PIN-FORMED (PIN) proteins work as auxin efflux proteins with multiple transmembrane domains and mediate auxin flow throughout the plant. As tomato is an important cash crop, studies aimed to regulate its growth and development are of great significance. Studies have shown that PIN proteins play an important role in regulating the growth and development of fruits. In this study, we predicted the characteristics of ten tomato PIN members by using on-line software, constructed a phylogenetic tree for SlPINs, and analyzed expression changes of SlPINs in different tissues and during fruit growth and development. This study will provide a basis for future study on the biological functions of SlPINs.

Acetic acid bacteria are an important factor that influences the efficiency of vinegar production by pure culture liquid-state fermentation. The goal of this study was to obtain an outstanding acetic acid bacterial strain for vinegar production by routine screening combined with molecular biological techniques. The target strain was isolated from the biofilm formed in enrichment culture in the presence of high concentrations of alcohol and acetic acid. It was identified as Acetobacter pasteurianus JST-S (BJST-S) based on physiological and biochemical characteristics combined with 16S rDNA sequence analysis. Comparative analysis of fermentation characteristics indicated that the BJST-S was better than Acetobacter pasteurianus CICC 20001 in term of growth rate, acid production rate, alcohol resistance and acid resistance. The concentration of acetic acid was maintained in the range of 58.10–59.68 g/L and the fermentation strength in the range of 1.21–1.24 g/(L·h) in three batches of semi-continuous fermentation, implicating that the fermentation characteristics of BJST-S were stable. Our findings in this work may provide a valuable reference for strain breeding for the improvement of industrial vinegar production.

To isolate Lactobacillus with great application potential from traditional homemade dairy products in Inner Mongolia, eight strains of Lactobacillus were screened for their antimicrobial activity. Strain Q-1-4 was found to have a broad spectrum of antimicrobial activity and was identified as Lactobacillus paracasei by physiological and biochemical characterization and 16S rDNA sequencing analysis. The antimicrobial activity of the cell-free culture supernatant (CFS) of L. paracasei Q-1-4 against Salmonella typhimurium CMCC50115 still existed after eliminating the interference factors such as lactic acid, acetic acid, and hydrogen peroxides. However, the CFS of L. paracasei Q-1-4 was inactivated after treatment with proteolytic enzymes. Inhibitory activity of the CFS against S. typhimurium CMCC50115 was observed in the pH range from 2.0 to 5.5. The antimicrobial substance had good thermal stability in this pH range and was not sensitive to ultraviolet. SDS and EDTA could enhance the antimicrobial activity, but surfactants, organic solvents and metal ions had no effect on the antimicrobial activity. In addition, the antibacterial activity had good storage stability with a broad inhibitory spectrum.

In this study we compared the influences of fermentation by pure cultures of two strains of lactic acid bacteria and two strains of yeast and natural fermentation on the quality of instant rice noodles. The results showed that the highest tensile stress, hardness, elasticity, cohesiveness, chewiness, resilience and water absorption rate and the lowest cooking loss were obtained after 36–48 h fermentation by Lactobacillus plantarum CSL23 among the four strains tested. By contrast, 48 h fermentation by L. fermentum CSL30 provided the second highest tensile stress, elasticity, cohesion, resilience, water absorption rate and cooking loss rate in instant rice noodles, but the lowest hardness, viscosity and chewiness. Instant rice noodles produced by 60 h natural fermentation displayed better tensile stress, hardness and chewiness with texture characteristics and cooking properties being at a middle level. Instant rice noodles obtained by S. cerevisiae CSY13 fermentation had distinct flavor characteristics with higher viscosity and lower cohesion. The effect of T. asahii CSY07 fermentation on the tensile stress, texture characteristics and cooking properties of instant rice noodles was inferior to that of natural fermentation, but it had the second largest effect on the flavor after S. cerevisiae CSY13. In short, lactic acid bacteria is conducive to the eating quality of instant rice noodles, whereas yeast is beneficial for the flavor; the quality of instant rice noodles can be assured by pure culture fermentation in a shorter time.

The potential mechanism for glutathione oversynthesis in the Saccharomyces cerevisiae mutant Y518 was researched using transcriptome analysis combined with physiological and biochemical characteristics. The results indicated that the rate-limiting enzyme of glutathione synthesis, antioxidant enzymes activities and the expression levels of their encoding genes, and the contents of hydrogen peroxide and nicotinamide adenine dinucleotide phosphate (NADPH) were significantly increased in the mutant whereas pyruvatekinase activity, the contents of pyruvate, citrate and succinate were markedly decreased. Besides, the expression levels of genes involved in the citrate cycle were significantly down-regulated while those involved in the pentose phosphate pathway were significantly up-regulated. Therefore, under endogenous oxidative stress, the mutant might strengthen the synthesis of glutathione by adjusting the activities of rate-limiting enzymes of glutathione synthesis to defend against oxidative stress together with the antioxidant enzymes. Meanwhile, weakened pyruvatekinase activity decreased pyruvate generation, which led to declined citrate cycle flux and increased NADPH production by the pentose phosphate pathway and consequently provided appropriate reducing power for glutathione biosynthesis.

This study aimed to rationally identify new targets for improving isoleucine production. The transcription levels of the key genes and intermediate metabolite levels involved in the isoleucine synthesis pathway of Corynebacterium glutamicum ATCC 13032 and C. glutamicum YILW, a isoleucine-producing strain derived from the parental strain ATCC 13032, were compared. The gene pyc was down-regulated, which might consequently lead to reduced supply of oxaloacetate. Then pyc was overexpressed in C. glutamicum YILW (denoted as YILW-1), resulting in increased oxaloacetate concentration and isoleucine production (from 1.32 to 3.32 μmol/g (md) and from 5.18 to 5.81g/L) but higher accumulation of lysine and intracellular 2-ketobutyrate as byproduct. The ilvBNC operon was further overexpressed in YILW-1 (denoted as YILW-2), resulting in production of up to 6.63 g/L isoleucine. To enhance exportation and consequently further increase the production of isoleucine, the isoleucine exporter genes brnE and brnF was overexpressed in YILW-2 (denoted as YILW-3), leading to increased production of isoleucine (7.31 g/L) by 10.3% as compared to that of YILW-2. The strategy resulted in 41.1% higher isoleucine production (from 5.18 to 7.31 g/L) and 40.0% higher yield (from 0.10 to 0.14 g/g glucose) together with lower by-product lelvels by YILW-3 as compared to C. glutamicum YILW. It could be concluded that overexpression of the pyc, ilvBNC operon as well as brnE and brnF based on transcription and metabolite pool analysis could significantly elevate isoleucine production and decrease by-product concentration levels.

