

To improve the activity of lactic acid bacterial starter cultures during their production and application, we investigated the induction and resuscitation of viable but non-culturable (VBNC) state in Lactobacillus delbrueckii subsp. bulgaricus ND02 (Lactobacillus bulgaricus ND02), which had excellent fermentation characteristics. Lactobacillus bulgaricus ND02 was cultured under different conditions to induce the VBNC state. The plate count method and fluorescence microscope were used jointly to examine the VBNC state, and then the VBNC cells were resuscitated by varying temperature and medium components. The results showed that Lactobacillus bulgaricus ND02 in MRS at 4 ℃ could enter the VBNC state after 190 days. It was also found that skim milk (10%) plus yeast powder (0.1%) was effective for resuscitation. This study would provide a reference basis to prevent Lactobacillus bulgaricus ND02 from entering the VBNC state and thus to improve its activity for future work.

In order to make better use of Cordyceps militaris, the optimization of medium components and culture conditions was investigated for improved zinc enrichment of C. militaris in liquid-sate fermentation. Meanwhile, the optimal LiCl concentration was chosen to mutate C. militaris. Finally, zinc concentrations in the mycelia of the parental and mutant strains were determined by graphite furnace atomic absorption spectrometry. Results showed that the optimal culture conditions for C. militaris to enrich zinc were as follows: 3% sucrose as the best carbon source, 3% peptone as the best nitrogen source, fermentation time, 6 d; inoculum size, 5%; medium volume, 100 mL/250 mL; and initial ZnSO4 concentration, 100 μg/mL. Under these conditions, the rate of zinc enrichment was 18.54%. The LiCl concentration of 0.15% was optimal for the mutation of C. militaris. Five strains with higher zinc enrichment ability were obtained, giving the highest rate of zinc enrichment of 24.68%, which was increased by nearly 42% as compared with that of the original strain. Therefore the mutants would have promising applications for industrial production.

The genomic DNA extracted from Aspergillus niger 3.316 was used as template to amplify the β-glucosidase gene bgl by PCR to obtain a 2 080-bp amplicon. Bioinformatic analysis showed that the encoded protein was predicted to contain 860 amino acid residues with 4 major hydrophobic regions. Its secondary structures might contain 63.26% random coils, 20.58% α-helix, and 16.16% β-sheet. The protein consisted of (β/α)8 TIM barrel domain, (β/α)6 sandwich domain, and fibronectin Ⅲ-like domain. The active site and heat tolerance mechanism were predicted to be located in the active center of the enzyme. Its active sites might be Asp280 of (β/α)8 TIM barrel domain and Glu509 of (β/α)6 sandwich domain. The thermal stability of the glucosidase might be related to the presence of 211 amino acid residues in the hydrophobic region, 48 proline residues and α- helix.

This study was designed to optimize the enzymatic preparation of hypoglycemic peptides from red deer (Cervus elaphus) antlers. Alcalase, flavourzyme, neutral protease and trypsin were comparatively evaluated based on α-glucosidase inhibitory activity of hydrolysates to select two suitable enzymes for sequential hydrolysis of red deer antlers. The sequences of two hydrolysis steps were compared for better hypoglycemic activity in vitro and the hydrolysis conditions were optimized based on degree of hydrolysis (DH), α-glucosidase inhibitory activity and protein recovery with one-factor-at-atime method and orthogonal array design. The results showed that alcalase and flavourzyme were found to be more suitable and sequential use of alcalase followed by flavourzyme was optimal for higher percentage inhibition of α-glucosidase activity, DH and protein recovery, reaching 21.11%, 19.88% and 39.12%, respectively. The optimal hydrolysis conditions were obtained as follows. Red deer antlers were hydrolyzed firstly with 5 000 U/g alcalase at an initial pH of 8.0 and 60 ℃ with a substrate concentration of 12% for 3 h, and then with 6 000 U/g flavourzyme for 1 h at 45 ℃ with a substrate concentration of 5% after pH adjustment to 6.5. The final hydrolysate exhibited concentration-dependent α-glucosidase inhibitory activity, with a percentage inhibition of 94.09% at 3 mg/mL and IC50 value of 1.82 mg/mL. It was concluded that alcalase-flavourzyme hydrolysis would provide an efficient way to prepare hypoglycemic peptides from red deer antlers.

This paper deals with the optimization of the process conditions for the enzymatic hydrolysis of Undaria pinnatifida protein using response surface methodology (RSM). With this aim in mind, after selection of an appropriate enzyme, the effects of hydrolysis time, pH, hydrolysis temperature, substrate concentration and enzyme dosage on the degree of hydrolysis and the antioxidant activity of hydrolysates were investigated using RSM based on one-factor-at-atime experiments. The optimized hydrolysate was compared with the natural antioxidant ascorbic acid and the synthetic antioxidant butyl hydroxyanisole (BHA) in regard to their antioxidant activity. The results showed that protamex was the best enzyme for the hydrolysis of U. pinnatifida protein. The optimal conditions that provided ferrous ion-chelating ability and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity were determined as follows: hydrolysis time, 8.1 h; pH, 7.0; hydrolysis temperature, 50 ℃; substrate concentrate, 15 g/L; and enzyme dosage, 0.2% (0.3 AU/g). Under these conditions, the rate of chelation of ferrous ion by the hydrolysate was up to 88.58%, which was significantly higher than that by 0.01% ascorbic acid and BHA (P < 0.05). However, in terms of DPPH free radical scavenging percentage (59.22%) and reducing power, the hydrolysate was inferior to 0.01% ascorbic acid and BHA (P < 0.05).

