In this paper we studied the covalent cross-linking mechanism of soy protein isolate (SPI) with different concentrations of anthocyanins in the presence of either laccase or alkali, and we also investigated the effect of this crosslinking on protein structure and absorption. The degree of cross-linking as well as the resulting conformational change of SPI was evaluated by three-dimensional fluorescence spectroscopy. The gastrointestinal digestion and nutritional absorption of anthocyanins-SPI conjugates were simulated using pepsin, pancreatin, and Caco-2 cells. And we also evaluated the degree of hydrolysis, antioxidant capacity, and the permeability of peptides during the digestion process. The results showed that the fluorescence intensity of SPI was reduced, and polypeptide chain unfolding and consequently tertiary structure changes occurred after cross-linking with anthocyanins. At the same time, the cross-linking increased the digestibility and antioxidant capacity of the protein and this effect was positively correlated with anthocyanin concentration, especially in the presence of laccase. It is worth noting that anthocyanins had an inhibitory effect on the permeability of peptides in a concentrationdependent fashion, which was stronger in the presence of laccase than in the presence of alkali at the same concentration of anthocyanins.

In this work, the application of soy protein isolate (SPI)-steviol glycosides (STE) mixtures as natural stabilizers to prepare nanoemulsions was evaluated. The effects of stabilizer composition, homogenization parameters and oil phase concentration on the formation of nanoemulsions were investigated. The storage stability and microstructure of nanoemulsions were characterized. The results showed that when the oil phase concentration was 10%, the particle size of emulsion prepared with pure SPI (1%) was larger (d43 = 0.548 μm) while the emulsion stability was poorer. When 0.25%–1% STE was added, the particle size distribution of emulsions stabilized by SPI-STE mixtures was more uniform and the particle size was smaller. The droplet size of the emulsions with 0.5% or 1% STE was smaller than 200 nm, and these nanoemulsions showed good storage stability for 30 days. The addition of 2% STE resulted in the complete replacement of proteins on the surface of droplets, thereby weakening the long-term stability of emulsions. The increase in homogenization pressure, number of homogenization cycles and STE concentration could reduce the particle size of emulsions, whereas the increased oil phase concentration had the opposite effect. Further, the nanoemulsions were freeze-dried, yielding a well-structured oil powder with high oil content. Compared to the pure SPI-stabilized oil powder, the structure of oil powders prepared with SPI-STE mixtures was more compact, and the powder surface was less viscous.

In order to study the effect of inulin on the cryoprotection of myofibrillar protein from silver carp surimi during frozen storage, salt extractable protein content, Ca2+-ATPase activity, total sulfhydryl content, surface-reactive sulfhydryl content and surface hydrophobicity were analyzed. The results showed that inulin could inhibit the denaturation of myofibrillar protein as evidenced by the smaller decrease in salt extractable protein content, Ca2+-ATPase activity, total sulfhydryl content and surface-reactive sulfhydryl content as well as the smaller increase in surface hydrophobicity after 5 weeks of storage at -18 ℃. The cryoprotective effect of 1.5% inulin was better than that of any other experimental groups and close to commercial cryoprotectant. This study has provided a theoretical basis for the development of low-calorie cryoprotectant.

In the present study, protein isolates were recovered from the muscle of blue round scads (Decapterus maruadsi) using acidic- or alkaline-aided isoelectric solubilization/precipitation. The physiochemical, gelation, and digestive properties of acid (API)- and alkali (KPI)-recovered proteins were investigated, as compared to total proteins (TP) and myofibrillar proteins (MP). D. maruadsi muscle proteins were even more soluble in alkali than in acid. The recovery yield (65.0% and 84.6%, respectively) of API and KPI were much higher as compared with MP (54.0%). API, KPI and MP contained far smaller amounts of lipid and ash, whereas KPI contained the highest protein content. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that there were no significant differences in the protein composition of TP, KPI and API. However, compared with TP, API and KPI had lower contents of Gly and Pro. Textural and rheological analysis revealed that API and KPI possessed lower gel strength and storage module G’ than TP and MP. Meanwhile, although no significant changes occurred in API, remarkable decreases in the G’ values of TP, MP and KPI were observed in the temperature range from 50 to 55 ℃, indicating the occurrence of modori phenomenon. This finding was well consistent with the microstructure observed by scanning electron microscopy (SEM), whereas KPI, TP and MP showed looser, porous and disorganized network when incubated at 55 ℃ for 30 min than at 90 ℃. The results of simulated gastrointestinal digestion showed that MP had the best digestibility among four proteins, while KPI and API possessed better digestibility than TP. In conclusion, ISP can greatly improve the recovery yield of protein from blue round scads. Due to their higher digestibility and poorer gelation ability, the use of the protein isolates as protein ingredients in food products is proposed.

In order to improve the apparent solubility of curcumin (CCM), phytoglycogen (PG) was used as the carrier to load CCM, yielding phytoglycogen-curcumin complex (PG-CCM). The effects of PG concentration, CCM concentration, pH, and ion concentration on the apparent solubility of CCM were examined. Dynamic laser light scattering was used to study the particle size distribution of the composite, and the morphology was observed by transmission electron microscopy. The interaction between PG and CCM as well as changes in the state of CCM and the microenvironment surrounding CCM before and after loading onto PG was investigated by infrared spectroscopy, differential scanning calorimetry (DSC) and fluorescence spectroscopy. The results indicated that PG was an efficient carrier for CCM and PG-CCM significantly increased the apparent solubility of CCM. The loading efficiency was found to be related to the concentrations of PG and CCM. The loading system was sensitive to pH, but immune to low concentration ions. The apparent solubility of 4 mg/mL CCM loaded on 10 mg/mL PG at pH 7 was 18.68 μg/mL. The average particle size of the composite nanoparticles, electrically neutral, was 70–75 nm, and the particle size distribution was uniform; the carrier PG presented a smooth spherical structure, while the PG-CCM complex presented a large, irregular planar sheet. CCM in the complex existed in an amorphous structure. Hydrogen bonding was the main interaction between CCM and PG. CCM shifted from a more polar microenvironment to a less polar region under the action of PG. This study concludes that PG is an efficient carrier and the preparation of PG-CCM is simple and can significantly improve the apparent solubility of CCM. It is expected to broaden the application of CCM in the food industry.

The effects of sucrose addition as a cosolute (0%, 5%, 10%, and 15%) on the evolution of the elastic modulus (G’) and viscous modulus (G”) of agar/konjac blends during sol-gel transition were investigated. The kinetics of structure formation was explored by analyzing the average rate of gel structure development (SDRa), instant gelation velocity (vg) and gelation acceleration (αg). The results showed that the G’, SDRa, vg and αg of agar/konjac blends were increased significantly with sucrose concentration up to 5% (P < 0.05) and then decreased. Addition of low concentration of sucrose could promote the agar intermolecular hydrogen bonding interaction of agar/konjac blends and induce the double helix formation of agar molecules. Consequently the rheological and textural properties of agar/konjac blend gels were improved by significantly reducing the gelation activation energy (Ea) in the high temperature scope and promoting the formation of compact and flat three-dimensional network microstructure.

