In order to evaluate the effect of roasting on the potential allergenicity of peanut allergen Ara h 1, total protein was extracted from raw and roasted peanuts with chaotropic salt solution and submitted to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The major peanut allergen Ara h 1 separated in the gel was analyzed by mass spectrometry (MS) and Swiss-Model. SDS-PAGE results showed that the roasted peanut protein sample were separated into one macromolecular aggregate band and multiple scattered protein bands, indicating that the protein could aggregate or degrade during roasting. In raw peanut samples, 70 Ara h 1 peptides were detected with a coverage rate of 79.2%. After roasting, 40 of these peptides were found to disappear, but one new peptide was acquired, and the coverage rate consequently decreased to 43.9%. The 71 peptides involved 18 linear IgE-binding epitopes of Ara h 1, and 16 epitopes in raw peanuts were destroyed after enzymatic hydrolysis, while only 12 were destroyed in roast peanuts. Roasting could enhance the allergenicity of peanut Ara h 1 by damaging the spatial structure of the protein and masking some cleavage sites to protect linear IgE-binding epitopes from enzymatic cleavage.

In order to study the antifungal mechanism of tea tree oil (TTO) on Penicillium expansum in postharvest fruits and vegetables, the fungal spores, mycelia and mitochondria treated with TTO were tested for the accumulation of reactive oxygen species (ROS) and changes in six enzyme activities associated with mitochondrial function. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were also used to observe the morphology and ultrastructure of mitochondria. The results showed that TTO treatment caused severe wrinkling and shriveling of mitochondria along with the formation of vesicles within mitochondria and a loss of mitochondrial matrix, thereby seriously damaging the mitochondrial structure. Meanwhile, TTO treatment induced the accumulation of a large amount of ROS in P. expansum spores, thus resulting in a decrease in intracellular adenosine triphosphate (ATP) content and the activities of citrate synthetase (CS), isocitrate dehydrogenase (ICDH), α-ketoglutarate dehydrogenase (α-KGDH), malic dehydrogenase (MDH), and succinate dehydrogenase (SDH) in the mycelial cells and blocking the tricarboxylic acid (TCA) cycle. Therefore, TTO treatment can damage mitochondrial structure and function in P. expansum, cause high accumulation of ROS, and consequently lead to the disruption of the TCA cycle and abnormal energy metabolism. Clearly, causing serious damage to mitochondrial function is the primary mechanism by which TTO inhibits P. expansum.

The Longissimus dorsi muscles of 20 pigs were measured for pH and the expression levels of integrin, vinculin and talin at 45 min, 3 h, 9 h, 12 h and 24 h postmortem, as well as drip loss, and the relationships among them were analyzed. The results showed that the drip loss and talin expression level in the high pH group (pH45 min ≥ 6.00, n = 6) were lower than those in the low pH group (pH45 min ≤ 5.78, n = 14), while the expression levels of integrin and vinculin were higher than those in the low pH group. pH and the expression levels of integrin and vinculin had a negative correlation with drip loss, while talin expression level had a positive correlation with it. pH and the expression levels of integrin, vinculin and talin respectively accounted for 77%, 41%, 44% and 34% of the variation in drip loss. The above results indicated that changes in pH and cytoskeletal protein expression both affected the water-holding capacity of pork, and the decrease in pH had a greater effect on pork water-holding capacity than did the degradation of cytoskeletal proteins. pH could affect the integrity of the cytoskeleton and thus the water-holding capacity of pork. pH at 45 min postmortem can be used to predict the drip loss of pork during postmortem aging.

