The rheological properties and degradation kinetics of pectin at various concentrations (0.5, 1.0, 1.5 and 2.0 g/100 mL) subjected to microwave treatments for different time periods (0, 1, 3, 5, 8, 15, 20 and 30 min) were assayed. The results showed that both the apparent viscosity and intrinsic viscosity [η] of the samples decreased with the reduction of pectin concentration, and with the increase of microwave processing time and shear rate. Using power law equation to describe their rheological behaviors, the pectin solutions were a share-thinning non-Newtonian fluid. Microwave treatment had the greatest impact on fluid behavior at low concentrations of pectin. The microwave-induced degradation of pectin was fitted based on [η] to a first-order kinetic model, and pectin at 0.5 g/100 mL was degraded fastest and at 1.5 g/100 mL slowest. Compared with the samples subjected to boiling without microwave treatment, microwave treatment also had non-thermal effects in pectin degradation.

The interaction modes and nanoparticle characteristics of bovine serum albumin (BSA) with quercetin (QUE) and anthocyanin (ACN) were comparatively investigated. The fluorescence of BSA was greatly quenched by QUE in both static (at low concentration) and dynamic (at high concentration) modes, while fluorescence quenching of BSA by ACN was just in a static mode. The binding constant of BSA with QUE was higher than that with ACN. BSA interacted with QUE and ACN by hydrophobic force and electrostatic force, respectively, to form BSA-QUE and BSA-ACN nanoparticles. The average diameters of BSA-QUE and BSA-ACN were 42.5 nm and 53.7 nm, respectively. The ζ-potentials of BSA-QUE and BSA-ACN were −25.64 and −21.50 mV, respectively. One mole of BSA could combine 8 moles of QUE or 10 moles of ACN. BSA-QUE nanoparticles were smaller and more stable than BSA-ACN nanoparticles. The DPPH and ABTS radical scavenging rates of BSA-QUE were higher than those of BSA-ACN.

The polyphenols from young pear fruits were purified by 5 kinds of macroporous adsorption resins, and their antioxidant activity was determined. The results indicated that NKA-9 resin had better adsorption and desorption properties than four other resins. Therefore, it was the most suitable resin to purify polyphenols from young pear fruits. The optimum conditions for purification were as follows: after pH adjustment to 5.0, the polyphenol at 2 mg/mL was passed through the resin at a flow rate of 1 mL/min, followed by desorption with 70% ethanol at a flow rate of 1 mL/min. Under these conditions, the purity of the polyphenols from young pear fruits increased from 6.23% to 30.68%. Both the crude and purified samples had the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals and nitrite, with IC50 values of 151.07, 152.48 and 490.35 mg/mL versus 122.12, 130.78 and 392.09 mg/mL, respectively. Conclusively, the antioxidant capacity of the purified polyphenols was better than that of the crude sample.

In the present study, rabbit skin collagen was analyzed for its processing characteristics. The results showed that the water absorption capacity of rabbit skin collagen was 14.89 mL/g. The collagen had a high solubility in acidic environment, especially at pH 3, and the solubility was decreased to 50% in alkaline environment. Ionic strength had a significant effect on the solubility of the collagen. At NaCl concentrations in the range of 0?2 g/100 mL, the solubility of the collagen remained relatively stable, whereas it decreased sharply with NaCl concentration up to 4 g/100 mL, and then did not change significantly at NaCl concentrations higher than 4 g/100 mL. The emulsifying capacity of the skin collagen increased with its concentration up to 1 g/100 mL, and then it began to decline with further increasing its concentration, but the opposite trend was observed for emulsion stability. Both emulsifying properties decreased with increasing pH from 3 to 6 and then gradually increased to a plateau with further increasing pH to 9. Emulsifying capacity presented a decreasing trend after an initial increase with NaCl concentration up to 7.02 g/100 mL, while emulsion stability remained stable after an initial increase. Both emulsifying capacity and emulsion stability were good at a NaCl concentration of 5.85 g/100 mL.

In order to optimize the current peeling techniques and develop a new one, the effects of different peeling methods, including manual peeling, hot water treatment, and alkali treatment and power ultrasound treatment alone and their combination on the peeling efficiency and quality parameters of tomatoes were compared. The peeling efficiency was evaluated based on the ease of peeling and weight loss, and the quality of peeled tomato based on texture, color, lycopene yield, pH, and titratable acid. Scanning electron microscopy (SEM) was used to compare the microstructure of tomato skins obtained by different peeling methods. Results showed that compared with hot water and alkali treatments, power ultrasound treatment achieved easier peeling of tomatoes with lower weight loss, higher lycopene yield and similar quality. Combined power ultrasound and alkali treatment reduced the difficulty of peeling but caused too high peeling loss than the other peeling methods. Power ultrasound caused more severe destruction to the cuticular structure of tomato skins than hot water and alkali as observed by SEM, likely because ultrasound cavitation allowed easier separation between the flesh and the skin to reduce peeling loss. Therefore, power ultrasound is potentially an environmental friendly way of peeling tomatoes.

Soybean 7S globulin was modified by ultrasonic treatment, and the changes in its in vitro digestibility, and the antigenicity and potential allergenicity of its digestion products were evaluated. Results showed that the 7S globulin was resistant to saliva and gastric juice, but it was easy to be digested in the duodenum after ultrasonic processing 300 W for 80 min. The antigenicity assessed by in vitro IgG binding showed that the antigenicity of the digestion products increased firstly but then decreased as the ultrasonic processing time (0?120 min) increased, reaching the lowest level at 100 min. The potential allergenicity assessed by in vitro IgE binding exhibited an initial increase followed by a decrease with ultrasonic processing time up to 120 min, reaching the lowest level at 80 min. These results suggest that soybean 7S globulin with ultrasonic processing for 80 min has a lower potential allergenicity.

Nano-sized bone products were made from fish bone, pig bone, bovine bone and chicken bone using highenergy wet milling, respectively. Their properties were investigated in order to provide a theoretical foundation for the production and application of nano-sized bone products. The proximate compositions of bones of four different animals were significantly different (P < 0.05). Briefly, ash content was the highest in fish bone while crude fat and protein were the highest in chicken bone. After high temperature treatment (120 ℃), the wavenumbers and intensities of the characteristic absorption bands assigned to phosphate group (PO4 3-) did not significantly change. However, the protein absorption bands at 1 450?1 700 cm-1 were obviously different between fish bone and the others. Average particle size of fish bone was reduced to nanometer range (162 nm) after 1 h milling, and was 135 nm after 2 h milling, while average particle sizes of pig bone, bovine bone and chicken bone were below 200 nm after 2, 2 and 5 h milling, respectively. The minimum average particle size for fish bone, pig bone, bovine bone and chicken bone were 117, 105, 89 and 153 nm, respectively. During the milling process, the release rate of calcium linearly increased, pH increased and then kept steady, lightness and whiteness significantly increased, free amino acid and trichloroacetic acid-soluble peptide contents dramatically increased. Therefore, fish bone may be the most suitable material for producing nano-sized bone product with improved breakage efficiency and whiteness.

