In this paper, we studied the effects of the covalent interaction of soy protein isolate (SPI) and different concentrations of anthocyanin on protein structure under enzymatic and alkaline conditions. The covalent bonding rate and free sulfhydryl content were used to compare the degree of bonding between anthocyanin and SPI in different covalent cross-linking modes. Fourier transform infrared (FT-IR) spectrocopy, UV-Vis absorption spectroscopy and fluorescence spectroscopy were used to analyze the structure and conformation of the anthocyanin-SPI conjugates. The results showed that the bonding rate of anthocyanin-SPI conjugates increased and its content of free sulfhydryl decreased with the increase of anthocyanin concentration. The secondary structure of SPI was changed and the protein was unfolded after anthocyanin was linked covalently to it. And the microenvironment around the aromatic amino acid residues in the protein was also changed, thereby resulting in its conformational change. Furthermore, the anthocyanin-SPI conjugates had a higher bonding rate, a lower content of free sulfhydryl and more obvious structural and conformation changes in under enzymatic conditions than alkaline conditions. This indicated that anthocyanin has a stronger covalent binding ability to SPI under enzymatic conditions than alkaline conditions.

Nano-titanium dioxide (TiO2) solution was prepared from titanium tetraisopropoxide (TTIP) using the solgel method. The molar ratio between TTIP and water was optimized for smaller particle size. The nano-titanium dioxide was amorphous nanoparticles with high visible light utilization as characterized by Fourier transform infrared (FTIR) spectroscopy, UV spectroscopy, X-ray diffraction and particle size analysis. Furthermore polylactic acid/titanium dioxide (PLA/nano-TiO2) composite film was prepared by solution blending method, and the properties of composite films with different titanium dioxide contents were studied. The PLA/0.6% nano-TiO2 composite film had the maximum tensile strength of 63.3 MPa and the minimum elongation at break of 2.3%. The water resistance test indicated that the contact angle of the PLA/nano-composite film was lower than that of pure PLA film (72.83° versus 78.40°). In addition, the water absorption rate of was significantly higher than that of pure PLA film (1.48% versus 0.56%) and there was also an increase in water vapor permeability as compared to pure PLA film (4.66 × 10-8 (g·m)/(m2·h·Pa) versus 3.46 × 10-8 (g·m)/(m2·h·Pa)). Meanwhile, the composite film had a significant antibacterial effect under ultraviolet light.

The aim of this study was to address the effect of zingibain on the quality characteristics of dry-cured mutton ham with promoted degradation of myofibrillar protein through air-drying ripening. Fresh mutton hind legs with bone were used as experimental material and design 4 groups (for the experiment, one for the control group, and the other three for the experimental groups): control group without any treatment and three experimental groups with the addition of zingibain at concentrations of 0.01%, 0.03% and 0.05% (per 1 000 g sample), respectively. All samples were air dried in three stages; shear force, pH value, moisture content, water-holding capacity (WHC), thiobarbituric acid (TBA) value, total nitrogen (TN) content, non-protein nitrogen (NPN) content and proteolysis index (PI) were monitored during the drying process. The results showed that compared with the control group, after 30 d of maturation, shear force of the 0.05% zingibain group decreased by 28.17%, TN increased by 32%, NPN increased by 68%, PI increased by 29% (by 31% after 23 d of maturation). TBA increased by 11% within the allowable range. After 23 d of maturation, moisture content was 44.71%, approaching that (46.96%) of the control group after 30 d. pH value showed a gradual upward trend, while WHC exhibited the opposite trend. The addition of 0.05% zingibain was found to be optimal to significantly promote the degradation of protein and fat of dry-cured mutton ham, improve the tenderness and promote water loss, thus shortening the maturation cycle to 23 d.

After removal of starch by enzymatic treatment and deproteinization by the Sevag method, the crude polysaccharides extracted from chickpea seeds were fractionated by DEAE Cellublose-52 and Sephadex G-75 column chromatography into neutral and acidic polysaccharides. The structure, monosaccharide composition and morphology of the purified polysaccharides were obtained by UV absorption spectroscopy, gas chromatography (GC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that both polysaccharides exhibited no absorption peak at 260 or 280 nm, interpreting the absence of nucleic acids, proteins and peptides. Monosaccharide composition analysis showed that the neutral polysaccharide consisted of rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose at a molar ratio of 2.48:1:3.92:0.87:32.82:18.79:28.06, while the acidic polysaccharide was composed of rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose at a molar ratio of 2.22:1:3.92:2.10:5.92:15.99:8.57 (both with fucose as the standard). Their FTIR spectra indicated characteristic absorption peaks of polysaccharides. SEM indicated that the structure of the neutral polysaccharide was linear whereas the acidic polysaccharide was lamellar and curly.

Objective: To establish a real-time fluorescent quantitative PCR assay for the rapid and accurate detection of Lactobacillus acidophilus in probiotic beverages. Methods: Specific primers and probes were designed based on the conserved SPIDR region of L. acidophilus NCFM. The established method was assessed with respect to specificity, sensitivity and reproducibility, and it was applied to model and commercial samples. Results: The method had good specificity. The absolute sensitivity was 3 pg and the relative sensitivity was 103 CFU/mL. The repeatability expressed as relative standard deviation (RSD) was below 2.6%. At the same time, the amplification was not affected by the coexistence of pure genome or culture of Escherichia coli, indicating that the method has good anti-interference ability. This method showed good linearity (R2 = 0.987) and it was feasible to detect actual samples. Of 11 commercial samples, 6 contained L. acidophilus strains while the rest did not. L. acidophilus was detected in all samples labeled with L. acidophilus in the range of 5.83 × 102 to 3.68 × 104 CFU/mL. Conclusion: The real-time fluorescence quantitative PCR method can quickly and accurately detect L. acidophilus in probiotic beverages.

In order to understand the bacterial diversity and microbial safety of air-dried meat products, we sequenced the V4 region of the bacterial 16S rRNA gene from air-dried meat products by using Illumina MiSeq sequencing and evaluated the variability of the bacterial community structure and diversity. A total of 466 975 valid sequences and 975 operational taxonomic units (OTUs) were obtained for 14 samples. Air-dried naturally fermented meat products showed high microbial diversity. The analysis of bacterial community composition indicated that Firmicutes (39%), Proteobacteria (40%) and Bacteroidetes (14%) were the dominant bacteria in naturally fermented meat products, while Firmicutes (92%) were the dominant bacteria in samples fermented under controlled conditions. A total of 241 and 102 bacterial genera were identified in naturally and artificially fermented meat products, respectively, and the bacterial diversity was significantly different at the genera level (P < 0.05). The results from this research provide a theoretical basis for ensuring the quality and safety and optimizing the manufacturing process of air-dried meat products.