Angiotensin converting enzyme (ACE) inhibitory peptides from oyster were prepared by the combined use of enzymatic hydrolysis and Plastein reaction. Papain, pepsin, alcalase, neutural protease and trypsin were tested for their efficiencies in hydrolyzing oyster based on ACE inhibitory activity and degree of hydrolysis and it turned out that papain was the optimal choice. The hydrolysis conditions were optimized by one-factor-at-a-time method and orthogonal array design as follows: solid-to-liquid ratio (g/mL), 1:8; concentration of papain, 2.0%; hydrolysis time, 1.0 h; hydrolysis temperature, 65 ℃; and initial pH, 6.0. Under these conditions, the percentage inhibition of ACE activity by oyster hydrolsate was 63.30%. The hydrolysate was modified via the Plastein reaction. Based on ACE inhibitory activity and reduction in free amino acid content, the optimal values of Plastein reaction parameters including the type of enzyme, enzyme dosage, substrate concentration, temperature and reaction time were determined to be papain, 1.0%, 40%, 2.5 h and 30 ℃ for hydrolysis at an initial pH of 7.0, respectively. The modified product showed maximum percentage inhibition against ACE activity of 82.31%, which was increased by 19% compared to that before modification.

This study aimed to prepare and characterize monoclonal antibodies (Mab) against outer membrane protein K (OmpK) of Vibrio. We injected Balb/c mice with OmpK of the Vibrio parahaemolyticus wild-type strain B expressed by a prokaryotic expression system. Spleen cells from the immunized mice were fused with SP2/0 tumor cells. Then the hybrid cell lines which can stably secrete monoclonal antibody were screened out by using the limited dilution method and indirect enzyme linked immunosorbent assay (ELISA) method. Ascites was produced in the mice and then purified by saturated ammonium sulfate precipitation and Protein G affinity chromatography. Finally, we obtained two hybridoma cell lines namely OmpK-Mab-4B7 and OmpK-Mab-3C5, which can stably secrete anti OmpK monoclonal antibody. The Mab subtypes secreted by both hybrid tumor cell lines were IgG1 and their titers reached 1:128 000. The sensitivity IC50 of 3C5 and 4B7 antibodies were 2.5 and 5.0 μg/mL, respectively. The results of Western blotting showed that the Mab could combine with the outer membrane proteins of 12 strains Vibrio parahaemolyticus (A, B, C, D, E, F, G, H, I, J, ATCC17802, and ATCC33847), 3 (A, B, and C) of 4 Vibrio alginolyticus strains and 1 Vibrio anguillarum strain (MVM). The monoclonal antibodies can be used for basic research and rapid detection of OmpK.

Trypsin was immobilized onto epoxy resin under microwave irradiation. Using one-factor-at-a-time method and response surface methodology (RSM), the optimal conditions of immobilization were obtained as follows: trypsin dosage, 41 mg/g; microwave irradiation time, 10 min; pH, 6.2; and temperature, 30 ℃. Under these conditions, the activity of immobilized trypsin was 322.56 U/g resin, which was higher than that of traditional immobilized trypsin and the immobilization time was shortened from 20 h to a few minutes. Furthermore, immobilized trypsin had a good stability. Thus, microwave-assisted immobilization provides an efficient way of immobilizing trypsin.

Indigenous Saccharomyces cerevisiae KDLYS9-16, a high-yield β-D-glucosidase producing strain, can promote the release of monoterpenes to enhance the aroma of wine during the winemaking process. In this research, we fermented Cabernet sauvignon and Merlot grapes cultivated in Changli and Shacheng regions of Hebei province by the strain KDLYS9-16 to determine sugar consumption, alcohol production and wine aroma as a function of fermentation time in comparison with those achieved by using the commercial strains F15 and SC. The results showed KDLYS9-16 had the advantages of earlier initiation of fermentation, faster sugar consumption, shorter fermentation period, and higher sugar conversion rate compared with those of F15 and SC. In the wine from Cabernet Savignon grapes grown in Changli fermented by KDLYS9-16, 32 aroma substances were detected, accounting for 98.94% of the total volatile substances, demonstrating a significant increase in both the types and amounts of aroma compounds as compared with its counterparts fermented by the control strains. Consequently, the strain KDLYS9-16 showed a good wine-making performance and had the potential for increasing wine aroma, thereby possessing promising applications.