By constructing the targeting vector of the uracil phosphoribosyl transferase gene (upp), the upp gene deletion mutant K. vulgare Δupp was obtained using homologous recombination. The mutant was selected as the chassis cell in seamlesss genome modification system. An upp gene expression vector was constructed and transformed into mutant K. vulgare Δupp. After the transformation, an upp gene reverse mutation strain named PBB-upp was obtained, and the feasibility of upp as a negative selectable marker was verified. The results showed that Δupp mutants rather than the wildtype and reverse PBB-upp strains could grow in a medium with 1 mg/mL 5-fluorouracil. Moreover, there were significant differences among the three strains in terms of 5-fluorouracil resistance, indicating that by combining the upp gene as a negative marker with a positive marker, double homologous recombinations could occur on the chassis cell without the upp gene. In this way, the modification can be achieved without antibiotic marker in Ketogulonigenium vulgare.

With the aim of developing a generic enzyme-linked immunosorbent assay (ELISA) for the detection of heterocyclic amines, a new approach was used to prepare hapten, in which, methyl 4-chloro-4-oxobutyrate (MCO) was attached to the 2-amino group of 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx). The antigen was obtained by a modified carbodiimide method. In pH buffer system at the appropriate pH, the hydrolysis of ester and the coupling step were completed simultaneously. Compared with the traditional method, the new method shortened the reaction time and cut down the cost effectively. The results of UV identification and polyclonal antibody titer indicated that the coupling was successfully achieved. And the immunogens produced polyclonal antibody for 4,8-DiMeIQx with a high titer of 1:450 000. High-affinity antibody against 4,8-DiMeIQx was optimized and a direct competitive ELISA assay was developed. It was shown that the analyte concentration giving 50% inhibition of color development (IC50) was 24.0 μg/L and that giving 15% inhibition of color development (IC15) was 1.8 μg/L for 4,8-DiMeIQx, and IC50 was 35.0 μg/L for 7,8-DiMeIQx, 30.0 μg/L for 8-MeIQx, 28.0 μg/L for IQx, and 40.0 μg/L for TriMeIQx, respectively, while almost no cross-reactivity (CR < 0.01%) with other heterocyclic amines having a structure different from that of 4,8-DiMeIQx, such as PhIP, IQ and MeIQ, was observed. The developed ELISA method was suitable for the rapid quantitative and qualitative determination of heterocyclic amines in processed meat products.

The yeasts in Moutai-flavor Daqu were counted and screened. Through morphological characteristics, physiological and biochemical tests, yeast 26S rDNA and molecular biology, we identified and classified the isolated yeasts. In addition, the flavor compounds produced by the yeast strains in solid-state fermentation and their fermentation performance were also analyzed. The results showed that the number of yeasts in Moutai-flavor Daqu was 103 CFU/g. The yeasts isolated were classified into 6 species. All the yeast strains showed different aroma-producing abilities. Among them, the solid-state fermented products of FBKL2.0071 (Saccharomycopsis fibuligera) smelled like full-bodied fruity fragrance, and the main volatile flavor compounds included ethyl acetate, isoamyl acetate, phenylethyl alcohol, phenyl ethyl acetate and ethyl palmitate. Moreover, the solid-state fermented products of FBKL2.0082 (Hyphopichia burtonii) smelled like fullbodied flowery fragrance, and the major volatile flavor components, included ethyl acetate, isoamyl acetate and phenylethyl alcohol. These two strains not only could produce a large amount of alcohols and esters, but also produce small amounts of aldehydes and ketones. Besides, all the yeast strains showed different and poor ethyl alcohol-producing abilities.

To explore the effect of acid and osmotic pressure on the growth of planktonic and detached cells of Salmonella enteritis, the Baranyi model and modified square root model were used to simulate the growth of S. enteritis in the two states, respectively. The growth of attached cells cultivated for 7 days under different environments was studied as well. The experimental results demonstrated that both the planktonic and detached cells pre-cultivated at 25 ℃ for 72 h showed similar growth rates under most subsequent environmental conditions (P ≥ 0.05). However, the growth curves and growth kinetic parameters of both cells were significantly different (P < 0.05) under four conditions including pH 5.0 + 0.0 g/100 mL NaCl, pH 7.0 + 4.0 g/100 mL NaCl, pH 6.0 + 4.0 g/100 mL NaCl, and pH 5.0 + 4.0 g/100 mL NaCl. Moreover, the first- and second-order models showed high determination coefficient (R2) and low root mean square error, and the model parameters Aw min, pHmin, as well as the evaluation indicators accuracy factor (Af) and deviation factor (Bf) were within the acceptable range under the experimental conditions of pH 5.0–7.0 and NaCl concentration of 0.0–4.0 g/100 mL. The initial adsorbance quantity of attached cells cultivated at 25 ℃ for 72 h was (5.604 ± 0.117) (lg (CFU/cm2)), and the value reduced gradually with the decrease in pH value or the increase in NaCl concentration after subsequent cultivation for 7 days under different acid and osmotic pressures. Consequently, this research could provide a reference for understanding and controlling the growth of S. enteritis in different states during food processing.

To obtain polyclonal antiserum with high sensibility and specificity, artificial antigens were synthesized by coupling glyphosate (PMG) with the carrier proteins bovine serum albumin (BSA) and ovalbumin (OVA) separately by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and glutaraldehyde (GA) methods in this study. As a result, the immune antigen PMG-BSA and detection antigen PMG-OVA were obtained and identified by UV spectroscopy and SDS-PAGE. New Zealand white rabbits were immunized with PMG-EDC-BSA and PMG-GA-BSA, respectively to obtain polyclonal antisera. The titer of the antisera was determined by indirect ELISA and their sensibility and specificity were determined by indirect competitive ELISA. The results showed that the titer of antiserum of all three immunized rabbits was higher than 1:104. The antiserum of rabbit 2 exhibited the highest sensibility with an IC50 of 30.9 μg/mL and good specificity. The successful synthesis of artificial antigens and the obtainment of PMG polyclonal antiserum with high sensibility and specificity may lay the foundation for rapid immunological detection of PMG.

In this study, the bacterial diversities in three Jiangshui (a traditional Chinese fermented vegetable product) samples collected from three different locations were analyzed in order to isolate lactic acid bacteria for massive production of Jiangshui. The dominant lactic acid bacteria with a significant bacteriostatic effect against four common foodborne pathogens were isolated and identified from the Jiangshui samples. Total bacterial DNA was extracted from Jiangshui for sequencing of the 16S rRNA V3–V4 region using the MiSeq sequencing technique to understand the bacterial diversity. The results showed that Lactobacillus was dominant in all three Jiangshui samples, showing differences in their bacterial diversity. The compositions of bacterial communities in Jiangshui samples from Chang’an district of Xi’an and Taian county of Tianshui were similar, but significantly different from that of the sample from Yanta district of Xi’an. Both spoilage bacteria and potential pathogens (or opportunistic pathogens) were detected in each sample. A total of 35 stains able to form calcium dissolution circle, were isolated using a modified MRS medium. Ten strains were selected for their outstanding inhibitory activity against Staphylococcus aureus, Escherichia coli, Salmonella enteritidis and Shigella dysenteriae, which were identified through 16S rDNA sequencing as 8 strains of Lactobacillus plantarum and 2 strains of Lactobacillus rhamnosus, indicating that Lactobacillus plantarum and Lactobacillus rhamnosus are the dominant bacteria in Jiangshui. This study can provide some theoretical and practical bases for the production of Jiangshui by applying both lactic acid bacteria or one of them in the future.