In order to study the mechanism of action of lipoxygenase (LOX) in lipid oxidation and flavor formation during the storage and processing of pork, the gene encoding the catalytic domain of porcine muscle 12-lipoxygenase (12-LOXcd) was obtained by sequence analysis and PCR amplification. The amplified gene was inserted into an inducible expression vector and expressed in E. coli by isopropyl β-D-1-thiogalactopyranoside (IPTG) induction. The recombinant protein was purified by consecutive Ni-NTA affinity chromatography and Superdex 200 gel filtration chromatography. Then the enzymatic properties of the purified 12-LOXcd were studied. The results showed that the recombinant vector pMBP-12- LOXcd successfully expressed porcine 12-LOXcd in the culture supernatant of E. coli. With linoleic acid as substrate, the purified enzyme had a specific activity of 2 826.7 U/mg, and the maximum enzymatic activity was observed at pH 6.0 and 30 ℃. The Km values obtained for linoleic acid (Km= 0.40 mmol/L), linolenic acid (Km=0.55 mmol/L) and arachidonic acid (Km= 4.15 mmol/L) revealed preferential use of linoleic acid as the substrate. Compared with soybean LOX, 12-LOXcd could keep active at a high concentration of NaCl (9%). 12-LOXcd exhibited a better thermal stability than soybean LOX, and it was fully deactivated at 60 ℃. Besides, 12-LOXcd showed better pH stability than soybean LOX, and it could retain part of its activity under alkaline conditions.

In this study, a recombinant strain expressing the tuf gene of Lactobacillus plantarum LR-1 was constructed by electrotransformation. The growth status, stress resistance, adhesion capacity and biofilm formation of the recombinant strain were evaluated, and the impact of tuf overexpression on the expression of other genes was examined. The results indicated that overexpression of tuf could improve the heat resistance, adhesion capacity and biofilm formation but did not significantly influence the growth of L. plantarum LR-1. Transcriptional analysis suggested that overexpression of tuf could upregulate the expression of genes involved in glycolysis pathway (fba, pgm, and gap), type II quorum sensing system (luxS), and ribose metabolism (rib). Collectively, this study provides useful information for the exploration of gene functions of Lactobacillus and offers a theoretical basis for the application of genetically engineered strains as probiotics or starter cultures.

For high cell density cultivation of Saccharomyces boulardii, we attempted to optimize medium composition and culture conditions. Plackett-Burman design was used to recognize the significant medium components. Subsequently, response surface methodology and artificial neural network (ANN) based on central composite design (CCD) were applied to model the relationship between dry biomass production and medium composition. The optimization of medium composition was carried out using genetic algorithm (GA). The results showed that the ANN model, more suitable for complex and nonlinear modeling, had better goodness of fit and prediction performance. The optimal medium composition was obtained as follows (g/L): glucose 40.52, peptone 36.8, corn steep liquor 17.32, KNO3 14, yeast nutrients 1.5, KH2PO4 0.6 and MgSO4 0.8 shake flask cultivation using the optimized medium gave a dry biomass yield of 8.21 g/L, which was 2.39 folds higher than that obtained from the original medium. Based on these results, we determined the optimal high cell density culture conditions for S. boulardii cultivated in a 1-L fermentor as follows: temperature 30 ℃, 10% inoculum, pH 5.0 and 40% dissolved oxygen. Furthermore, we scaled up the culture process in a 50-L fermentor with the addition of glucose and peptone to maintain the glucose concentration at 3 g/L and the ammonia nitrogen concentration at 0.06 g/L. The dry biomass yield of S. boulardii reached 51.21 g/L in the large scale experiment.

In this experiment, a mixture of grape pomace and molasses wastes from the brewing of fruit wine and fruit vinegar was fermented sequentially with yeast and acetic acid bacteria followed by lactic acid bacteria to produce a functional beverage with higher nutritional value through the transformation and utilization of substances during the fermentation process. Under the ultrasonic conditions of frequency 40 kHz, power 50 W and temperature 30 ℃, the influence of inoculum amount, initial pH value, sugar addition, and ultrasonic time on the activity of superoxide dismutase (SOD) and the number of viable bacteria were examined. The interaction among these variables was also investigated. Using response surface methodology based on a four-variable three-level experimental design, the optimum fermentation conditions were obtained as follows: initial pH value 5.0, sugar concentration 8%, inoculum amount 12%, and ultrasonic time 60 min. The optimized process was scaled up to a 5 L fermentor with improved feeding mode. At the end of the fermentation, the pH was 3.5, the titratable acidity was 2.89%, and the total phenolic content was 5.5 mg/mL. Functional components such as procyanidins (3.78 mg/mL) and SOD activity (988 U/mL) were detected in the fermented grape pomace. The 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging capacity (Trolox equivalent antioxidant capacity, TEAC) was determined as (44.5 ± 2.5) μg/g using a commercial total antioxidant capacity assay kit. The fermented grape pomace was rich in tartaric acid, malic acid, succinic acid, and citric acid. During the fermentation process, the unique aroma compounds alcohol, phenol, and quinones were emitted. The fermented grape pomace had a unique and dense aroma. The fermented supernatant was transparent and bright in color, with soft aroma and high sensory scores for taste and mouthfeeling.

The chitosanase-encoding gene of Bacillus amyloliquefaciens was optimized, synthesized and expressed in Pichia pastoris. The protein concentration of the expressed product was 0.23 mg/mL. The optimum pH and temperature of the enzyme were 5.0 and 45 ℃, respectively, and the specific activity reached 52.2 U/mL. The chitosanase was continuously thermo-stable at 50 ℃. Chitosan with low deacetylation was hydrolyzed by this enzyme and the composition and structure of the hydrolysate were analyzed. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) analysis showed that this hydrolysate contained chitooligosaccharides with degree of polymerization of 3–15 and different degrees of deacetylation. Nuclear magnetic resonance (NMR) results indicated that both the reducing and nonreducing ends of oligosaccharide fractions were mainly composed of glucosamine. In summary, we efficiently expressed chitosanase from B. amyloliquefaciens and prepared chitooligosaccharides with determined terminal structures, which will lay a theoretical foundation for the study of the structure-function relationship of chitooligosaccharides.

A strain of phage, designated vB_EcoS_IME18 (IME18), was isolated using Escherichia coli BL21 as the indicator bacterium. The morphology of the phage was observed by electron microscopy and the multiplicity of infection, one-step growth curve, lysis spectrum and in vitro bactericidal effect were determined; the genomic sequencing was performed by Illumina MiSeq sequencer and genomic features were analyzed by comparative genomics; the cause of phage resistance was analyzed by screening for phage resistant strains and confirmed by receptor gene silencing mutation, phage spotting, and phage adsorption assay. The results showed that phage IME18 had an icosahedral head and a non-contractile tail, belonging to the T1-like in the Tunavirinae subfamily in the family of Siphoviridae. The multiplicity of infection of phage IME18 was 0.01, latent period 5 min, burst period 50 min and burst size 223 PFU/cell; in vitro, phage IME18 could effectively kill BL21 in the log phase in 90 min. The total length of the genome was 50 354 bp with a G + C content of 45.6%. In addition, the proteins FhuA and TonB were proved to play a key role in the adsorption and infestation of phage IME18.