In the present work, the growth-promoting effects of Chinese yam oligosaccharides on Bifidobacterium adolescentis and Bifidobacterium animals in vitro were examined. Being used as a substitute of carbon source for glucose in culture medium, Chinese yam oligosaccharides had significant promoting effects on the growth of bifidobacteria. With the increase in added Chinese yam oligosaccharides, the viable count of the probiotic bacteria increased, while the pH value decreased. By glucose substitution with 0.5% Chinese yam oligosaccharides, the viable counts of B. adolescentis and B. animals increased by (10.70 ± 4.93)% and (6.02 ± 2.00)%, respectively, and the pH value decreased by (2.64 ± 0.001)% and (3.85 ± 0.65)% respectively. Meanwhile, Chinese yam oligosaccharides promoted the growth rate of bifidobacteria and resulted in earlier onset of the stationary growth phase.

In the present study, 28 Yucha (a traditional fermentation rice food of Li nationality in Hainan) samples collected from different Li nationality households in Baoting and Baisha areas of Hainan province were used to isolate and purify microbes by conventional culture method and further to determine microbial diversity by 16S rRNA sequencing analysis and quantitative real-time polymerase china reaction (qRT-PCR). A total of 22 bacterial species from six genera were identified. Among these, Lactobacillus, Bacillus and Enterococcus accounted for 68.56%, 18.04% and 10.82% of the total bacteria, respectively. Meanwhile, the copy numbers of genes in Lactobacillus, Bacillus and Enterococcus were 2.24 × 107, 1.72 × 105 and 1.07 × 106, respectively, meaning that Lactobacillus was the most predominant genus, with Lactobacillus plantarum and Lactobacillus pentosus being the most predominant species. The microbial diversity in Yucha from different areas was different. Lactobacillus rossiae was exclusively found in Yucha from Baoting while L. coryniformis, L. fermentum, L. namurensis and L. senioris in Yucha from Baisha. The results of the present study revealed the abundant microbial diversity and microbial community structure in Yucha, which could provide evidence to develop and use the beneficial microbial resources from Yucha.

The crude tannase from Aspergillus niger N5-5 was purified by hollow fiber membrane ultrafiltration and Sephadex G-150 gel chromatography. The properties of the purified tannase were then determined. The results showed that the tannase from Aspergillus niger N5-5 could be purified about 20 folds with a 23.30% recovery. The enzyme was a 64.2 kD protein with a single peptide chain by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The optimal temperature for the enzyme was 45 ℃, and it had good thermostability in the range of 25–45 ℃; the optimal pH value was 5.0, and the enzyme displayed good pH stability in the pH range of 5.0–5.5. In addition, the results of reaction kinetics showed that the Km and vmax values towards the substrate propyl gallate were 0.916 mmol/L and 0.877 mmol/(L·min), respectively.

In this work, a three-level Box-Behnken factorial design was employed to optimize the culture conditions for liquid-state fermentation of Pleurotus eryngii. By the combined use of one-factor-at-a-time method and response surface methodology, the effect of four different factors on dry mycelial biomass was determined to be in the order of rotation speed > initial pH > inoculum quantity > medium volume and their optimal levels were 147.00 r/min, 5.90, 9.50% and 95.00 mL/250 mL, respectively. Under these conditions, the dry mycelial biomass was 1.265 7 g/100 mL. In conclusion, this study will provide evidence for the cultivation and bioactive components analysis of P. eryngii.

A total of 95 bacterial strains were isolated from Chinese liquor pit mud by the microencapsulation culture method through cell sorting using flow cytometry. Out of these isolates, the strains LS4, LS27, LS32, LS37, LS64, LS66, LS69’ and LS85 were selected for slow growth rates. Gas chromatography analysis demonstrated that LS66 was determined as the best one for the production of an abundance of aroma compounds in Chinese liquor. By morphological observation, physiological and biochemical tests and 16S rDNA sequence analysis, it was tentatively identified as an uncultured functional bacterium, termed N8-7. The optimal culture temperature, pH and inoculums size for this strain were determined to be 35 ℃, 6.5 and 4%, respectively.

The present work was aimed at optimizing the enzymatic removal of protein from the fermentation broth rich in hyaluronic acid using a combination of one-factor-at-a-time method and response surface methodology. The results showed that trypsin was selected as the best enzyme for minimum protein content. The optimal hydrolysis conditions were obtained as follows: initial pH value, 8.4; temperature, 50 ℃; enzyme dosage, 44 000 U/g; and time, 6 h. Under these conditions, the protein content was reduced to 6.75% with a percentage removal of 66.25%. After further processing with diatomite, the protein content was decreased to as low as 0.1% with a percentage removal of over 99%, which reached the standard of pharmaceutical grade hyaluronic acid.