In this research, we used the gradient dilution and streak plate methods to isolate and purify microorganisms from wheat Qu for Beizong rice wine. A total of seven bacterial strains and five fungal strains were obtained. Through observation of their morphological characteristics and molecular biological characterization, the bacterial strains were identified as Bacillus licheniformis, Bacillus subtilis, Bacillus pumilus, Bacillus atrophaeus, Bacillus clausii, Bacillus rhizosphaerae, and Bacillus sonorensis, and the fungal strains were identified as Aspergillus oryzae, Aspergillus niger, Talaromyces radicus, Neurospora crassa, and Absidia corymbifera.

This study aimed to find out whether mold DNA can be amplified from traditional mold fermented foods and whether Aspergillus besides Monascus carries pksCT gene. The effect of thermal sterilization conditions on the degradation of the pksCT gene in red kojic rice wine was examined as well. Eleven samples of soy sauce, rice vinegar, fermented bean curd and yellow rice wine collected from local market were used for DNA extraction. Polymerase chain reaction (PCR) amplification was carried out with internal transcribed spacer (ITS) and pksCT gene primers. Rice wine was fermented by wheat koji and red koji, respectively, and then the pksCT gene was amplified and citrinin contents were measured before and during fermentation, after sterilization, and during storage. Samples were sterilized at 70, 80, 90, 100 ℃ for 10, 20, and 30 min, respectively, and then were subjected to PCR amplification. The results showed that DNA fragments were successfully amplified with the ITS primer from 4 samples, including soy sauce, rice vinegar, fermented bean curd and yellow rice wine. However, the pksCT gene was successfully amplified only from red bean curd fermented by Monascus. We failed to amplify the pksCT gene from yellow rice wine fermented by wheat koji. The pksCT gene was successfully amplified from red kojic rice wine during fermentation and after sterilization. Meanwhile, citrinin content increased rapidly at these sampling points. When red kojic rice wine was sterilized at 80 ℃ for 20 min or 90 ℃ for 10 min, the pksCT gene remained amplifiable, while after sterilization at 90 ℃ for 20 min or 100 ℃ for 10 min, DNA structure was damaged. The pksCT gene was amplifiable in Monascus fermented foods, but not in Aspergillus fermented foods. It is implied that mold DNA in fermented foods can be amplified by PCR and sequenced, which may be helpful for inspectors to find out what kinds of strains are contained in mold fermented foods, and provides a new terminal monitoring method for mold fermented foods.

The fermentation kinetics at a constant temperature and antioxidant activity of cactus wine produced from cactus juice using SY-type Angel-branded yeast were studied. Yeast count, alcohol content, and reducing sugar in cactus wine were determined after every 12 h, and the experimental data were nonlinearly fitted to the Logistic, SGompertz and DoseResp models. Meanwhile, changes in the contents of total phenol and flavonoids and antioxidant activity of the wine were investigated as a function of fermentation time. The experimental results showed that the fitness of all the three models was confirmed by a satisfactory value of determination coefficient, which was calculated to be greater than 0.99. In addition, it was also shown that the contents of total phenol and flavonoids were relatively high in cactus wine. Cactus wine exhibited remarkable free radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl and 2,2’-azinobis-(3-ethylbenzthiazoline- 6-sulphonate and potent Fe3+ reduction power.

A multiplex polymerase chain reaction (mPCR) assay for the rapid identification of Lactobacillus acidophilus- Bacillus natto fusant was developed in this paper. The primer pair P1/P2 was designed based on the spo0A gene encoding the stage 0 sporulation protein A of Bacillus subtilis, as well as the primer pair P3/P4 according to the conserved sequence of the β-galactosidase gene of 13 lactic acid bacterial (LAB) strains. Using the genomic DNA of the parental strains as template, PCR systems for each primer pair were optimized under the predetermined annealing temperature. The specificity analysis showed that P1/P2 could amplify the spo0A fragment (308 bp) but all seven LAB strains gave negative results; P3/P4 could amplify the target fragment (576 bp) from all LAB and five identified positive fusants but not from Bacillus subtilis. Results of multiplex PCR demonstrated that the optimal PCR system for P1/P2 could only amplify its own 308 bp target DNA, while in the optimal system for P3/P4 both target DNA fragments could be obtained. The results of identification of 50 fusant strains by multiplex PCR showed 100% consistency with that of traditional PCR and phenotype identification. The mPCR system contained 1 ng/μL template DNA, 0.4 μmol/L primer (each), 0.25 mmol/L dNTP, 0.06 U/μL Taq polymerase, and the PCR conditions were as follows: 5 min predenaturation at 94 ℃, 30 cycles of denaturation at 94 ℃ 30 s, annealing at 53 ℃ for 30 s, and extension at 72 ℃ for 60 s. This method proved to be a rapid, convenient method with high specificity for the efficient identification of spore-forming bacteria, LAB and their fusant.

This study aimed to obtain a yeast strain suitable for the alcoholic fermentation of pepino fruit (Solanum muricatum Ait.) from the Hexi Corridor in Gansu. A total of 20 indigenous yeast strains were isolated from spontaneously fermented pepino juice. Out of these, 11 isolates were screened for their good fermentation performance as examined by microscopy, which were named TY8, TY5, TY6, Y3, Y4, Y5, LY3, LY1, Y1, Y2 and TY2, respectively. By comparing fermentation capacity, alcohol tolerance, SO2 tolerance, physicochemical properties and sensory evaluation with active dry wine yeast, TY8 was found to be suitable for the fermentation of pepino fruit wine. The wine fermented by this strain had distinct aroma characteristics and developed a typical flavor, being clear and transparent.