The fermentation conditions for the production of fermented apple pulp with a probiotic mixture were optimized and the change of volatile flavor components was investigated before and after fermentation. Lactobacillus plantarum 21805 and Lactobacillus acidophilus 20250 were selected for use as mixed starter culture. The effects of inoculum composition and amount, fermentation temperature, fermentation time, sterilization conditions, and apple pulp-to-water ratio on the quality of fermented apple pulp as evaluated by viable bacterial count and sensory score were studied. One-factor-at-atime and orthogonal array design methods were used to optimize the fermentation conditions. Head-space solid phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to analyze the volatile flavor components. The results showed that the optimum fermentation conditions were determined as follows: fermentation temperature 32 ℃, fermentation time 36 h, inoculum amount 2%, L. plantarum 21805 to L. acidophilus 20250 ratio 4:1, apple pulp to water ratio 2:1 (g/mL), and sterilization at 100 ℃ for 15 min. The flavor of the fermented apple pulp produced under the optimized was good, and the viable bacterial count reached 8.93 (lg (CFU/mL)). A total of 27 volatile flavors were detected in the fermented apple pulp, including 6 alcohols, 10 esters, 5 ketones, and 2 aldehydes. Apple pulp produced 15 new volatile flavors after fermentation. The relative contents of esters, alcohols and ketones increased after fermentation, while aldehydes showed a decreasing trend. Hierarchical cluster analysis (HCA) indicated that the volatile flavor composition of apple pulp was significantly changed after fermentation.

Electrophoretically pure inulinase for use in enzymatic production of high fructose corn syrup was isolated from the fermentation broth of Paecilomyces variotii XS27 by consecutive ammonium sulfate precipitation, dialysis, DEAESepharose Fast Flow chromatography and Sephacry S-100 gel filtration chromatography. The enzyme was purified 37.85 folds with a specific activity. Its relative molecular mass was estimated to be 62.0 kDa by SDS-PAGE, consisting of a single subunit. This inulinase was active over a broad pH range of 3.5–6.5 and the optimum pH was 4.0; it had a high activity at temperatures ranging from 40 ℃ to 65 ℃, and the optimum temperature was 60 ℃. Thin-layer chromatography (TLC) analysis showed that the final hydrolysis product of inulin by this enzyme was fructose. When inulin was used as a substrate, the Km and Vmax values were 5.93 μmol/L and 75.18 μmol/(L·min), respectively. The inulinase could be activated by Mg2+, Mn2+ and Ca2+, but inhibited by Ba2+, Ni2+ and Hg2+. The inulinase activity was inhibited by β-mercaptoethanol, DTT and EDTA but was not affected by surfactants (SDS, Tween 80 and Trition X100) or the organic solvent ethanol. In summary, the strong activity and stability of this inulinase against strong acid and high temperature as well as ethanol makes it suitable for the production of fructose and fructooligosaccharides.

This study aimed to evaluate the sensory quality of Merlot dry red wine produced by sequential inoculation of Lachancea thermotolerans and Schizosaccharomyces pombe instead of malolactic fermentation, in order to provide technical support for the application of non-Saccharomyces cerevisiae strains in quality improvement of dry red wine. In this work, Merlot grapes from Wuwei region of Gansu province were used for wine-making. Sequential inoculation of one of three strains of L. thermotolerans and one strain of S. pombe at intervals of 4 days and single inoculation of S. pombe were conducted as experimental treatments, and single inoculation of S. cerevisiae was taken as control. Yeast populations were monitored during the fermentation process, and the main physicochemical indexes, flavor components and sensory quality of wine were analyzed. The results showed that the treatment groups completed the alcoholic fermentation in 16 days. The viable cell population of S. pombe was stable until the alcoholic fermentation started. The population of L. thermotolerans reached the maximum on the 4th day, and it decreased significantly after the addition of S. pombe and disappeared completely from the 10th to 12th day. L-lactic acid concentrations in three sequential inoculation groups were not significantly different (2.46–2.86 g/L), but they were significantly higher than that in the control group (P < 0.05). Sequential inoculation reduced the volatile acidity by 0.11–0.16 g/L and increased the total acidity by 0.96–1.97 g/L. In addition, it increased the color aroma and decreased the hue. The production of esters, higher alcohols and acids in the sequential inoculation groups were decreased by 38.46%–49.34%, 13.36%–19.42%, and 46.84%–49.71%, respectively, compared with the control. However, the concentrations of terpenes, phenylethyl alcohol and damascene were increased and the aroma complexity was enhanced. Sensory analysis showed that the wines produced by sequential fermentation were more acidic than the control, while they had a better color appearance and stronger fruity and flowery aroma. These results indicated that sequential inoculation of L. thermotolerans and S. pombe is a potential alternative to malolactic fermentation and has a positive effect in improving the acidity and sensory quality of wine.

Adzuki bean (the seed of Vigna angularis) is a medicinal and edible legume. In order to better understand its nutritional value, phenolics from adzuki bean were extracted with 80% methanol and separated into free, glycoside and esterified forms. The phenolics were qualitatively and quantitatively analyzed. The results showed that the 80% methanol extract contained 3.44 mg/g phenolic acid and 2.50 mg/g flavonoid. The contents of the three forms of phenolics and their antioxidant activities varied significantly, among which the glycosidically bound fraction was found to be the richest in phenolic acid, up to 1.44 mg/g, whereas the free fraction was had the highest flavonoid content of 0.85 mg/g. The glycosidically bound fraction showed the strongest ferric reducing antioxidant power (FRAP) (15.76 mmol/g), while the ester bound fraction presented the strongest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulphonate sulfonic acid) (ABTS) radical cation scavenging abilities. The 80% methanol extract was analyzed by high performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-Q TOF-MS), and a total of 25 compounds including 3 organic acids, 6 phenolic acids and 16 flavonoids were identified. Quantitative analysis by HPLC-QQQ-MS showed that adzuki bean was rich in both rutin (327.40 μg/g) and catechin (210.70 μg/g).

A rapid method for the determination of the fatty acid content in mung bean was established based on gas chromatography (GC) with a dielectric barrier discharge ionization detector combined with micro sample pretreatment. The chromatographic column adopted in this method was HP-88 (100 m × 0.25 mm, 0.25 μm) (88% cyanopropyl/aryl polysiloxane stationary liquid), and the carrier gas was super pure helium (purity 99.999 9 %) with a flow rate of 1.5 mL/min. The column temperature was programmed. The inlet temperature was 250 ℃, septum purge flow rate 3 mL/min, and split ratio 1:60. The detector temperature was 280 ℃ and plasma discharge gas flow rate 40 mL/min. The sample injection volume was 1 μL. The target compounds in samples were extracted with isooctane and esterified with potassium hydroxide/ methanol before analysis. The results showed that the sensitivity for 8 fatty acids in mung bean samples ranged from 0.105 to 0.196 μg/mL, with relative standard deviations ranging from 1.04% to 1.35%. The established method required very small amounts of samples and chemical reagents, and the sample pretreatment was simple, rapid and reproducible, and thus this method could accurately measure the content of fatty acids in mung bean.