The purpose of this study was to develop a novel emulsifier from germinated brown rice protein (GBRP) and dextran through the Maillard reaction. Fourier transform infrared (FTIR) spectroscopy and X-ray diffractometry analysis were used to evidence the formation of GBRP-dextran conjugate (GBRP-Dex Con). Experimental results indicated that the solubility of GBRP-Dex Con was 10% higher than that of GBRP (pH 7.0) through covalent bonding with dextran. The denaturation temperature of GBRP-Dex Con (122.2 ℃) was 14.7 ℃ higher than that of GBRP (107.5 ℃). The radical scavenging activity and reducing power of GBRP-Dex Con were significantly higher than those of GBRP (P < 0.05). Measurements of the droplet size and physical stability of Sacha Inchi oil emulsion demonstrated that GBRP-Dex Con was more effective in stabilization of the emulsion than the protein alone, their physical mixture and the common emulsifier soy protein isolate (SPI). Thus, GBRP-Dex Con as a new emulsifier with excellent properties has a great potential for applications in the food industry.

The aim of this study was to investigate the impact of preheated soy protein isolate (SPI) on the gelation and rheological properties of heat-induced myofibrillar protein isolate (MPI) extracted from common carp muscle. SPI heated at 90 ℃ for 0, 30 and 180 min were incorporated into MPI (0:1, 1:1, 1:2, 1:3, and 1:4), and protein content in the mixture solutions was kept at 40 mg/mL. Results showed that the gel hardness, springiness, whiteness, and water-holding capacity of MPI with preheated SPI were significantly higher than those with native SPI (P < 0.05), and a greater increase was observed with longer (180 min) versus shorter (30 min) heating time (P < 0.05). In addition, the hardness, springiness, whiteness and water-holding capacity of the mixed protein gels increased significantly with decreasing SPI/MPI ratio from 1:1 to 1:4 (P < 0.05). The rheological properties suggested that protein denaturation temperature increased after the addition of SPI, and preheated SPI significantly increased protein storage modulus (G’). The results of thermal stability suggested that the maximum transition temperature Tmax3 was significantly reduced with the addition of native SPI to MPI (P < 0.05) while the Tmax1 and Tmax2 were not affected (P > 0.05). However, the addition of preheated SPI to MPI significantly reduced the Tmax1 and increased the Tmax3 (P < 0.05). In short, compared with native SPI, preheated SPI can improve the gelling and rheological properties of myofibrillar proteins.

The effect of dietary fiber (DF) and ferulic acid (FA) individually and in combination on the structure and properties of dough and gluten was examined. The results showed that addition of 3% to 12% DF significantly (P < 0.05) increased the water absorption, development time and breakdown viscosity of dough by 2.36%–7.76%, 18.15%–69.18%, 61.11%–283.33%, respectively, while addition of FA significantly increased the regeneration value by 90.48%–97.62%. The combined addition of DF and FA improved the effect of either alone on dough thermomechanical properties. The viscoelastic modulus of gluten with the individual addition of DF and FA was significantly higher than that of the control group, whereas the heat-denaturation temperature (Tp), heat denaturation enthalpy (ΔH), and disulfide bond content were significantly lower than those of the control group. In addition, the mass loss rate was significantly increased, indicating that the structural stability of gluten is decreased by the addition of DF and FA. The results of scanning electron microscopy showed that the smooth and orderly microstructure of gluten became loose and disordered after the addition of either DF or FA, while this change was reversed by adding them together.

In this work, monoglycerides, beeswax and rice bran wax were utilized to improve the stability of sesame paste. The oil syneresis, texture, rheological properties and microstructure of sesame paste were investigated, and we modelled the influences of these organogelators on the rheology. Results showed that all the sesame pastes exhibited a shearthinning behavior and pseudoplasticity, and the non-Newtonian index n was in the range from 0.12 to 0.68 based on the Herschel-Bulkley model. The flow activation energy of sesame paste stabilized by rice bran wax was the largest, followed by monoglyceride and beeswax based on the relationship between apparent viscosity and temperature from the Arrheniustype model. Furthermore, acceptable sesame pastes in both oil syneresis and hardness were obtained by adding 4% monoglyceride, 5% beeswax and 5% rice bran wax, respectively, under the optimized conditions.

The poor water solubility of policosanol hinders it from being applied in clear and stable functional beverages. To solve this bottleneck problem, a microemulsion with high loading of policosanol was prepared in this study. The optimum emulsification conditions were obtained. The microemulsion area was determined by constructing a pseudo-ternary-phase diagram and the stability was evaluated. The microemulsion was used as a functional ingredient in beverage. The results indicated that the microemulsion, prepared with an emulsifier mixture with a hydrophile-lipophile balance (HLB) value of 10 at emulsifying temperatures of 70–75 ℃, was stable and transparent, in which the amount of each additive was within the limits of the national standards for food safety. The microemulsion was stable against centrifugation, alternating hot and cold cycles and dilution. It was stable and transparent for 65 days at room temperature. With the decrease of the Km value, the microemulsion area in the pseudo-ternary-phase diagram decreased. A stable and transparent functional beverage was prepared based on the policosanol-loading microemulsion. The microemulsification of policosanol effectively improved its poor water solubility and stability in beverage, which provides a valid way of preparing high quality, transparent and stable functional beverage containing policosanol and lays the foundation for the development of new products.

Hericium erinaceus β-glucan (HEBG) was obtained from the fruiting body of H. erinaceus by water extraction and alcohol precipitation. The primary structure of HEBG was characterized by high performance liquid chromatography (HPLC), gas chromatography (GC), infrared spectroscopy (IR), periodate oxidation, Smith degradation, methylation analysis and nuclear magnetic resonance (NMR) analysis. The solution properties of HEBG were investigated by viscosity measurement and Congo red tests, and its microstructure was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that HEBG was a homogeneous polysaccharide composed of β-D-glucose (Glu). Periodate oxidation, Smith degradation, methylation analysis and NMR analysis indicated that the HEBG backbone consisted of 1,3-β-D-Glu residues and the branches were composed of 1,6-β-D-Glu residues with a molar ratio of 1,3-β-D-Glu to 1,6-β-D-Glu residues of 1:1. The intrinsic viscosity and Congo red tests showed that the dilute HEBG solution had both a random coil and triple helix structure, and the random coil structure of the polysaccharide and the branching structure of its molecular chain were more clearly observed by SEM and AFM. The molecular chain diameter was (0.55 ± 0.11) nm and the width was 1.9 nm. This study provides the rationale for an in-depth study of the biological activity and structure-activity relationship of H. erinaceus β-glucan.