The purpose of this study was to investigate the effects of different salt concentrations (0.3%, 0.4%, 0.5%, 0.6% and 0.7%) on the formation of micro/nano particles (MNPs) in tuna head soup, prepared under the following conditions: shallow frying 120 ℃ for 40 s and then boiling for 150 min in an eight-fold excess of water. The migration of nutrients from fish head into soup was investigated, and the formation of MNPs during the boiling process was analyzed using a Zetasizer nano ZEN 3600. Furthermore, the morphology of MNPs was observed by optical microscopy, and the interactions among MNPs components were studied by the combined use of laser scanning confocal microscopy and fluorescence labelling. The amount of dissolved nutrients in the soup reached a maximum value at 0.5% salt concentration. The results of Zetasizer nano ZEN 3600 showed that the average particle size, polymer dispersity index (PDI), and zeta-potential value of MNPs were significantly affected by salt concentration (P < 0.05). MNPs had the smallest size at 0.5% salt concentration. These results demonstrated that salt could promote the formation of MNPs in the soup. Moreover, at 0.5% salt concentration, MNPs had an average particle size of (519.1 ± 3.11) nm and formed a stable spherical bilayer in the soup. Cl- was found to permeate into the core of MNPs to bind to triglycerides. Meanwhile, Na+ bound to electronegative polysaccharide molecules dispersed around the surface of MNPs, counteracting the negative charges. At an appropriate salt concentration, the migration of nutrients from fish head into soup reached a maximum value, and so did the stability of MNPs formed by self-assembling of triglycerides, phospholipids, proteins, and glycosylated molecules (glycoproteins and glycolipids) being beneficial to improve the stability of nutrients in the soup.

Cabernet Sauvignon (Vitis vinifera L.) grape berries were used to investigate the influences of three training systems, single guyot (SG), spur-pruned vertical shoot-positioned (VSP), and four-arm kniffin (4AK) , on non-anthocyanin phenolics, and then the clustering analysis and partial least squares-discriminant analysis (PLS-DA) were conducted to evaluate the characteristic non-anthocyanin phenolic constituents from each training system. The results showed that compared to SG and 4AK, VSP resulted in higher contents of quercetin-3-O-glucuronide, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, quercetin-3-O-rhamnoside in grape skins. Besides, the contents of flavonols including myricetin-3-O-glucoside, isorhametin-3-O-glucoside and syringetin-3-O-glucoside, flavan-3-ols including gallocatechin and catechin as well as protocatechuic acid and vanillic acid in grape skins were higher in SG and VSP than in 4AK, while only procyanin C1 was more abundant in 4AK. The clustering analysis showed that some non-anthocyanin phenolics were significantly affected by vintages, and SG and VSP impacted non-anthocyanin phenolics similarly to each other, but quite differently from 4AK. PLS-DA results showed significant differences in the contents of individual non-anthocyanins among training systems. Flavonols such as quercetin-3-O-glucosid and myricetin-3-O-glucoside were the differential non-anthocyanin phenolic components among training systems, which were found to be more important contributors to VSP and more abundant. In summary, VSP training system plays a positive role in the accumulation of non-anthocyanin phenolics, and can be used in wine grape cultivation in the Guanzhong region of Shaanxi.

In this paper, a polysaccharide from Porphyra yezoensis (PSPY) was prepared by water extraction followed by alcohol precipitation and was degraded by a combination of hydrogen peroxide and ascorbic acid. Based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, the optimum degradation conditions were established by one-factor-at-a-time method combined with response surface methodology as follows: both H2O2 and VC concentrations 4.1 mmol/L, temperature 52.4 ℃, and reaction time 2.1 h. The molecular masses of PSPY and the degraded polysaccharide (DPSPY) were 452 and 17 ku, respectively. The contents of total sugar and sulfate in DPSPY increased and protein content decreased relative to PSPY. Fourier transform infrared spectroscopic analysis revealed no significant structural different between PSPY and DPSPY. DPSPY was more biologically active than PSPY in terms of in vitro antioxidant activity, bile salt binding capacity and cellular immunoregulatory activity. This study provides the theoretical basis for the deep processing and product development of PSPY.

In order to investigate the effect of myofibrillar protein on postmortem meat quality and to determine the best post-mortem aging time for Sunit sheep carcasses, the Biceps femoris of Sunit lambs slaughtered at six months of age was evaluated for meat quality, myofibrillar protein functional characteristics, and protein degradation-related indicators during post-mortem aging (from day 0 to 3). The results showed that three meat quality attributes (pH, shear force, and cooking loss rate) reached optimal values on the second day of post-mortem aging, not significantly different from those recorded on the third day. On the first day, the functional properties of myofibrillar protein including hydration properties (solubility and hydrophobicity), gel properties (water-holding capacity and hardness) and emulsifying properties (emulsifying activity index (EAI), emulsion stability index (ESI)) were poor, improved on the second day and then leveled off. Measurement of myofibril fragmentation index (MFI) and sodium dodecylsulphate-polyacrylamide gel electrophoresis indicated that the degree of protein degradation was low on the second day and thereafter remained stabled. Correlation analysis demonstrated that MFI, solubility, hydrophobicity, EAI, ESI, and gel water-holding capacity were correlated with meat quality indicators. In summary, during the post-mortem aging of Sunit sheep carcasses, the degradation of myofibrillar protein and changes in its functional characteristics had a great impact on meat quality, and the best post-mortem aging time was two days.