In order to provide a guidance for the overall evaluation and comprehensive utilization of ginseng, we compared the contents of ginsenosides, total sapoins, total polysaccharides, amino acids and protein in different parts of ginseng of different ages. Ultra-high performance liquid chromatography, the vanillin-sulfuric acid method, the phenol-sulfuric acid method, cation-exchange chromatography and Dumas combustion method were adopted to determine the contents of ginsenosides, total sapoins, total polysaccharides, 17 amino acids and crude protein. Among samples with different ages (3–6 years old), 6-year-old ginseng roots had the highest contents of ginsenosides, total sapoins, amino acids and crude protein, which were 30.94, 59.77, 96.53, and 170.11 mg/g, respectively. The content of total polysaccharides was the highest in 5-year-old ginseng roots (22.80 mg/g). The highest contents of polysaccharides, amino acids and crude protein of 25.94, 121.76, and 193.36 mg/g, respectively were found in rhizome among different medicinal parts of 5-year-old ginseng (rhizome, main root, lateral root and fibrous root), whereas fibrous root had the highest contents of ginsenosides and total sapoins (75.01 and 67.94 mg/g). Among different biological parts (root, stem, leaf and flower) of 5-year-old ginseng, leaves contained the highest total polysaccharides (35.09 mg/g), while flowers had the highest contents of ginsenosides, total sapoins, amino acids and crude protein, which were 105.99, 113.78, 137.53 and 255.05 mg/g, respectively. This study showed that among ginseng samples with different ages, 6-year-old ginseng roots had the highest content of saponins, and among different parts of 5-year-old ginseng, ginseng flowers have the highest content of saponins, with important biological activities. From a nutritional viewpoint, 6-year-old ginseng roots and 5-year-old ginseng flowers had higher levels of nutrients.

In order to optimize the indexes to evaluate the quality of Nostoc commune Vauch., 19 quality attributes including crude protein, total ash, phosphorus, total sugars, lipid classes, total lipids, water-soluble ash, water-insoluble ash, Ca, Na, K, Mg, Fe, Zn, Mn, Cu, Pb, Ni and Cd of N. commune Vauch. from 8 regions in Gansu province were analyzed by principal component analysis (PCA) and cluster analysis (CA). The results showed that the variation coefficients of total lipids, lipid classes, total sugars, Mn, Na and Zn were more than 30%, while those of other quality indexes were only about 3%. PCA showed that five principal components represented the 19 quality indicators N. commune Vauch., making 92.71% cumulative contribution to the total variance. According to the cluster analysis, six quality indexes including total sugar, water-soluble ash, lipids, Fe, Ca and P were sufficient to evaluate the quality of N. commune Vauch.. Among the 8 producing areas, N. commune Vauch. from Shandan had the best quality, followed by Tianzhu, and that from Ganzhou had the worst quality.

This study aimed to develop a rapid method for the quantification of nine polymethoxyflavones (PMFs) in the peels of fourteen citrus varieties. The citrus peel samples were compared for their PMFs contents in order to provide useful data for discovering PMFs-rich citrus peels with potent bioactivity for both medicinal and culinary purposes. Citrus peel extracts were prepared by ultrasonic-assisted extraction using ethanol as a solvent. A rapid and accurate high performance liquid chromatography (HPLC) method was used to measure the content of PMFs in citrus peels. The method showed good linearity repeatability and precision. The types and quantities of PMFs greatly varied with citrus variety. Pericarpium Citri Reticulatae from Citrus reticulata Kinokuni and the dried peels of Chongqing tangerine, Guangxi Emperor tangerine and Shatangju mandarin contained high contents of PMFs (more than 7 495.19 μg/g). Notably, total PMFs of Shatangju mandarin peel was as high as 10 412.18 μg/g. The HPLC method is simple and reliable and can provide a useful approach for study of PMFs in citrus peels.

Objective: To analyze the chemical compositions in different parts of the seeds of three Paeonia species for the purpose of exploring the prospects for the development and comprehensive utilization of Paeonia seeds. Methods: Thousand seed mass, shell and kernel percentage, seed oil meal content, seed oil content and fatty acid composition, and main chemical components of shell and seed oil meal were evaluated by high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). Results: Thousand seed mass for P. ostii, P. rockii, and P. lactiflora was 280.16, 263.64 and 187.68 g, respectively. For all three species, seed shell accounted for more than 31%, and seed oil meal represented over 37% of the mass of the seeds. Seed oil meal from all these species were rich in protein and monoterpenoid glycoside, and seed shell contained considerable amounts of oligostilbene compounds, cellulose, hemicellulose and lignin. Conclusion: The fatty acid constituents and the contents of main unsaturated fatty acids of P. lactiflora seed oil are similar to those of the seed oils of P. ostii and P. rockii. P. lactiflora seed oil has the potential to be developed as a high-quality edible oil. Seed shell and seed oil meal from all three Paeonia species contain a wide range of bioactive constituents and thus they are worthy of research and development. The development and utilization of seed meal and shell from P. ostii and P. rockii are of great significance for the healthy development of the oil peony industry.

Highly pure flax lignan was prepared from flaxseeds by n-hexane defatting, ethanol extraction, AB-8 macroporous resin separation and high-speed countercurrent chromatography (HSCCC) purification. Flax lignan was eluted with 80% ethanol from AB-8, and the HSCCC solvent system was composed of tert-butyl methyl ether, n-butanol, acetonitrile and water (1:3:1:5, V/V). The results showed that the impurity content was less than 0.5%, as detected by thin layer chromatography (TLC), high performance liquid chromatography (HPLC), HPLC-DAD-ELSD and HPLC-MS. The purity of flax lignan was between 99.3%–99.5%, as calculated by peak area normalization under various HPLC conditions. The structure was identified by ultraviolet spectroscopy (UV), infrared spectroscopy (IR), high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) and elemental analysis. The purification method proved to be simple and feasible, and the methods used for purity analysis were accurate and reliable. The flax lignin prepared in this study is enough pure to be used in method validation and quality control.

The volatile compounds of hops extracts were extracted by solid-phase microextraction (SPME) or solventassisted evaporative extraction (SAFE), and analyzed by gas chromatography-mass spectrometry (GC-MS). Then the aromaactive compounds were identified by gas chromatography-olfactory (GC-O) combined with aroma extraction dilution analysis (AEDA), and the key odorants were confirmed by odor activity values (OAV). Results showed that a total of 111 volatile compounds were identified by the two extraction methods combined with GC-MS. Twenty-seven aroma-active compounds were identified by GC-O/AEDA, with ethyl isobutyrate, diethyl succinate and 2-methyl butyric acid being the most abundant ones. Ethyl isobutyrate, 2-methyl butyric acid, ethyl isocaproate, ethyl octanoate, and ethyl caprate were confirmed as the key odorants of hops extracts based on flavor dilution (FD) factors and OAVs.

Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to analyze the aroma characteristics and volatile compounds of faint-scent chili powder from eight different varieties. One hundred and twelve volatile compounds were detected in all samples, and 63 of these were selected as characteristic aroma compounds and were investigated by partial least-squares regression analysis. The results showed that the sensory attributes of faint-scent paprika were mainly related to cooked vegetable-like, grassy and fresh notes. The cooked vegetable-like note was significantly and positively correlated with β-myrcene, (E)-2-pentenol, (E)-2-hexenal, octanal, 4-octen-3-one and 2-pentylfuran, and was positively but not significantly correlated with most volatile compounds, while it was significantly and negatively correlated with hexanal, (E,E)-2,4-decadienal and 2,3-butanedione. The grassy note was significantly and positively correlated with cedarone, (Z)-3-hexenol, hexanal, (E)-2-heptenal and isobutyric acid and significantly but negatively correlated with 4-methyl-1-pentanol, hexanol, (E)-2-octenal and hexyl 2-methylbutyrate. The fresh note was significantly and positively correlated with 3-carene, limonene, (E,E)-2,4-decadienal, (E)-2-nonenal, 2-methylpropionic acid and 2-isobutyl-3-methoxypyrazine, while it was significantly and negatively correlated with hexanol, nonanal and hexyl 2-methylbutanoate. Therefore, the aroma characteristics and characteristic volatile components of faint-scent chili powder were preliminarily determined, which can provide a scientific basis for the quality control of faint-scent chili powder and the development of flavored products.

Ovalipes punctatus meat was used to investigate the effects of electron beam (EB) irradiation on its nutritional and taste components in order to provide a basis for scientific application of EB irradiation. The results showed that the contents of total amino acids and non-essential amino acids in crab meat irradiated with doses equal to or greater than 7 kGy decreased obviously. Irradiation did not change the first or second limiting amino acids of crab meat. The ratio of essential amino acids to total amino acids (EAA/TAA) and the ratio of essential amino acids to non-essential amino acids (EAA/NEAA) in both unirradiated and irradiated groups exceeded 40% and 60%, respectively, indicating good protein quality. The results of fatty acid composition showed that EB irradiation had no significant effect on the content of saturated or unsaturated fatty acids. With the increase of irradiation dose, the total amount of free amino acids in crab meat showed a downward trend, whereas the contents of umami and sweet-umami free amino acid increased, which indicates that the appropriate irradiation dose could improve the taste of amino acids in crab meat. The main flavor nucleotide in crab meat was IMP. After EB irradiation, the contents of AMP and IMP while GMP content decreased thereby enhancing the umami taste of crab meat. Based on the synergistic effects of umami amino acids and flavor nucleotides, equivalent umami concentration (EUC) value in each irradiation group was higher than in the control group. The 1 kGy irradiation group had the highest EUC value of 17.92%. Collectively, EB irradiation at doses of 1–9 kGy had no obvious negative effect on the nutrition or taste of crab meat and it could be suitable for the pretreatment of crab meat.

A new method based on high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-DAD-Q-TOF-MS) was developed for the rapid screening for and identification of antioxidant compounds in burdock root extract. The sample was divided into two parts by the first HPLC; one part flowed through the second HPLC with the 1,1-diphenyl-2-picrylhydrazyl (DPPH) solution for on-line screening for the antioxidants; the other was flowed through DAD-Q-TOF-MS for on-line rapid identification. Caffeic acid and its 18 derivatives were identified by their relative molecular masses as determined by high resolution MS in the negative ion mode and by comparison of their UV absorption characteristics with literature data and reference standards. Overall, this method is a powerful tool for rapid screening for and identification of antioxidant compounds from complicated systems such as foods and Chinese traditional medicinal materials.

High performance liquid chromatography (HPLC) fingerprints of seven grades of Xinyang Maojian tea were established using 41 samples. Based on 15 characteristic flavor components found in all samples, discriminant analysis (DA) was used to differentiate between grades of Xinyang Maojiao tea with nearly 100% accuracy. All seven fingerprint similarity calculation methods employed could reflect the difference between grades of tea, while the new improved extent similarity method was proved to be the best. The results of similarity calculation in grading of tea were consistent with the actual grades and allowed quantification of the difference between grades of tea.

Objective: To establish a high performance liquid chromatography (HPLC) method for the determination of five phenylpropanoids in Eucommia ulmoides Oliv. from different ages and parts. Methods: The samples were separated on HiQ Sil C18 column (250 mm × 4.6 mm, 5 μm) using a mobile phase consisting of 0.2% formic acid (A) and acetonitrile (B) with gradient elution (4%–12% B between 0 and 12 min; 12%–14% B between 12 and 35 min) at a flow rate of 1.0 mL/min and detected at 277 nm, and the column temperature was kept at 25 ℃. The injection volume was 5 μL. Results: The method had good linearity in the ranges of 0.04–1 mg/mL (R2 = 0.999 7) for chlorogenic acid, 0.001 6–0.029 mg/mL (R2 = 0.994 0) for caffeic acid, 0.001 6–0.04 mg/mL (R2 = 0.998 9) for protocatechuic acid, 0.008–0.04 mg/mL (R2 = 0.998 7) for coniferin, and 0.013–0.029 mg/mL (R2 = 0.998 6) for syringoside. The average recoveries of spiked samples ranged from 94.05%–107.02%, with relative standard deviations (RSDs) in the range of 0.95%–4.11%. Conclusion: This method met the requirements of methodological validation, and it could be used for the determination of chlorogenic acid, caffeic acid, protocatechuic acid, coniferin, and syringoside in different parts of E. ulmoides Oliv. The total content of five phenylpropanoid compounds in leaves was higher than in barks, suggesting that E. ulmoides Oliv. leaves can be considered an alternative to its barks in functional foods.

In order to explore the difference in the volatile components of different varieties of roasted, gas chromatographymass spectrometry (GC-MS) was used to separate and identify the volatile components of 10 different varieties of roasted hulless barley. The influence of roasting on the flavor of the variety Kunlun 15 was examined, and then different varieties of roasted hulless barley were classified by using aroma analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results showed that a total of 140 aroma components were detected in all samples, including 32 heterocyclics, 26 esters, 21 alcohols, 19 aldehydes, 16 ketones, 13 acids, 9 hydrocarbons and 4 nitriles. After roasting, the number of aroma components of Kunlun 15 increased from 48 to 60, and the newly formed aroma components were mostly pyrazines. The most abundant aroma substances were geterocycles (38.59%–64.42%) in all hulless barley varieties, followed by esters (1.85%–35.98%) and aldehydes (7.56%–21.79%). Aroma analysis showed that the flavor of roasted hullness barley was dominated by cocoa-like, roasted and nutty aromas, while raw hullness barley from Kunlun 15 had a strong fruity and sweet aroma. The aroma of roasted hulless barley was related to variety and chemical composition, and Dulihuang might be the most suitable variety for processing of roasted barley. Cluster analysis showed that the samples could be classified into two categories. Kunlun 15 and Zangqing 320 were plotted as one class due to their high similarity. The other varieties could be classified into the other group when the euclidean distance was 9.