The effect of individual polyphenols extracted from blueberry leaves on the thermal decomposition of trimethylamine oxide (TMAO) in TMAO-Fe(Ⅱ) model system was studied, and the reaction mechanism was also explored with respect to free radical. The results showed that the individual polyphenols could inhibit the thermal decomposition of TMAO, and reduce the contents of TMA, DMA and FA. The inhibition was more significant at higher concentrations of polyphenols. At the same concentrations, the inhibitory effect of quercetin-3-D-galactoside was better than that of chlorogenic acid. With the increase of temperature, chlorogenic acid and quercetin-3-D-galactosidase significantly inhibited the thermal decomposition of TMAO. When the heating time was less than 75 min, the inhibitory effect of chlorogenic acid and quercetin-3-D-galactoside was significant. The best inhibition of quercetin-3-D-galactosidase and chlorogenic acid was observed at pH 8.0 and 5.0, respectively. Free radicals were produced during the thermal decomposition of TMAO.Chlorogenic acid and quercetin-3-D-galactosidase could inhibit the production of (CH3)3N free radicals in a concentrationdependent fashion. The generation of formaldehyde was suppressed by chlorogenic acid and quercetin-3-D-galactosidase by inhibiting the formation of free radicals.

Acetylated epigallocatechin gallate (EGCG) was chemically synthesized in ethyl acetate solvent system for improving the lipid solubility and bioavailability of EGCG. The effects of acetyl anhydride dosage, catalyst pyridine dosage, ethyl acetate dosage, reaction temperature and reaction time on the substitution degree of acetylated EGCG were studied. As a result, it was found that 0.04 mL of acetic anhydride, 0.02 mL of pyridine, 20–60 mL of ethyl acetate, a reaction temperature of 20–25 ℃ and a reaction time of 1–3 h were optimal for the synthesis of acetylated EGCG with a degree of substitution in the range from 1 to 3 from 0.19 g of EGCG. The optimal synthesis conditions for EGCG acetylation that provided a substitution degree between 4 and 6 were 0.12–0.20 mL of acetic anhydride, 0.06–0.20 mL of pyridine, 10–20 mL of ethyl acetate, a reaction temperature of 17–25 ℃, and a reaction duration of 5–9 h, while those for a substitution degree of 7–8 were 0.40–0.80 mL of acetic anhydride, 0.01–0.20 mL of pyridine, 5–10 mL of ethyl acetate, a reaction temperature of 25–40 ℃, and a reaction duration of 5–9 h.

The effect of cabbage maturity on the monosaccharide composition and antioxidant activity of cabbage dietary fiber was studied. The data obtained suggested that, with cabbage maturation, the content of soluble dietary fiber (SDF) kept decreasing, whereas insoluble dietary fiber (IDF) and total dietary fiber (TDF) tended to firstly increase and then drop. The constituent monosaccharides of cabbage dietary fiber at different maturity stages were identical, namely galacturonic acid, glucuronic acid, glucose, galactose, rhamnose and arabinose, despite a significant difference in their percentages. In the case of cabbage SDF, with the increase in maturity, the percentage of glucuronic acid decreased, glucose and galactose increased significantly, and galacturonic acid, rhamnose and arabinose showed a parabola, reaching its peak at maturity B. As for cabbage IDF, with increasing maturity, the percentages of glucuronic acid and galacturonic acid increased significantly, glucose and galactose had no change at first and then decreased significantly starting from maturity D, arabinose showed a parabola reaching the highest level at maturity D, and rhamnose had no significant difference. The antioxidant activity of cabbage dietary fiber was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging capacity, and ferric reducing antioxidant power (FRAP). Our results showed that the DPPH radical scavenging capacity and FRAP of cabbage SDF and IDF significantly increased with cabbage maturation, and the ABTS radical scavenging capacity at maturity C was at the highest level.

In this study, the effects of phosphorylated ovalbumin (PP-OVA) on heat-induced aggregation of native ovalbumin (N-OVA) were investigated. Results showed that PP-OVA effectively suppressed N-OVA aggregation, and the inhibited ability is little weakened when the ionic strength ranged from 10 to 100 mmol/L. Dynamic light scattering analysis showed that the size of the formed N-OVA aggregates decreased in the presence of PP-OVA. Transmission electron micrographs further showed that the N-OVA/PP-OVA mixture exhibited a more uniform size distribution than N-OVA alone. After heat treatment solution of N-OVA, the ζ-potential increased with PP-OVA increased, suggesting that the system became more stable. The result of native-PAGE suggested that the N-OVA/PP-OVA aggregates possess a well-solubility and homogeneity. These results indicate that PP-OVA exhibits a chaperone-like activity under heating, and provide an insight into the possible mechanism through which PP-OVA stabilizes proteins to resist heat-induced N-OVA aggregation.

The aim of the present work was to illustrate the effect and mechanism of action of NaCl concentration on the adsorption capacity of myofibrillar proteins (MPs) to flavor compounds. We selected 17 typical flavor compounds including alcohols, aldehydes, ketones and esters as flavor compounds for investigation of their adsorption properties onto MPs in the NaCl concentration range of 0.0?1.0 mol/L, and we also researched the effect of NaCl concentration on the structure of MPs. Our results showed that the hydrophobicity of MPs significantly increased in the NaCl concentration range of 0.0?0.4 mol/L but remarkably decreased as NaCl concentration rose further to 1.0 mol/L. The α-helix and β-sheet turned into β-turn at NaCl concentration of 0.0?0.4 mol/L and the secondary structure of MPs did not significantly change at higher NaCl concentration. MPs exhibited low adsorption efficiency for alcohols. The adsorptivity for alcohols, aldehydes and ketones in general decreased with increasing NaCl concentration, and the adsorptivity for esters tended to decrease at NaCl levels of 0.0?0.4 mol/L and increase with increasing NaCl level up to 1.0 mol/L. The decreased adsorption to aldehydes and ketones was attributed to the shielding of Schiff sites caused by the unfolding of secondary structure at low salt concentration, and the decrease of hydrophobicity at high salt concentration. The adsorption capacity to esters was negatively related to hydrophobicity, since the binding depended on electrostatic interaction.

