This study aimed to improve the physical properties and cooking stability of edible casings. Gelatin (GA) and chitosan (CH)-based edible films were made containing different contents of cinnamaldehyde (CA). The effect of CA content on physical and chemical properties of the films was analyzed. We found that the addition of CA significantly improved the film performance. The tensile strength was 40.2 MPa, which was 195% higher than that of pure film, and the oxygen permeability and moisture permeability were improved by about 17% and 10% when the contents of CA, glycerol, and tween accounted for 13%, 35%, and 0.75% of the total mass of GA and CH, respectively. The addition of CA formed a denser network structure and effectively improved the cooking stability. The microscopic morphology showed a good compatibility and a strong force, which further improves the thermal stability of the film.

In this study, malondialdehyde (MDA), a natural lipid peroxidation product, was used as an initiator to investigate the influence of MDA-induced protein structural modifications on stability and digestibility of emulsion stabilized by soy protein isolate (SPI). Results obtained showed that the contents of protein carbonyl and Schiff base significantly increased along with increasing MDA concentration, accompanied by a noticeable decrease in protein sulfhydryl content. Meanwhile, MDA promoted protein aggregation through disulfide/non-disulfide covalent bonding, where β-conglycinin (7S) was mainly involved in the latter case. O/W emulsion was further prepared with oxidatively treated SPI. It was found that MDA-induced protein oxidation had less influence on emulsion formation, but they could significantly alter the protein composition of the interface. Herein, for SPI treated with MDA at concentrations of 2.5-10 mmol/L, more 7S fractions participated in interface formation in an aggregate state. Furthermore, results from in vitro simulated gastrointestinal digestion demonstrated that emulsion digestion occurred mainly in the intestinal tract, and oxidation-induced cross-linking/aggregation of proteins could delay or reduce the replacement of bile salts at the interface, which in turn slowed emulsion digestion and decreased lipid digestibility.

In this study, β-carotene-loaded protein emulsion was prepared and then used to prepare hydrogel microparticles cross-linked with different concentrations of Ca2+. The influence of Ca2+ crosslinking on the basic properties and stability of hydrogel microparticles was investigated. It turned out that there were no significant differences in the particle size of hydrogel microparticles cross-linked with different concentrations of Ca2+. Both the viscosity and gel strength of hydrogel microparticles increased with the increase of Ca2+ concentration. The cross-linked hydrogel microparticles had better centrifugal stability. There was an obvious phase separation in the emulsion at pH 3–5, while the hydrogel microparticles were relatively stable to at pH 3–7. A slight phase separation occurred in the cross-linked hydrogel microparticles with a low concentration of Ca2+ (0–2 mmol/L) at high salt levels (> 2 mol/L NaCl). However, the cross-linked β-carotene-loaded hydrogel microparticles with 2–4 mmol/L Ca2+ concentrations were stable at different salt levels. In the storage experiments, the retention of β-carotene in the hydrogel microparticles was higher than in the emulsion, and it was improved by Ca2+ cross-linking.

In this paper, a umami peptide was isolated and purified from air-dried and fermented Megalobrama amblycephala using ultrafiltration, nanofiltration and reversed phase high performance liquid chromatography (RP-HPLC). The umami taste was measured with an electronic tongue. Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), an automatic amino acid analyzer and Fourier transform infrared spectroscopy (FTIR) were used to measure the molecular mass, amino acid composition and secondary structure of the umami peptide and furthermore, we investigated the relationship between structure and umami taste. The results showed that a single umami peptide P2a-2 with a molecular mass of 1 304.59 Da was obtained and identified. Moreover, the umami amino acids glutamic acid (21.97%), alanine (10.67%) and glycine (9.51%), as well as the umami enhancer histidine (27.54%) were found in P2a-2, and the secondary structure was beta-turn (90.16%). We deduced that P2a-2’s strong umami taste may be due to the high content of umami amino acid and beta-turn structure.

Glycosylated squid (Symplectoteuthis oualaniensis) myofibrillar protein with dextran and acid- and alkaliextracted squid proteins were applied to prepare biodegradable films. The effect of adding different concentrations of tannic acid (TA) on the physical properties of these films was evaluated. The results showed that glycosylated protein had the lowest free amino group content. TA incorporation significantly reduced the free amino group and --SH content of protein solutions (P < 0.05). Film formed by glycosylated protein had the lowest moisture content, higher water solubility and better mechanical properties. The film exhibited a yellower color and rougher surface due to TA cross-linking under alkaline pH condition. In addition, TA led to higher film tensile strength but lower elongation at break. Among the samples, glycosylated protein-based film with 1% TA had both higher tensile strength and higher elongation at break, which were 1.26 MPa and 118%, respectively. Meanwhile it also had lower water vapor permeability. This study has important implication for exploring squid protein as packaging films to extend the shelf-life of foods.

The aim of this study was to investigate the impact of Moringa oleifera leaf powder (MOLP) on the quality of wheat dough. MOLPs with different particle sizes were prepared by ordinary grinding and superfine grinding. The following parameters were measured: particle size and color of MOLP, color, dough rheological quality and gelatinization properties of wheat flour with added MOLPs. The results showed that the water absorption rate and gelatinization temperature of wheat flour did not change significantly after adding 5% MOLP. In contrast, addition of MOLP decreased significantly dough formation time and stability time, reduced maximum tensile resistance after 45 min of proofing from 234.9 BU to about 130 BU and decreased extensibility. Additionally, MOLP addition significantly decrease the peak viscosity from 531 BU to 303–355 BU, lowered the setback value, and increased the breakdown value of wheat starch. The results indicated that the gluten strength and starch viscosity of wheat dough could be weakened to a certain extent by adding MOLP, but the setback of wheat starch was weakened as well. Superfine MOLP had a weaker negative effect than the ordinary one. This study provides a theoretical rationale for the application of MOLP in the flour industry.

β-lactoglobulin (β-LG), epigallocatechin gallate (EGCG) and glucose (Glc) were conjugated to obtain two covalent complexes by alkali method and the Maillard reaction with different addition sequences. The complexes were named as β-LG-EGCG-Glc con and β-LG-Glc-EGCG con, respectively. Compared with the non-covalent conjugates β-LGEGCG- Glc mix and β-LG-Glc-EGCG mix, the effects of different addition sequences on the structural and functional properties of ternary complexes were investigated. The results showed that the addition order had a greater effect on the covalent complexes than on the non-covalent complexes. The structure and function of β-LG-EGCG-Glc con and β-LGGlc- EGCG con were significantly different from each other, while there was little difference between β-LG-EGCG-Glc mix and β-LG-Glc-EGCG mix. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and UV absorption spectroscopy results displayed that the order of addition had a great influence on the covalent bonding process of ternary complexes. Structural characterization revealed that the fluorescence quenching and surface hydrophobicity of the covalent complexes were higher than those of the non-covalent complexes. Compared with β-LG-EGCG-Glc con, β-LG-Glc-EGCG con had stronger fluorescence quenching and higher surface hydrophobicity, while there was no obvious change between β-LG-EGCGGlc mix and β-LG-Glc-EGCG mix. In addition, compared with the non-covalent complexes, the covalent complexes were superior in functional properties. The emulsification and emulsion stability, foaming and foaming stability of β-LG-Glc- EGCG con were superior to those of β-LG-EGCG-Glc con, but there was little difference between the non-covalent complexes.