In order to understand the relationship between lipid oxidation and the formation of flavor components in Decapterus maruadsi during two different dry-salting processes, i.e. traditional high salt (HS) and low-salt lactic acid fermentation (LAF), the changes in lipoxygenase (LOX), thiobarbituric acid reactive substance (TBARS) value, peroxide value (POV), and flavor components were measured. The relationship between lipid oxidation and flavor components was analyzed by the Pearson correlation coefficient. The results showed that LOX activity increased in the first three stages and then decreased in the final stage for both dry-salting processes, and it was higher in HS samples in the first three stages but lower in the final stage compared with LAF samples. LOX activities in the final dried products produced by HS and LAF were increased by 25% and 34.8% in comparison with fresh fish, respectively. The values of POV and TBARS showed similar changes to LOX, but POV decreased sharply in the final stages for both processes. The major volatile compounds of the final products, which were generated mainly during the drying period, were aldehydes, alcohols, ketones and hydrocarbons. Compared with HS, LAF additionally produced a floral flavor. A positive correlation was seen between LOX and fat oxidation as well as the formation of flavor substances, and fat oxidation played an important role in the formation of flavor substances. LAF could improve the activity of LOX and thus promote the formation of flavor substances, particularly aldehydes.

This study investigated the effects of six different dietary microalgae species on the flavor components of juvenile Sinonovacula constricta by solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GCMS). The results showed that there were differences in the species and relative contents of volatile components detected in Sinonovacula constricta fed different microalgae species. A total of 71 components were detected, including 43 aldehydes, ketones and alkanes, together accounting for 60.56% (22.54%, 21.12% and 16.90% for aldehydes, ketones and alkane, respectively). Besides, some alcohols and ether esters in small amounts were also detected. 3-Methyl-butyl aldehyde was identified as the major flavor compound (61.37%?77.28%) in Sinonovacula constricta fed the diatom species Thalassiosira pseudonana, Conticribra weissflogii and Chaetoceros calcitrans. Besides, dimethyl sulphide, responsible for special flavor, was detected in the Isochrysis galbana and Platymonas helgolandica groups (29.39% and 51.53%, respectively).

The hexane, ethyl acetate and methanol extracts of Tibetan hull-less barley (THB) bran displayed dose-dependent inhibitory activities on α-glucosidase in vitro. The hexane and ethyl acetate extracts had higher inhibitory activities than did acarbose, which is used in clinical treatment of type 2 diabetes. Gas chromatography-mass spectrometry (GC-MS) analysis showed that linoleic acid, oleic acid, palmitic acid and α-linoleic acid were the main fatty acids in the hexane extracts, accounting for 96.5% of the total fatty acids. All of these four fatty acids have been reported to be potent inhibitors of α-glucosidase. Moreover, 65 peaks were separated from the unsaponifiable fractions, with 17 of them identified as sterols, triterpenes and long chain fatty alcohols, respectively. The total free phtosterol content was 7 357.72 mg/kg, which presented β-sitosterol, campesterol, desmosterol, stigmasterol, and fucosterol as the primary phytosterols. In addition, β-sitosterol and campesterol accounted for 83% of the total phtosterols. These results show that THB can be a natural source of potent α-glucosidase inhibitors.

Crude polysaccharides were extracted from ginger peels by hot water extraction and alcohol precipitation. DEAEcellulose 52 and Sephadex G-100 gel filter column chromatographies were sequentially used to purify crude polysaccharides. The purified polysaccharides were designated as GE-1, GE-2 and GE-3, respectively. Their molecular weight distribution and monosaccharide compositions were analyzed by high performance liquid chromatography (HPLC). The structure of the deproteinized polysaccharides from ginger peels were analyzed and characterized by ultraviolet (UV) and infrared (IR) spectroscopy. The results showed that the total sugar contents of GE-1, GE-2 and GE-3 were (98.06 ± 0.15)%, (97.41 ± 0.42)% and (97.89 ± 0.22)%, respectively. Their molecular weights were 462, 194 and 376 kD, respectively. The structural analysis demonstrated that GE-1 was composed of mannose, glucose and xylose at a molar ratio of 1.25:6:1, GE-2 was composed of mannose, glucose and fucose at a molar ratio of 2.51:9.25:1, and GE-3 was composed of mannose, ribose, galactose and arabinose at a molar ratio of 17.39:1:1.89:1.23.

Noni (Morinda citrifolia) powders are botanical dietary supplement providing purported health benefits, such as scavenging free radicals, anti-cancer activity, and anti-inflammatory effect. This study aimed to optimize the ultrasonic extraction condition and to determine the contents of scopoletin, rutin, and quercetin in noni powders by high performance liquid chromatography (HPLC). The optimized extraction parameters that provided the maximum extraction efficiency were determined as follows: a mixture of methanol and water as extraction solvent, 80%; extraction time, 30 min; temperature, 20 ℃ and ultrasonic frequency, 45 kHz. With an Elite Hypersil ODS column (4.6 mm × 250 mm，5 μm), the HPLC separation was achieved by a gradient mobile phase composed of acetonitrile, methanol, and H2O with a flow rate of 1.0 mL/min at a column temperature of 25 ℃. The quantitative analysis of scopletin, rutin, and quercetin exhibited a good linear relationship, r2≥0.999 8, low detection limit (≤ 1.30 μg/L), high recovery (90.67%–113.00%), and good repeatability (RSD ≤ 1.46%, n = 8). The method proved to be accurate reliable, and suitable for the determination of scopletin, rutin and quercetin in noni powders.