The effect of thermal treatment time on physicochemical properties and film-forming ability of acid-soluble collagen (ASC) from tilapia skin was investigated. No significant difference in UV absorption or molecular weight distribution of ASC was observed during thermal treatment. With increasing thermal treatment time, the specific viscosity of ASC was decreased, and the denaturation temperature and thermal transition temperature were decreased from 32.6 to 27.0 ℃ and from 38.15 to 29.19 ℃, respectively. When thermal treatment time was more than 10 min at 42 ℃, The results of turbidity experiments indicated that the ASC did not possess fibril-forming ability after 10 min treatment at 42 ℃. Furthermore, the fibril formation of natural collagen was also hindered by thermally denatured collagen. On the other hand, the tensile strength of collagen films was increased from 30.81 to 41.33 MPa, the elongation at breaks from 8.95% to 11.59%, and the transparency value from 2.42 to 3.33 with increasing thermal treatment time. Based on the results of scanning electron microscopy, it was found that the fibrous structure of collagen films was gradually converted to a wrinklelike structure during thermal treatment. From the above results, it could be concluded that the fibril-forming ability of ASC from tilapia skins was decreased after thermal denaturation, while the film-forming ability was increased.

The interaction between the mycotoxin aflatoxin G1 (AFG1) and human serum albumin (HSA) was investigated by molecular docking, fluorescence spectroscopy, 3D fluorescence spectrum, and circular dichroism (CD) under simulated physiological conditions (pH 7.4). According to the double logarithmic equation, the major binding mechanism between AFG1 and HSA was a static quenching process. At four different temperatures, the magnitude of binding constants was 104 and the number of binding sites was approximate to 1. Through the molecular docking and the calculation of thermodynamic parameters, the binding site of AFG1 was in the ⅠB hydrophobic cavity, and hydrophobic interaction and hydrogen bonding were the major forces in the binding process. By studying the effect of metal ions on AFG1-HSA reaction, the affinity of AFG1 to HSA could be increased by Mg2+ and Fe3+ but greatly reduced by Zn2+, Mn2+ and Cu2+. The binding distance between AFG1 and HSA was calculated to be 3.26 nm based on Förster’s non-radiation energy transfer theory. The 3D florescence spectra revealed that the microenvironment of amino acid residues became more hydrophobic after the binding reaction. CD spectra revealed that the conformation of HSA was changed during the binding reaction as shown by an increase in α-helix.

Static adsorption experiments were carried out with simulated Chinese liquor containing 57% alcohol (V/V) added with dimethyl phthalate (DMP), di-n-butyl phthalate (DBP), diisobutyl phthalate (DIBP) and diethylhexyl phthalate (DEHP) to investigate the adsorption efficiency of four macroporous resins and four special-purpose liquor carbon adsorbents towards the phthalate plasticizers. Further validation experiments were performed with Luzhou-flavor base liquor containing 57% alcohol (V/V) to find the optimal adsorbent for the removal of plasticizers from Chinese liquor based on the adsorption efficiency of plasticizers and losses of four major aroma components including ethyl acetate, ethyl butyrate, ethyl lactate and ethyl caproate. The results showed that the adsorption efficiency of JT201 and JT203 liquor carbon adsorbents towards four phthalate esters was better for simulated Chinese liquor, with average adsorption rates of 91.01% and 87.21%, respectively. The nonpolar resin D4006 had the best adsorption efficiency among four macroporous resins, giving an adsorption rate of 73.67%, while the average adsorption rates of the polar resin NKA-II and active carbon were only less than 60%. Therefore, JT201 and JT203 were chosen as the ideal absorbents. The adsorption rates of DMP and DBP onto JT201 and JT203 were higher than 90%, and the adsorption rates of DIBP and DEHP onto JT201 were higher than 80%, and were 78% and 72% onto JT203, respectively. The loss rates of ethyl acetate, ethyl butyrate, ethyl lactate, and ethyl caproate were 7.7%, 6.1%, 11.9%, 11.6% and 10.4%, 8.6%, 33.9%, 16.0% respectively. In conclusion, JT201 active carbon was chosen as the optimal absorbent for the removal of plasticizers from Luzhou-flavor base liquor in the present study.

In this study, a composite gel was prepared with konjac glucomannan (KGM) and whey protein (WP). The change in partial molar free energy was calculated through mathematical analysis of equilibrium swelling to predict swelling equilibrium parameters. Rheological experiments were applied to evaluate fluid behavior and viscoelastic properties of KGM-WP gels. The results revealed that the composite system achieved swelling equilibrium when the ratio between KGM and WP was greater than 7:3 (m/m). In this situation, the dynamic modulus remained constant with stress changes, and it was not significantly affected by temperature. At a KGM-WP ratio lower than 7:3 the stability of the composite gel decreased with increasing WP proportion. Frequency scanning and swelling behavior analysis indicated that a synergistic effect existed between KGM and WP at a ratio above 70%.

The functional characteristics of the protein from mung bean starch processing wastewater were studied. The results showed that the protein was most soluble at 40 ℃ and pH 9. The highest water-holding capacity (up to 362.63%) was observed at 40 ℃ and the oil-holding capacity did not change significantly between 150% and 170% with temperature. The emulsifying capacity, emulsion stability, foaming capacity and foam stability of the protein increased by increasing its concentration. Electrophoresis results showed that the protein consisted of five fractions of 62.5, 46.1, 27.0, 20.9 and 16.2 kD, respectively. The amino acid analysis showed that the contents of total amino acids and essential amino acids were 616.802 mg/g and 233.960 mg/g, respectively. Methionine was the first limiting amino acid. In addition, the secondary structure contained 39.68% α-helix, 20.13% β-sheet, 16.56% β-turn and 23.71% random coil. The range of characteristic decomposition temperatures was determined as 220?360 ℃.

In order to improve the quality of heat-induced myofibrillar protein gel from squilla, the influence of addingdifferent amounts of Artemisia sphaerocephala Krasch. gum (ASK gum) namely, 0%, 0.2%, 0.4%, 0.6%, 0.8% and 1.0%, was investigated on the properties of heat-induced myofibrillar protein gels under different conditions of NaCl concentration (0.1, 0.2, 0.3, 0.4 and 0.5 mol/L) and temperature (60, 70, 80 and 90 ℃). The results showed that with addition of the same amount of ASK gum, the water-holding capacity of heat-induced myofibrillar protein gels at 90 ℃ was higher than at 60 and 70 ℃ (P < 0.05). Gel hardness and elasticity at 80 ℃ were higher than at 60 and 70 ℃ (P < 0.05), but the difference in whiteness was not significant (P > 0.05). With the increase in NaCl concentration, the water-holding capacity and hardness of the gels rose at first before reaching the maximum values at 0.3 mol/L followed by a decrease, and elasticity and whiteness kept increasing. At 90 ℃, the gel with 1.0% ASK gum added had the best water-holding property. At the same temperature, the elasticity of the gels was strengthened with the increase of ASK gum addition; the maximum hardness was achieved with addition of 0.6% ASK gum, and whiteness presented a decreasing trend. These results may provide a basis for the application of ASK gum in squilla products.