This study was performed in order to explore the antioxidant activity and structural characteristics of purple speckled kidney bean protein during simulated gastric digestion in vitro. Experimental results showed that as the digestion proceeded, the degree of hydrolysis (DH) and the solubility of the protein increased significantly due to enzymatic action, and more and more peptides with low molecular masses were produced resulting in increased antioxidant activity of the digestion product. At the end of digestion, the total antioxidant capacity and ferric ion reducing power increased by 296.97% and 54.01% as compared to the protein, respectively. Fourier transform infrared (FTIR) spectroscopy analysis showed that the secondary structure of the protein changed significantly after the digestion process. The relative contents of α-helix and β-turn increased and the relative content of β-sheet decreased with increasing digestion time. The contents of free sulfhydryl group and total sulfhydryl group of kidney bean protein decreased greatly after simulated gastric digestion, although they only slightly increased with the extension of digestion time. Under scanning electron microscopy (SEM), the digested protein exhibited granules that were arranged in a disorderly manner to form a dense reticular structure.

Papain was selected to hydrolyze three tilapia muscle proteins (sarcoplasmic, myofibrillar and stroma proteins) and the antioxidant activities of the resulting hydrolysates were investigated. The antioxidant peptides derived from tilapia sarcoplasmic protein were separated and purified by using ultrafiltration, gel filtration chromatography and reversed-phase high performance liquid chromatography (RP-HPLC), and their amino acid composition was determined. The results showed that the antioxidant activity of tilapia sarcoplasmic protein hydrolysates (TSPH) was higher than that of myofibrillar and stroma protein hydrolysates. The TSPH obtained by after 4 h of hydrolysis (6 mg/mL) exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate (84.61%), hydroxyl radical scavenging rate (50.01%) and reducing power (0.629) of the various hydrolysates tested. It was then separated by ultrafiltration, and the fraction with molecular masses of less than 5 kDa was found to possess high antioxidant activity. This fraction was further separated into four sub-fractions (E1–E4) by gel filtration chromatography. It was found that sub-fraction E3 (0.8–0.3 kDa) possessed the highest antioxidant activity, which was determined to be 83.61% and 0.953 in DPPH radical scavenging capacity and reducing power at a dose of 3 mg/mL. Finally, E3 was separated into nine fractions (F1–F9) by RP-HPLC, and F4 exhibited the highest DPPH radical scavenging activity with a half-maximal inhibitory concentration (IC50) of 0.78 mg/mL. Its amino acid composition was dominated by Trp, Gly and His, which accounted for 31.20%, 27.25% and 8.97% of the total amino acids, respectively.

In this paper, nano-scaled fish bone (NFB) and micro-scaled fish bone (MFB) were prepared from silver carp bones and were added separately to silver carp myosin. Using CaCl2 as a control, the effects of these different calcium sources on the gel properties of myosin were comparatively evaluated through measurements of static rheology, dynamic rheology, surface hydrophobicity, reactive sulfhydryl content and solubility. The results showed that all myosin samples exhibited a shear thinning phenomenon. The addition of NFB and CaCl2 could increase the apparent viscosity of myosin, which was closely related to the promotion of protein-protein interactions by the release of calcium ions from NFB and CaCl2, while the opposite result was observed for MFB, which could interfere with protein-protein interactions due to its large particle size. Upon heating, the addition of NFB and CaCl2 could promote myosin viscoelasticity through the formation of disulfide bonds and hydrophobic interactions. NFB was similarly effective to CaCl2 and significantly more effective than MFB in improving the gel properties of myosin. This study will provide data support for the application of NFB in surimi products.