A new method was developed for the determination of nuciferine in Nelumbinis Folium and liensinine in Nelumbinis Plumula by capillary electrophoresis coupled with electrochemilumolinescence (ECL) detection. The optimized experimental conditions were determined as follows: Ru(bpy)3 2+ concentration, 5 mmol/L; detection potential, 1.20 V; 10 mmol/L phosphate buffer (pH 5.74) as running buffer, 60 mmol/L (pH 8.30) phosphate buffer contained in the detection reservoir; injection time, 10 s; separation voltage, 13 kV. Detection limits (LOD) of 7.7 × 10-7 mol/L (RSN = 3) for nuciferine and 7.8 × 10-7 mol/L (RSN = 3) for liensinine were obtained. Relative standard derivations of electrophoretic peak area and migration time were 3.76% and 0.83% for 6.8 × 10-5 mol/L nuciferine and 4.28% and 1.37% for 3.1 × 10-5 mol/L liensinine from five replicate determinations, respectively. The method can be applied to detect nuciferine in lotus leaves and liensinine in Nelumbinis Plumula with satisfactory results.

The influences of hot air drying, freeze drying and vacuum drying on the basic components, antioxidant properties and aromatic composition of whole flour from Pueraria lobata roots were studied. The results indicated that the contents of starch, protein, fat and other basic components in flours produced by different drying methods were significantly different (P < 0.05). The contents of total flavonoids and total phenolics in the flour prepared by freeze drying were 2.46 and 1.37 g/100 g, respectively, which were significantly higher than those obtained by the other drying methods (P < 0.05). The free radical scavenging activity, reducing power and metal ion chelating ability of the flour prepared by freeze drying were found to be the highest. On the other hand, the antioxidant capacity of hot air dried flour was the lowest. Analysis by solid-phase micro extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) showed that a total of 43, 68, 66 and 64 volatile aromatic components were identified in fresh Pueraria lobata roots, and hot air dried, vacuum dried and freeze dried flours, respectively. This study found that vacuum drying and freeze drying provided better retention and even enhancement of the aroma components in fresh Pueraria lobata roots, while reducing some components contributing negatively to the flavor.

The one-factor-at-a-time method was used to investigate the effect of slice thickness, hot air temperature and loading amount on the hot air drying characteristics of shiitake mushrooms including moisture content on a dry basis, moisture ratio and drying rate. The drying parameters were optimized by response surface methodology with a three-variable, three-level experimental design. The changes in soluble protein content, total phenolics and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity before and after hot air drying were compared. The results showed that slice thickness, hot air temperature and loading amount in the range of 3–12 mm, 50–70 ℃ and 5–15 g/dm2, respectively were suitable for moisture content on a dry basis, moisture ratio and drying rate. The optimized drying parameters obtained by response surface methodology were as follows: slice thickness, 4.99 mm; hot air temperature, 55.21 ℃; and loading amount, 7.88 g/dm2. The phenolics and DPPH scavenging capacity but not soluble protein or free amino acid contents of shiitake mushrooms were significantly decreased after hot air drying. These results indicate that hot air drying can maintain the contents of protein and free amino acids, but severely destroy the total phenolics and antioxidant activity of shiitake mushrooms.

Response surface methodology was adopted to optimize the extraction of patulin from an aqueous matrix. Meanwhile, the optimal solid-to-liquid ratios (V/V) for four different aqueous matrixes were selected. Optimization of the extraction conditions for improved recovery of patulin was done by the combined use of one-factor-at-a-time method and response surface methodology. Recovery experiments were conducted with spiked samples at solid-to-liquid ratios using four different aqueous matrixes. The optimal extraction conditions established were as follows: acetonitrile to aqueous sample ratio, 7:3; NaCl dosage, 1.4 g/3 mL sample; and extraction temperature, 34 ℃. Under these conditions, the recovery of patulin was 90.47%, and the optimal solid-to-liquid ratios were 7:3 for apple pulp matrix and 1:9 for concentrated apple juice, wine grape and wine, giving a recovery of 91.08%, 85.51%, 88.74% and 89.17% from spiked samples, respectively. At the same time, over the entry-exit inspection and quarantine industry standard method (SN/T 2008-2007), the pre-treatment method was advantageous in terms of less solvent consumption, simple operation and good reproducibility. Collectively, we concluded that the solvent induced phase transition extraction of patulin optimized by response surface methodology yielded reliable predictions and it had the potential to provide a new pretreatment method for the extraction of patulin from aqueous matrices.