In this paper, the effect of the addition of different amounts of lipoxygenase extracted from soybean whey wastewater as a food improver to noodles on its cooking characteristics, texture characteristics and sensory quality were studied. The results showed that the water absorption rate of noodles increased with increasing addition of lipoxygenase in the range of 0.2%–1.0%, while the dry matter loss rate, springiness and hardness showed a V-shaped curve. At an addition level of 0.6%, the optimum cooking time, and the minimum stripping rate and dry matter loss rate were attained, while the hardness, springiness and chewiness increased to 7 861.318 g, 0.903 and 3 719.072, respectively. Moreover, the adhesiveness decreased at first, reaching ?102.62 (g·s) at an addition level of 0.6% and then increased with increasing addition of lipoxygenase. In addition, according to the sensory evaluation results, lipoxygenase could effectively improve the sensory properties such as viscoelasticity, color and appearance of noodles, and the noodles with 0.6%–0.8% lipoxygenase were well accepted by consumers.

Escherichia coli ATCC13027 is a strain capable of producing polysialic acid (PSA). In order to put it into industrial application, strain mutagenesis combined with optimization of the fermentation process was used to increase the PSA yield. Firstly, low energy nitrogen ion beam injection was performed to obtain different strains with varied PSA yields and three different strains were chosen out. Then the respiration quotient (RQ) curves of the three strains were compared during the fermentation process. Finally, a strategy for feeding corn steep powder (CSP) was formulated based on the effect of pulsed feeding of CSP on the RQ. Results showed that the highest PSA titer attained was 3.94 g/L, which was increased by 36.81% as compared with that of the wild strain when the ion beam dose was set as 10 × 1014 ion/cm2. The RQ value of the strain with the highest yield was the lowest during the rapid synthesis phase of PSA. Considering that pulsed feeding of CSP had a significant effect on RQ (P < 0.01), CSP was fed starting from 16 h to control RQ around 0.8 in a 50 L fermentor and as a result, PSA titer reached 12.83 g/L, which was 45.30% and 88.95% higher than that of the control and the original strain, respectively. The high PSA yield strain and the strategy of real-time online regulation for PSA production presented in this study provide theoretical support for PSA industrialization.

The effect of different substrates such as glucose, sucrose and xylose on the production of pullulan by Aureobasidium pullulans CCTCC M 2012259 in batch fermentation was investigated. It was shown that sucrose was favorable to improve pullulan production to a maximum titer of 72.33 g/L, while glucose was propitious to achieve pullulan with a maximum final molecular mass of 5.9 × 105 Da. The fermentation kinetic parameters with different substrates were calculated and physiological and biochemical indexes were determined. Sucrose was indicated to increase the activities of key enzymes involved in the metabolic pathway for pullulan biosynthesis, improve the levels of intracellular uridine diphosphate glucose (UDPG), and increased the energy supply from ATP, ultimately resulting in an improvement of pullulan production. In addition, glucose decreased the activity of pullulan-degrading enzyme during batch fermentation, helping to maintain the molecular mass of pullulan at a higher level. The results presented in this study partially revealed the physiological mechanism underlying the effect of substrates on pullulan biosynthesis, which will provide a feasible approach for efficient production of pullulan with different molecular masses.

The effect of the luxS gene on the NaCl tolerance of Lactobacillus plantarum wild-type strain KLDS1.0391 was investigated by comparing it with its luxS deletion mutant strain. Meanwhile, the influence of the luxS gene on the growth rate and bacteriocin synthesis of this strain under various concentrations of NaCl stress (0%, 2%, 3%, 4% and 6%) were measured. The expression levels of genes related to bacteriocin biosynthesis were determined by real time quantitative PCR technique at the transcriptional level. The results showed that the survival rates of the two strains decreased gradually with the increase of NaCl concentration. The tolerance to NaCl concentrations over 3% of the wild type strain was significantly stronger than that of its mutant (P < 0.05) at the same condition. Moreover, the growth rate and bacteriocin synthesis of the mutant were significantly lower than those of the wild-type strain (P < 0.05) at each NaCl concentration. Real time quantitative PCR showed that the expression of the bacteriocin structure gene plnEF and the double regulator genes plnD and plNC8HK were all significantly down-regulated (P < 0.05) when the mutant was cultured to the stationary phase for 24 h. Therefore, luxS gene deletion significantly reduced the NaCl tolerance of L. plantarum KLDS1.0391. Meanwhile, its growth rate and bacteriocin synthesis ability under NaCl stress decreased significantly due to deletion of the luxS gene.

In this study, high-throughput sequencing technology was adopted to analyzed the V3-V4 region of the bacterial 16S rRNA gene in pasteurized milk stored at different temperature (0, 4, and 10 ℃) for 0, 3, 6, 9, 12 or 15 d. Our aim was to reveal the dynamic changes in the microbial community composition. The results showed that a total of 1 887 operational taxonomic units (OTUs) were obtained and 34 genera of bacteria, including Mycoplasma, Oxalobacteraceae, Pseudomonas, Actinetobacter, and Streptococcus were detected. Bacterial diversity analysis showed that the composition and diversity of the bacterial community in pasteurized milk were significantly different at both the phylum and genus levels. The bacterial diversity in pasteurized milk stored at 0 ℃ for day was the most intact of all samples and its nutritional quality was also maintained well. Nonetheless, both the bacterial diversity and the nutritional quality were greatly affected by storage at 4 and 10 ℃. Under this circumstance, the flora composition and the dominant bacterial community both changed. The dominant bacteria became Pseudomonas and Aeromonas with the increase of storage temperature. Furthermore, this study found that days 3 and 9 of storage at 4 ℃ and day 6 at 10 ℃ were key points of time for pasteurized milk spoilage because Paenibacillus and Serratia were detected at this time point but not earlier. It is speculated that these two genera are the key determinants of pasteurization dairy product spoilage.

Three Shewanella sp. strain and three Pseudomonas sp. strains isolated and purified from iced Pseudosciaena crocea were evaluated in this study for their surface hydrophobicity, auto-aggregation ability and biofilm formation ability together with their correlation with adhesion characteristics to fish mucus (gut, gill and surface). Meanwhile, the characteristics of biofilm formation were investigated under different conditions. The results showed that compared with Pseudomonas sp., Shewanella sp. had stronger surface hydrophobicity and auto-aggregation ability and enhanced ability to adhere to fish mucus and form biofilm. Principal component analysis (PCA) and clustering analysis (CA) showed an inter-genus difference but intra-genus similarity in bacterial adhesion ability. Both the auto-aggregation ability and biofilm formation ability were highly correlated with the adhesion ability to gut and gill mucus, while the surface mucus adhesion ability was correlated exclusively with the biofilm formation ability. In addition, biofilm formation was related to initial concentration, incubation time, temperature, pH, NaCl concentration and other environmental factors. The spoilage bacteria formed biofilm rapidly from 12 to 24 h of culture and biofilm biomass reached the highest peak at 36 h, and then gradually reduced with incubation time. The optimum conditions for biofilm formation by Shewanella were as follows: bacterial suspension greater than 106 CFU/mL, temperature 37 ℃, NaCl concentration 0.8% and pH 7–8. Biofilm formation was significantly influenced by fish mucus. Gill mucus promoted biofilm formation, whereas the opposite effect was true for gut mucus.