In this research, the phenolic composition of fresh fruit of wild black wolfberry from Ningxia autonomous region was qualitatively and quantitatively analyzed by high-performance liquid chromatography/triple-quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS). Our data showed that black wolfberries were rich in phenolic compounds including 20 anthocyanins and 16 non-anthocyanin phenolics identified. Among them, the main anthocyanins were petunidin-3,5- O-diglucoside and some 6-O-coumaroyl acylated 3-O-glucosidic anthocyanins, and the main non-anthocyanin phenolics were a series of hydroxy cinnamic acids such as chlorogentic acid, which were quite different from those present in some other dark-colored fruits rich in phenolics such as grapes and blueberries. The composition of anthocyanins was typically species specific. The present study provides a theoretical basis for the consumption of fresh black wolfberries as well as the development of black wolfberry products.

The difference in the chemical composition of quinoa samples from different regions of China and abroad was studied. Fatty acids and non-polar small molecules were analyzed by gas chromatography-mass spectrometry (GC-MS), and the correlation between geographical origin and composition was evaluated by principal component analysis (PCA) and orthogonal partial least squares (OPLS) analysis. The results showed that fatty acid composition was similar in quinoa samples from different regions, with unsaturated fatty acid being dominant and accounting for more than 80% of total fatty acids. However, there were significant differences in fatty acid contents. Linoleic acid was the most abundant fatty acid, which represented about 50% of total fatty acids in all samples. The contents of non-polar small molecules were significantly correlated with geographical origin, and D-glucose, sucrose, maltose, and ribitol were different among samples from different regions.

The aroma of sweet flavorings derived from reaction of L-arabinose is soft and rich. The use of these flavorings in foods gives a natural and full-bodied aroma. In this research, in order to generate sweet flavorings, L-arabinose was reacted separately with alanine, glycine, threonine, and serine. The volatile flavor compounds of sweet flavorings were analyzed by solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). The results showed that the reaction of L-arabinose with each of the amino acids produced 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine, with strong roasted and cocoa aromas. The reaction of L-arabinose with threonine produced menthol, a green aroma compound. The reaction of L-arabinose with alanine produced the floral and fruity aroma compound 5-indanol.

Storage time and conditions are the important factors affecting the aging of raw Pu-erh tea. Tea samples produced in the years 2008, 2010, 2012, 2014 and 2016 and stored in Xinjiang and Guangdong were detected for their characteristic components by high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS) and an automatic amino acid analyzer. Orthogonal partial least squares-discriminant analysis (OPLS-DA) was employed for differential clustering of Pu-erh tea from these two different storage areas. Variable importance in projection (VIP) and S-plot were applied to find out the important components for classification. The results showed that the aging rate of raw Pu-erh tea was faster when stored in Guangdong than in Xinjiang, but its quality was inferior to that in Xinjiang. The contents of all main chemical components except for gallic acid in Guangdong samples were lower than those in Xinjiang samples, and the degradation rate was also faster than that in Xinjiang samples. Beta-damascenone, 2,6,6-trimethyl-1-cyclohexene- 1-carboxyaldehyde, alpha-pineol, carbamate, palmitoleic acid, beta-cyclocitral, linolenic acid, neroli, benzaldehyde and linoleic acid were the important differential volatile components. The volatile components changed sharply in Guangdong, while they changed slowly in Xinjiang. This study provides a theoretical basis for the scientific storage of tea, and also helps to guide the market for scientific consumption.

The enzymatic hydrolysis of Qula casein with either alkaline protease or trypsin was optimized based on degree of hydrolysis (DH). The effects of hydrolysis time, temperature, pH, substrate concentration and enzyme concentration on DH were investigated by one-factor-at-a-time method. Subsequently, response surface methodology was used to optimize four significant variables. The resulting hydrolysates were comparatively evaluated for their 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion and hydroxyl radical scavenging capacity, Fe2+ and Cu2+ chelating ability, and reducing power. The results showed that the optimal hydrolysis time, temperature, substrate concentration, pH and enzyme concentration were 3.8 h, 49.8 ℃, 60 g/L, 8.5 and 140 U/g for alkaline protease; and 2.5 h, 47.8 ℃, 35 g/L, 7.5 and 2 900 U/g for trypsin, yielding the maximum DH value of 24.25% and 13.57%, respectively. The alkaline protease hydrolysate had significantly lower superoxide anion radical scavenging capacity and Fe2+ chelating ability (P < 0.01) but higher hydroxyl radical scavenging capacity than the trypsin hydrolysate (P > 0.05). For both hydrolysates, Cu2+ chelating ability, DPPH radical scavenging capacity and reducing power increased with increasing concentration from 1 to 5 mg/mL, and Cu2+ chelating ability was lower than Fe2+ chelating ability (P > 0.05). Significant difference (P < 0.01) was found as far as DPPH radical scavenging capacity and reducing power were concerned. In summary, the two proteases had different impacts on the antioxidant activity of hydrolysates and the alkaline protease hydrolysate better antioxidant properties.

Based on mechanical properties of films including tensile strength and elongation at break, the preparation of chitosan-hexahydro-β-acids edible antibacterial films was optimize using one-factor-at-a-time method and orthogonal array design. The release behavior of hexahydro-β-acids from films was also investigated in ethanol aqueous solutions at concentrations of 95%, 75%, and 55% (V/V), respectively. Results showed that chitosan concentration exhibited the greatest effect on the mechanical properties of films, followed by interaction between chitosan and glycerol concentration. Drying temperature had the weakest effect. The optimized conditions were determined as follows: chitosan concentration 1.75 g/100 mL, drying temperature 40 ℃, and glycerol concentration 1.4%. The chitosan-hexahydro hexahydro-β-acids edible bacterial films prepared under these conditions showed the best mechanical properties with tensile strength and elongation at break of up to 29.26 MPa and 81.29%, respectively. The release of hexahydro-β-acids was gradually increased with increasing time and temperature, and stopped when the equilibrium was reached. According to the Peppas and Peleg equations, the release of hexahydro-β-acids in 95% ethanol followed Fick’s low of diffusion, but in 75% and 55% ethanol accorded with Peleg’s equation. The diffusion coefficient increased with rising temperature, and the most obvious release was found in 55% ethanol, which indicated that the water content and temperature in the release solvent were the key factors affecting the diffusion of the active ingredients.