This study researched the effects of water extracts from six different species of edible mushroom, Flammulina velutipes, Lentinus edodes, Auricularia auricula, Pleurotus ostreatus, Agaricus bisporus and Pleurotus eryngii, on the microbial community composition and structure in the human intestine. Towards this goal, MiSeq PE250 Illumina nextgeneration sequencing platform was used to identify the sequence of the 16S rDNA V4 region from the bacterial cells. Sequencing results showed that different species of edible mushrooms had different impacts on the intestinal mictrobiota. Higher populations of Firmicutes were found in the Flammulina velutipes group, Bacteroidetes, Proteobacteria, Firmicutes, Bifidobacterium and Lactobacillus in the Lentinus edodes group, Bacteroidetes, Actinomycetes, Firmicutes, Bifidobacterium and Lactobacillus in the Auricularia auricular group, Bacteroidetes, Actinomycetes, Firmicutes and Lactobacillus in the Pleurotus ostreatus group, Bacteroidetes and Actinomycetes in the Agaricus bisporus group, and Actinomycetes in the Pleurotus eryngii group.

Wheat gluten was glycosylated with glucose after ultrasonic pre-treatment to investigate changes in solubility and emulsifying activity. Meanwhile, the structural properties of glycosylated wheat gluten were characterized. Results indicated that appropriate ultrasonic pretreatment facilitated the glycosylation of wheat gluten. It was found that the glycosylation of wheat gluten with 40 min ultrasonic pretreatment at 40 kHz, 300 W significantly improved its solubility at the isoelectric point by 82.15% compare to the control group. In addition, the emulsifying capacity and emulsion stability reached the maximum level of 56.82 m2/g and 36.27 min, respectively. Appropriate ultrasonic pretreatment could increase the surface hydrophobicity (H0) of wheat gluten, while it decreased after grafting with glucose. Fourier transform infrared spectroscopy indicated that wheat gluten grafted with glucose through covalent bonds to form glycoprotein.

In this study, the composition and structural characteristics of angiotensin converting enzyme (ACE) inhibitory peptides derived from albumin extracted from red pine nuts were evaluated. The hydrolysate of albumin was separated by ultrafiltration, Sephadex G-25, Sephadex G-15 and reversed-phase high-performance liquid chromatography (RPHPLC). The structural characteristics of the purified fraction (D2) were identified by electrospray ionization tandem mass spectrometry (ESI-MS/MS), and one ACE inhibitory peptide was obtained with amino acid sequence of Tyr-Leu-Leu-Lys (YLLK) and molecular mass of 535.34 D. According to the amino acid sequence, an ACE inhibitory peptide was synthesized with a purity of 99.8%. The half maximal inhibitory concentration value of YLLK was 0.282 5 μmol/L.

Chitosan-citric acid complex was prepared by acylation reaction between chitosan and citric acid, and its weightaverage molar mass and water solubility were determined. Then, the structural characterization was investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) to validate the occurrence of acylation reaction. In addition, we explored the adsorption efficiency of chitosan and its complex for cadmium ions and their scavenging capacity against hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals. Results indicated that compared with chitosan, the weightaverage molar mass and water solubility of chitosan-citric acid complex significantly increased. At the same time, structural characterization directly or indirectly proved that citric acid was successfully introduced into chitosan via acylation reaction and the structure differences resulted in differences in the properties of chitosan and its complex. In addition, the adsorption efficiency for cadmium ions and free radical scavenging capacity of chitosan-citric acid complex were better than those of chitosan. This research can provide some evidence for the practical application of chitosan and its derivatives.

The viscosity of mango pulp is an important factor that can provide the necessary information for the optimum design of processing units and influence consumers’ acceptability of the product. This study aimed to examine how the particle size and water soluble pectin (WSP) of un-blanched and blanched mango pulps could be affected by high pressure processing (HPP, 400 MPa/5 min or 600 MPa/1 min) and high-temperature short-time (HTST, 110 ℃/8.6 s) treatment and in turn influence the viscosity. Results showed that HPP did not change the particle size distribution of mango pulp and molar mass distribution of WSP, but it resulted in a decrease in galacturonic acid content and degree of esterification (DE) of WSP. Pectin with lower DE tended to form a stable network structure with Ca2+ bridge easily, leading to increased viscosity of mango pulp. However, HTST significantly increased the particle size distribution of mango pulp and WSP content, which may contribute to an increase in the viscosity of HTST-treated mango pulp.

The objective of this research was to reveal the effect of high pressure homogenization on the change in protein secondary structure and physicochemical and functional properties of soybean protein isolate (SPI)-lecithin system through characterizing conformational changes by circular dichroism spectroscopy and through measuring emulsifying capacity, emulsion stability, surface hydrophobicity and droplet size distribution. The results showed that high pressure homogenization improved emulsion activity index and emulsion stability index of the complex system significantly. The surface hydrophobicity of SPI significantly increased at higher pressure of homogenization, implicating considerable exposure of surface hydrophobic groups and increased interaction between soybean protein and phospholipid. After the homogenization treatment, the average droplet diameter of the composite system decreased from 33.21 to 3.61 μm, and the droplet size distribution was uniform with a slight shift towards smaller droplet sizes. Circular dichroism spectral results showed that high pressure homogenization resulted in conformational changes of the composite system, implying the occurrence of interaction between protein and lecithin. However, with further increasing homogenization pressure, only a little reduction in α-helix content was observed compared with untreated samples.

The experiment was carried out with Bamei × small tailed sheep fed in a drylot and slaughtered at 6, 12, 18 and 24 months of age (10 half male and half female animals with similar carcass weights at each age) to determine physicochemical parameters, muscle fiber characteristics, and the yield and sensory quality of instant-boiled mutton from hindquarters. The results showed that except pH24 (pH at 24 h postmortem) and the elasticity and yield of instantboiled mutton, there were significant differences in all investigated parameters of hindquarters from sheep carcasses at different slaughter ages (P < 0.05). Both hardness and chewiness were positively correlated with sarcomere length (r = 0.639 and 0.618, P < 0.05), and likewise springiness was positively correlated with muscle fiber density (r = 0.588, P < 0.05). Collagen content was inversely correlated with the yield of instant-boiled mutton (r = −0.458, P < 0.05). The color, tenderness, flavor and overall acceptance score of instant-boiled mutton from sheep slaughtered at 6 months of age were significantly better than those of sheep slaughtered at 24 months of age (P < 0.05). The sensory quality of instantboiled lamb was more popular among sensory panelists than that of sheep slaughtered at older ages. Therefore, meat from young lambs was more suitable for instant boiling than older ones.