To determine the effect of constitutively overexpressed isoleucine dioxygenase gene (ido) on 4-hydroxyisoleucine production, an ido constitutively expressing plasmid pXM01-ido and a strain HIL017 harbouring the plasmid were constructed. The transcription level of ido and the activity of IDO in HIL017 were significantly increased as compared with those in HIL016, inductively expressing the gene. Moreover, 4-hydroxyisoleucine production by HIL017 was increased by 19.4%. To further improve 4-hydroxyisoleucine production, corn steep liquor, glutamic acid and FeSO4·7H2O were recognized as main medium components using the Plackett-Burman design. By using he steepest ascent method and response surface methodology the optimal values of these factors were determined as follows: corn steep liquor 34.1 mL/L, glutamic acid 2.98 g/L, and FeSO4·7H2O 0.016 7 g/L, giving a predicted yield of 5.57 g/L. Validation experiments showed that 4-hydroxyisoleucine production was 5.53 g/L, increasing by 19.7% compared with that before optimization.

In this study, the gene encoding chitosanase (BsCsn46) was cloned from Bacillus subtilis and expressed at high level in Pichia pastoris GS115. The enzymatic and hydrolytic properties of BsCsn46 were further investigated. The extracellular chitosanase activity and protein concentration was up to 50 370 U/mL and 15.7 mg/mL after the high cell-density fermentation of the recombinant P. pastoris in a 5 L fermentor, respectively. BsCsn46 was purified by ion-exchange chromatography using Q-Sepharose Fast Flow. The purified enzyme had a high specific activity of 4 065.7 U/mg towards chitosan and showed maximal activity at pH 6.0 and 55 ℃, and it was stable at temperature below 45 ℃. The hydrolysis of 3 g/100 mL chitosan by BsCsn46 yielded predominantly chitooligosaccharides with degree of polymerization (DP) 2–4. The degree of hydrolysis reached 92.8% and the yield of chitooligosaccharides was up to 90.9%. The high enzyme production level and the remarkable hydrolysis efficiency make BsCsn46 a promising candidate for application in the industrial preparation of chitosanase and chitooligosaccharides.

In order to increase the expression level of Candida antarctica lipase B (CALB), the CALB gene was designed and synthesized according to the codon preference of Aspergillus niger, and then the CALB expression vector was constructed with PnaII/tpi as promoter and transformed into A. niger HL-1. The enzymatic activity of recombinant CALB was 171 U/mL after shaking flask fermentation for 120 h. Then, the enzymatic properties of recombinant CALB were studied. The optimum reaction temperature and pH for the enzyme were 50 ℃ and 8.0, respectively. The enzyme was very stable at pH 6.0–9.0 and temperature below 45 ℃. Its activity was strongly inhibited by 10 mmol/L Cu2+, Zn2+ and 0.1 g/100 mL SDS but was potently activated by 1 mmol/L Ca2+ and 0.1 g/100 mL sorbitol. Furthermore, the CALB was immobilized using diatomite as the carrier, and the activity of immobilized enzyme was 187 U/g under the optimal immobilization conditions. The yield of ethyl hexanoate in a solventless system was up to 91% when biosynthesized using immobilized CALB under the optimized reaction conditions.

This study aimed to understand the microbial diversity of rice wine koji in Guizhou and to compare the bacterial and fungal community structures of rice wine kojis from different regions of this province. The composition and structure of bacterial and fungal communities in Huaxi (A), Panzhou (B) and Anshun (C) kojis were analyzed by high-throughput sequencing of the bacterial 16S rDNA V3-V4 region and of the fungal ITS1 region. Then the basic physicochemical indicators of kojis were determined and correlated with the diversity of major bacterial populations. The results showed that a total of 129 510 bacterial effective sequences and 1 030 operational taxonomic units (OTUs) were obtained, together with 60 945 fungal effective sequences and 19 OTUs. The bacterial diversity analysis showed that the Shannon index in koji B was significantly lower than those in kojis A and C, while the bacterial community structures of kojis A and C were more similar. The fungal diversity analysis showed that the Shannon index in koji C was significantly lower than those in kojis A and B, and the fungal community structures of kojis A and B were more similar to each other. At the level of phylum, Proteobacteria was the dominant bacteria and Zygomycota was the dominant fungi in koji A; Firmicutes was the dominant bacteria and Zygomycota was the dominant fungi in koji B; Proteobacteria was the dominant bacteria and Ascomycota was the dominant fungi in koji C. At the genus level, the dominant bacteria of koji A was Rhodococcus, and the dominant genus of kojis C and B was Bacillus. The dominant fungal genus of both kojis A and B was Rhizopus, while the dominant fungal genus of koji C was Saccharomyces. There was a significant regional variation in the microbial composition and diversity in rice wine koji at both the genus and phylum levels. The physicochemical indicators exhibited a correlation with the bacterial community structure.

In this paper, R-phycoerythrin with relatively high purity (A565 nm/A280 nm = 5.4) was obtained from Porphyra haitanensis by ammonium sulfate fractionation and DEAE-Sepharose anion exchange chromatography. Prolyl endopeptidase (PEP) inhibitory peptides from R-phycoerythrin were prepared by two-step enzymatic digestion with gastrointestinal fluid proteases. Optimal hydrolysis conditions were determined as sequential hydrolysis with 0.5% pepsin at an enzyme-tosubstrate ratio of for 30 min at an initial pH of 1.2 and 37 ℃ followed by a 1:1 mixture of trypsin and chymotrypsin at an enzyme-to-substrate ratio of 0.25% for 30 min at pH 7.5 and 37 ℃. Tricine-SDS-PAGE showed that R-phycoerythrin was completely degraded by two-step enzymatic hydrolysis. Gel filtration chromatography analysis revealed that fractions with molecular mass lower than 3 kDa accounted for 86.06% of the total peptides. The half-maximum inhibitory concentration (IC50) of R-phycoerythrin hydrolysate toward PEP was 136.35 μg/mL. Inhibition kinetic study revealed that the hydrolysate acted as a noncompetitive inhibitor and the constant of inhibition (Ki) was 14 μg/mL. Successful preparation of R-phycoerythrin peptides with potential PEP inhibitory activity provides a theoretical rationale for the processing and utilization of P. haitanensis.

In this study, out of 119 bacterial isolates from duck foods, a novel selenium-enriched probiotic strain, designated as D1-019, was selected for its tolerance to selenite. This strain was obtained after four rounds of screening, which did not cause a red selenium phenomenon. Strain D1-019 was identified as Bacillus pumilus based on its colonial morphology, Gram staining, 16S rDNA analysis, and phylogenic tree analysis. Using an orthogonal experiment design, we obtained the optimum culture conditions for selenium enrichment as follows: pH 5, 30 ℃ for 48 h, and addition of 20 μg/mL selenite at 6 h of cultivation. Under these conditions, B. pumilus D1-019 eliminated selenite in the medium with a conversion rate of 100% and produced (1 327 ± 113) mg/kg of organic selenium, which was superior to the currently available seleniumenriched microbes. Our results indicated that B. pumilus D1-019 can be a promising candidate for selenium-enriched probiotics in the food industry.