In this study, cold-pressed hemp seed cake was pulverized and hydrolyzed sequentially by Viscozyme L and alkaline protease Protex 6L, followed by low-temperature re-pressing. Cold-pressed hemp seed cake, produced at 50 ℃ and 3.5 MPa, was found to still contain 21.6% oil. It was pulverized to pass through a 60 mesh sieve and hydrolyzed with 3.0% (m/m) Viscozyme L for 4.5 h. A maximum oil yield of 65.0% was obtained after 2.8 h of hydrolysis with 1.1% Protex 6L at pH 10 and pressing at 52 ℃ and 3.5 MPa, as determined by response surface methodology. The secondary hemp oils obtained with and without enzymatic hydrolysis were compared for their physicochemical properties and contents of cannabinoids and tocopherols. Our results showed that enzyme-assisted low-temperature re-pressing had the advantages of high oil yield, stable physical and chemical properties, and enhanced migration of functional ingredients to the oil phase. This method provides a new theoretical basis and approach for the industrial production of hemp seed oil.

The enzymatic extraction of sulforaphane from broccoli stems and leaves was optimized by one-factor-at-a-time method and response surface methodology. Scale-up experiments were carried out under optimized conditions, and the crude extract was purified by preparative high performance liquid chromatography (HPLC) and identified by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The results showed that the optimal extrac tion conditions were determined as follows: pH 5.0, temperature 35 ℃ and time 67 min. Under these conditions, the maximum yield of sulforaphane of 151.39 μg/g (on a dry matter basis) was obtained, which agreed with the predicted value (156.33 μg/g). The yield of purified sulforaphane was 28.62 mg from 200 g of broccoli powder, with a 94.52% recovery and 80.74% purity. The tandem mass spectrum and fragment ion information confirmed the substance as sulforaphane.

Objective: In order to develop a highly sensitive and green immunoassay for deoxynivalenol (DON) anti-idiotypic nanobody, obtained in our previous study, was used as an alternative to enzyme-labeled antigen in a fluorescence real-time immuno-PCR system. Methods: The phage displayed nanobody (P-28), which specifically binds with anti-DON antibody, was used as a competitive antigen and the DNA encoding P-28 Nanobody was used as a target for primer design. Important experimental parameters including annealing temperature, anti-DON antibody concentration and P-28 amount were optimized. Finally, we proposed a fluorescence real-time immuno-PCR method based on indirect competition for the detection of DON. Results: The linear range of the immuno-fluorescence PCR method was 0.1–1 000 ng/mL with an IC50 of (3.96 ± 2.21) ng/mL, and the limit of detection (LOD) was 0.048 ng/mL. This method showed no crossreaction with other mycotoxins. Conclusion: This method avoids the defects of environmental pollution and operational toxicity caused by using traditional synthetic enzyme-labelled antigen and has good specificity and sensitivity.

The traditional method for detecting the total viable count of bacteria in liquid egg is laborious and time consuming. To overcome these drawbacks, the present study was undertaken to develop a fast method for predicting the total viable count of bacteria in liquid egg by using hyperspectral image technology (400–1 000 nm). The hyperspectral images of artificially inoculated liquid egg samples with different contamination levels of Pseudomonas aeruginosa were acquired. Then successive projections algorithm (SPA) was used to extract feature wavelengths, and partial least squares (PLS) and support vector machine (SVM) models were developed based on the feature wavelengths and the full spectra, respectively. Finally, the performance of the multivariate prediction models were compared and analyzed. The result showed that the Autoscale method was the best pretreatment method and the SVM model was the best prediction model for the total viable count of bacteria in liquid egg. The correlation coefficient of prediction (RP) and the root mean square error of prediction (RMSEP) was 0.81 and 0.63 (lg(CFU/g)) for egg white, 0.82 and 0.47 (lg(CFU/g)) for egg yolk, 0.75 and 0.75 (lg(CFU/g)) for liquid whole egg, respectively. Overall, hyperspectral imaging combined with chemometrics enables quantitative prediction of the degree of microbial contamination in liquid egg.

In this study, sequential window acquisition of all theoretical fragment ions (SWATH)-based proteomics was established for relative quantitation of proteins by ultra-high performance liquid chromatography coupled to quadrupole time of flight (UPLC-Q TOF) mass spectrometry. Chemometric tools were used to discover protein biomarkers for discrimination of wild and farmed Fenneropenaeus chinensis. The result showed that wild and farmed F. chinensis could be well discriminated through the protein biomarkers. This study may provide technical support for discrimination of wild and farmed F. chinensis.

This study aimed to establish a new method for quick detection of camellia oil purity. Adulterated camellia oil samples were detected by gas chromatography-ion mobility spectrometry (GC-IMS) and the two-dimensional spectral data obtained were analyzed by multi-way principal component analysis (MPCA) and partial least squares (PLS) regression. Mixtures of camellia oil with three other vegetable oils at different concentrations respectively were analyzed by GC-IMS. MPCA was used to reduce the dimensionality of the data and extract a score matrix from the three-dimensional matrix for principal component analysis (PCA), and quantitative predictive models for adulterated oils were established by PLS analysis of the score matrix. The experimental results showed that pure and adulterated samples were clearly distinguished in the PCA plots with MPCA processing and that each adulteration ratio exhibited an obvious region in the plots. PLS regression analysis of the scores matrix extracted by MPCA enabled accurate quantitative analysis of camellia oil adulteration levels. The presented method proved to be a fast, accurate and non-destructive method for the detection of camellia oil adulteration. This method can also be applied to data analysis in other combined instruments, and has a great potential for applications in the quality control and evaluation of edible oils.

Acetylcholinesterase (AChE) liposomes bioreactor (ALB), prepared by encapsulating the enzyme AChE into L-α- phosphatidylcholine liposomes, was spherical in shape. A novel AChE biosensor based on multilayer films containing SiO2, chitosan (CS) and ALB was developed. The results showed that ALB had a mean diameter of (7.26 ± 0.75) μm. The biosensor based on six bilayers of multilayer films was the best. The properties of the biosensor were evaluated by electrochemical measurements. Based on the inhibition of organophosphate pesticides on the AChE activity, by using dichlorvos as a model organophosphorus compound, we observed that the inhibition of dichlorvos was proportional to its concentration within the range from 0.25 to 1.75 μmol/L and from 2.00 to 10.00 μmol/L, and the corresponding equations were I = 28.58C + 5.35 and I = 2.38C + 51.25, with a detection limit (LOD) of (0.72 ± 0.065) μg/L estimated at a signal-to-noise ratio of 3. The fabrication of the biosensor was simple, with fast response and acceptable selectivity.

Both qualitative and quantitative detection models were established for thawed beef patties (with different proportions of fat) adulterated with pork using near infrared spectroscopy combined with chemometrics. The results showed that for the qualitative determination of samples with different proportions of adulteration, partial least squares discriminant analysis was better than principal component analysis (PCA) combined with support vector machine method, and the discriminant analysis gave an accuracy of 100% for both calibration and validation sets. Partial least squares regression method was applied to quantitative detection of thawed beef patties with different proportions of adulteration. The correlation coefficient of calibration (Rc) and prediction (Rp) and the root mean square error of prediction (RMSECP) of the model were 0.968 9, 0.861 1 and 7.221%, respectively. Therefore, near infrared spectroscopy (NIS) can be applied to both qualitative and quantitative detection of thawed beef patties with different proportions of fat adulterated with different amounts of pork.