The synergistic antibacterial effect and underlying mechanism of phenyllactic acid (PLA) combined with acetic acid (ACE) were studied against Escherichia coli. Based on the fractional inhibitory concentration index and the time-killing curve, PLA and ACE exhibited a synergistic antibacterial effect. The zeta potential analysis suggested that PLA and ACE could change the distribution of bacterial surface charge. The fluorescence spectral data obtained using fluorophore DiSC3(5) demonstrated that they synergistically dissipated the membrane potential of E. coli on the results of flow cytometry and fluorescence microscopy using the?fluorophores SYTO9 and propidium iodide (PI) showed that PI staining rates of the bacterial cells treated with PLA at 1/4 minimum inhibitory concentration (MIC), ACE at 1/2 MIC, and their combination were 8.8%, 1.6%, and 12.8%, respectively, indicating that the PLA and ACE could synergistically but weakly damage the integrity of the cell membrane. Scanning electron microscopy observation demonstrated that PLA and ACE could result in sunken deformation of E. coli cells. Finally, fluorescence spectroscopic analysis indicated that PLA and ACE, especially their combination, could lead to fluorescence quenching of genomic DNA, suggesting that PLA and ACE could synergistically damage genomic DNA. Conclusively, PLA and ACE could exert synergistic antibacterial effect against E. coli by changing the distribution of surface charge on the cells, dissipating the membrane potential, deforming the cells, and disrupting genomic DNA.

In this study, docosahexenoic acid (DHA)-rich emulsions were prepared and further microencapsulated. The effect of emulsifiers, pH and metal ions on the stability, interfacial film strength, particle size distribution and zeta potential of emulsions was investigated. The results showed that the mixed emulsifier of Span 80 and Tween 60 with hydrophile-lipophile balance (HLB) value of 11.19 had the strongest effect in improving the emulsion stability. Compared with the HLB value, the type of emulsifier had a more significant effect on the stability of emulsions, and the underlying mechanism was closely related to the interfacial film strength. The interfacial film strength and the emulsion stability increased with increasing total amount of the 58:42 mixture of Tween 20 and monoglyceride up to 1.2%, and then leveled off at higher addition levels. In addition, the emulsion stability was significantly affected by pH and metal ions. Higher pH resulted in stronger electrostatic repulsion force and consequently led to higher emulsion stability. The emulsion stability was improved by low concentrations of metal ions. In contrast, high concentrations of metal ions, especially high-valence metal ions, could significantly reduce the emulsion stability. High concentrations of Fe3+ could destroy the emulsions through the oxidation of DHA, even resulting in the formation of an insoluble suspension. This study can provide a reference for improving the stability of DHA-rich microalgae oil emulsion and developing high-quality microcapsule.

The effect of salt reduction on the formation of biogenic amines in farmhouse fermented soybean paste in northeast China was studied in this paper. The contents of total and individual contents of eight biogenic amines (spermine, putrescine, tryptamine, phenethylamine, cadaverine, histamine, tyramine, and spermidine) in samples with salt reduction by 0 (control), 10%, 20%, 30% and 40% were analyzed. Besides, physicochemical and microbial parameters were measured, namely amino nitrogen content, acidity, and the total number of colonies and sensory quality scores were determined. Compared with the control group, the total and individual contents of all the biogenic amines except spermine and spermidine increased to varying degrees with the decrease in salt content, with the most significant increase being observed in cadaverine and histamine. At the same time, acidity, the total number of colonies and sensory quality scores changed to varying degrees, while amino nitrogen content did not change significantly. In the samples with 10% and 20% salt reduction, the total and individual contents of the eight biogenic amines did not increase significantly, and histamine contents were respectively 58.00 and 64.32 mg/kg, which were lower than the EU recommended limit of 100 mg/kg. In addition, sensory quality scores but not acidity or the total number of colonies increased significantly. In the samples with 30% and 40% salt reduction, the total and individual contents of all tested biogenic amines increased significantly, and histamine contents were 103.46 and 107.42 mg/kg, respectively, which were higher than EU recommended limit of 100 mg/kg. Moreover, acidity and the total number of colonies increased significantly, and sensory quality scores significantly decreased. Therefore, salt reduction by about 20% was suitable for farmhouse fermented soybean paste in northeast China.