This study aimed to optimize the formulation of milk coagulant and coagulation conditions for improved quality and productivity of milk cake (Chinese cheese) produced from fresh Holstein cow milk and milk-coagulating protease from the stems of Dregea sinensis var. corrugata using combination of one-factor-at-a-time method and response surface methodology. The results showed that the best formulation of milk coagulant consisted of the protease from Dregea sinensis var. corrugata 17.95%, citric acid 0.023 3%, and calcium chloride 0.009 85%, and the best coagulation temperature was 83.25 ℃. The sensory score of milk cake made by the optimized process was 85.7 ± 1.32, which was significantly higher than that made by the traditional acidic water method (P < 0.05). Water, crude protein and crude fat contents of our product were (52.94 ± 1.03)%, (20.09 ± 0.57)%, and (22.54 ± 0.48)%, respectively. The contents of ash, calcium, and phosphorus were increased significantly as compared with that obtained using the traditional process (P < 0.05). The contents of free amino acid and free fatty acid in milk cake obtained in this study were (77.64 ± 5.80) and (1 953.76 ± 53.53) mg/100 g, respectively. It was a good source of vitamin containing significantly contents of fat-soluble VA and VE (P < 0.05). The microstructure of milk cakes made by the traditional and new methods was different; the former showed a lamellar or cluster structure, whereas the latter presented a three-dimensional network structure. Moreover, the milk cake made by the optimized process was bright in color, having a homogeneous texture, unique flavor and plant aroma. It was a highly nutritional product with improved quality compared with that made by the traditional process.

Antibacterial peptide (AP) G-K liposomes were prepared by thin film evaporation-sonication method. The effects of formulated ingredients and processing conditions on the average particle diameter and encapsulation efficiency of liposomes were examined. The stability and antibacterial activity were analyzed as well. The results showed that spherical liposomes with average particle size of (128.27 ± 2.69) nm, encapsulation efficiency of 62.83%, and effective loading of AP G-K of 5.08% were obtained when phospholipid at 7.5 mg/mL in PBS buffer was blended with cholesterol and AP G-K at a mass ratio of 6:1 and 4:1 separately with sonication at 300 W. The liposomes were more stable when stored at 4 ℃ than at 25 ℃. Growth curve and propidium iodide staining experiments showed that AP G-K liposomes had a strong antibacterial effect on Escherichia coli in a slow-release way.

This study aimed to optimize the extraction of polyphenols from Titeban wild Polygonatum cirrhifolium using ethanol as the extraction solvent. Towards this goal, one-factor-at-a-time method and orthogonal array design were employed to analyze the effects of extraction temperature, solid to liquid ratio, ethanol concentration, and extraction time on extraction efficiency. Furthermore, the antioxidant activities of polyphenol extracts were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion and hydroxyl free radical scavenging assays. The results showed the maximum extraction efficiency of polyphenols was achieved after 2.5 h extraction using 70% ethanol as the extraction solvent at a solid to solvent ratio of 1:25 (g/mL) at 70 ℃. The polyphenol extracts from P. cirrhifolium obtained under the optimized conditions had strong free radical scavenging capacities in comparison with VC, thus being a potential source of natural antioxidants.

Purpose: To prepare slow-release erinacines microspheres with poly (lactic-co-glycolic acid) (PLGA) as carry using the emulsification solvent evaporation method and to investigate their release characteristics in vitro. Methods: The one-factor-at-a-time method was adopted to examine the factors affecting encapsulation efficiency, and their levels were optimized using response surface methodology. Results: The optimum preparation conditions were obtained as follows: erinacines to PLGA ratio, 1:1.64 (g/g); concentration of PLGA in dichloromethane, 15%; and stirring speed, 1 200 r/min. The obtained microspheres were complete and smooth with an encapsulation efficiency of 99.66% and a cumulative release rate in vitro of 84.30% in 384 h. Conclusion: The emulsification solvent evaporation method has been successfully applied to prepare erinacines microspheres with high entrapment efficiency and good sustained release performance.

This study investigated the removal of pigment and wax from alkali-refined corn oil. The decolorization was carried out by adding 1.2% activated clay and stirring for 0.5 h at 100 ℃, followed by dewaxing by allowing the crystal nucleus of activated clay to grow for 13 h after cooling down to 11 ℃ by stirring at 13 r/min. Purified corn oil with a yellowness value of 19 and a redness value of 2.1 containing 26.28 mg/kg wax was obtained after filtration. The purification process was simplified by retention of activated clay in the oil after decolorization without addition of diatomite filter aid during crystal growth for dewaxing. In addition, oil adsorption by diatomite was avoided, cutting down on the cost.

The hydrogenation of soybean oil in a cylindrical reaction kettle (180 mm high with an internal diameter of 120 mm) with first-grade soybean oil as liquid phase and Pt/C catalyst as solid phase was investigated by numerical stimulation using the FIUENT software. It was found that the fluidity of the liquid phase and catalyst distribution were optimal using a tilting blade 40 mm in diameter 80 mm above the bottom of the reaction kettle at a stirring speed of 300 r/min. A high pressure reaction kettle was developed using the major simulation parameters. After adding 90.0 g of first-grade soybean oil and 0.15% Pt/C catalyst (m/m) to the reaction kettle, CO2 was initially introduced to a pressure of 8 MPa, followed by H2 to a final pressure of 12 MPa. Under the optimized reaction conditions: temperature, 97 ℃; time, 87 min; and stirring speed 285 r/min, the iodine value of hydrogenated oil was 79.50 g I2/100 g. In conclusion, the simulation was accurate and thus could provide the theoretical basis for displaying the hydrogenation process in large equipment.