In this study, phospholipase A1 was used to hydrolyze Antarctic krill phospholipids in aqueous media in order to obtain lysophospholipids rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The degree of phospholipid hydrolysis was measured by acid value. The composition of phospholipids was analyzed by high performance liquid chromatography (HPLC) and the acyl migration was further confirmed by measuring the content of glycerophosphatidylcholine (GPC). The fatty acid composition of phospholipids was analyzed by gas chromatographymass spectrometry (GC-MS). The results showed that the acid value increased firstly and then decreased with the increase of enzyme loading. As the hydrolysis proceeded, the content of Sn-2-lysophosphatidylcholine (Sn-2-LPC) increased initially and then reached an equilibrium value. The content of Sn-1-lysophosphatidylcholine (Sn-1-LPC) increased first and then decreased. This was due to the acyl migration of some Sn-2-LPC to form Sn-1-LPC, which was further hydrolyzed by LPA1 into glycerol phosphatidylcholine (GPC). Additionally in a short reaction period, temperature had no significant effect on the acyl migration. Finally, GC-MS analysis showed that the contents of EPA and DHA in the enzymatic hydrolysate Sn-2-LPC were relatively high, and the emulsion stability was also improved.

The effect of malondialdehyde (MDA) as a representative reactive secondary oxidation product from lipid peroxidation reaction on the structure and functional properties of rice bran protein (RBP) as well as its structure-activity relationship was investigated by means of the theory of protein chemistry and spectroscopies. It was found that the carbonyl content of RBP increased with increasing MDA concentration, while the free amino content decreased gradually. Besides, the α-helix and β-sheet content of oxidized RBP increased with MDA concentration, whereas the opposite was true for the random coil and β-turn. The maximum absorption wavelength (λmax) of oxidized RBP was blue-shifted. The subunit composition of RBP was not significantly affected by low concentrations of MDA. With increasing the MDA concentration, the intensity of bands near 53, 49, 36, 21 and 14 kDa all decreased and the color became lighter; the 36, 21 and 14 kDa bands gradually disappeared. Increasing MDA concentration led to higher, particle size, polydispersity index (PDI), turbidity and foam stability but lower solubility, surface hydrophobicity, emulsifying capacity, emulsion stability and foamability of oxidized RBP.

This study aimed to investigate the effects of a mixed starter culture of moderate halophilic bacteria and exogenous L-Lys on the fermentation quality of fish paste. After 60 d of mixed-culture fermentation with Halobacillus campisalis, Halobacillus faecis, Bacillus aquimaris and Bacillus hwajinpoensis, the pH, total acidity, amino nitrogen, volatile base nitrogen, free amino acid and volatile compounds were measured. Leiocassis longirostris meat was used as the fermentation substrate. Four groups were set up. Group 1 was added only 15% salt (control), group 2 was added with 15% salt and 0.1% L-Lys, group 3 was added with 15% salt and the mixed culture, and group 4 was added with 15% salt, 0.1% L-Lys and the mixed culture. The results demonstrated that the total acidity in groups 1–4 were 0.382 5%, 0.63%, 0.607 5% and 0.585%, respectively, suggesting a significant increase for the experimental groups relative to the control group (P < 0.05). On the other hand, there was no significant difference in amino nitrogen content between group 3 and the control (P > 0.05), while a significant increase was observed for groups 2 and 4 compared to the control group (P < 0.05). All three experimental groups exhibited a significant reduction in volatile base nitrogen content in comparison to the control group (P < 0.05). Moreover these groups contained higher amounts and more varieties of amino acids and were rich in volatile flavor compounds, and their sensory evaluation and flavor were better than the control.

1,3-Dioleoyl-2-palmitoylglycerol (OPO), a nutritional fortifier, is usually supplemented into commercial infant formulas in the form of OPO-enriched plant-oil formula (namely OPO formula powder) to enhance the nutritional value of infant formulas. In order to demonstrate the nutritional function of OPO formula powder and to improve the applicability of OPO, anaerobic fermentation in vitro of OPO formula powder at different concentrations by the intestinal bacteria isolated from healthy college students’ feces was conducted in this study. Traditional culture techniques and gas chromatography (GC) were employed to study the changes in intestinal microbial counts as well as pH and short-chain fatty acids during 24 h of in vitro fermentation. Prebiotic index (PI) and Bifidobacterium/Enterobacter ratio (B/E) values were calculated. The results showed that supplementation of OPO formula powder promptly decreased the pH value compared with the blank control group, and the reduction was directly proportional to the concentration of OPO formula powder. Besides, it significantly increased the production of short-chain fatty acids, especially acetic acid and butyric acid. Furthermore, OPO formula powder could promote the growth of Bifidobacterium and Lactobacillus, but inhibit the growth of Enterobacteriaceae and Bacteroidetes, and increase PI and B/E ratio. The 50 g/kg of OPO supplemented group exhibited the highest PI at the end of the 24 h fermentation period. The increase in Bifidobacteria and B/E ratio were positively correlated with OPO concentrations during the first 12 h. Therefore, 50 g/kg of OPO supplemented is recommended for improved probiotic efficiency.

Twelve kinds of culinary medicinal plant matrices were used as new substrates for making koji. The effect of Rhizopus inoculum size, matrix moisture content, cultivation time and temperature on glucoamylase and liquefaction enzyme activity was examined. Optimization of the process conditions was carried out by the combined use of single factor method and the Box-Behnken design. Glucoamylase activity was used as the response value. The results showed that the optimum process conditions were determined as follows: inoculum size 0.3%, culture time 40 h, matrix water content 65% and culture temperature 28 ℃. Under these conditions, the predicted value of glucoamylase activity was 778.65 mg/(g·h), while the average of three replicate experiments was (779.233 ± 0.577) mg/(g·h). This good agreement indicates that this scheme is feasible. The glucoamylase and liquefaction enzyme activity measured were about 1.3 and 2.8 times higher than that of traditional koji, respectively. A total of 33 volatile components were detected from the two rice wines. Isoamyl alcohol (10.065 versus 109.394 μg/100 mL) and ethyl butyrate (0.867 versus 187.552 μg/100 mL), acetic acid (135.240 versus 560.939 μg/100 mL) and phenol (0.156 versus 0.858 μg/100 mL) showed the greatest differences between the two rice wines. Based on the above results, the new koji had good fermentation performance and the brewed rice wine had a richer taste, showing that this koji to be a promising starter culture for rice wine.

In order to analyze the diversity of acetic acid bacteria in naturally fermented Noni juice and enrich our knowledge of acetic acid bacteria, conventional culture method and 16S rRNA sequence homology analysis were used to identify the acetic acid bacteria from naturally fermented Noni juice and their fermentation characteristics were studied. The results showed that of the 67 strains isolated at different fermentation stages, 24 were identified as acetic acid bacteria, including Acetobacter fabarum (9 strains), Acetobacter syzygii (7 strains), Acetobacter pasteurianus (2 strains), Acetobacter tropicalis (1 strain), Acetobacter lambici (1 strain) and Gluconobacter japonicus(4 strains), and A. syzygii and A. fabarum were the dominant strains during the fermentation process. In terms of fermentation characteristics, A. tropicalis N21 showed the best performance. Its acid yield was the highest, which reached 28.92 g/L. It was able to grow well at 40 ℃ and produce 14.85 g/L of acid. At an ethanol concentration of 7%, the acid yield was decreased slightly, but it was still as high as 23.60 g/L, which shows that the temperature and ethanol tolerance of A. tropicalis N21 are superior to those of any other strains.