The C-domain selective angiotensin-converting enzyme (ACE) inhibitory activities of food-derived dipeptides, including Ile-Trp (IW) and Val-Trp (VW), were recently verified by experiments. However, their interaction modes with the C-domain and N-domain of ACE and the molecular mechanism remain unclear. In the present study, flexible molecule docking technology was used to elucidate the active sites, interaction energy and intermolecular force types between the peptides and ACE. The results demonstrated that hydrogen bond, hydrophilic, hydrophobic and electrostatic interactions, and coordinate bond existed between the active pockets of the C-domain and IW and VW. The interaction of the N-domain with the peptides was similar to that of the C-domain, which had fewer hydrogen bonds and no electrostatic interactions. By calculating the binding energy difference between the two domains, we could seek the theoretical support for the different inhibitory potency of IW and VW. The above information will be helpful for the development of C-domain selective ACE inhibitory peptides.

The bitter and astringent substances in Ma bamboo shoots (Dendrocalamus latiflorus) were determined by quantitative analysis, and their relationship with taste was assessed by sensory evaluation. The fresh bamboo shoots were boiled at 100 ℃ for five different time periods i.e., 0, 30, 90, 150 and 420 s, respectively, and the residues and soups were measured for soluble tannin, oxalate and bitter amino acids (Phe, Val, Arg, Met and Leu), and sensory evaluation of bitter and astringent intensity by trained panelists. The bitterness and astringency of food-grade oxalic acid and tannin standard alone and their mixture at different concentrations were evaluated by sensory panelists to develop a characteristic function describing the relationship between concentration and taste intensity. The results showed that the bitter and astringent tastes of bamboo shoots was overwhelmingly ascribed to the presence of soluble tannin, and the relationship between both tastes and tannin was highly significant with a correlation coefficient of 0.896 and 0.867, respectively. The relationship between bamboo shoot astringency and oxalic acid was significant with a correlation coefficient of 0.448, but there was no significant relationship between bamboo shoot bitterness and oxalic acid. Moreover, no significant relationship existed between the two taste attributes and free bitter amino acids. The functions with tannin concentration as independent variable were used to explore the cause of the heavy bitterness and astringency of bamboo shoots. The results obtained from the analysis of nine samples showed that the models were reliable with a relevancy up to 60.6%–136.4% for astringency and 63.4%–132.0% for bitterness. The heavy bitterness and astringency of Dendrocalamus latiflorus was mainly caused by high contents of soluble tannin.

To understand the dielectric properties of different types of protein in aqueous solutions and further to develop a method for detecting protein adulteration of liquid foods, an open-ended coaxial-line probe was used to explore the changing patterns of the dielectric constant ε’ and dielectric loss factor ε” of aqueous protein solutions (soy protein, whey protein and egg albumin) at a concentration of 0%–4.63% in the frequency range of 20–4 500 MHz at 25 ℃. The results showed that ε’ decreased with increasing frequency, and ε” decreased at first and then increased. At the same protein concentration, the values of ε’ and ε” in soy protein and whey protein solutions had no significant difference, but they were smaller than those in egg albumin at a certain frequency. There were good linear correlations between protein concentration and dielectric properties with a correlation coeffiient of 0.90 and 0.99, respectively. This study indicated that different proteins and their concentration had different influences on dielectric properties of protein solutions, which makes it possible to detect protein types and concentration in protein-based beverage based on dielectric properties.

Quality changes of smoked skipjack tuna processing byproduct during enzymatic hydrolysis under optimized conditions (trypsin to flavourzyme activity, 2:1; and total enzyme dosage, 3 000 U/g) were analyzed. The results showed that the degree of hydrolysis (DH) kept increasing during 30 h hydrolysis. Sensory evaluation showed that the hydrolysates had a favorable sensory score within 10 h, and then began to fall sharply. The content of TVB-N increased slowly during the first 10 h and then increased sharply. The nitrogen solubility index kept rising during the first 20 h and then increased slightly. Free amino acid content gradually increased during the entire hydrolysis process, but increased slower from 20 h onwards. Glutamic acid, giving a relatively higher TAV value and umami taste, contributed most to the overall taste of the hydrolysates. Although they continuously decreased as the reaction time extended, phenols and aldehydes made significant contribution to the flavor of the hydrolysates, especially the latter, which had a higher relative odor activity value (ROAV). The results of the present study is useful for the preparation of high-quality smoked skipjack tuna hydrolysate with good flavor, and could also provide a theoretical basis for further development of related seafood seasoning products.

The aim of this study was to determine the differences in the physicochemical properties of starch granules extracted from native and microwave precooked white sorghum by scanning electron microscopy, polarizing microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. It was found that the polarized crosses of the microwave-treated starch became more blurred, with nearly half disappearing. In addition, the starch granules became swelled, along with a reduction in resistant starch, relative crystallinity, phase transition temperature range and endothermic enthalpy. But both starches had the same structural characteristics as demonstrated by the infrared spectra of the samples. The results showed that microwave treatment was helpful for starch gelatinization while not changing the chemical composition of white sorghum starch.

Objective: The effect of cryogenic treatment on the structure of grape skin cells was investigated to reveal the mechanism of wine quality improvement. Methods: Grapes of the cultivars Hutai No. 8 and Cabernet Sauvignon were treated at 4, −8, −20 and −32 ℃ and with liquid nitrogen, respectively, and then examined with an electron microscope. The contents of tannins, total phenols, total anthocyanins and aroma compounds were also determined. Results: Grape skin cells had no significant change after treatment at 4 ℃, but cell plasmolysis and crystals of tannin and starch were observed after treatment at −8 ℃. Serious deformation of cells, clutter of intracellular contents, cracking of the cell membrane and organelles, and exosmosis of cell inclusion were observed in parallel with the increase of ergastic substances and crystals after treatment at −20 ℃. The structures of the cell wall and membrane were destroyed completely after treatments at −32 ℃ and with liquid nitrogen. These data showed that cryogenic treatment especially at −8, −20 and −32 ℃ allowed the extraction of more tannins, total phenols, total anthocyanins and aroma compounds from grape skins, and the contents of these substances were significantly different at different treatment temperatures. However, aroma substances could not be extracted at 4 ℃ and liquid nitrogen. Conclusion: Cryogenic treatment results in cell damage of grape skins and improved exosmosis of phenolics and aromatic compounds, thereby being beneficial to wine quality.