In this research, three different methods namely cooking soybean slurry before filtration, cooking soybean milk after filtration of soybean slurry to remove okara and adding hot water into soybean slurry with stirring before filtration were compared in terms of tofu yield and water retention to find the best one to produce northern Chinese tofu. Furthermore, the effects of soybean-to-water ratio for grounding, curding temperature, MgCl2 dosage and curding time on the quality characteristics of tofu were examined and tofu yield and water retention were correlated with texture properties of tofu. The results showed that tofu yield and water retention obtained from the second method were significantly higher than those obtained from the other two. The optimized conditions that provided maximum tofu yield and water retention were determined as follows: soybean-to-water ratio for grounding, 1:7 (g/mL); curding temperature, 80 ℃, 0.6 mol/L MgCl2 dosage, 18 mL/L; and curding time, 20 min. The correlation analysis showed that under different processing conditions, tofu yield and water retention were correlated negatively with hardness, cohesiveness and resilience but positively with chewiness, gumminess and flexibility.

The aim of this study was to find the optimum processing conditions for the microwave vacuum puffing of duck breast after hot-air dehydration. Firstly, the one-factor-at-a-time method was used to examine the effects of initial moisture content, microwave intensity, microwave irradiation time and vacuum degree on volume shrinkage, rehydration ratio, sensory score of puffed duck breast. Subsequently, response surface methodology was used optimize initial moisture content, microwave intensity, microwave irradiation time. Results showed that all the above four factors had influences on the quality of puffed duck breast. When the vacuum degree was fixed at 0.08 MPa, the influences of three other factors on volume shrinkage (Y1) and sensory score (Y2) of puffed duck breast from prediction model were in the descending order of microwave intensity > microwave irradiation time > initial moisture content. The optimum processing parameters obtained by superimposition of contours were as follows: 59%–63%, 20.5–24.7 W/g and 6.1–6.6 min for initial moisture content, microwave intensity and microwave irradiation time, respectively. Under these conditions, volume shrinkage rate of puffed duck breast was lower than 34% and sensory score was 4.75 and above. These experimental results can provide a theoretical reference for the industrial production of puffed duck products.

This study attempted to establish the optimal conditions for three-stage drying of paddy. Hot air temperature at stage Ⅰ, moisture content at the end of stage Ⅰ, holding time at stage Ⅱ and hot air temperature at stage Ⅲ were selected as independent variables. In the first step, the ranges of the variables were determined by one-factor-at-a-time method for optimization. Subsequently, a mathematical model was developed for comprehensive evaluation of the drying characteristics of paddy using principal component analysis (PCA). Finally, optimization experiments were carried out based on the comprehensive evaluation using response surface methodology. As a result, the optimal drying conditions were determined as follows: air temperature at stage Ⅰ, 76.30 ℃; moisture content at the end of stage Ⅰ, 19.99%; holding time at stage Ⅱ, 11.34 d; and hot air temperature at stage Ⅲ, 35.53 ℃. Under these conditions, the composite score (F) was 1.284 with a cracking rate of 51% and a head rice rate of 64%, and the average drying rate was calculated to be 1.21%/h.

For more reasonable and effective classification of eggs, a method for non-destructive identification of egg varieties based on dielectric properties was developed. In this experiment, four groups of eggs (caged eggs from Zhenjiang, Jiangsu province, and free-range eggs from Zhenjiang, Jiangsu province, from Laonangou, Anhui province, and from Dongtai, Jiangsu province) were measured for dielectric properties in the frequency range of 10–200 kHz by the parallel plate method. A classification model for egg varieties by the support vector machine (SVM) algorithm was established. The effects of different kernel functions (linear, polynomial, RBF, and Sigmoid) and different parameter optimization algorithms (grid search, genetic algorithm, and particle swarm optimization) on the accuracy rate of the classification model were analyzed. The results showed that the performance of the SVM classification model based on linear kernel function and particle swarm optimization was the best, giving a prediction accuracy of 95.83% and 95.83% for the training and test sets, respectively. The non-destructive testing technology based on SVM algorithm using dielectric properties achieved good classification results. This study has provided a new effective method for the identification of egg varieties.

The derivatization conditions for the determination of semicarbazide by enzyme-linked immunosorbent assay (ELISA) were optimized using combination of one-factor-at-a-time method and response surface methodology with Box- Behnken design. The independent variables were volume and concentration of derivatization agent, derivatization temperature and time and the recovery of semicarbazide was used as response variable. The linear range of ELISA was 0.13-10.51 ng/mL and the 50% inhibitory concentration (IC50) value was 1.17 ng/mL. The optimal derivatization conditions were determined as follows: using 415 μL of 15 mmol/L derivatization agent and derivative at 57 ℃ for 50 min. Under these conditions, the recovery of semicarbazide was in the range of 98.57%-103.76%. The cross-reactivity value of the derivatization product was 7.63% with furacilin and lower than 0.17% with its structural and functional analogues. The recoveries in spiked negative samples ranged from 93.45% to 103.21%. The intra-assay and inter-assay coefficients of variation wer e 1.86%-6.15% and 3.88%-8.84%, respectively. The derivatization conditions were highly efficient and the ELISA method was sensitive, accurate, and suitable for the fast screening of semicarbazidee in animal-derived foods.