In order to explore the dynamic changes of volatile flavor components and microbial community structure during the traditional brewing of Hongqu glutinous rice wine, headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to systematically compare the volatile flavor components in fermented grains samples collected at different brewing stages. Meanwhile, high-throughput sequencing was used to analyze the microbial community dynamics. The results showed that the volatile flavor components and the community structure of microflora changed significantly during the brewing process. Spearman correlation analysis of volatile flavor components and microbial community demonstrated that most of the aroma components in Hongqu glutinous rice wine were positively correlated with the dominant microbes in the middle and late stages of brewing. The results preliminarily clarified the relationship between the formation of aroma components and the microbial flora during the traditional brewing process of Hongqu glutinous rice wine, and also determined the microbes closely related to the formation of the key aroma components. This study provides basic data for the isolation and screening of functional microbes and the beneficial regulation of the fermentation of Hongqu glutinous rice wine.

This study aimed to investigate the exopolysaccharide (EPS) of Lactobacillus casei HS4 and its effect on the microstructure and rheological properties of fermented milk. Two fractions of EPS, named as HS4-1-EPS and HS4-2-EPS, were obtained by size exclusion chromatography on a Sephadex G-50 column. HS4-1-EPS was mainly composed of glucose with a peak area of 0.940. HS4-2-EPS was mainly composed of glucose and mannose with a peak area ratio of 0.383:0.364. Fourier transform infrared (FT-IR) spectroscopy revealed that HS4-1-EPS and HS4-2-EPS were both heteropolysaccharides. The rheological properties and microstructure of three fermented milks made respectively with a mixed starter culture of Streptococcus thermophilus and Lactobacillus bulgaricus (1:1) in the presence and absence of the purified EPS and a monoculture of L. casei HS4 were observed to determine the effect of supplementation of the purified EPS versus in situ EPS on the rheological properties of fermented milk. These fermented milks showed different rheological properties during storage at 4 ℃. Based on the microstructure observation, we concluded that the type and space barrier effect of EPS correlated with the rheological properties of fermented milk.

In order to select a suitable mixed culture of probiotics for cloudy apple juice fermentation, 10 strains of common probiotics were screened based on their acid and bile tolerance and fermentation performance. The antagonism between the selected strains was evaluated and the mixing ratio of these strains was determined. Furthermore, we modelled the kinetics of biomass growth, metabolite production and substrate consumption. The kinetic parameters of the models developed were determined and verified. The results showed that: 1) a mixture of Lactobacillus acidophilus 6005, Lactobacillus plantarum 21805, and Lactobacillus fermentum 21828 was found to be the most suitable for the fermentation of apple juice at a ratio of 1:1:1 as determined based on sensory evaluation and viable cell counts, and the fermented apple juice had the best flavor and mouthfeel as well as the highest viable cell counts; and 2) the errors between the theoretical values from all these kinetic models and the experimental data were less than 10%, suggesting excellent goodness of fit. Hence, the kinetic models could predict the dynamic changes during the mixed culture fermentation of cloudy apple juice.

Protein glycosylation is one of the most important post-translational modifications, which influences the functions of the modified proteins. The aim of this study was to elucidate the N-glycosylation of proteins in bovine milk. Using glycoproteomics, a total of 154 N-glycoproteins with 246 glycosylation sites were identified in bovine milk, including 117 N-glycoproteins with 183 glycosylation sites in colostrum, and 109 N-glycoproteins with 145 glycosylation sites in mature milk. The glycosylation site of N-283 on clusterin was expressed at the highest level in colostrum while N-93 on alphalactalbumin showed the highest expression in mature milk. Considering the quantitative and exclusive differences, 190 glycosylation sites on 129 glycoproteins were differentially expressed between colostrum and mature milk. According to gene ontology annotation, these differentially expressed glycoproteins participated in biological regulation, response to stimulus, multicellular organismal processes, localization and immune system processes; they were cellular components in the extracellular region and organelles and had various molecular functions such as binding, catalytic activity and molecular function regulators. The differentially expressed glycoproteins were mainly involved in the complement and coagulation cascades, Staphylococcus aureus infection and the lysosome pathways. In addition, some highly connected glycoproteins were identified through protein-protein interaction analysis. Our results enrich the knowledge on the glycoproteome of cow’s milk, including the N-glycoprotein composition and glycosylation sites and also reveal the functions of protein N-glycosylation in bovine milk whey, which provide a theoretical foundation for the evaluation and improvement of bovine milk quality, the development of infant formula closer to human milk, and the production of functional foods.

Based on sensory scores and viable microbial counts, we selected suitable probiotic strains of lactic acid bacteria for the fermentation of kiwifruit juice, which are tolerant to both low pH and bile salt conditions. Subsequently, the fermentation conditions were optimized and the changes in aroma composition during fermentation were detected by electronic nose. The results showed that a mixture of Lactobacillus plantarum 21805 and Lactobacillus acidophilus 20250 was used to initiate the fermentation process. The optimal fermentation conditions obtained were as follows: ratio between two probiotic strains, 1:1; inoculum size, 3%; fermentation time, 24 h; and temperature, 36 ℃. The sensory score of the fermented kiwifruit juice produced under these conditions was 81.45 points and viable cell count was 2.185 × 108 CFU/mL. The electronic nose data were analyzed by linear discriminant analysis and loadings analysis. We found that the fermented kiwi juice samples at different time points could be correctly differentiated by LDA, which confirmed the feasibility of applying electron nose to detect the flavor changes during the fermentation of kiwi juice. The flavor differences may come from terpenes, alcohols, alkanes, aromatic compounds and others. The fermented aroma started forming at 8 h of fermentation, and the key time point for producing aroma composition was at 12 h; the late stage was crucial for the flavor formation in fermented kiwifruit juice.

Based on gas chromatography-mass spectrometry (GC-MS), metabolomics studies were conducted on 60 rice varieties growing in Jiansanjiang and Xiangshui, Heilongjiang. By applying the multivariate statistical analysis methods principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), we examined rice samples collected from the two growing areas. A total of 143 peaks were detected in the samples, and a total of 39 metabolites including amino acids, fatty acids, nucleotides, organic acids, polyols, sugars were identified. The effect of the geographical origin on rice metabolome was evaluated. The results showed significant differences in both the kinds and quantities of metabolites in rice samples from different growing areas. A total of 16 differential metabolites with significant changes (P < 0.05, variable importance in the projection (VIP) > 1) were identified. The results showed that GC-MS combined with multivariate statistical analysis could be used to study the differences in the metabolite profiles of rice samples collected from different growing regions. This study provides the basis for studying the geographical traceability of rice.