In this paper, the content and particle size distribution of glutenin macropolymer (GMP), protein secondary structure, and starch gelatinization properties in doughs made with hot water at different temperatures (55, 65, 75, 85 and 95 ℃) were investigated by the Kjeldahl method, particle size analysis, Fourier transform infrared spectroscopy and a rapid visco analyzer. The results showed that the content of GMP in hot-water dough increased significantly with the increase of water temperature (P < 0.05), and GMP was transformed from small to medium and large particle sizes; the α-helix and β-sheet structures were partially converted into β-turn and random coil structures. The degree of starch gelatinization in hot-water dough gradually increased with the increase in water temperature, while the peak viscosity, minimum viscosity, breakdown value, final viscosity, setback value and time to peak viscosity decreased, more steeply above 75 ℃.

It has been reported that peony seed oil is rich in α-linolenic acid and fat-soluble companions. Different extraction methods have significant effects on the quality and bioactive ingredients of peony seed oil. In this paper, peony seed oils were prepared by five different methods (aqueous enzymatic extraction, microwave-assisted aqueous enzymatic extraction, aqueous extraction, cold pressing, and solvent extraction), and their physicochemical properties, shelf life, fat-soluble concomitant contents, and volatile components were evaluated. The results showed that the acid and peroxide values of the oil obtained by aqueous enzymatic extraction were relatively low. Among the five oils, this one had the longest shelf life of 4.67 h, and exhibited the highest retention rate of fat-soluble concomitants (γ-tocopherol content of 45.787 mg/100 g, squalene content of 8.925 mg/100 g, and β-sitosterol content of 293.55 mg/100 g). In addition, the volatile components common to the five oils included aldehydes (α-methylcinnamaldehyde and hexanal), esters (ethyl palmitate), and hydrocarbons (octadecamethyl cyclononasiloxane and other alkanes). Among these oils, the one prepared by cold pressing contained the largest number of volatile components while the smallest number was found in the one obtained by solvent extraction. To sum up, the peony seed oil obtained by aqueous enzymatic extraction had the best the quality.

The ultrasonic-microwave assisted extraction of free phenolic acids from Chinese bayberries was optimized and compared with the individual use of either extraction treatment. The distribution and contents of eight major phenolic acids from Chinese bayberries of different maturities were determined by the optimized extraction process combined with high-performance liquid chromatography. Thereafter a comparative study of the antioxidant activity of phenolic acid extracts was carried out. According to the results of the single-factor experiments, ethanol concentration, solid-to-solvent ratio and ultrasonic-microwave treatment time were selected as independent variables for Box-Behnken design. The optimal extraction conditions were determined as follows: ethanol concentration 60%, solid-to-solvent ratio 1:23 (m/V), and 30 s microwave and then 15 min ultrasonic treatment. The yield of phenolic acids was determined to be 36.21 μg/g under the optimized conditions. The main phenolic acids in Chinese bayberries were gallic acid, protocatechuic acid and p-hydroxybenzoic acid, and the distribution and content of phenolic acids varied with the maturity of the fruit. The content of phenolic acids was the highest (45.50 μg/g) at 50% maturity. Phenolic acid extract from 50% mature bayberries exhibited strong antioxidant activities as determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical scavenging and ferric reducing antioxidant power assays. The total phenolic acid content was significantly positively correlated with the DPPH radical scavenging capacity and reducing power (P < 0.01). In summary, this study can provide a scientific basis for the comprehensive utilization and development of Chinese bayberry fruit.

Lycopene is a functional fat-soluble carotenoid, its poor stability limits its bioavailability in food. The preparation of lycopene-loaded nanostructured lipid carriers by the ethanol injection-sonication method was optimized by central composite design combined with response surface methodology. The results showed that lycopene-loaded nanostructured lipid carriers were prepared as a pink suspension under the optimized conditions, with encapsulation efficiency of (90.84 ± 0.41)% and drug loading rate of (2.56 ± 0.01)%. The particle diameter of the product was (126.48 ± 3.87) nm, and polydispersity index 0.188 ± 0.028, and zeta potential (?48.53 ± 2.40) mV. After storage at 4 ℃ for 30 days, the encapsulation efficiency of lycopene was (84.49 ± 0.44)%, and particle diameter (135.48 ± 7.31) nm, indicating that the nanostructured lipid carriers can improve the stability of lycopene.