Objective: To determine the antibacterial susceptibility to 15 antibiotics and quinolone resistance genes of 30 Salmonella isolates from beef and mutton ürümqi, Xinjiang for the purpose of better understanding the development and transmission pathways of antibiotic resistance in Salmonella and hence providing basic information for preventing and controlling Salmonella-related diseases. Methods: The drug sensitivity of Salmonella isolates was evaluated by the agar dilution method. In addition, polymerase chain reaction and gene sequencing were used to detect the quinolone resistancedetermining regions mutations and the plasmid-mediated quinolone resistance genes. Results: The drug resistance rates of 30 Salmonella isolates to trimethoprim, chloramphenicol nalidixic acid, tetracycline, sulfisoxazole, streptomycin, trimethoprim/ sulfamethoxazole, amoxicillin/clavulanic, ampicillin were 100%, 86.7%, 66.7%, 60.0%, 50.0%, 33.3%, 26.7%, 6.7% and 6.7%, respectively. All the Salmonella isolates were sensitive to ciprofloxacin, ceftriaxone, gentamicin, kanamycin, cefoxitin and amikacin. The number of Salmonella carrying gyrA mutations was 14, and the main type of mutation was Ser83Phe; the number of Salmonella having parC mutations was 25, and the main type of mutation was Thr57Ser. Conclusions: The Salmonella isolates from beef and mutton retailed in ürümqi are resistant to multiple antibiotics. Therefore, we should be seriously concerned about this phenomenon. The antibiotic resistance mutations and the plasmid-mediated quinolone resistance genes may be an important cause of the antimicrobial resistance of Salmonella isolates from beef and mutton in some extend.

Listeria monocytogenes is a common foodborne pathogen. Cell wall-anchored surface proteins are closely related to the pathogenicity and biofilm formation of the bacterium. The srtA gene is a key factor that mediates the membrane anchoring of surface proteins, and as an important virulence gene of L. monocytogenes it can covalently bind surface proteins to the cell wall by recognizing specific peptide sequences. For a better understanding of the function of srtA and its role in bacterial virulence regulation, we knocked out the srtA gene in L. monocytogenes by homologous recombination in this study, and evaluated the biological properties of the mutant strain. Based on its growth curve examination, we found that the growth rate of the mutant strain was slower than that of the wild-type one. Furthermore, the invasion efficiency of the mutant strain in glioma U251 cells was lower than that of the wild-type one. These results indicate that srtA may play an important role in regulating the invasiveness of L. monocytogenes, which will provide a theoretical basis for further understanding of the regulatory mechanisms of virulence genes in L. monocytogenes and biofilm formation.

This study aimed to improve the yield of α-amylase inhibitor and the efficiency of carbohydrate utilization during the fermentation of Streptomyces coelicoflavus (S. coelicoflavus). The metabolic network leading to the biosynthesis of α-amylase inhibitor was analyzed to find out the key nodes which influenced the production of α-amylase inhibitor. The effects of sodium glutamate on the metabolic flux distributions during the middle and late periods of fermentation were studied, and metabolic flux analysis for α-amylase inhibitor production at pseudo-steady state was also conducted. The results showed that the metabolic flux channeled to the α-amylase inhibitor biosynthesis pathway was 1.84 in batchwise fermentation without the addition of sodium glutamate, while, with the addition of sodium glutamate (the concentration was maintain at 4.0 g/L), the metabolic flux was 3.18, suggesting that the addition of sodium glutamate could change the metabolic flux distributions of the key nodes (glucose-6-phosphate, sedoheptulose-7-phosphate, and glutamate) and enhance the biosynthesis of α-amylase inhibitor.

In the present study, the variations in fruit quality characteristics related to the flavor and physiological quality in two strawberry cultivars, ‘Mira’ and ‘Honeoye’, were investigated during three ripening stages. Results showed that total soluble solids (TSS), volatile aromatic components and anthocyanins accumulation significantly increased, while total acid (TA), total phenolics and total flavonoid contents as well as antioxidant capacity declined during strawberry ripening. The correlations between the quality traits were analyzed by principal component analysis. It was indicated that there were high correlations (r = 0.859 1–0.994 7) between the changes in total phenolics, flavonoids, total soluble solid or titratable acid and antioxidant capacity (FRAP) as well as oxygen radical absorbance capacity (ORAC) during strawberry ripening, while the correlation coefficients between total anthocyanin and ferric reducing antioxidant power (FRAP) as well as ORAC were only 0.315 0 and 0.385 3, respectively. Furthermore, a positive correlation between the maturity of strawberry fruits and the accumulation of aromatic volatile components and anthocyanins was also observed.

This study aimed to analyze the main chemical constituents of ethanol extracts of grape, mango and strawberry by high performance liquid chromatography-mass spectrometry (HPLC-MS) and compare the antioxidant interactions among the three extracts using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate (ABTS) radical scavenging assays. The isobolographic analysis method was used to analyze the differences in the antioxidant activity of mixtures in various proportions of the extracts. Results demonstrated that the grape extract had the highest contents of total phenols and total flavonoids among three fruit extracts. Gallogen, pelargonidin-3-glucoside, pelargonidin-3-acetylglucoside and pelargonidin-3-rutinoside were the main compounds of the strawberry extract. Gallogen, mangiferin and maclurin were the main compounds of the mango extract. Trans-resveratrol and anthocyanin were the main compounds of the grape extract. The same combination showed different antioxidant activities in different antioxidant models. The strawberry extract had the highest antioxidant capacity followed by the mango extract and the grape extract. In the same antioxidant model, the highest synergistic antioxidant effect of the strawberry extract was achieved when combined with the mango extract at a ratio of 1:9 and 1:1 (V/V) for scavenging of DPPH and ABTS radicals, respectively.

Objective: To establish a method for and the simultaneous determination of gallic acid, catechin, rutin, quercetin, kaempferol and apigenin in Rosae Laevigatae Fructus by ultrasonic-assisted extraction combined with high performance liquid chromatography (HPLC). Methods: The analytes in Rosae Laevigatae Fructus were separated on an InertSustain C18 column (150 mm × 4.6 mm, 5 μm). The mobile phase consisted of methanol and 0.1% acetic acid (pH 3.0) for gradient elution at a flow rate of 1.0 mL/min. The UV gradient wavelength for detection was set at 280 nm (0–5.00 min) and 350 nm (5.00–20.00 min). The column temperature was kept at 35 ℃. Results: The complete separation of 6 active ingredients was achieved under the above conditions. The calibration curves of the analytes showed a good linear relationship (r ≥ 0.999 1, n = 6). The average recoveries were in the range of 96.21%–110.39% with relative standard deviation (RSD) ≤ 3.14%. Conclusion: The method is simple, rapid and accurate and can provide a basis for the quantitative detection and quality control of Rosae Laevigatae Fructus.