Sour pork was prepared from pork longissimus dorsi muscle and the structural changes of proteins were studied during the fermentation process of sour pork. The results showed that the electrostatic force of proteins decreased with fermentation time, while the hydrophobic interaction and the disulfide bonding increased significantly followed by small fluctuations. The results of ultraviolet absorption spectroscopy showed that the aromatic amino acid residues of myofibrillar proteins were shifted to a more hydrophobic environment, and the polarity of the microenvironment around sarcoprotein tyrosine and tryptophan residues increased. The endogenous fluorescence spectra showed that the fluorescence intensity decreased generally, and red shift occurred when compared with before fermentation, which indicates that tryptophan underwent oxidative degradation, and its residues were mainly exposed to the polar environment. Raman analysis showed that the α-helical content decreased, while the β-sheet content increased gradually, and the secondary structure of proteins was reorganized after 110 days of fermentation. These results showed that long-time fermentation could change the secondary and tertiary structures of proteins in sour pork, which explains the effect of fermentation on sour pork quality at the level of protein structure.

The effect of cold stress (4 ℃) on metabolites of six strains of the cold resistant yeast Wickerhamomyces anomalus was investigated in this paper. The fermentation broths of these yeast strains was derivatized with methoxamine and BSTFA-TMS, and then the products were determined by gas chromatography-mass spectrometry (GC-MS). A total of 49 metabolites with more than 10 mg/L concentrations were identified, including 34 saccharides, sugar alcohols and sugar acids, several of which had prebiotic activity. These results indicate that the W. anomalus has complex saccharide metabolic ability. In addition, W. anomalus produced squalene, thymol-β-D-glucoside, β-hydroxy-phenylpropionic acid, and isolongifolene, suggesting that this yeast has metabolic pathways of terpenoids and phenylpropanoids. According to the results of metabolome analysis, glycerol, squalene, erythritol, galactose, L-ascorbic acid-2,6-dipalmitate, mannose, and thymol-β-Dglucoside were the bio-markers of W. anomalus under cold stress. This study provides a theoretical basis for the studying the response mechanism of yeast to cold stress and the mechanism underlying flavor formation in yeast-fermented foods, and for the development of new products.

In this study, anhydrous milk fat was fractionated by stepwise melting into high-melting fraction (S40), middle-melting fraction (L40 and L30) and low-melting fraction (L20). Fatty acid (FA) and triacylglycerol (TAG) composition of each fraction were analyzed by gas chromatography-mass spectrometry (GC-MS). The crystal form and the thermodynamic profile were evaluated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. From the results, S40 was found to be rich in saturated long-chain fatty acids but lack short-chain fatty acids and unsaturated fatty acids, while the opposite was true for L20. L40 and L30 were between L20 and S40. The heat map showed that high-melting triacylglycerols (TAGs) were concentrated in S40, whereas low-melting TAGs predominated in L20. L40 and L30 were rich in middle-melting TAGs. There were striking differences in the thermodynamic profiles of the milk fat fractions, whose crystallization temperature (TC) and melting temperature (TM) followed the decreasing order of S40 > L40 > L30 > L20 (P < 0.05). When the the TC or TM was higher, the phase transition enthalpy was higher. Moreover, the β’ crystal was dominant in milk fat (MF), L40 and S40, but not in L20 or L30. Crystallization of MF, S40 and L40 showed the formation of 2L (40.76 and 13.49 ?) and 3L (29.44 ?) lamellar structures, whereas L30 and L20 showed the formation of only 2L. In summary, higher degree of fat saturation leads to stronger crystal stability and larger enthalpy during the crystallization-melting process, which is suitable for the preparation of hard dairy products. In contrast, lower degree of fat saturation is suitable for preparing soft dairy products. This research provides a theoretical basis for the different requirements of milk fat production.

Objective: To establish a high performance liquid chromatographic (HPLC) method for the simultaneous determination of the contents of 13 phenolic constituents in three fruit parts of Annona squamosa Linn., and to analyze the correlation between phenol content and antioxidant activity. Methods: Total phenols were evaluated by a colorimetric method, and the HPLC method was used to measure the composition and contents of phenols. The antioxidant activity was analyzed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity assays. Results: The total phenol content of peel was the highest, ranging from 59.48 to127.84 mg/g, sequentially followed by pulp and seeds. The contents of some individual phenolic compounds in peel significantly higher than in any other parts. There were significant regional differences in the composition and contents of phenols in the same fruit parts. The contents of p-hydroxybenzoic acid, catechin, caffeic acid and (-)-epicatechin were relatively higher in peel and pulp and the highest (-)-epicatechin level was 2 398.17 mg/mL. All of the fruit parts were had more potent scavenging activity against DPPH radical than against ABTS radical cation and peel had the strongest radical scavenging with the highest percentage inhibition of DPPH radical and ABTS radical cation being observed at concentrations of 0.39 and 1.56 mg/mL, respectively. Conclusion: The composition and contents of phenols in the peel, pulp and seeds of A. squamosa fruit are significantly different. The peel contains the highest number and amount of phenols and possesses the highest antioxidant activity, indicating that it can be considered as a potential and valuable source of natural antioxidants.

Using gas chromatography coupled with time-of-flight mass spectrometry (GC-TOF-MS), we assessed the constituents and relative quantities of fatty acids in five woody seed oils extracted with supercritical carbon dioxide. Tea and hazelnut seed oils contained a high concentration of oleic acid, linoleic acid was found to be the primary fatty acid in sea buckthorn and yellow horn seed oils while the highest amount of linolenic acid occurred in peony seed oil. Sea buckthorn seed oil was considered a functional edible oil based on its ratios of monounsaturated to saturated fatty acids (1.57:1) and linoleic to linolenic acids (1.56:1). Peony seed oil was an excellent edible oil with high concentrations of omega-3 fatty acids. Tea and hazelnut seed oils were both suitable for the food industry. Interestingly, yellow horn seed oil exclusively contained three long-chain monounsaturated fatty acids (such as nervonic acid). Our study has important implications for industrial production of bioactive oils and for promoting the health of people consuming them.

A method for the determination of volatile compounds in Pueraria Radix by headspace solid-phase microextraction (HS-SPME)-gas chromatography-mass spectrometry (GC-MS) combined with the automatic deconvolution software automated mass spectral deconvolution and identification system (AMDIS) was established. Total peak area and number of peaks were used as response variables to optimize the extraction conditions of HS-SPME by one-factor-at-atime and orthogonal array design methods. The results showed that the extraction conditions were optimized as follows: 3.0 g of sample, equilibration time 13 min, extraction for 50 min at 90 ℃ using 50/30 μm DVB/CAR/PDMS fiber and then desorption for 5 min. Under these conditions, 67 volatile components were identified, including 11 esters, 22 aldehydes, 9 alcohols, 5 ketones, 8 terpenes, and 12 others.