The objective of this study was to establish a multiplex polymerase chain reaction (PCR) detection method for Listeria monocytogenes, Salmonella typhimurium and E. coli O157:H7 on fresh-cut cantaloupe. Three pairs of specific primers were designed according to the inlA gene of L. monocytogenes, the invA gene of Salmonella typhimurium, and the wzy gene of E. coli O157:H7. The primer concentration, annealing temperature, Mg2+ concentration and dNTP concentration were optimized. The results showed that the PCR reactions were performed in a total volume of 25 μL consisting of 2.5 μL of 10 × PCR buffer, 3.5 μL of 25 mmol/L MgCl2, 2 μL of 2.5 mmol/L dNTPs, 1 μL of DNA template, 0.3 μL of exTaq DNA polymerase, 1 μL of 5 μmol/L upstream and downstream primers for inlA and invA and 2 μL of 5 μmol/L upstream and downstream primers for wzy made up to 25 μL with ddH2O. The reaction conditions were as follows: pre-degeneration at 95 ℃ for 3 min followed by 32 cycles of degeneration at 94 ℃ for 30 s, annealing at 53.9 ℃ for 30 s and extension at 72 ℃ for 30 s and a final extension step at 72 ℃ for 10 min. The sensitively of the multiplex PCR was 2.7 × 104 CFU/g for L. monocytogenes, 3.3 × 104 CFU/g (E. coli O157:H7) and 3.8 × 104 CFU/g Salmonella typhimurium inoculated onto freshcut cantaloupe. This method can lay the basis to detect and control these pathogenic microorganisms on fresh-cut cantaloupe.

The temporal distribution characteristics of five diarrhetic shellfish toxins (DST) and six paralytic shellfish toxins (PST) in oysters cultured in Sanggou Bay were determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). At the same time, the adsorption quantities of both kinds of toxins in their growing waters onto HP20 and SP700 macroporous adsorption resins were measured by HPLC-MS/MS to establish the relationships of DST and PST contents between oysters and their growing waters. The results showed that four DST (OA, DTX-1, GYM and PTX-2) and two PST (STX and dcSTX) were detected from both the oysters and seawater samples. During the monitoring period, the shellfish toxins in the seawater increased firstly, reaching a peak, and then gradually reduced. There was a positive correlation between shellfish toxin contents in oysters and their growing seawater. It is surprising that the peak of shellfish toxin contents appeared for oysters 14 days later than for their growing seawater. Thus, solid phase adsorbent and toxin tracking (SPATT) enables warning of the presence of shellfish toxins in oysters 14 days in advance.

Sensory evaluation of thirty-five sesame pastes in the market was carried out. Their chemical components including crude fat, crude protein, crude fiber, VE, sterolin, calcium, and phosphorus contents were determined as well. Principal component analysis (PCA) was used for comprehensive assessment. A comprehensive score for each sample was obtained by PCA and sensory evaluation. The results showed that color and texture had significant effects on sensory scores for both white and black sesame pastes. In general, white sesame paste had higher sensory scores than black sesame paste. The chemical components of sesame pastes showed different degrees of variation. While water content and acid value showed bigger degrees of variation, the variations in crude fat and crude protein contents were smaller. The first six principal components identified based on PCA were mineral, lignan, crude protein, acid value, VE and sterol, accounting for 75.33% the total variability. The ranking orders of comprehensive scores of the principal components and sensory evaluation were basically consistent. Out of 35 samples tested, six (17.14%) were unqualified mainly in terms of acid value, water content and oil content.

This study aimed to evaluate the uncertainty of measurement in the determination of salbutamol, clenbuterol hydrochloride and ractompaine in pork by ultra performance liquid chromatography-tandem mass spectrometry (UPLCMS/ MS). According to JJF 1135-2005 Evaluation of Uncertainty in Chemical Analysis Measurement and JJF 1059.1-2012 Evaluation and Expression of Uncertainty in Measurement, a mathematical model was established for uncertainty evaluation. The sources of uncertainty that may be introduced were analyzed and each component of uncertainty was quantified for the calculation of the combined uncertainty. The results showed that an expanded uncertainty of 0.25 μg/kg (k = 2) was obtained for the determination of the presence of 1.99 μg/kg salbutamol in pork, the expanded uncertainty was 0.24 μg/kg (k = 2) for the determination of pork samples containing 2.04 and 1.97 μg/kg salbutamol. The preparation of standard solution, curve fitting and measurement repeatability were found to be the main sources of uncertainty.