In this study, changes in optical density (OD) during the fermentation of apple juice with pure and mixed cultures of lactic acid bacteria were monitored by a UV-Vis spectrophotometer. The aroma components of nine fermented apple juices were identified by head-space solid phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), and the characteristic aroma components were evaluated by odor activity value (OAV) and odor threshold value (OTV). Sensory evaluation was also carried out on the samples. The results showed that the OD value of apple juice increased logarithmically with time. Forty eight aroma components were identified from nine fermented apple juices, mainly including alcohols, esters, aldehydes, ketones and phenols. Esters were the most abundant components with the highest species diversity, followed by alcohols. In addition, according to their aroma values, butyric acid ethyl ester, ethyl-2-methylbutyrate, 2-methylbutyl acetate and hexyl acetate were the main aroma components in all the fermented samples. The contents of aroma components and aroma values from single and mixed culture fermentation of apple juice were significantly different (P < 0.05). It was shown that the total contents of alcohols, esters and other aroma components with mixed culture fermentation were significantly higher than those of single culture fermentation and apple juice fermented with single cultures had a stronger fruity, green and flowery aroma. The overall sensory score of apple juice fermented with mixed cultures was higher than that of single culture fermentation. A mixed culture of Lactobacillus paracasei 20241, Bifidobacterium animalis 6165, Streptococcus thermophilus 6063 and Lactobacillus acidophilus 6005 at a ratio of 1:1:1:1 was the optimal combination in sensory acceptance. These results can provide a theoretical basis for the research and application of lactic acid bacteria in fermented fruit and vegetable juice.

The volatile compounds of Gujinggong liquor were extracted by headspace solid-phase microextraction (HSSPME) and stir bar sorptive extraction (SBSE) separately, and identified by gas chromatography-mass spectrometry (GCMS). Important extraction parameters including sample alcohol content, extraction temperature, and extraction time were optimized. Overall, the two methods were highly precise and reproducible. On the other hand, the SBSE method was superior to HS-SPME in terms of sensitivity and recovery. A total of 190 volatile compounds were determined by comparison of the retention index data with those of standards and with NIST 14 mass spectral library data, 143 of which were identified with pure standards. Four volatile esters, i.e. hexyl 3-methylbutyrate, octyl butyrate, propyl decanoate, and isobutyl decanoate, were identified for the first time in Chinese liquor.

The volatile flavor components and fatty acids of Longissimus dorsi, Biceps femoris and Triceps brachii muscles of 12-month-old Sunite sheep were extracted by using solid-phase micro extraction (SPME) and distillation extraction separately and then analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that a total of 44 volatile compounds were identified, including 6 hydrocarbons, 17 aldehydes, 3 ketones, 3 acids, 11 alcohols, and 4 miscellaneous compounds. Hexanal, nonanal, 1-octen-3-ol and 2,3-octanedione may be mainly responsible for the formation of meat flavor. The contents of aldehydes and alcohols compounds in Longissimus dorsi were higher than those of Biceps femoris and Triceps brachii. The contents of saturated fatty acid and polyunsaturated fatty acids in the three muscles were no significantly different, whereas the contents of monounsaturated fatty acids in Longissimus dorsi were higher than those of Biceps femoris and Triceps brachii. Unsaturated fatty acids are abundant in sheep muscles and can affect their flavor.

An analytical method was established for the simultaneous determination of glutathione and free amino acids in shellfish using a fully automatic amino acid analyzer. The extraction of the analytes was carried out using 0.02 mol/L hydrochloric acid solution as the extraction solvent followed by protein precipitation with 5% sulfonic acid solution. The buffer composition and the elution procedure were optimized at the same time. The linear range, limit of detection (LOD), precision and recovery rate of the method were determined. The results showed that good separation of glutathione and free amino acids in shellfish was achieved by this method with a good linear relationship. The correlation coefficients of the calibration curves were between 0.999 1 and 0.999 9. The minimum LODs at a signal to noise ratio (RSN) of 3 ranged from 0.07 to 0.27 μmol/L. The average recovery rates of spiked samples were between 86.40% and 102.42%. The relative standard deviations (RSDs) of intra-day and inter-day assays were 0.31%–0.73% and 1.14%–2.60%, respectively. Free amino acids were abundant in muscle tissue of four shellfish species, and their total free amino acid contents in decreasing order were clam (1 396.39 mg/100 g) > Cyclina sinensis (1 016.04 mg/100 g) > razor clam (911.15 mg/100 g) > oyster (287.01 mg/100 g). The main free amino acids were taurine, glutamic acid, alanine, and arginine. The glutathione contents of Cyclina sinensis, clam, razor clam and oyster were 103.20, 82.53, 61.77, and 33.37 mg/100 g, respectively. This method is suitable for the determination of glutathione and free amino acids in shellfish.

An analytical method for determining K, Ca, Mg, P, Na, Al, B, Fe, Mn, Zn, Cu, Sr, Mo and Ba in buckwheat bran, oat bran and rye bran by inductively coupled plasma-optical emission spectrometry (ICP-OES) after microwave digestion with HNO3/H2O2 mixture was established. The optimal conditions of ICP-OES were obtained by optimizing the operating parameters and selecting the suitable detection wavelengths for analytes. The elimination of spectral interferences from coexisting elements was also investigated in detail. The results showed that the detection limits (LODs) of the method were in the range of 0.26–52.66 μg/L. The correlation coefficients of the calibration curves were in the range of 0.999 5–0.999 9. As validated by the analysis of wheat reference material (GBW10011), the method had high precision and good accuracy. Wheat bran contained large amounts of beneficial inorganic elements.

The compositions and contents of anthocyanins and nonanthocyanin phenolics in three cultivars of sweet cherry (‘Rainier’, ‘Hongyan’ and ‘Hongdeng’) were analyzed by using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The separation of anthocyanins was achieved on a Kromasil 100-5C18 column (250 mm × 4.6 mm, 6.5 μm) using a mobile phase consisting of water/formic acid/acetonitrile at a flow rate of 1.00 mL/min by gradient elution. The injection volume was 30 μL and the column temperature was set at 50 ℃. The detection wavelength was 525 nm. Meanwhile, the separation of nonanthocyanin phenolics was accomplished a Zorbax SB-C18 column（50 mm × 3.0 mm, 1.8 μm）using a mobile phase consisting of 1% acetic acid aqueous solution and 1% acetic acid acetonitrile solution at a flow rate of 1.00 mL/min by gradient elution. The injection volume was 2 μL and the column temperature was set at 25 ℃. The detection wavelength was 280 nm. The results showed that a total of 9 anthocyanin compounds were detected in these cultivars of sweet cherry, mainly cyanidin-3-rutinoside and cyanidin-3-glucoside, their contents in the skin of ‘Hongyan’, ‘Rainier’, ‘Hongyan’ cherries and the pulp of ‘Hongdeng’ cherries were 5.21, 2.51, 75.70 and 7.40 mg/g, and 0.09, 0.07, 3.57 and 0.34 mg/g, respectively. In addition, two nonanthocyanin phenolic compounds were also detected, namely quercetin-3-rutinoside and kaempferol-3-rutinoside. The contents of quercetin-3-rutinoside and kaempferol-3-rutinoside in the skin of ‘Hongyan’, ‘Rainier’ and ‘Hongdeng’ cherries were 0.30, 0.63 and 0.74 mg/g, and 1.17, 2.91 and 2.37 mg/g, respectively.