Objective: To identify the chemical constituents from the rhizome of Curcuma longa L. and to assess their antioxidant activity. Methods: The chemical constituents were purified consecutively by silica gel column chromatography, Sephadex LH-20 gel column chromatography, and preparative high performance liquid chromatography (HPLC). Their structures were identified by spectroscopic analyses, and their antioxidant activity were evaluated by 2,2’-azinobis-(3- ethylbenzthiazoline-6-sulphonate) (ABTS) radical cation scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and potassium ferricyanide reduction assays. Results: Seven compounds were isolated from C. longa L. and were identified as zingerol (1), dihydroferulic acid ethyl ester (2), ethyl 3-(4-hydroxy-phenyl)-propionate (3), zingerone dimer [4,4’-(6,6’-dihydroxy-5,5’-dimethoxy-[1,1’-biphenyl]-3,3’-diyl)bis(butan-2-one)] (4), zingiberone (5), 4-(3,4-dimethoxyphenyl) butan-2-one (6), and vanillin (7). Among them, compounds 1–5 showed antioxidant activity. The IC50 of compounds 1 and 2 were (3 ± 0.2) and (12 ± 1.0) μmol/L, respectively, in ABTS assay. Compound 1 was found to exhibit higher antioxidant activity than the positive drug, VC (VC, IC50 value = (13 ± 1.1) μmol/L), while the activity of compound 2 was equivalent to VC. In the reducing power assay, compound 1 showed higher activity than VC at all investigated concentrations, while compound 2 had higher activity than VC only when the concentration was lower than 0.125 μmol/mL. Conclusion: Compound 4 is a new natural product, and compounds 1, 2, 3 and 6 are found from this plant for the first time. The stronger antioxidant activity of compound 1 may be related to hydroxyl substitution at C-2, In addition, the phenols from the ethanol extract may be one of the material bases for the antioxidant activity of C. longa L..

This study was aimed to analyze the main volatile compounds and aroma profiles of a liquor made from the juice of Guanxi honey pomelo (Citrus grandix). The volatiles were analyzed by headspace solid phase micro-extraction (HP-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector-olfactory (GC-FID-O). In addition, the aroma profile was measured using sensory evaluation. A total of 40 volatile components, including 8 alcohols, 14 esters, 10 terpenes and 8 others, were identified from the liquor. The quantitative analysis showed that the main volatile components were ethyl caprate (744.73 μg/L), ethyl caproate (524.74 μg/L) and ethyl laurate (193.42 μg/L). Sensory evaluation showed that fruity and citrus-like notes were the main odors of the liquor. The GC-olfactory analysis indicated that D-limonene, ethyl valerate and ethyl caproate were the main aroma-active components. These results provide an experimental basis for future studies on the aroma of wine and liquor products made from pomelo and other citrus fruits.

A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method and a high performance liquid chromatography (HPLC) method were established to simultaneously detect the contents of ergosterol and VD2 in white Hypsizygus marmoreus and methodological evaluation was performed to determine the linearity range, sensitivity and accuracy of the two detection methods under optimized detection parameters. The differences between the two detection methods in qualitative and quantitative analysis of ergosterol and VD2 extracted from samples by alcohol-alkali saponification reflux method were verified in order to provide technical support for the detection of effective bioactive components and the study of the conversion between ergosterol and VD2 in white H. marmoreus. In the HPLC-MS/MS method, the chromatographic peak retention times of ergosterol and VD2 were 4.303 min and 4.22 min, respectively, under optimized chromatographic conditions using Agilent SB-C8 Rapid Res column (2.1 mm × 50 mm, 3.5 μm) as the separation column. Ergosterol and VD2 were quantified by selecting m/z 379.3/125.3 and 397.3/125.3 as ion pairs under the multi-reaction monitoring (MRM) mode using an electrospray ionization (ESI) source operating in the positive ion mode. The results showed that the concentration and peak area presented a good linear relationship for ergosterol and VD2 in the range of 0.15–6 mg/L and 0.01–1 mg/L, respectively. The average recoveries of ergosterol and VD2 from spiked samples were 93.51% and 90.56%, respectively, and the relative standard deviations (RSDs) of intra-day and inter-day differences were both less than 7%. In the HPLC method, the peak retention times of ergosterol and VD2 were 12.891 min and 9.919 min, respectively, under optimized separation conditions on a COSMOSIL 5C18-MS-II column (4.6 mm × 250 mm, 5 μm) . The methodology evaluation results of HPLC showed a good linear relationship between concentration and peak area for ergosterol and VD2 in the range of 15–750 and 0.5–50 mg/L, respectively. The average recoveries of ergosterol and VD2 from spiked samples were 98.51% and 94.05%, respectively, and the RSDs of intraday and inter-day differences were lower than 1%. Some differences existed between the two methods. Compared with HPLC, the HPLC-MS/MS method established in this research exhibited the advantages of short detection time, low detection limit and high sensitivity.

This study aimed to explore the cause of the flavor quality differences between green areca nut and smoked areca nut. Fresh areca nut was used as a control. We determined the contents of soluble sugar and titratable acid as taste-active compounds in the areca nut samples. The volatile components were extracted, identified and analyzed by head-space solid phase microextraction-gas chromatography-mass spectrometry. The results showed that there was a significant difference in titratable acid and some volatile components such as aldehydes and phenols between green and smoked areca nut, which affected the flavor quality of processed areca nut. The titrable acid content of green areca nut was significantly lower than that of smoked areca nut, while there was no significant difference in soluble sugar contents between them, causing a significantly higher sugar-acid ratio of green relative to smoked areca nut (P < 0.05). A total of 37, 46 and 29 volatile compounds were identified in green, smoked and fresh areca nut, respectively. The main volatile components of green areca nut were aldehydes, phenols and hydrocarbons, with relative contents of 10.81%, 9.71% and 2.84%, together with a small amount of ethers, alcohols, ketones, esters and naphthalene, which were similar to those of fresh areca nut. The main volatile component of smoked areca nut was phenols, with a relative content of 70.86%, which was far higher than other volatile components such as ketones, aldehydes, hydrocarbons, alcohols and esters, and it had typical smoky flavor characteristics. In addition, through principal component analysis (PCA), the 11 classes of components such as titratable acid that contribute to the overall flavor quality of areca nut could be divided into 4 categories. Moreover, PCA analysis showed obvious differences in the of flavor quality of green and smoked areca nut.

In this work, hydrothermal treatment was carried out on a commercial pectic polysaccharide, and the antioxidant activities of the degradation products were investigated. The results showed that the optimal degradation conditions were found to be treatment at 140 ℃ and pH 6 for 30 min. Under these conditions, the efficiency of degradation was 46.2%. On this basis, the degradation products were fractionated by ethanol precipitation into three fractions (S1, S2 and S3). The weight average molecular masses of S1, S2 and S3 were 13.4, 7.5 and 5.7 kDa, respectively. The antioxidant activities of the pectic polysaccharide and the three degradation products were evaluated. The results showed that the 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical scavenging rate of S1 was 49.8%, which was 4 times as high as that of the pectin, while the superoxide anion scavenging rate of S3 was 58.7%, which was 10 times as high as that of the pectin. These results indicated that the hydrothermal degradation of pectic polysaccharides could significantly improve its antioxidant activity. This study provides a theoretical basis for the efficient utilization of pomace wastes.

In order to reduce the drying time and at the same time to improve the quality of dried bamboo shoots, a combined microwave-hot air drying process was developed and optimized by examining the effect of microwave drying time and power and hot air drying temperature on sensory score, total drying time, rehydration rate, color difference and hardness using a combination of single factor method and central composite design coupled with response surface methodology. The results showed that the optimal drying conditions were as follows: microwave power, 6.3 W/g; microwave drying time, 60 s; and hot air drying temperature, 65 ℃. Under these conditions, the sensory score of dried bamboo shoots was 85.6 points, the total drying time was 200 min, and the rehydration rate was 6.17; the color difference ΔE* and hardness were 19.99 and 19 511.23 g, while those of the rehydrated product were 13.92 and 20 010.71 g, respectively. The proposed drying process will be of great significance to the future development of the bamboo shoot industry.