In this study, oil sufu was fermented with different Mucor strains. Protease activity, maturity, microstructure, rheology and sensory properties were analyzed to explore the influence of starter cultures on sufu quality. The results showed that the protease activity of Actinomucor elegans was the highest in the fermentation process among the four strains tested. The contents of water-soluble protein, amino nitrogen and total acid in oil sufu fermented with Mucor racemosus were higher than in the other sufus. However, the effects of Mucor species on the water and salt content of oil sufu were not significant. The microstructure of oil sufu fermented with M. racemosus was the densest; the spreadability of oil sufu fermented with A. elegans was better than that of the other three; the sensory evaluation scores of sufus fermented with M. racemosus and A. elegans were higher. These Mucor strains all had their own advantages. This study can provide a theoretical basis for mixed culture fermentation of oil sufu with Mucor.

In this study, we analyzed the microbial community structure of Luzhou-flavor liquor Daqu samples collected from different regions of Sichuan province by high throughput sequencing technology. The results showed that the dominant bacteria in the Daqu were Staphylococcus, Weissella, Bacillus, Lactobacillus, Kroppenstedtia, Thermoactinomyces, Saccharopolyspora, and Brevibacterium. The proportions of Thermoactinomyces and Weissella in Yibin Daqu and Luzhou Daqu, with higher temperature, were higher than those in two samples of Suining Daqu. The dominant strains in Suining Daqu were Staphylococcus and Bacillus, and Staphylococcus was much higher than in Yibin Daqu and Luzhou Daqu. On the other hand, the fungal communities in all four Daqu samples were predominated mainly by Thermomyces, Aspergillus, Thermoascus, Byssochlamys, and Wallemia. In Yibin and Luzhou samples, Thermomyces and Thermoascus were the dominant species, and their proportions were much higher than those in Suining Daqu. Aspergillus was the dominant species in Suining Daqu, and its proportion was much higher than those in Yibin Daqu and Luzhou Daqu. The diversities of bacteria and fungi in Suining Daqu were higher than in Yibin Daqu and Luzhou Daqu. Principal component analysis revealed that the microbial community structures of the Suining samples were more similar to each other while the microbial community structure of Yibin Daqu was more similar to Luzhou Daqu.

Glucose oxidase from Trichoderma viride WX24 (TvGOD) was isolated, purified and characterized to provide a theoretical basis for its application. Purified TvGOD was obtained from the cultured broth of T. viride WX24 by using ammonium sulfate precipitation, dialysis, DEAE-Sepharose Fast Flow anion exchange chromatography, Phenyl Sepharose 6 Fast Flow hydrophobic chromatography and Sephadex G-75 molecular sieve gel chromatography and its enzymatic properties were studied. SDS-PAGE revealed one single band with a molecular mass of about 93 kDa, indicating that the enzyme was purified to electrophoretic homogeneity. The specific activity of TvGOD was 426.67 U/mg; a 14.36-fold purification was achieved with 19.15% yield. The optimum temperature and pH were 60 ℃ and pH 6.0, respectively. The enzyme was stable at temperatures below 70 ℃ and at pH ranging from 4.0 to 7.0. Among the metal ions studied, Mg2+ and Ca2+ had activation effects on TvGOD activity and Na+ and K+ had no effect, while Fe2+, Cu2+ and Zn2+ showed somewhat inhibitory effects and the heavy metals Hg2+ and Pb2+ almost completely inhibited the enzyme. The enzyme was markedly inhibited by PMSF and EDTA. TvGOD was stable in the presence of detergents (Triton X-100, SDS, CTAB and Tween -80). When glucose was used as a substrate, its Km and Vmax values were 11.62 μmol/L and 8.244 mmol/(L·min), respectively. The excellent physicochemical properties including high thermostablity and acidic stability and excellent stability to detergents and high affinity for glucose make TvGOD promising in the fields of flour processing, food and beverage, the feed industry, biosensors and biotechnological industries that require high GOD activity under high temperature and acid conditions.

The effect of calcium chloride on the biofilm forming-ability of Pseudomonas fluorescens was analyzed in this study. The influences of Ca2+ on biofilm formation, planktonic bacterial growth, polysaccharide secretion, biofilm structure and the expression levels of related genes in P. fluorescens were measured by crystal violet method, bacterial counting, phenol-sulfuric acid method, confocal laser scanning microscopy (CLSM) and qPCR, respectively. The results showed that Ca2+ at 0.1 mmol/L promoted biofilm formation of P. fluorescens. Biofilm biomass gradually increased with increasing concentration of Ca2+ up to 1 mmol/L, and then decreased at Ca2+ concentrations higher than 10 mmol/L. Planktonic bacterial growth was not significantly affected by various concentrations of calcium. Similarly, the production of extracellular polysaccharides, the pellicle and swimming motility were enhanced with the addition of Ca2+ at 0.1 and 1 mmol/L while an inhibitory effect was observed at higher concentrations. CLSM observations revealed that the thickness of matured biofilm in the control, 1 mmol/L Ca2+ and 20 mmol/L Ca2+ treated groups was 20.0, 40.0 and 25.0 μm, respectively and that 1 mmol/L Ca2+ resulted in significantly higher biofilm thickness and more adhered cells/extracellular secretions together with a more compact biofilm structure. qPCR revealed that the expression levels of lapA, alg and flgA genes were up-regulated about 3 to 4 folds by 1 mmol/L Ca2+. Furthermore, Ca2+ at low or high concentration positively stimulated the expression level of luxI, an acyl homoserine lactone (AHL) synthetase, suggesting that effect of Ca2+ on the biofilm may be closely related with quorum sensing. Thus, these results indicated that calcium chloride induced changes in the characteristics and structure of biofilm formation in P. fluorescens by affecting the adherence, extracellular secretions and the expression of related genes. This study provides a basis for exploring the biofilm formation and adherence characteristics of spoilage bacteria in complex food matrices.

The abilities of six Zygosaccharomyces mellis strains to metabolize carbon sources, nitrogen sources and vitamins were investigated. It turned out that Z. mellis 6-7431 had stronger ability of utilizing nutrients than the other strains. Then the physiological response of Z. mellis 6-7431 to high-glucose stress was characterized. Its morphology and reproduction pattern under high-glucose stress were observed using scanning electron microscopy (SEM). The concentrations of metabolites such as glycerol, trehalose and malic acid were also determined. Results showed that Z. mellis 6-7431 exhibited a normal budding reproduction and the concentrations of these metabolites were elevated in the glucose concentration range of 300-500 g/L relative to a 100 g/L concentration. When glucose concentration increased from 550 to 700 g/L, Z. mellis 6-7431 started to form spores gradually, and the concentrations of these metabolites varied. At a high glucose concentration of 750 g/L, strain 6-7431 was dehydrated and its morphology became wizened. All the metabolic activities of this strain were inhibited, and the alcoholic concentration was only 0.6% in the fermented broth. These findings facilitated our understanding of the physiological response to high-glucose exposure and glucose-tolerant mechanism of Z. mellis 6-7431.

The purpose of this study was to isolate and identify Eurotium cristatum from Fuzhuan tea and to explore its growth characteristics and application in liquid-state fermentation. A phylogenetic tree was constructed based on the amplification and sequencing of the specific segment internal transcribed spacer (ITS). Nine of the isolates shared a sequence similarity of greater than or equal to 99% to the homologous sequence deposited in GenBank. The colonial morphology of strain HNYYWX.13, with a 100% similarity to the homologous sequence, was observed and its microscopic morphology was examined by optical microscopy and scanning electron microscopy. Also the growth rhythm of this strain was investigated. In order to evaluate the effect of carbon source and sterilization treatment on the liquid-state fermentation of tea infusion from Camellia japonica leaves grown in Pingli, Shaanxi province by the spore suspension of strain HNYYWX.13, the contents of total polyphenols and amino acids were monitored dynamically. The results showed that addition of carbon source and the absence of sterilization treatment both facilitated the growth of E. cristatum in liquid-state fermentation.