This study investigated the effects of ultrasound-assisted immersion freezing (UIF) under different ultrasonic powers on the water distribution and quality of pork dumpling filler during frozen storage. The results showed that the sample subjected to UIF at 90 W ultrasonic power (UIF-90) had the best water-holding capacity, the lowest cooking loss and the greatest damage strength in the late storage period indicating that UIF-90 significantly reduced the water loss (P < 0.05) and maintained the best texture of pork dumpling filler. Compared to those treated by air freezing and immersion freezing, UIF samples had significantly lower peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) value (P < 0.05), and the lowest values were observed for the UIF-90 sample, demonstrating the lowest degree of protein and fat oxidation. As the ultrasonic power increased, a* value increased first until reaching a maximum at 90 W, and then decreased for all samples (P < 0.05). According to the low-field nuclear magnetic resonance (LF-NMR) analysis, the relaxation times T21 and T22 of the UIF-90 sample were the shortest, indicating that proper ultrasonic power levels could reduce the mobility of free water and immobilized water. Therefore, UIF at an appropriate ultrasonic power can significantly improve the quality of pork dumpling filler during frozen storage, being the most effective at 90 W.

The objective of this study was to investigate the effects of different cooking methods (steaming, roasting, steaming and then roasting, roasting and then steaming, and alternate steaming and roasting) on the eating quality of shrimps. The color difference, texture properties and total free amino acid content of cooked shrimps were determined by using a color difference meter, a texture analyzer and high performance liquid chromatography and sensory evaluation was carried out as well. The results showed that the L* values of the meat and shell shrimps cooked by roasting and then steaming was significantly lower than of those of shrimps cooked by the other methods (P < 0.05). The hardness and chewiness of roasted shrimps were significantly higher than those of shrimps cooked by the other methods (P < 0.05). Steamed shrimps had the highest total amount of free amino acids, and shrimps cooked by alternate steaming and roasting had the highest proportion of sweet amino acids and the lowest proportion of bitter amino acids. According to the results of sensory evaluation, steaming and alternate steaming and roasting were superior to the three other cooking methods.

The aim in this work was to explore the digestion characteristics of breads with added konjac glucomannan, guar gum or oat β-glucan by using a simulated gastrointestinal digestion model. The digestive characteristics were evaluated in terms of estimate glycemic index (eGI), estimate glycemic load (eGL), starch hydrolysis rate, and the contents of rapidly digestible, slowly digestible and resistant starch, in comparison to bread without added polysaccharides and white bread. Moreover, in vitro simulated intestinal fermentation of the digested product of each polysaccharide-supplemented bread was carried out by the fecal bacteria from normal people or the fecal bacteria from diabetic patients in order to observe the changes in pH and sugar consumption with inulin as the positive control. The results showed that the eGI values of the bread without added polysaccharide and the breads with added konjac glucomannan, guar gum and oat β-glucan were 53.24, 52.41, 52.84 and 52.71, respectively, and the eGL values were 9.79, 9.16, 9.00 and 8.76, respectively. In addition to having eGL values significantly lower than that of the bread without added polysaccharides (P < 0.05), the three polysaccharide-supplemented breads exhibited lower starch hydrolysis rate and higher resistant starch content as compared to white bread. During fermentation, the pH of the normal and diabetic groups decreased gradually, and a large quantity of non-digestible sugars in the digested products were consumed by the intestinal bacteria, with sugar consumption rates above 72%, significantly higher than that observed for inulin. Collectively, it can be concluded that the three breads with added polysaccharides are low GI, low GL foods, which are helpful to maintain the stability of postprandial blood sugar and are suitable for diabetic people to consume within a certain range.

In this study, the physicochemical properties, phenolic content, and antioxidant activity in vitro of jujube honeys collected from four regions of Shaanxi province: Jiaxian, Fugu, Dali and Weinan were investigated as well as their effect in protecting plasmid pBR322 against hydroxyl radical-induced oxidative DNA damage and protecting mouse lymphocytes against oxidative DNA damage induced by hydrogen peroxide (H2O2). The results showed that the jujube honeys contained 196.55–454.95 mg/kg of total phenolics, and 22.03–39.40 mg/kg of total flavonoids. By high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC/ESI-Q-TOF-MS), a total of 15 phenolic compounds were detected in the samples, including four phenolic acids and 11 flavonoids. In vitro antioxidant test indicated that the jujube honeys had strong 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging capacity with a half maximal inhibitory concentration (IC50) of 38.03–122.81 mg/mL, ferrous ion chelating activity (110.93–158.45 mg/kg), and ferric reducing power (166.68–365.06 mg/kg). Furthermore, the jujube honeys had a protective effect against oxidative DNA damage in plasmid pBR322 induced by hydroxyl radical and could significantly reduce oxidative DNA damage induced by H2O2 in mouse lymphocytes. The present study provides a theoretical basis for the development and utilization of jujube honey resources.