The selection and optimization of processing parameters as well as their levels for the production of quinoa tea were done by the combined use of Plackett-Burman design and response surface methodology. Sensory score and total phenolic content were employed as the response variables. The composition of phenolic compounds in quinoa and quinoa tea were analyzed by high performance liquid chromatography (HPLC). Results showed that the optimal processing conditions were as follows: drying for 30 min and then baking at 201 ℃ for 10 min. The sensory score of quinoa tea produced under these conditions was 86.32 points and total phenolic content was 3.73 mg/g. Compared with quinoa, the phenolic content of quinoa tea was higher; the contents of free phenolics and free flavonoids increased by 54% and 16%, respectively, and the free total phenols index and the bound total phenols index were 2.3 and 1.2 times as high as those of quinoa, respectively. The contents of gallic acid, protocatechuic acid, rutin, quercetin and kaempferol increased most significantly.

In order to improve the nutritional properties of infant soybean-based infant formula products, a low-phytic acid soybean-based formula was developed from the viewpoints of reducing phytic acid and improving digestibility. Soaked soybeans were blanched in 3‰ NaHCO3 solution at (85 ± 2) ℃ for 10 min, and then protein extracts were obtained after milling/slag removal and whey removal by acid precipitation. The proteins were then hydrolyzed with 1% phytase at pH 5.15 and 50 ℃ for 60 min, yielding a removal rate of phytic acid close to 90%, and specific hydrolysis of 7S globulin for 10 min at pH 7 and 45 ℃ was achieved with 0.5% neutral protease. The protein base obtained was blended with fat and sugar to develop a soybean-based powder. In in vitro simulated digestion in comparison to soybean milk powder and commercially available milk powder, the soybean-based formula powder hardly formed clots in simulated infant gastric environment, which was beneficial to the digestion of soybean proteins and improved comfortableness of babies after consuming the formula; it could be completely digested in the small intestine for 30 minutes, which means that the soybean-based formula powder has good digestive properties.

In this paper, the effect of starch aging on the quality of potato vermicelli was investigated. Single factor and orthogonal array experiments were conducted considering three factors, i.e. shaping time, aging time and aging temperature to optimize the manufacturing process of potato vermicelli. Sensory score was used as the dependent variable in the orthogonal array design. The thermodynamic and gelatinization properties of vermicelli at different aging times and temperatures were tested by differential scanning calorimetry (DSC) and rapid viscosity analyzer (RVA). A texture analyzer was used to analyze the changes in springiness, shear force, breaking rate and hardness during storage. The results showed that the optimal conditions for preparing potato vermicelli were as follows: shaping time 60 s, and sequential aging for 90 min at room temperature followed by at ?2 ℃. The vermicelli prepared under these conditions had good sensory quality with moderate hardness, good elasticity and low breaking rate. The thermodynamic and viscosity parameters of the vermicelli were affected by both room temperature aging and low temperature aging. The springiness, shear force, breaking rate, hardness, swelling degree and cooking loss were all increased with prolonging storage time. In short, the aging of potato starch has a great influence on the quality of potato vermicelli. The quality of potato vermicelli changes greatly during storage, and even excessive aging occurs.

In this study, 6 kinds of oligosaccharides in rape honey were determined by gas chromatography-mass spectrometry and 18 kinds of phenols by high-performance liquid chromatography-mass spectrometry (HPLC-MS). A new method was used to discriminate rape honey samples from different geographical origins through analysis of oligosaccharides and polyphenols combined with partial least squares discriminant analysis (PLS-DA). For this study, we collected 51 samples from Zhongxiang city of Hubei province, Yancheng city of Jiangsu province and Gangcha county of Qinghai province, among which there are significant geographical, climatic and environmental differences. The results of analysis of variance (ANOVA) showed that there were significant differences in the turanose content of rape honey samples from the three regions, and the oligosaccharide content of rape honey form Gangcha was relatively higher. There were significant geographical differences in the contents of most polyphenols and the polyphenols content of rape honey from Zhongxiang was relatively higher. Multivariate statistical analysis showed that polyphenols were a significant indicator for the geographical origin of honey, and the geographical origins of rape honey could be predicted with an accuracy of 97% by the contents of oligosaccharides and polyphenols combined with PLS-DA.

Six primers specific to the mitochondrial cytochrome b gene of swine were designed for use in loop-mediated isothermal amplification (LAMP). A simplified procedure was used for mitochondrial DNA extraction, and the reaction system was optimized. The specificity was tested with mitochondrial DNA samples from beef, mutton, chicken, duck meat, horse meat, and donkey meat as the negative controls, and the limit of detection (LOD) was determined with gradient dilution of adulterated meat with pork. A visual LAMP method for the detection of pork components in common meat products was established. The results showed that the modified mitochondrial DNA extraction method was simple and repeatable, and the visual LAMP method with 4-(2-pyridylazo)-resorcinol sodium salt as the indicator could accurately detect pork adulteration in common meat products with an LOD of 10 pg/μL.

In this experiment, we established an analytical method for the determination of patulin in apple juice and apple beverage by high performance liquid chromatography (HPLC). Samples were pretreated and purified by solid phase extraction (SPE). The target compound was separated on a C18 column with acetonitrile-water as the mobile phase, and detected by a diode array detector. The results showed that the limit of detection (LOD) of this method was 8 μg/kg and its limit of quantitation (LOQ) was 25 μg/kg. The determination coefficient was 0.999 6 in the patulin concentration range of 50.0–500.0 μg/L. The recovery rates of patulin at spiked levels of 25–100 μg/kg ranged from 90.2% to 102.8% and the precision coefficients of variation were 0.57%–1.44%. This method was accurate, cost-efficient and easy-operating. Hence, it can be suitable for product safety control in apple juice concentrate manufacturers.

Parvalbumins were extracted and purified from the muscle of Japanese flounder (Paralichthys olivaceus). A mixed solution of Tris, glycine, and DL-dithiothreitol was used as the extraction solvent. Parvalbumins were purified by adding ammonium sulfate to different degrees of saturation, and then identified using enzyme-linked immunosorbent assay (ELISA), Western-blot and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Three proteins (PVI, PVII and PVIII) with different molecular masses were obtained with high purity ( > 90%). Serological results demonstrated that each of these parvalbumins had the ability of binding to the specific IgG and IgE. The molecular masses of PVII and PVIII were determined to be 12 151 and 11 645 Da with Isoelectric point (pI) of 5.14 and 4.69, respectively. This method can meet the requirements for the extraction and purification of parvalbumins. These proteins were proved to represent different isotypes of parvalbumins with allergenicity.