In this study, some chemical properties including pH, carbohydrates, organic acids and free fatty acids of a fermentation starter for dietotherapeutic koumiss in Kerqin, Inner Mongolia were analyzed. To investigate the diversity of the bacterial community in the starter culture, second-generation sequencing of the V3-V4 region of the 16S rDNA genes was performed on the Illumina MiSeq platform. Thereafter, the species abundance, distribution and alpha diversity were analyzed. The analytical results indicated that the pH averaged at 3.54; the mean values of lactose and galactose were (0.281 ± 0.011)% and (0.100 ± 0.003)% respectively, and no glucose was detected. The levels of lactic acid, propanoic acid, acetic acid and butyric acid were (1.506 ± 0.069)%, (0.053 ± 0.002)%, (0.345 ± 0.014)%, and (1.143 ± 0.061)%, respectively. A total of 19 fatty acids were detected, including 12 saturated fatty acids and 7 unsaturated fatty acids. α-Linolenic acid was the most abundant unsaturated fatty acid at a level of (14.12 ± 0.36) mg/L. The results of bacterial diversity detection showed that (62 082.7 ± 4 868.8) clean reads were obtained, and the number of operational taxonomic units (OTUs) was 34.3 ± 2.3. The rarefaction curve showed that the sequencing depth was sufficient and the number of OTUs was close to saturation. The bacteria community in this sample was mainly distributed in the following 4 genera: Lactobacillus (84.08%), Acetobacter (9.83%), Lactobacillus (2.41%), and Streptococcus (2.18%) with the dominant genus being Lactobacillus. The above results showed that this fermentation starter sample was rich in unsaturated fatty acids and probiotics, and could guarantee food safety.

A synthetic derivative of hydrocortisone (HYD) as a hapten was coupled to keyhole limpet hemocyanin (KLH) using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). The KLHHYD conjugate as an immunogen was used to immunize mice. A stable hybridoma cell line HYD-C1 secreting monoclonal antibody against HYD was generated to induce large amounts of antibodies in the ascites of mice. Moreover, the HYD hapten and another hapten synthesized from dexamethasone (DEX) were conjugated separately to ovalbumin (OVA) to obtain coating antigens. The final aim of this study was to develop an indirect competitive-enzyme linked immunosorbent assay (ic-ELISA). The results showed that the IC50 of homologous ic-ELISA was 1.63 ng/mL while that of heterologous ic- ELISA was 0.24 ng/mL. Cross inhibition tests revealed that the sensitivity of heterologous ic-ELISA for all glucocorticoids tested was higher than homologous ic-ELISA, which shows the broad-spectrum specificity of heterologous ic-ELISA. The average recoveries of glucocorticoids from spiked liquid milk by heterologous ic-ELISA were in a reasonable range of 77.5% to 111.3%, meeting the requirements for detection. In conclusions, a monoclonal antibody specific for HYD was successfully prepared and used for homologous and heterologous ic-ELISA. Heterologous ic-ELISA was found to be more sensitive and have a broader-spectrum specificity.

In order to understand the difference in the quality of traditional fermented soybean paste products, sensory evaluation of fermented soybean paste samples from Changchun of Jilin province, and Huanan, Baoquanling and Heihe of Heilongjiang province (designated as ChangC, HuaN, BaoQL, and HeiH) was carried out by quantitative descriptive analysis (QDA). Meanwhile, microbial community structure was analyzed using high-throughput sequencing and free amino acid composition was detected on an amino acid analyzer; the correlation between them was investigated. The results showed that BauQL was ranked the best of the four samples in sensory evaluation. The microbial community compositions of different soybean paste samples varied greatly, and so did the dominant bacteria and the dominant fungi. The dominant bacteria in HuaN and HeiH were both Tetragenococcus, while those in ChangC and BaoQL were Lactobacillus and Weissella, respectively. The dominant fungus in both HuaN and HeiH was Penicillium; the dominant fungus in ChangC was unclassified-k-Fungi; the dominant fungus in BaoQL was Aspergillus. According to principal component analysis and comprehensive evaluation, the free amino acid contents of these four samples were different. The free amino acid score of BaoQL was the highest, followed by ChangC, and HeiH was the lowest. A partial least squares regression (PLSR) model was used to analyze the correlation between microbial diversity and free amino acid composition of soybean paste. It was found that the species and abundance of the flora had a great influence on the composition and contents of free amino acids, thus affecting the product quality. Free amino acid content was largely influence by the bacterium Weissella and the fungi Millerozym and Aspergillus. The correlation between free amino acids and microbial community composition in soybean paste that we found in this study provides a theoretical basis for the industrial production of soybean paste products.

Six raw dark tea samples from the same batch were exposed to a high humidity environment to induce mildew. Besides, two naturally mildewed samples were collected from the market. The volatile components of all these samples were analyzed by simultaneous distillation extraction (SDE) combined with gas chromatography-mass spectrometry (GC-MS) and were evaluated based on the existing literature data on dark tea aroma. The results showed that a total of 23 volatile components were detected in all samples. A total of 38 and 43 volatile compounds were common to the artificially mildewed samples and the naturally mildewed ones, respectively. Palmitic acid, hexahydrofarnesyl acetone, isophytol, chlorophyllic acid, linoleic acid and methyl linolenate were the main volatile components of mildewed dark tea samples. The principal component analysis performed on the aroma components of mildewed dark tea showed that 1-octen- 3-ol, isophytol, phytol, 2,3-octanedione, octadecanoic acid, nonanal, longifolen, phthalic acid diisobutyl ester, β-cyclocitral, 2,6-dimethylcyclohexanol and linalol were highly positively correlated with the first principal component, which were responsible for the floral aroma with rancid and earthy odor and were related to the mildew flavor of sensory evaluation.

Monolithic material sorptive extraction (MMSE) combined with gas chromatography-mass spectrometryolfatometry (GC-MS-O) was used to identify the key odor-active compounds of white croaker and small yellow croaker. A total of 42 and 49 volatiles were identified in white croaker and small yellow croaker, respectively. Out of these volatiles, 12 and 6 were selected respectively from the two fish by aroma extraction dilution analysis (AEDA), among which 9 volatiles were identified by comparison of their mass spectra and linear retention indices with published data. For each fish, the top 10 major odor-active compounds were screened out by the modified frequency (MF) method. The compounds with the highest FD value of 40 in white croaker were identified as trimethylamine, 2-octen-1-ol, nonanal, and an unknown compound that smelled like metal. According to MF ranking, trimethylamine and 2-octen-1-ol had greater contributions to the odor of white croaker. The odorants with the highest FD value of 40 in small yellow croaker were hexanal and 2-octen-1-ol, but trimethylamine and unknown compounds that smelled like barbecue had greater contributions to its odor according to MF ranking. 6-Methyl-5-heptane-2-one was another odorous compound that was present in each fish and responsible for their metallic or bloody odor. According to MF ranking, this compound had a greater effect on the odor of white croaker than on small yellow croaker. 2,3-Pentanedione and 1-penten-3-ol, ranked higher among the top 10 odor-active compounds in small yellow croaker, together with trimethylamin, unknown barbecue-like odorants and dimethyl disulfide which was not identified in white croaker may be one of the reasons for the difference in odor between the two fish.