Flavor components of jujube brandy were analyzed by direct injection method and gas chromatographyolfactometry- mass spectrometry (GC-O-MS). The qualitative analysis was conducted using mass spectrometry and olfactometry by comparison of retention index with those reported in the literature, and the quantitative analysis was performed by GC-MS using three internal standards. The main constituents contributing to the overall flavor were evaluated through odor activity value (OAV) and aroma intensity. The results showed that a total of 56 compounds were isolated, the structures of 52 of which were identified, accounting for 99.72% of the total flavor components in jujube brandy. Evaluation of OAV and aroma intensity values indicated that ethyl acetate, butanoic acid ethyl ester, pentanoic acid ethyl ester, hexanoic acid ethyl ester, octanoic acid ethyl ester, acetic acid, butanoic acid, pentanoicacid and hexanoic acid were the main flavor components. 2-Phenylethyl acetate and benzenepropanoic acid ethyl ester also contributed to the jujube aroma in jujube brandy. This study could provide a theoretical basis to study the flavor and control the quality of jujube brandy.

This study aimed to determine the volatile aroma components of fruit peels of four varieties of citrus with different aroma characteristics by solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrophotometry (GC-MS). Results showed that a total of 39, 37, 43 and 41 volatile components were identified in the peels of ponkan, naval orange, Shatang mandarine and Citrus reticulata Blanco cv. Manau Gan. Esters were not detected in ponkan or Shatang mandarine and ketones were not detected in naval orange. The aroma component identified in Citrus reticulata Blanco cv. Manau Gan included alkanes, aldehydes, ketones, alcohols, esters, aromatic compounds and other miscellaneous compounds. The differences in the aroma profiles of these citrus varieties were explained in terms of aroma composition, the relative contents of common aroma components and unique aroma compounds, and the differences in the aroma types of citrus were chemically demonstrated.

The volatile compounds in fermented Chinese jujube wine were analyzed by headspace solid phase microextraction (HS-SPME) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS). Extraction and GC-MS conditions were systematically studied and the contributions of the main components to the overall aroma of fermented Chinese jujube wine were evaluated by odor activity value (OAV) combined with aroma intensity value. The optimal extraction parameters were achieved on Rt-Wax column under the following conditions: 50/30 μm poly two vinyl benzene/ carbon molecular sieve/poly two methyl siloxane (DVB/CAR/PDMS) solid-phase micro extraction fiber, extraction of 8.0 mL of sample in a 20.0 mL vial for 40 min at 55 ℃ with the addition of 0.40 g/mL of NaCl, 20 min equilibration and 5 min desorption. The results showed that a total of 108 compounds were isolated the structures of 86 compounds of which were identified by HS-SPME-GC-O-MS, accounting for 97.09% of the total volatile substances. Evaluation of OAV and aroma intensity values indicated that 1-butanol 3-methyl-acetate, 3-methyl-1-butanol, hexanoic acid ethyl ester, 2-hexenoic acid ethyl ester, heptanoic acid ethyl ester, acetic acid, 1-octanol, decanoic acid ethyl esterl, benzoic acid ethyl ester, pentanoic acid, acetic acid 2-phenylethyl ester, hexanoic acid, benzyl alcohol, benzenepropanoic acid ethyl ester, phenylethyl alcohol, octanoic acid, and n-decanoic acid were the main aroma components. These results could provide a theoretical basis for quality control and aroma evaluation of fermented Chinese jujube wine.

To find the relationship between the chemical composition and geographic origin of Artemisia argyi leaves, leaf samples from Nanyang, Henan province and Xinjiang were comparatively analyzed for phenolic compounds and essential oil composition. The phenolic compounds were ultrasonically extracted with 60% ethanol, and then detected by high performance liquid chromatography (HPLC) using standard substances. The essential oils were extracted by simultaneous distillation extraction method and analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the yields of essential oil from A. argyi leaves from Nanyang and Xinjiang were 2.644% and 0.805%, respectively. A total of 19 and 14 phenolic compounds were identified from A. argyi leaves grown in the two areas, with total contents of 13.43 and 9.75 mg/g, respectively. A total of 29 and 12 compounds were identified from the two essential oils different geographic origins, which accounted for 80.24% and 71.22% of the total amount, respectively. A. argyi leaves from Nanyang contained more abundant phenolic compounds and essential oils than those from Xinjiang.

Octenyl succinic anhydride modified-gum arabic (OS-GA) was prepared from gum arabic (GA) and octenyl succinic anhydride (OSA) by a wet method. The synthesis process was optimized by the combined use of one-factor-at-atime method and response surface methodology, and emulsification properties of the synthesized product were determined. The optimal synthesis conditions for OS-GA were determined as follows: OSA, 3.0% (based on the dry weight of GA); initial mass concentration of GA, 40 g/100 mL; pH, 8.85; reaction temperature, 33 ℃; and reaction time, 130 min. Under these conditions, the grafting rate of OS in OS-GA was 1.99%, and its emulsion capacity and emulsion stability were enhanced significantly compared with those of GA.

Crude protein extract from black soybean seeds was fractionated by addition of different concentrations (0, 5, 10, 15, 20 and 25 mmol/L) of divalent cations (Ca2+, Mg2+ and Zn2+). After the precipitated protein fractions (7S globulin and 11S globulin) were freeze dried, total nitrogen was determined by the Kjeldahl method and the yield and purity of the two fractions were measured. The results revealed that the type and concentration of divalent cations significantly affected the yield and purity of 7S and 11S globulin. Based on comprehensive consideration of yield and purity, 10 mmol/L of Mg2+ was selected to extract black soybean globulin. The purity and yield of the obtained 7S protein were (86.29 ± 3.25)% and (2.90 ± 0.14)%, respectively, while the purity and yield of the obtained 11S protein were (87.42 ± 3.30)% and (9.11 ± 0.28)%, respectively. Anthocyanins from black soybean seeds were extracted with ethanol. It turned out that the content of anthocyanins was (0.58 ± 0.03) mg/g and total phenol was (2.22 ± 0.12) mg/g. By high performance liquid chromatography tandem-mass spectrometry (HPLC-MS/MS) analysis, the isolated anthocyanins were characterized as delphinidin-3-O-glucoside, cyanidin 3-O-glucoside, petunidin 3-O-glucoside and mallow-3-O-glucoside, respectively.