In order to study the influence of gelatinization and gelling properties of potato starch on the quality of fresh wet potato noodles, the gelatinization and gelling properties of six different commercial potato starches were evaluated by using a rapid visco analyzer (RVA) and a texture analyzer, and the relationship between the quality of fresh wet potato noodles and these starch properties was discussed. The results showed that there was a close relationship between gelatinization and gelling properties of potato starch, and the quality of fresh wet potato starch was closely related to gelatinization and gelling properties of potato starch. Gelatinization properties of potato starch were significantly correlated with the sensory quality and breaking rate of potato noodles, and they could be ranked according to their significance (correlation coefficient, r) as follows: setback > trough viscosity > peak viscosity > final viscosity > breakdown > gelatinization temperature. Similarly, gelling properties of potato starch were significantly correlated with the sensory quality and breaking rate of potato noodles, and they could be ranked according to their significance (correlation coefficient, r) as follows: chewiness > gelling strength = viscosity > hardness > resilience > springiness. In the process of fresh wet potato noodles production, we could take the setback, chewiness, gumminess and gelling strength of potato starch as indicators to evaluate the quality of raw materials. This study would provide the theoretical basis for raw material selection for and quality improvement of fresh wet potato noodles.

The structural and functional properties of defatted rice dreg protein, obtained by different simulated industrial degreasing methods including alkaline hydrolysis, lipase hydrolysis and ethanol soaking, were determined. The degreasing rates were 95.66% for ethanol soaking, 81.29% for lipase hydrolysis, and 77.35% for alkaline hydrolysis, respectively. Besides, results showed that all three degreasing methods had no significant effect on the primary and secondary structures of rice dreg protein, but changed the protein composition and tertiary structure to a certain degree. In addition, surface microstructure analysis showed that the degreasing process affected the aggregation of rice dreg protein. The degreasing process could significantly affect the functional properties of rice dreg protein by modifying its composition and structure. It is worth noting that lipase degreasing could significantly improve the functional properties of rice dreg protein.

This study investigated the peptide profiling of four yogurt samples (Youweishu flavored fermented milk, plain flavored fermented milk, Churu 24+K flavored fermented milk and Shitian flavored fermented milk) from local market by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 152, 125, 364 and 274 peptides were identified from the yogurts by LC-MS/MS, respectively. Angiotensin converting enzyme (ACE) inhibitory activity was used to evaluate the biological activities of yogurt peptides. The ACE inhibition rates of peptides from these yogurts were 46.84%, 42.75%, 77.41% and 63.84% at a concentration of 2.0 mg/L, respectively. The large number of identified peptides and high ACE inhibitory activities in Churu 24+K flavor fermented milk may be related to its special ingredients. This study may provide the theoretical basis for further study on the functions and ACE inhibitory activity of yogurt peptides.

The antioxidant and acetyl cholinesterase inhibitory activities and polyphenol contents of ethanol extracts from the peel, pulp and pit of avocado fruits of four different cultivars were assayed and compared in this work. The results showed that the contents of total polyphenolics in three parts of avocado fruits ranged from 9.6 to 27.8 mg gallic acid equivalents (GAE) per gram dry weight. The antioxidant and acetyl cholinestera inhibitory activities of all samples were in a concentration-dependent manner. Among four avocado cultivars, the peel and kern of the Reed cultivar exhibited the greatest activity in scavenging 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical (ABTS＋·), as well as inhibiting acetyl cholinesterase, whereas the peel and pit of the Reyan 1 and Fuerte cultivars displayed the highest hydroxyl free radical scavenging activity. For the same variety, the activity of extracts from the peel and pit was much stronger than that of the pulp. Therefore, we should improve the utilization of inedible parts (peel and pit) of avocado fruits as much as possible during processing in order to turn the wastes into treasure and achieve high value-added utilization.

To understand the effect of Lactarius deliciosus Gray polysaccharide (LDG-A) on the proliferation of specific immunocytes and tumor cell apoptosis, we tested and observed the proliferation and morphological changes of T lymphocytes and B lymphocytes in the presence of LDG-A, determined the number of T lymphocytes and B lymphocytes in each stage of the cell cycle, and also evaluated antibody secretion by B lymphocytes under the stimulation of LDG-A. In addition, the apoptosis and cytoskeleton of lung cancer cell A549 were evaluated. The results showed that the proliferation of B lymphocytes and T lymphocytes’ proliferation was promoted LDG-A in a dose-response manner. LDG-A could also reduce the number of B lymphocytes at the G0/G1 phase and promote them to enter the G2/M phase. Meanwhile, LDG-A also promoted the secretion of IgM, IgD and IgE by B lymphocytes. In addition, LDG-A in the range of 12.5–50.0 μg/mL could induce the apoptosis of lung cancer cell A549 in a dose-dependent manner. Moreover, we observed fractured F-actin filaments in the cells as well as damaged protein fiber networks during apoptosis. In conclusion, LDG-A has a promoting effect on the proliferation of specific immunocytes, and accelerates the apoptosis of tumor cells in vitro.

Purpose: To investigate the effect of oligopeptide from Panax ginseng grown in Jilin province (GOP) on hyperlipidemic rats. Methods: Totally 108 specific pathogen free (SPF) male SD rats were randomly divided into 9 groups: normal control, model, whey protein group, and six GOP groups with different doses. The rats from the normal control group were fed a basal diet only. The rats from the rest groups were fed a high-fat diet for 2 weeks. Then, the rats in six GOP groups were gavaged with GOP at doses of 0.062 5, 0.125 0, 0.250 0, 0.500 0, 1.000 0 and 2.000 0 g/kg, respectively, those in the normal control and model groups with the same volume of distilled water, and those in the whey protein group with whey protein at a dose of 0.250 0 g/kg for 30 days. At the same time, all rats were provided with the corresponding diets uninterruptedly. Results: The TC, LDL-C, HDL-C and TG levels in serum had no significant change in rats from the GOP groups at each dose. The MDA level was significantly decreased and SOD and GSH-Px activities were significantly elevated in serum and liver tissue of rats from the GOP groups. Besides, serum NO and NOS levels were significantly elevated in the GOP groups. Conclusion: GOP does not has a hypolipidemic effect, but it may have an anti-atherosclerosis effect.