The odor-active compounds in two brands (BTQ and YH) of Chinese sesame-flavor Baijius were extracted by liquid-liquid extraction and analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). A total of 75 compounds in BTQ and 68 compounds in YH were identified by comparison of their retention indices (RI) and odor characteristics with those of reference standards. Among them, 48 odor-active compounds in BTQ and 46 in YH were further confirmed by GC-MS-O with aroma extract dilution analysis (AEDA). The highest flavor dilution (FD = 6 561) factor was determined for methional in BTQ. Phenethyl alcohol, 3-methyl-1-butanol, ethyl butanoate, and ethyl pentanoate had the highest FD factor (FD = 2 187) in YH. A total of 51 odor-active compounds and 28 compounds that were not detected by GC-MS-O were quantitated, and odor activity value (OAV) was used to rank their contributions to the overall aroma. The results of OAVs showed that there were 40 compounds with OAVs ≥ 1 in BTQ and 36 compounds with OAVs ≥ 1 in YH. It turned out that ethyl hexanoate, 3-methyl butanal, ethyl butanoate, and ethyl 3-methyl butanoate made the greatest contributions to the aroma of Chinese sesame-flavor Baijiu. Based on FD factors and OAVs, ethyl hexanoate, ethyl butanoate, 3-methyl butanoate made important contributions to the aroma of Chinese sesame-flavor Baijiu.

This study was undertaken in order to establish a rapid and sensitive method for detecting the content of phospholipids in the muscle of Ergthroculter ilishaeformis. Chloroform methanol was used to extract lipids, and the composition of phospholipids was detected by high performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). A Chromolith? Performance-Si type positive phase silica gel column (100 mm × 4.6 mm) was used as the separation column, and gradient elution was performed using a ternary mobile phase consisting of n-hexaneisopropanol- 13% acetic acid solution at a flow rate of 1.5 mL/min. The column temperature was set at 30 ℃, and sample volume at 20 μL. The ELSD drift tube temperature was 70 ℃, and atomization gas (nitrogen) pressure 320 kPa. All the phospholipid components were completely separated, and the peak area of each had a good linear relationship with its concentration in the tested ranges. The method had high precision with coefficient of variation (CV) less than 3%. The average recovery was 88.38%–107.41% with relative standard deviation (RSD) of 0.40%–4.95%. This method is simple, fast, sensitive, reproducible, accurate and reliable and can be suitable for the determination of phospholipid contents in freshwater fish such as E. ilishaeformis.

The effect of delayed harvest on grape flavonoids of Merlot and Cabernet Sauvignon was qualitatively and quantitatively analyzed. The results showed that delayed harvest decreased berry mass and longitudinal diameter. In addition, it increased soluble solid content (SSC) and reduced titrable acid content. A total of 19 anthocyanins, 6 flavanols and 15 flavonols were detected in the berry skin of Merlot. The contents of flavanols and flavonols in grapes harvested 1 week later than normal increased by 69% and 1.67%, respectively, compared with the control, and decreased with delayed harvest time up to 2–3 weeks. The content of anthocyanins decreased with delayed harvest. A total of 15 anthocyanins, 4 flavanols and 15 flavonols were detected in the berry skin of Cabernet Sauvignon. When harvest was delayed by 3 weeks, the contents of anthocyanins, flavanols and flavonols increased by 22%, 102%, and 80% compared with the control, respectively.

Purpose: In order to provide the basis for the processing and value-added utilization of Crassostrea hongkongensis, we analyzed the chemical composition and odor characteristics of cultured C. hongkongensis from different coastal areas in China. Methods: Nutrient components, amino acids, betaine, heavy metal elements and microelements, adenosine triphosphate (ATP) and ATP-related compounds, the composition and contents of volatile odor compounds were determined in oysters from Qinzhou of Guanxi, and Yangjiang, Zhanjiang and Shantou of Guangdong. Results: The highest contents of ash, protein and taurine were found in Qinzhou oyster, the highest content of glycogen in Yangjiang oyster, the highest contents of water and betaine in Zhanjiang oyster, the highest contents of fat and total sugar in Shantou oyster , and the highest amount of amino acids in Qinzhou oyster. Inosinic acid (IMP) contributed the most to the taste of oyster, and the contents of Fe, Zn and Cu in Shantou oyster were the highest. (E,Z)-2,6-nonadienal played a significant role in the characteristic odor of Chengcun, Qinzhou and Zhanjiang oysters, whereas 1-octen-3-one was found to be the most important volatile odor substance in Shantou oyster. Conclusion: The flavor and volatile components of C. hongkongensis varied among different culture areas, with significant differences being found in the contents of nutrients, amino acids and elements.

The present study aimed to investigate the effects of different cooking methods (microwaving, steaming, boiling, and deep-frying) on the contents of 1-deoxynojirimycin (DNJ) and phenolic compounds in leaves of mulberry (Morus alba L.). The total phenolic contents were determined by the Folin-Ciocalteu method. The contents of DNJ and phenol monomers were measured by high performance liquid chromatography (HPLC). The results showed that all the cooking methods except steaming for 5 min, increasing the total phenolic content, significantly reduced the levels of DNJ and phenolics. The highest contents of DNJ and phenolics were detected in steamed mulberry leaves, while the lowest contents of DNJ and phenolics were obtained by deep-frying and microwaving at 70 W for 3 min, respectively. All the cooking methods had significant effects on the composition of phenolics. Steaming for 3 min and microwaving at 700 W for 3 min increased the contents of isoquercitrin and astragalin. Notably, certain amounts of kaempferol-acetyl-glucoside (KAG), quercetin and kaempferol were found in the deep-fried mulberry leaves, but not in the other samples. In conclusion, steaming can be considered as a suitable cooking method for mulberry leaves to ensure the maximum retention of bioactive components.

In this study, we analyzed the saponins of Panacis japonici Rhizoma by ultra-fast liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry (UFLC-Triple TOF MS/MS). The chromatographic separation was performed on a SynergiTM Hydro-RP 100 ? (2.0 mm × 100 mm, 2.5 μm) with gradient elution using a mobile phase comprised of 0.1% formic acid solution (A)-0.1% formic acid acetonitrile (B). MS data were collected in the negative ion mode. Based on the accurate molecular mass information of quasi-molecular and fragment ions provided by highresolution mass spectrometry combined with standard reference data and relevant literature data, a total of 53 saponins were finally identified, including 18 glycosides of protopanaxadiol (PPD), 21 glycosides of protopanaxatriol (PPT), 10 glycosides of oleanolic acid and 4 glycosides of ocotillone. This study paves the way for exploring the pharmacodynamic material basis of P. japonici Rhizoma and developing a comprehensive quality evaluation system.