Objective: To investigate the intervention effect of chitooligosaccharide (COS) on intestinal injury induced by chronic drinking. Methods: Male Wistar rats were randomly divided into five groups: blank control, model, low-, medium-, and high-dose COS treatment groups. The rats in all groups except the blank control group were intragastrically administered with 4.5 g/kg mb of alcohol for 42 successive days to induce intestinal injury, which was preceded by COS for the treatment groups. Results: COS could significantly improve the performance of the rat duodenal?smooth muscle (P < 0.05), restore small intestinal health, significantly reduce the concentration of D-lactic acid (D-LA), diamine oxidase (DAO) activity, the levels of pro-inflammatory cytokines including interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6, malondialdehyde (MDA) concentration and protein carbonyl content in plasma (P < 0.05) and claudin-4 gene expression (P < 0.05), and significantly inhibit the gene expression of claudin-4 (P < 0.05). High-dose COS could significantly increase the gene expression of the tight junction proteins occludin and ZO-1 (P < 0.05). Medium- and high-dose COS could significantly reduce gene the expression of IL-6, IL-1β and TNF-α in the duodenum (P < 0.05). Conclusion: COS alleviates intestinal damage caused by chronic drinking in rats by improving small intestinal health, enhancing intestinal mucosal barrier, reducing inflammatory responses and alleviating oxidative damage.

The objective of this study was to investigate the absorption characteristics of selenium-enriched soybean protein and peptides derived from it in selenium-deficient rats. Protein was extracted from selenium-enriched soybean by alkali extraction and acid precipitation, enzymatically hydrolyzed, and ultrafiltrated to obtain peptides. The composition, selenium content and distribution, and amino acid contents of the extracted proteins and the hydrolysate were analyzed. Selenium-enriched soybean protein and the peptides with molecular mass below 3 kDa derived from it were orally administered by gavage to SD male rats at a dose of 18 μg of selenium/kg mb. Subsequently, blood samples were withdrawn from the tail at 0, 5, 10, 20, 30, 40, 60, 80, 90 and 120 minutes for measuring and plotting plasma selenium and amino acid contents as a function of absorption time. The results showed that the main selenium-binding subunits of selenium-enriched soybean protein had a molecular mass of 26–35 kDa, and the selenium content of 11S selenium-enriched soybean protein was significantly higher than that of 7S selenium-enriched soybean protein (P < 0.05). The selenium content of selenium-enriched soybean peptides with molecular mass below 3 kDa was 110.40 μg/g, which was significantly higher than that of selenium-enriched soybean peptides with molecular mass of 3–10 kDa and above (P < 0.05), and the methionine (189.32 μmol/g) and cystine contents (47.09 μmol/g) were also significantly higher (P < 0.05). After administration of selenium-enriched soybean protein, plasma selenium concentration peaked at 20 and 80 min, with a maximum value of 1.070 mg/L; plasma total free amino acid concentration peaked at 10 and 80 min, with a maximum value of 4.172 μmol/L. After administration of the selenium-enriched soybean peptides, plasma selenium concentration peaked at 10 and 40 min, with a maximum value of 1.338 mg/L; plasma total free amino acid concentration peaked at 5 and 40 min, with a maximum value of 5.053 μmol/L. Compared with selenium-enriched soybean protein, the peptides advanced the peak concentration times of plasma selenium and free amino acids, and significantly increased the rate of selenium absorption in vivo, suggesting its potential to be developed as a functional oral nutraceutical.