In this work, we optimized the frying process for sweet potato chips using combination of one-factor-at-a-time method and uniform design through multiple regression analysis of the uniform design experimental data. The results of the one-factor-at-a-time experiments showed slice thickness, pre-drying and frying to be the factors with a great influences on the oil content, L* and b*. Uniform design and stepwise regression analysis indicated that frying time significantly influenced the oil content (P = 0.011), saline concentration influenced significantly water content (P = 0.022), frying temperature and frying time affected very significantly L* (P = 0.001), drying time and frying time significantly influenced b*, and saline immersion time, saline concentration, pre-drying temperature and time and slice thickness affected brittleness, which was fitted to a quadratic polynomial regression model (P = 0.001). Principal component analysis (PCA) showed that the two principal components extracted accounted for 87.4% of the total variation, thus achieving dimensional reduction. Through ridge regression analysis, we established a regression model for comprehensive score with a correlation coefficient R of 0.997, suggesting a good degree of fitting. Partial least squares regression analysis predicted that the best process parameters were as follows: slice thickness, 2 mm; blanching time, 1 min; saline immersion time, 20 min; saline concentration, 1%; pre-drying temperature, 60 ℃; pre-drying time, 70 min; frying temperature, 150 ℃; and frying time, 1 min. The validation experiment gave a comprehensive score of 0.89, which was higher than the highest score (0.86) from uniform design. The product obtained under the optimized conditions had a low oil content, and accepted color and brittleness, and the proposed model had good prediction ability.

A culture medium containing rapeseed meal was designed for prodigiosin production by Serratia marcescens. Optimizations of culture medium composition and fermentation conditions by response surface method were performed for improved production of prodigiosin. The results indicated that the optimal medium composition was composed of corn powder 10 g/L, rapeseed meal 21.7 g/L, inoculum concentration 5.5%, and zinc sulfate 0.05 g/L at an initial pH of 5.8. When the strain was cultured for 24 h in 80 mL of the medium contained in a 250 mL flask with shaking at 200 r/min, the fermented broth had the highest prodigiosin content of 11.56 g/L. This study could provide a basis for the microbial production of prodigiosin from high-temperature rapeseed meal.

The extraction of crude polysaccharides from cultivated Cardamine hupingshanensis was optimized by the combined use of one-factor-at-a-time method and response surface methodology. The results of one-factor-at-a-time experiments demonstrated hydrolysis with a mixture (2:1, m/m) of cellulase and pectinase at a dosage of 2% (m/m) at 60 ℃ and an initial pH of 4.0 for 90 min to be optimum for the extraction of polysaccharides. Furthermore, the extraction conditions optimized by response surface methodology were as follows: hydrolysis time, 91.8 min; hydrolysis temperature, 57.1 ℃; and intial pH, 4.17. Under these conditions, the predicted maximum yield of polysaccharides of 4.14% was obtained, and experiments gave an average value of 4.07%, indicating a relative error of about 1.62% the predicted and experimental values. The results of antioxidant assays showed that Cardamine hupingshanensis. polysaccharides possessed antioxidant activity better than that of VC. Our experimental results provide an experimental basis for studying the extraction and properties of Cardamine hupingshanensis polysaccharides.

Microcapsules of star anise oil with β-cyclodextrin were prepared by an ultrasonic method in attempt to improve the stability of star anise oil. An orthogonal array design was used to optimize the preparation conditions for increased embedding rate. Thermal release characteristics of the microcapsules were also investigated. The optimized conditions were obtained as follows: mass ratio of star anise oil to β-cyclodextrin, 1:6 (g/g); ultrasonication time, 40 min; temperature, 50 ℃ and ultrasonic power, 198 W. Under these conditions, the embedding rate, drug loading and average diameter of microcapsules were 94.21%, 6.93%, and 2.53 μm, respectively. Temperature and ultrasonic power had significant effects on the embedding rate. The successful formation of microcapsules of star anise oil in β-cyclodextrin was confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Results of thermal release characteristics demonstrated that only 4.60% of free star anise oil was retained after being heated at 200 ℃ for 120 min, while at the same time and temperature the retention rate of star anise oil in microcapsules was 78.38%, which was 17.04 times higher than that of free star anise oil, indicating improvement of the thermal stability of star anise oil by encapsulation. There was no significant difference in drug loading of the microcapsules prepared by the ultrasonic and saturated aqueous solution methods, while microcapsules prepared by the ultrasonic method had higher embedding rate and recovery with 7.80% and 4.98% improvement as compared to those prepared by the saturated aqueous solution method, respectively. Meanwhile, the microcapsules prepared by the ultrasonic method exhibited higher embedding rate (by 14.68%) and recovery (by 1.88%), and had higher drug loading (by 1.85%) than the kneading method. The ultrasonic method is an easy and feasible method for preparing star anise oil-β-cyclodextrin microcapsules with high quality. Encapsulation with β-cyclodextrin can provide an efficient way to increase the stability of star anise oil, thereby making it valuable for food preservation applications.

An indirect competitive chemiluminescene enzyme immunoassay (icCLEIA) for the rapid determination of isotenuazonic acid (ITeA) in fruit juice and tomato sauce was developed. The optimized experimental parameters were obtained as follows: the coating antigen concentration was 15.6 ng/mL, the antibody was diluted 96 000 folds, the buffer pH was 7.4, and the time of competition and anti-mouse IgG reaction were 40 and 50 min, respectively. The half maximal inhibitory concentration (IC50) of the proposed method was 2.13 ng/mL with limit of detection (LOD) of 0.10 ng/mL in the linear range from 0.50 to 9.12 ng/mL. The cross-reactivity with ITeA analogues was lower than 0.1%. The recoveries of ITeA from spiked samples ranged from 78.60% to 110.83%. The coefficient of variation was lower than 15%. This proposed icCLEIA provided an efficient method for rapid detection of ITeA in real samples.

In this work, we prepared graphene-based nanocomposite material by electrochemically depositing Prussian blue (PB) nanoparticles on the surface of graphene. Differential pulse voltammetry (DPV) was used to characterize the electrode and study the electrochemical behavior of nitrite ion on the modified electrode, and the electrode was used to detect nitrite in soy sauce. The results showed that the Prussian blue/graphene modified electrode had a good electrocatalytic activity to nitrite ion in 0.10 mol/L PBS buffer solution (pH 7.0). In the concentration range of 1 × 10-6-1 × 10-2 mol/L, the method presented a linear relationship. The limit of detection (LOD) was 3 × 10-8 mol/L at a signal-to-noise ratio of 3. The Prussian blue/graphene modified electrode showed a good stability, reproducibility and anti-interference ability.