Rapid evaporative ionization mass spectrometry (REIMS) was employed for lipidomic profiling of Patagonian toothfish, a kind of low-fat fish. The instrumental parameters were optimized using response surface methodology with a Box-Behnken design as follows: power output 25 W, cutting speed was 0.50 mm/s, and cutting length 1.0 cm. Under these optimized conditions, a total of 17 fatty acid molecular species were detected, among which the signal intensity of m/z 327.23 (FA 22:6, 17.81%) was the highest, followed by m/z 255.23 (FA 16:0, 9.81%), and m/z 281.25 (FA 18:1, 9.09%). A total of 10 phospholipid molecular species were tentatively identified in the m/z range from 736.49 to 909.55. The peak at m/z 885.55 was the most intensive with a relative content of 19.30%, which was identified as phosphatidylinositol (PI) species [PI 38:4–H]–, followed by phosphatidylethanolamine (PE) species at m/z 790.54 ([PE 40:6–H]–, 15.24%). The method was validated and the results showed that the signal-to-noise ratios of the target ions were in the range of 35.4–95.3, with error values of 4.17 × 10-6–9.78 × 10-6. The relative standard deviations (RSDs) of intra-day and inter-day precision were 3.7%–5.6% and 5.9%–7.3%, respectively. The results indicate that this method is sensitive and stable with high resolution. It provides a totally new technology for lipidomic and bioinformatics analysis of fish.

A new high performance liquid chromatography (HPLC) method was used to analyze the contents of 6 selected phenolic compounds and total phenolics in the leaves and stems of wild (five-leaf, seven-leaf and nine-leaf) and cultivated (seven-leaf) Gynostemma pentaphyllum (Thumb.) Makino. The total phenolics and antioxidant activity of the methanol extracts of these plant samples were determined. The chromatographic column used was poroshell 120 PFP (4.6 mm × 100 mm, 2.7 μm) and the mobile phase was composed of 1% formic acid (A) and acetonitrile (B). The detection wavelengths were set at 254 and 350 nm. The results showed that the six phenolic compounds could be separated well within 35 min, with good repeatability (relative standard deviation (RSD) ≤ 4.6%), high precision (RSD ≤ 2.68%), good stability (RSD ≤ 2.45%) and reliable recovery (average recovery rate 84%–99%, RSD ≤ 4.02%). The contents of the phenolic compounds and total phenolics and antioxidant activities in G. pentaphyllum varied greatly among different varieties. For all the samples, rutin was the most dominant phenolic constituent whereas p-hydroxybenzoic acid was the least dominant one. Total phenols content and antioxidant activity were both highest in the leaves (respectively 75, 39.65, 70.48 mg/g) and lowest in the stems (respectively 2.81, 2.1, 3.7 mg/g) of wild G. pentaphyllum among the 8 samples. In general, the content of total phenols and antioxidant activity in the leaves were higher than in the stems of G. pentaphyllum.

In this study, headspace solid phase microextraction-gas chromatography-mass spectrometry was used to analyze the volatile components of 20 samples of Morchella importuna, and principal component analysis (PCA) and cluster analysis (CA) were applied to analyze the data obtained. The results showed that the samples were rich in 81 volatile substances, including 8 classes of volatile substances, with alcohols, aldehydes and ketones accounting for 60%–80% of the total amount. A total of 24 volatile substances were common to these mushroom samples. PCA performed on the 24 volatile substances generated 6 principal components, explaining 90.081% of the total variance, which could reflect most of the sample information. By PCA and CA, the samples of M. importuna were divided into two categories, of which sample 4 was classified into one cluster, and the remaining samples into the other cluster. The samples within the same cluster had similar flavor. The results from this study provide a basis for species screening and further processing of Morchella.

In order to clarify the effect of drying method on the volatile flavor components of Pleurotus eryngii, four dried mushroom samples were obtained by freeze-drying (FD), hot air drying (HAD), short- and medium-wave infrared drying (ID) and microwave vacuum drying (MVD), respectively, and their volatile components were determined by electronic nose and headspace solid phase micro extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The data obtained analyzed by principal component analysis (PCA). Results showed that the electronic nose could distinguish the four dried samples using linear discriminant analysis. Moreover, a total of 99 volatile components were identified from fresh samples (FS) and four dried samples by HS-SPME-GC-MS, including alcohols, aldehydes, ketones, esters, alkanes and other compounds. In detail, alcohols (19) were the main volatile components in FS, FD, HAD and ID samples. Aldehydes (18) were the main volatile components in MVD samples. The main volatile components of dried P. eryngii were significantly different depending on drying methods. The PCA generated a quality evaluation model for dried P. eryngii, and the comprehensive scores of ID, FD, HAD and MVD decreased in that order. This study could provide a technical basis for the dry processing of P. eryngii.

The conditions for simultaneous ultrasonic-assisted extraction of alkali-soluble protein from broken indica rice mixed with Flammulina velutipes root waste were optimized using an orthogonal array design method, and the nutritional characteristics of the protein were studied by an amino acid analyzer and in vitro digestion. The results showed that the optimal extraction conditions were found to be extraction at 50 ℃ and 500 W for 25 min with a 9:2 ratio of rice to mushroom waste (m/m) and a solid-to-solvent ratio of 1:20 (g/mL), resulting in an extraction yield of (69.30 ± 1.30)% and a protein purity of (80.07 ± 0.63)%. The color difference of the protein was 50.31 ± 0.48, and the lysine content was increased compared with the protein extracted from pure rice. Moreover, the contents of 16 amino acids were complemented in the mixed protein, and the amino acid ratio coefficient was 79.70, which was higher than that of either protein source; the in vitro digestibility was (89.40 ± 0.90)%. Simultaneous ultrasonic-assisted extraction of protein from indica rice mixed with Flammulina velutipes is an effective method to improve the protein quality of either of them alone.

The microwave-assisted extraction of polysaccharides from Tremella fuciformis (TPS) was optimized. The rheological and gelling properties of TPS were studied. Using a combination of single factor and orthogonal array design methods, the optimum extraction conditions were determined as follows: solvent-to-solid ratio 50:1 (mL/g), particle size 120 mesh, microwave power 400 W, and radiation time 2.0 h, which resulted in a yield of polysaccharide of (33.25 ± 0.14)%. Fourier-transform infrared (FTIR) spectroscopy and rheological measurement showed that TPS was a distinctive acidic heteropolysaccharide, and the TPS solution behaved as a pseudoplastic fluid. The dynamic modulus was increased with increasing frequency and the TPS solutions could form a weak gel structure in the high-frequency region. Texture profile analysis (TPA) showed that TPS concentration significantly influenced its gel hardness and springiness. Rheology TPA suggested that TPS had good rheological and gelling properties for application as a partial substitute for colloids in food.

Water-soluble flavonoids (CBF) were extracted from Coreopsis tinctoria buds using water as the extraction solvent. By combined used of one-factor-at-a-time method and response surface methodology, the optimal extraction conditions that provided the maximum yield of total flavonoids of 145.45 mg/g were determined as follows: extraction time 15 min, temperature 96 ℃ and water-to-material ratio 71:1 (mL/g). The final aim of this study was to investigate the antiaging effect of CBF on D-galactose-induced aging mice and its impact on silent information regulator 1 (SIRT1) and p53 protein expression in the liver of aging mice. The aging mouse model was established by long-term subcutaneous injection of D-galactose (300 mg/(kg·d) for 45 consecutive days, and the mice were also orally administered with either vitamin E (VE, 50 mg/(kg·d)) or CBF at 180 and 700 mg/(kg·d) during this period. The body mass and behavioral state of mice in each group were observed. Hepatic histopathological changes were evaluated by HE staining. The protein expression of SIRT1 and p53 in the liver of aging mice were evaluated by Western blotting. Results showed that CBF had no adverse effects on the growth of mice but significantly improved the bad behavior of aging mice. It alleviated the pathological damage to liver tissues caused by D-galactose, increased the expression of SIRT1 protein (P < 0.05), and inhibited the overexpression of p53 induced by D-galactose (P < 0.05). In conclusion, the water extraction method was applied successfully to extract CBF. It was also demonstrated that CBF possessed promising anti-aging effect, and the mechanism might be related to the activation of the SIRT1/p53 signaling pathway.