The purpose of this study was to explore the protective effect of wolfberry and mulberry polysaccharides combined with lutein on visible light-induced retinal degeneration through their antioxidant activity. Pigmented rabbits were exposed to visible light to induce retinal light damage and then treated with different doses of polysaccharides extracted from a mixture of both dried fruits (1:1, m/m) and lutein for 21 days. Afterwards, lipid peroxidation, protein oxidation, DNA oxidation biomarkers and antioxidant parameters in the retina were evaluated. The results revealed that light exposure induced significant increases in oxidative damage to lipids, proteins and DNA in the retina of pigmented rabbits. In contrast, co-treatment with medium and high doses of polysaccharide extracts and lutein decreased the contents of malondialdehyde (39.02%; 54.08%, P < 0.05), 4-hydroxy azelaic acid (32.86%; 41.78%, P < 0.05), 3-nitro-tyrosine (17.20%; 19.69%) and 8-hydroxy-deoxyguanosine (6.12%; 28.81%), paralleling with increased activities of catalase (1.96-fold; 2.40-fold, P < 0.05) and total antioxidant capacity (1.98-fold; 2.11-fold, P < 0.05). Accordingly, combined intervention with wolfberry and mulberry polysaccharides and lutein can significantly alleviate visible light-induced retinal oxidative damage in pigmented rabbits.

Objective: To evaluate the improvement of blood glucose levels in type 2 diabetic rats using buckwheat hull extracts (BHEs) rich in flavonoids and to explore its possible mechanisms. Methods: The inhibitory effect of BHEs on α-glucosidase and α-amylase activities was evaluated in vitro, and the type of enzyme inhibition was determined by Lineweaver-Burk (L-B) analysis. Type 2 diabetic rat models were established with a high-fat diet and intraperitoneal injection of streptozotocin (STZ), and then the rats were randomly divided into control (without induction of diabetes mellitus, given distilled water), model group (given distilled water), positive control group (gavaged with metformin hydrochloride at 100 mg/(kg·d)), and low-, medium- and high-dose BHEs groups (50, 100 and 200 mg/(kg·d), respectively). The administration by gavage once a day last for 28 days. The body weight, fasting blood glucose (FBG), fasting serum insulin (FINS), fasting C-peptide and oral glucose tolerance test (OGTT) were determined during this period. Results: The inhibitory activity of BHEs on α-glucosidase-maltose system was dose dependent with a percentage inhibition of 41.12% at a concentration of 1 mg/mL. The data of enzyme kinetics showed the inhibition was competitive. In the model group, body weight was reduced by 33.1%, FBG was increased up to (17.85 ± 2.25) mmol/L as well as the levels of FINS and C peptide were reduced to 24.80% and 12.77%, respectively (P < 0.05), when compared with the normal control group. Compared with the model group, the BHEs groups showed a significant improvement in body weight loss after 28 days of invention, FBG levels in the medium- and high-dose groups were decreased by 39.4% and 48.2%, respectively, and the area under the curve (AUC) of OGTT was declined by 47.36% and 59.47%, respectively (P < 0.05). Compared with the model group, the middle- and high-dose groups improved the levels of FINS by 32.79% and 34.44% and C-peptide by 7.40% and 13.08%, respectively (P < 0.05). Conclusion: BHEs can improve blood glucose level in a dose-dependent manner in type 2 diabetes induced by STZ as α-glucosidase inhibitors, and simultaneously can repair islet β-cell function.

The anti-aging effect of polysaccharides from the fruiting body of Pleurotus geesteranus (PFP) on a D-galactoseinduced aging mouse model. The aged mouse model was established by the injection of D-galactose. These mice were simultaneously administrated by gavage with PFP at different dosages for 42 days. At 12 h after the last administration, the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the contents of malondialdehyde (MDA) in serum, liver and brain were measured by using commercial reagent kits. The activities of serum aspartate aminotransferase (AST), alkaline phosphatas (ALP) and alanine aminotransferase (ALT), and spleen and thymus indexes were also determined. The liver and brain were taken for histological analysis through HE staining. The results showed that PFP had antagonism effects on D-galactose-induced aging in mice, and could increase the activities of CAT, SOD and GSH-Px and reduce MDA levels in serum, and liver and brain tissues. Compared with the aging model group, the activities of serum AST, ALT, ALP in the medium- and high-dosage PFP group significantly decreased (P < 0.05, P < 0.01) in parallel with a highly significant increase in both spleen index and thymus index (P < 0.01). Histological sections showed that PFP displayed a significant protective effect on liver and brain injury induced by D-galactose. In conclusion, PFP has significant antioxidant and anti-aging effects. The underlying mechanism might be related to improving antioxidant function and enhancing immune function in the body.

Objective: To explore the effect of dietary blend of corn oil and lard at a ratio of 1:1 on blood lipid, liver function and liver antioxidant capacity in mice by simulating Chinese dietary habits. Methods: A total of 24 eight-week male SPF Kunming mice were randomly divided into blank, recommended intake and actual intake groups, which were fed a basal diet supplemented with 0%, 3.8%, and 6.5% of the oil blend, respectively. After 8 weeks, body weight was measured, and peripheral blood was collected for determining serum lipids and liver function indices. The intact liver tissue was collected for the calculation of liver index and morphological and histological examination under microscope. Moreover, liver homogenate was prepared for evaluation of oxidative stress. Results: The liver index in mice was positively correlated with the dietary amount of the oil bend. Alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities in mice from the blank group were significantly higher than those in mice from the recommended intake and actual intake groups. However, total antioxidant capacity in the liver of mice from the recommended intake group was significantly higher than in mice from the blank and actual intake groups. Oxidative liver injury in mice from the blank group was significantly greater than in mice from the two other groups. Conclusion: Insufficient dietary oil has a negative effect on liver function in mice. The recommended intake of corn oil/lard blend at 1:1 can enhance liver antioxidant capacity in mice and reduce oxidative damage.

Objective: To investigate the effect of Dioscorea opposita Thunb. polysaccharide (DTP) extracted from the rhizomes of the ‘Foshou’ cultivar on glycolipid metabolism and oxidative stress in type 2 diabetic rats. Methods: A rat model of type 2 diabetes mellitus (T2DM) was constructed by feeding SD rats a high-fat diet and intraperitoneal injection of streptozocin into them at a dose of 40 mg/kg. The model rats were randomly divided into model control group (MC), positive control group (PC) (metformin at 150 mg/(kg·d)), DTP group (400 mg/(kg·d)), and normal control group (NC). During an administration period of six weeks, the general condition of rats was observed. Body weight, hepatic glycogen, blood glucose, and triacylglyceride (TG), low density lipoprotein cholesterol (LDL-C), HDL-C, malonaldehyde (MDA), nitric oxide (NO) and the activties of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) in serum were tested. Results: Compared with the model group, DTP effetively lowered fasting blood glucose levels in rats with experimental T2DM, highly significantly reduced serum TC and LDL-C levels, significantly decreased serum TG levels, and significantly enhanced the activities of SOD and CAT, but it had no significant impacts on hepatic glycogen, serum HDL-C, MDA and NO levels or serum GSH-Px activity. Conclusion: DTP shows a significant hypoglycemic effect on T2DM rats, and can regulate lipid metabolic disorders and the underlying mechanism may be associated with the enhanced activities of CAT and SOD.