The secondary structures of DNA aptamers A3 and G10 against tetrodotoxin were analyzed using DNA folding form online software. Further, digoxin labeled 5’ end sequences of four regions in each aptamer were separately synthesized. Tetrodotoxin was fixed by acrylic acid-epoxy ethane beads. The core regions of these aptamers were identified using digoxin-anti digoxin alkaline phosphatase system to detect the affinity of these various regions with tetrodotoxin, after determining the appropriate dilution ratio of anti-digoxin alkaline phosphatase. The results showed that the suitable working concentration of anti-digoxin alkaline phosphatase was 2 × 104 times dilution. The core region of aptamer A3 was A3-2 area which had the strongest affinity with tetrodotoxin among the four regions, including 47 nucleotides, while the core region of aptamer G10 was G10-4 area, including 56 nucleotides.

In this paper, a gas chromatograph-mass spectrometry (GC-MS) was used to qualitatively and quantitatively analyze the migration of dodecamethylcyclohexasiloxane (D6) from food contact silicone rubber into a liquid food stimulant. Meanwhile, the uncertainty of each variable was also analyzed. The most important factors that affect the results of the experiment were identified. GC-MS analysis indicated that the migration level of D6 was about 125.6 mg/kg from a baking mat made from food contact silicone rubber . We summed up five kinds of uncertainties throughout the experimental process. The highest uncertainty was resulted from the standard curve fitting of D6, which was up to 0.028 5. The combined standard uncertainty was 0.046 5 and the relative expanded uncertainty was 0.093. The amount of D6 analyzed by GC-MS varied in the range of ± 11.68 mg/kg taking the experimental uncertainties into consideration.

Using a Kjeldahl distillation apparatus, a method for the simultaneous determination of sodium (or calcium) propionate and sodium diacetate in oyster sauce, soy sauce and fish sauce by high performance liquid chromatography (HPLC) was established. The sodium (or calcium) propionate and sodium diacetate in samples were converted to the corresponding acids by treatment with phosphoric acid. After that, both acids were collected by steam distillation using a Kjeldahl apparatus. The pH of the distillates was then adjusted to around 3.0 by adding phosphoric acid. Finally, the analysis was completed with HPLC. A good linear relationship was gained in the range from 0.005 to 1.000 mg/mL with a correlation coefficient of 0.999 9. Recoveries of sodium (or calcium) propionate and sodium diacetate were 88.5%–108.3%% and 86.5%–108.7% with relative standard deviations (RSDs) of 2.13%–6.42% and 2.02%–6.37% (n = 6), respectively. This method is simple, rapid, easy to operate, stable, reliable, and suitable for the determination of sodium (or calcium) propionate and sodium diacetate in oyster sauce, soy sauce, fish sauce and other liquid seasonings.

Combination of 1H nuclear magnetic resonance (1H NMR) spectroscopy and orthogonal partial least squares (OPLS) was successfully employed to detect rape honey adulteration with high fructose syrups. Three hundred and three authentic and 180 adulterated honey samples were analyzed. Glucose, sucrose and 13 minor components in honey samples were detected and identified from their 1H NMR spectra. The OPLS model based on NMR data was applied to detect adulteration in honey falsified by intentional addition of different concentrations of high fructose syrups. A distinct discrimination between authentic and adulterated honey samples was achieved in OPLS score plot. Overall classification rates of training set and testing set were 98.40% and 98.24%, respectively. Hence, 1H NMR spectroscopy coupled with OPLS offered a rapid and accurate tool for honey adulteration detection. The method avoided the disadvantage of monocomponent analysis and provided a potential standard for quality control of honey.

To meet the demands of enterprises engaged in eel farming, processing and trading and law enforcements, a DNA barcoding method for the identification of three main farmed eel species, Anguilla rostrata, A. Anguilla and A. japonica, was developed. Universal 16S rRNA primers were designed and used to amplify partial 16S rRNA gene fragments of A. rostrata, A. Anguilla and A. japonica and their PCR products were sequenced to be 638, 638 and 640 bp in length, respectively. The specific DNA fragment (243 bp) was selected as standard DNA barcode with eel species specificity to identify eel species conveniently, and a forward primer (22 bp) and a reversed primer (23 bp) were designed and used to establish the PCRDNA barcoding method. The results of the application of the proposed method over the past three years showed that it is convenient, accurate, stable, and useful to identify the three eel species.

Raman spectral signals and hyperspectral images of benzoic acid were collected by a Raman hyperspectral imaging spectrometer, and the information was analyzed. The original Raman signal of benzoic acid was preprocessed by a wavelet de-noising method. Optimal parameters for wavelet de-noising that provided the best signal-to-noise ratio (32.092) was determined using an orthogonal array design were established as follows: sym2 wavelet function was used, decomposition level was 2, reset mode was ‘sln’, and threshold option scheme was ‘Rigrsure’. The de-noised Raman spectra were assigned and analyzed. The characteristic vibration modes of benzoic acid in different wavenumber ranges were obtained. The strong spectral peaks at 1 636, 1 603, 1 000, 793, 615 and 420 cm-1 could be used as the Raman characteristic frequency of benzoic acid. The Raman characteristic frequencies corresponding to the gray level image obtained from the hyperspectral image were analyzed. The brightness of the image was correlated with the peak intensity of the characteristic frequency, and both changed in the same order. These research results provide a basis for the detection and analysis of benzoic acid.

Objective: Comparative experiments were designed to address the influence of the presence of PCR inhibitor on the results of detection of norovirus GⅡ in frozen strawberry by real-time fluorescent RT-PCR (RT-qPCR), aiming to improve the detection sensitivity and accuracy. Methods: After pretreatment of fecal suspensions containing norovirus GⅡ and known negative strawberry samples, the virus was enriched for the extraction and purification of RNA and a control group and an experimental group were established. After removal of the PCR inhibitor, the samples were determined by RTqPCR. Results: The effect of the inhibitor tended to increase obviously with decreasing concentration gradient of virus, thus giving false negative results which were two orders of magnitude higher than the lowest level detected without the presence of the inhibitor. Better detection results were obtained by removal of the inhibitor compared with the control untreated group, as the virus concentration gradient decreased. The stable detection limit (LOD) for the experimental group without PCR inhibitor was 10-6 (Ct value < 40), and the minimum LOD were 10-7. Conclusion: The detection of norovirus in frozen strawberries by fluorescence quantitative RT-PCR could be improved in terms of sensitivity by removal of the inhibitor. In addition, the improved method was quick, easy to operate, economic and practical.

In this study, an anti-Listeria monocytogenes (Lm) single chain Fv antibody fragment was expressed in Escherichia coli. After purification, the antibody fragment was used to prepare a colloidal gold probe with colloidal gold as a tracer and the preparation process was optimized. The activity of the probe was determined by using an immunofiltration assay. The results showed that the colloidal gold probe exhibited high specificity. Positive samples could be directly identified by color development using the probe. The detection limit (LOD) for Lm was approximately 107 CFU/mL and the whole process of immunofiltration assay took approximately 10 min. The method developed is simple, rapid and accurate, and it could be applied for Lm detection in food samples.