In order to control the softening of canned solid pack apples, the decompression pre-pumping-assisted alkaline calcium treatment process was optimized. The one-factor-at-a-time method was used to investigate the effects of Ca2+ concentration, vacuum degree and pre-pumping pH on the contents of different calcium forms (water-soluble Ca, sodium chloride-soluble Ca, hydrochloric acid-soluble Ca, and acetic acid-soluble Ca) and the contents of cell wall components (water-soluble pectin (WSP), chelator-soluble pectin (CSP), sodium carbonate-soluble pectin (NSP), and hemicellulose fraction (HF)) in Qinguan apples. Subsequently, the optimization with the contents of sodium chloride-soluble Ca and CSP as the response variables was carried out using a Box-Behnken design and Design-Expert 8.0 software. The results indicated that sodium chloride-soluble Ca and CSF were the most abundant of their respective kinds and were significantly affected by all the factors tested. Under optimized conditions as follows: Ca2+ concentration 2.0 g/L, vacuum degree 0.08 MPa and pre-pumping pH 2.8, the experimental contents of sodium chloride-soluble Ca and CSP were 55.26 and 17.45 mg/kg, respectively, in good agreement with the predicted values. This study can provide some theoretical information for regulating the softening of canned solid pack apples.

Optimization experiments showed that potato glucose medium was the optimal medium for sugar production by Thelephora ganbajun Zang, and using this medium, the mycelial yield and mycelial polysaccharide yield were 7.56 and 0.42 g/L, respectively. Plackett-Burman design and response surface methodology were used to optimize the ultrasonicassisted extraction of T. ganbajun Zang polysaccharides. Ultrasonic power, irradiation time and alcohol precipitation fold were found to be significant factors affecting the polysaccharide yield and their optimal levels were 400 W, 10 min and 3, respectively, which resulted in maximum polysaccharide yield of 6.98%. The results of in vitro antioxidant tests showed that the polysaccharides had a strong antioxidant capacity, and hydrolysis with enzymes (cellulase and snailase) or acid (sulfuric acid) could significantly enhance the antioxidant capacity of the polysaccharides. Monosaccharide composition analysis by stepwise acid hydrolysis combined with pre-column derivatization high performance liquid chromatography showed that the terminal residues of branches of the polysaccharides were composed of galactose as well as a small amount of mannose; galactose was mostly distributed on the outer side and at the end of the branches; glucose was the main monosaccharide component, and it was mainly distributed in the main chain and the inside of the branches; mannose was mainly distributed inside the branches. This study lays a theoretical foundation for the application of enzymatic hydrolysis and acid hydrolysis on polysaccharides and the exploitation and utilization of T. ganbajun Zang polysaccharides.

In this study, we investigated the effects of addition of different proportions of whole quinoa flour on the rheological properties of high-gluten wheat flour dough in order to determine the optimal proportion of whole quinoa flour. Furthermore, we optimized the processing of quinoa-wheat Mantou. The rheological properties of dough were determined using Mixolab and Alveolab. Yeast addition, fermentation time and proofing time were used as independent variables to investigate their effect on the sensory evaluation and texture characteristics of Mantou. Results indicated that the optimum addition level of whole quinoa flour was 15%; the optimum processing parameters were determined as 0.75%, 100 min and 15 min for yeast inoculum size, fermentation time and proofing time, respectively, which provided maximum sensory evaluation score (86.58 points) and specific volume (3.02 mL/g) as well as minimum hardness (9.76 N), chewiness (45.53 N) and adhesiveness (6.66 N).

In this study, a rapid high-throughput screening kit for the detection of mono- and multi-residues of common antibiotics in animal-derived foods was developed based on the microbial chromogenic assay. Bacillus sterothermophilus (CICC 10392) was used as the indicator strain. Its cells were immobilized under optimized conditions and seeded into the wells of a 96-well microplate to detect four types of common antibiotic residues in livestock and poultry meat. As a result, the problem of time-consuming cultivation and the difficulty of transporting liquid bacterial culture could be overcome. The results showed that use of 0.1 g/mL polyvinyl alcohol as the carrier, boric acid-phosphate solution (pH 6.0) as the crosslinking agent, and an initial bacterial suspension concentration (A600 nm) of 0.8 were the best immobilization conditions in terms of the mechanical stability and microbial activity. The detection limits for tetracyclines, aminoglycosides, macrolides, β-lactams separately, and aminoglycosides in combination with tetracyclines or β-lactams were 40–60, 60–120, 60–100, 20–40, 20–40, and 10 μg/kg, respectively, conforming to the requirements for antibiotic residue limits. The same results were obtained on 70 animal-derived food samples using the kit and chromatography. The results indicated that the kit could be used to reliably detect antibiotic residues in animal-derived food samples.

In this study, two batches of pork were used as experimental samples, and local partial least squares (LPLS) and dual-band visible and near-infrared spectroscopy were used in conjunction to build a prediction model for the detection of total volatile basic nitrogen (TVB-N). A similarity measurement method based on distance, information measurement, and projection was proposed. A similarity function to evaluate the similarity of different samples was also proposed by weighted summation of Euclidean distance and spectral information divergence-spectral angle (SID-SAM). Then, a similarity factor (SM) was defined and employed to determine the modeling neighborhood window for the establishment of LPLS model. Using the first batch of samples as the modeling basis set, LPLS models for each sample in the second batch of samples were built by optimizing the weights of Euclidean distance and SID-SAM and SM. Compared with the results obtained before establishing the LPLS models, the correlation coefficient (R) for the second batch of samples increased from 0.845 6 to 0.948 1, and the prediction error decreased from 4.581 0 to 2.650 8 mg/100 g, which improved the prediction accuracy of the model. The results showed that using the proposed similarity function and similarity factor, a local space can be dynamically selected in real time according to the spectral characteristics of the samples. The established LPLS prediction models can effectively improve the prediction ability for the validated samples.

An accurate method to quantitatively analyze the contents of apricot kernel-derived and peanut-derived components in apricot kernel protein drink products was established based on droplet digital polymerase chain reaction (ddPCR) in this study. We established a linear relationship between plant material mass (M) and DNA copy number (C) after the extraction of nucleic acids from both apricot kernels and peanuts. According to the results of ddPCR, we found that the relationships between the mass of each plant material and DNA concentration and between DNA concentration and DNA copy number were both significantly linear within a certain range. The DNA concentration was utilized as an intermediate value to establish the following formulae: Mapricot kernel = 0.13C + 1.24, Mpeanut = 0.081C ? 0.63. The accuracy and applicability of this method were tested and verified using known mixtures of apricot kernel and peanut and 12 commercial apricot protein drink products. This method enabled accurate and reliable quantitative analysis, and effective identification of whether the adulteration in apricot kernel protein drink products is inadvertent or intentional. Hence ddPCR has strong potential in quantifying apricot kernel and peanut in apricot kernel protein drink products and provides technical support for market supervision of plant protein drink products.