Objective: A nano-packaging material containing nano-silver, nano-titanium dioxide, nano-attapulgite and nano-silica was prepared, and the effect of this material on the preservation of the rice cultivar Huaidao 5 at high temperature (37 ℃) and high humidity (relative humidity 85%) was studied. Methods: The rice was packaged in nanocomposite pouches, polyethylene (PE) pouches and not packaged and then stored for 10 weeks, respectively. The effects of different packaging materials on color difference, O2 and CO2 percentages inside packages, peroxide value (POV), catalase activity, and the contents of carbonyl groups, sulfhydryl groups and disulfide bonds were investigated. Meanwhile, the flavor of rice was measured by electronic nose during storage. Results: The low O2 and high CO2 atmosphere was maintained inside nano-packages, and the percentages of O2 and CO2 were 16.4% and 1.4% after 10 weeks of storage, respectively. The nano-packaging material effectively maintained the original color and flavor of rice at the end of storage. Nano-packaging delayed the increase of peroxide value and the decrease of catalase activity during the storage period. Meanwhile, the increase of carbonyl groups and disulfide bonds and the decrease of sulfhydryl groups indicated that the oxidation of rice protein was delayed by nano-packaging. Conclusion: The nano-packaging material has antibacterial effects and can maintain low O2 content and high CO2 content in packages, thereby inhibiting mold growth, decrease catalase activity, and reduce peroxide production. Furthermore, it can also attenuate the oxidation of fat and protein and efectively maintain the original color and flavor of rice.

The microbial community structure of crucian carp was studied by polymerase chain reaction-amplification and denaturing gradient gel electrophorsis (PCR-DGGE) during storage at 4 ℃. Meanwhile, in order to use it for the preservation of crucian carp, the antimicrobial effect of antimicrobial lipopeptide was evaluated through the determination of total bacterial counts, total volatile basic nitrogen (TVB-N), pH and thiobarbituric acid (TBA). The results showed that the microbial community of crucian carp was diverse during storage. Specifically, Aeromonas sp., Pseudomonas sp., Acinetobacter sp. and Brochothrix thermosphacta were the main spoilage microorganisms, and Pseudomonas fluorescens was the dominant spoilage microorganism in the flesh of the fish, while Lactococcus raffinolactis, Comamonas sp. and Aeromonas sp. were the main spoilage microorganisms in the gill. These results also indicated that although the microbial community compositions in the flesh and gill of crucian carp were different, but they showed a similar trend during storage. On the other hand, the antimicrobial lipopeptide at different concentrations significantly inhibited the increase of total bacterial counts, TVB-N, pH and TBA. The lipopeptide at a concentration of 67 608 IU/mL extended the shelf-life of crucian carp by up to 6 days during storage at 4 ℃. All these findings demonstrated that the antimicrobial lipopeptide can significantly inhibit the growth of spoilage microorganisms in crucian carp, thus being a promising preservative.

Immersion chilling and freezing (ICF) is a new low-temperature processing technology with the features of instantaneousness and energy saving. In this study, the quality changes of sturgeon in terms of various parameters were comparatively investigated under the processing conditions of ICF and traditional air freezing (TAF) during 6 months of storage. Results indicated that the freezing rate of ICF was 12.47 times higher than TAF, and ICF could maintain relatively better the texture of sturgeon muscle. In addition, the resilience and L* value of sturgeon during ICF were higher than during TAF (P < 0.05), and a significant difference was also recorded in total volatile basic nitrogen (TVB-N) and peroxide value (POV) (P < 0.05). Thus ICF can better maintain the quality of frozen sturgeon, and it can be used in the freshness maintenance of sturgeon during storage.

The color, smell and taste with perfect blend of the five basic flavors namely sourness, sweetness, bitterness, spice and saltiness as core criterion are three aspects to describe traditional Chinese diet and food cooking and processing. The internationally recognized five tastes are identical to the Chinese ones except for the replacement of spice by umami. It is suggested that the taste of fat be defined as “aroma”, but the Chinese “aroma” belongs to the sense of smell, rather than the sense of taste. Accumulated evidences have demonstrated that the majority of taste receptors as a nutrient sensing system, such as bitterness, sweetness and umami, which have been used as the target for drug screening, belong to the super family of G protein coupled receptor, and its distribution is not restricted to the taste buds, intestinal tract and other tissues. Although a lot of achievements have made in the study of taste receptors, but so far, the instrumental determination of taste still depends on electronic nose and electronic tongue. Taste receptor-based biosensors and related technologies are still under exploration and research. The major reason is due to the effects of all receptors including taste receptors with weak interaction with their ligands. How to transform the weak interaction into signals such as light, sound, electric, magnetism and heat, which can be handled and amplified by sensors to realize quantitative measurement, is a critical problem. Because of the great prospects for the development and application of taste receptors in medical screening, functional evaluation of foods and additives, and the prevention of metabolic syndromes, developing detection methods based on using taste receptors is always one of the research focuses. This article aims to provide a systematic review of recent advances in our knowledge about taste receptors and in the development of taste receptor-based biosensors. The prospects for their future application are discussed as well.

Gelation is one of the main functional properties of protein. The gel formation of protein is affected by many physicochemical factors, and metal ion is one of the major factors affecting protein gelation behavior. The mechanism of the gel formation of protein is elaborated in this paper. Additionally, this article reviews the effects of metal ions on the microstructure, physicochemical characteristics, aggregation behavior, molecular conformation and main molecular forces of protein gels and the value of protein gelation for researchers is predicted in order to provide a theoretical guidance for further researches of the mechanism of action metal ions on protein gelation and the improvement of protein gel products.

Angiotensin converting enzyme (ACE) inhibitory peptides are a category of peptides derived from food proteins which can reduce blood pressure. ACE inhibitory peptides have gained extensive concerns because they can reduce blood pressure without side effects as antihypertensive drugs. In recent years, the structure-activity relationship of ACE inhibitory peptides has become one of the research focuses. Structural bioinformatics showed that the activity of ACE inhibitory peptides is related to not only their molecular masses, but also their amino acid sequences and spatial conformation. It is also found that the type of inhibit of ACE inhibitory peptides is related to their activity and structure-activity relationship. Intensive studies on ACE inhibitory peptide structure-activity relationship will be helpful to guide the development of new functional foods and antihypertensive drugs.