This study was undertaken to construct multiplex armored RNA (AR-MulV) containing the target RNAs of norovirus (NoV), hepatitis A virus (HAV), rotavirus (RV), and astrovirus (AstV) based on Qβ bacteriophage for foodborne virus detection. The armored RNA was purified and quantified as well. The recombinant plasmid was efficiently expressed in Escherichia coli and the molecular mass of the product was estimated to be 14.1 kDa on SDS-PAGE. The purified AR-MulV was found to be free of any unwanted protein or residual plasmid and it was observed as virus like particles with good structural and morphological integrity 25 nm in diameter under electron microscopy. The target RNAs of NoV (GI and GII), HAV, RV and AstV in the AR-MulV were quantified as (1.24 ± 0.2) × 107, (2.54 ± 0.6) × 107, (2.24 ± 0.3) × 107, (2.96 ± 0.5) × 107 and (3.19 ± 0.4) × 107 copies/μL respectively. The multiplex armored RNA based on Qβ bacteriophage could serve as a good positive control material candidate for use in the simultaneous detection of 4 foodborne viruses. Moreover, this study provides a new strategy for preparing positive reference material for use in the development of a multiplex real-time RT-PCR assay for foodborne viruses.

In this study, a specialized portable low-cost visible and near-infrared (Vis-NIR) instrument for the evaluation of grape quality was designed to meet the need for fast and non-destructive detection in the grape industry. A holographic concave diffractive grating combined with a charge-coupled device was used as the core component of this system to obtain diffuse reflectance spectral data of grape samples in the wavelength range between 400 and 1 100 nm, and the combined application of a halogen light source with low-OH Y-shaped quartz optical fiber as a reliable optical transmission medium was proposed to provide a stable Vis-NIR light source. In order to meet the requirements of different varieties with fruits of different sizes, an adjustable sample cuvette with both internal and external threads was designed. The software, written in C# based on windows operating system, was stable and could facilitate model updating. Two Vitis vinifera cultivars, Manicure Finger and Ugni Blanc, were detected using this instrument. CIE L*, a* and b* values, total solid soluble content (SSC) and total phenolic (TP) content were taken into consideration in the development of predictive models using least squares support vector machine (LS-SVM). The results showed that for both cultivars a* value, SSC and TP could be well predicted by the proposed models with a coefficient of determination for calibration (Rc 2 ) of 0.91, 0.94 and 0.90, respectively. In the external validation using 70 unknown samples, the root mean square error of prediction (RMSEP) of a* value, SSC and TP were 3.15, 1.39 °Brix and 0.24 g/kg for Manicure Finger; and 0.78, 1.56 °Brix and 0.22 g/kg for Ugni Blanc, respectively. This study has confirmed the feasibility of this Vis-NIR instrument for grape quality detection and can provide a technical basis for developing specialized Vis-NIR instruments to detect fruit and vegetable quality.

A method was developed for the simultaneous determination of 11 mycotoxins in minor food legumes, including aflatoxins B1, B2, G1, G2, ochratoxins A, T-2, deoxynivalenol, fumonisins B1, B2 and B3 and zearalenone. Sample extraction and purification conditions were optimized. Samples were extracted with methanol-water (70:30, V/V) and acetonitrilewater (84:16, V/V) consecutively (the extraction process took 3 min), and then the extract was purified using C18 sorbent. The results showed that the calibration curves for all mycotoxins were linear with correlation coefficients above 0.999. The average recoveries of spiked samples ranged from 70.0% to 108%, with relative standard deviations (RSDs) from 1.3% to 8.6%. The method was simple and rapid with high sensitivity and repeatability, and it was suitable for simultaneous detection of 11 mycotoxins in minor food legumes.

In this study, a quantitative duplex digital PCR method was established for insect-resistant genetically modified rice event KMD by using the sucrose phosphate synthase gene of rice and the KMD event-specific gene as the endogenous and exogenous genes, respectively. The optimal concentration of rice genomic DNA in the quantitative system was in the range of 10 pg to 13 ng, and the degree of template fracture and the annealing temperature of PCR amplification had little effect on the quantitative results. The absolute sensitivity and relative sensitivity of digital PCR were 1 copies/μL and 0.1%, respectively, while the relative sensitivity of the real-time PCR method established with the same pairs of primers and probes was only 1%. For standardization of the application of this method, an intra-laboratory repeatability validation was performed on two chip-based digital PCR platforms to verify the quantitative detection method established on the droplet digital PCR platform, and the results showed that the precision and accuracy of the assay still met the requirements for quantitative analysis. The method was proved to highly applicable the standardized quantitative analysis of GM rice KMD.

The present study aimed to develop a novel method to identify Shanxi aged vinegar (SAV) by a combination of aroma fingerprinting, hierarchical cluster analysis (HCA) and flavor characteristics analysis. For this purpose, representative samples of SAV from 4 different manufacturers were used to establish an aroma fingerprint based on the aroma compounds common to these samples as determined by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that a total of 44 aroma compounds were found to be common to all SAV samples, including three main flavor types, acidic flavor (AF), dense flavor (DF) and refreshing flavor (RF). SAV had stronger AF and DF but weaker RF compared with other vinegars; the characteristic parameter Ps resulting from acetic acid content (A), dense flavor content (D) and refreshing flavor content (F) gave a more clear discrimination between SAV and other vinegars. In conclusion, HCA based on the aroma fingerprint of SAV is a robust tool for fuzzy identification of SAV. Moreover, the application of Ps can improve the accuracy of identifying SAV. HCA and Ps are complementary in identification of SAV.

This study aimed to establish a method for identifying adulterated cod liver oils by analyzing the percentages of fatty acids in pure cod liver oil and the change of the characteristic fatty acids. The fatty acids in samples were methyl esterified by precolumn derivatization before being analyzed by gas chromatography (GC), and the percentage of each fatty acid in the total fatty acids was calculated by peak area normalization method. According to the results of multiplesample analysis, the ratio of docosahexaenoic acid (DHA) to eicosapentaenoic acid (EPA) and the content of cetoleic acid were identified as the characteristic indexes for authentication, which were in the range from 1.40 to 1.68 and from 7.0% to 9.4% in pure cod liver oil. Adulteration of fish oil in cod liver oil samples could be determined when the characteristic indexes exceeded the ranges. A quantitative model for the level of adulteration of cod liver oil was established based on these characteristic indexes, and discriminant analysis was performed for different levels of adulteration. Out of 46 batches of samples examined, 2 were suspected to be adulterated with fish oil at about 25%. This method is accurate, reliable, simple and feasible and can be used for the rapid identification of adulterated cod liver oil.