The aim of this study was to develop a high performance liquid chromatography (HPLC) method for the determination of imidacloprid residue in agricultural products. Different extraction and purification methods were compared for their applicability in the sample pretreatment procedure. Samples were extracted with acetonitrile and the extract was concentrated and purified using a WondaSep GC-e/PSA SPE cartridge. The target compound was separated on an XBridge C18 column using 0.1% phosphoric acid-acetonitrile as the mobile phase under gradient elution mode, detected with a diode-array detector and quantified by external standard method. The effect of water added to agricultural products on the extraction of imidacloprid was examined, and solid phase extraction (SPE) and the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method were compared for their efficiency in removing interfering matrices. The results showed that different extraction and purification methods had different effects on different agricultural products. The method developed in this study showed good linearity with correlation coefficients (R2) greater than or equal to 0.999 in the concentration range of 0.05 to 10.0 μg/mL. The average recoveries of the analyte were between 88.3%–109.1%, with relative standard deviations (RSDs) less than 3.5%. This method can provide strong technical support for the monitoring of imidacloprid residues in agricultural products.

Using molecularly imprinted solid phase extraction, a gas chromatography-isotope dilution mass spectrometry (GC-IDMS) method was developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in meat samples. Naphthalene-D8 was used as an internal standard, and a mixed solvent of n-hexane-dichloromethane (7:3, V/V) was used as an extraction solvent. The sample preparation consisted of homogenization, ultrasonic extraction, centrifugation, and purification by molecularly imprinted solid phase extraction cartridge. The qualitative and quantitative analysis were conducted under optimized instrumental conditions. The calibration curves showed a good linearity within the concentration range of 5–100 ng/mL with correlation coefficient no less than 0.999 9 and the limit of detection (LOD) was 0.125–0.625 μg/kg for meat and meat products. The recoveries at three spiked levels ranged from 85.7% to 109% with relative standard deviations (RSDs) of 0.75%–4.90%. The results indicated that this method was efficient, sensitive and accurate and could be successfully applied in the quantification of PAHs in meat.

In this study, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with gas chromatography-mass spectrometry (GC-MS) was established to determine 17 pesticide residues in Ganoderma tsugae. A total of 1.0 g of dry G. tsugae powder was mixed with 10 mL of water, and then extracted by homogenization with aceonitrile. The extract was cleaned up with n-propyl ethylenediamine (PSA) and MgSO4 to remove the interferences from co-extractives. The separation was accomplished on an HP-5 capillary column and programmed heating was carried out. The target compounds were detected by electron impact ionization in the single ion monitoring (SIM) mode. Under the optimum conditions, the method showed a good linear relationship for all these pesticides in certain concentration ranges, with correlation coefficients greater than 0.98. Moreover, the limits of detection (LODs) (RSN = 3) were 0.002–0.022 mg/kg, the limits of quantitation (LOQs) (RSN =10) were 0.007–0.072 mg/kg. The average recoveries of this method were in the range of 71.10%–119.55% with relative standard deviations (RSDs) between 0.47% and 20.05%. In comparison with previous methods, the new procedure has the characteristics of simple sample preparation and higher sensitivity.

The distribution characteristics of total arsenic and arsenic species in four sea crabs (Scylla serrata, Portunus trituberculatus, Charybdis japonica and Ovalipes punctatus) and their different tissues (chest muscle, clamp meat, hepatopancreas and female gonad and gill) were studied by inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Samples were acidified, digested in microwave and tested by ICP-MS for total arsenic. After samples were extracted with dilute nitric acid solution and degreased with n-hexane, an HPLC-ICP-MS method using a Dionex IonPac AS19 guard column (50 mm × 4 mm) and an AS19 anion exchange analytical column (250 mm × 4 mm, 10 μm) with 50 mmol/L carbon acid ammonium (pH 9.5) in isocratic elution as the mobile phase was used to analyze 5 arsenic species (AsB, MMA, DMA, As (III), and As (V)). The optimized method showed a good linear relationship over the concentration range of 0–300 μg/L (r2 > 0.998). The limits of detection (LOD) and the limits of quantity (LOQ) were 0.008–0.014 mg/kg and 0.025–0.055 mg/kg, respectively. The recovery rates at spiked levels of 0.4–2.0 mg/kg were 70.0%–105.0% with relative standard deviations (RSDs) smaller than 5%. Total arsenic contents in 158 sea crab samples were 0.37–35.81 mg/kg, and the analytical data of arsenic species in whole crabs and crab tissues showed that AsB, with low toxicity, was the main form of arsenic in sea crab, accounting for 60.9%–99.4% of the total arsenic. Additionally, average inorganic arsenic content was only 0–0.12 mg/kg in all samples, below the national standard limit. The contents of total arsenic and AsB in different sea crab species were in the ascending order of O. punctatus < S. serrata < P. trituberculatus < C. japonica, and those in different crab tissues were in the descending order of female gonad > hepatopancreas > chest muscle > clamp meat > gill. This research suggested that sea crabs have strong As accumulation ability, mainly in gonad and hepatopancreas.

Phenethylamine was determined by the integrated pulsed amperometric (IPA) method and the amperometric current-time curve method. The detection conditions of the two methods were optimized, and the obtained results were compared with each other. The results showed that the amperometric I-t curve method had better selectivity and higher sensitivity to phenethylamine based on gold nanoparticles (AuNPs) modified gold electrode (AuE) at an initial potential of 0.1 V. The difference of response current had a good linear relationship with the concentration of phenethylamine in the range of 4.13 × 10-8–4.72 × 10-6 mol/L. The limit of detection (LOD) was 1.4 × 10-8 mol/L. The recovery of phenethylamine from spiked fish sauce was in the range of 90.0%–110.8%. This method was rapid, inexpensive, highly selective, and suitable for determination of phenethylamine in aquatic products.

A rapid method for the determination of the residues of 19 anti-histamines and their metabolites in animal-derived foods by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. Samples were extracted with acetonitrile-ethyl acetate mixture, and the extract was purified with Enhanced Matrix Removal-Lipid sorbent (EMR-Lipid), and then salted out and concentrated with MgSO4 and NaCl. The chromatographic separation was accomplished on a Poroshell 120 EC-C18 column by gradient elution using 0.1% formic acid as mobile phase A and 0.1% formic acid-acetonitrile as mobile phase B at a flow rate of 0.3 mL/min. The column temperature was set at 35 ℃, and the injection volume was 10 μL. Data were collected by dynamic multi-reaction monitoring (MRM) in electrospray positive ion mode. The analytes were quantitated by external standard method. Statistical analysis indicated that the calibration curves for all analytes had a good linearity with correlation coefficients R2 greater than 0.999 in the tested concentration ranges. The average recoveries for different negative samples (beef, chicken and porcine liver) at three spiked levels were in the range of 75.1%–89.1%, with relative standard deviations (RSDs) of 2.3%–7.1%. The limits of detection (LODs) of this method were 0.2–2.0 μg/kg and the limits of quantitation (LOQs) were 0.6–6.0 μg/kg. In a word, this method proved to be simple, rapid, highly repeatable and sensitive, and reliable, and it could be suitable for rapid screening and quantitative determination of 19 antihistamines and their metabolites in anima-derived food samples.