Objective: To investigate the regulatory effects of mulberry leaf alkaloid on the transforming growth factor-β1 (TGF-β1)/Smads pathway and the expression of matrix metalloproteinase-13 (MMP-13) and inhibitor of metalloproteinase-1 (TIMP-1), and to explore its action mechanism in alleviating hepatic fibrosis in mice. Methods: Hepatic fibrosis in mice was induced by intraperitoneal injection of 10% (V/V) CCl4 in olive oil at a dose of 5 mL/kg mb every other day combined with feeding a high-fat diet for 8 consecutive weeks. Thereafter, the mice in the control and model groups were given distilled water, those in the low-, medium- and high-dose treatment groups were intragastrically administered with 50, 100 and 200 mg/kg mb mulberry leaf alkaloid, and those in the positive drug group were gavaged with 100 mg/kg of silibinin for 45 days. The contents of hepatic α-smooth muscle actin (α-SMA), collagen I (Col I) and collagen III (Col III) in mice were determined by enzyme-linked immunosorbent assay (ELISA) kits, and the mRNA expression levels of TGF-β1, Smad3, Smad4, Smad7, MMP-13 and TIMP-1 were detected by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Results: Compared with the model group, the contents of α-SMA, collagen I and collagen III in the high-dose group decreased by 19.55%, 19.93% and 13.84% (P < 0.05), respectively. Similarly, the mRNA expression levels of TGF-β1, Smad3, Smad4 and TIMP-1 significantly decreased by 59.04%, 56.73%, 50.70% and 49.09% (P < 0.05), respectively. Moreover, Smad7 and MMP-13 mRNA expression levels increased by 48.29% and 25.72% (P < 0.05), respectively. Conclusion: Mulberry leaf alkaloids can improve hepatic fibrosis in mice, and its underlying mechanism may be related to the regulation of the TGF-β1/Smads signaling pathway related factors and TIMP-1 and MMP-13 mRNA expression.

For improved protective effect of sodium alginate (SA) beads on lactic acid bacteria (LAB) exposed to simulated gastrointestinal fluid (SGF), soybean cellulose nanocrystals (SCNC) or cellulose nanofibrils (SCNF), both of which were prepared from soybean okara, in combination with SA was used to encapsulate LAB with calcium ions as a cross-linker. The microstructure of SA-nanocellulose beads was observed, Fourier transform infrared spectroscopy and low frequency nuclear magnetic resonance were analyzed. The effect of SA-nanocellulose beads on the viability of LAB in SGF was investigated by determining the number of viable bacteria before and after gastrointestinal digestion. Nanocellulose could increase the encapsulation efficiency of SA beads and decrease the surface pores. In addition, SCNF was better than SCNC in improving the hydrogen bonding capacity of SA, promoting the formation of a salt bridge between the SA chain and Ca2+, strengthening the structure of the gel network, and ultimately enhancing the mechanical strength of SA beads. Furthermore, SA-SCNF beads provided better protection of LAB after exposure to SGF with a reduction in viable cell count of 1.51 (lg(CFU/g)), significantly lower than that observed for SA beads (2.99 (lg(CFU/g))) and SA-SCNC beads (2.16 (lg(CFU/g))) (P < 0.05). These results indicated that SCNF can be applied as a nano-carrier for the encapsulation of LAB to keep it stable in the gastrointestinal tract.

Flavonoids from guava fruit were obtained though ultrasonic-assisted extraction and were purified using an AB-8 macroporous resin column before being used to prepare zein-guava flavonoid composite nanoparticles (ZGF) by a solvent evaporation-induced self-assembly method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to explore the morphology and characteristics of the as-prepared samples. In addition, the cytotoxicity of the flavonoids and the composite nanoparticles was studied by the methyl thiazolyl tetrazolium method and the impact of ZGF on cellular reactive oxygen species (ROS) production was evaluated using the fluorescent probe DCFH-DA. The antioxidant activity of ZGF was evaluated by measuring the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The release behavior of ZGF in artificial gastric juice was investigated. The results showed that the purity of the purified flavonoids was 67.0%. The maximum encapsulation efficiency of 93.29% was obtained when the mass ratio of zein to flavonoids was 16:1. The size of the prepared nanoparticles was approximately 500 nm with a spherical structure. ZFG had no obvious cytotoxicity on HepG2 cells in the concentration range of 0.5–5 mg/mL. Moreover, ZFG could protect HepG2 cells from oxidative damage induced by H2O2 in a concentration-dependent manner and could scavenge 86.02% of DPPH radicals at a concentration of 416.67 μg/mL. Furthermore, the cumulative release rate of ZGF in artificial gastric juice was increased from 1 to 6 h of digestion reaching 64.11%, suggesting good release performance. This study provides a theoretical reference for the comprehensive utilization of guava flavonoids.

In this study, indicator films were prepared using blends of methyl cellulose (MC) polyvinyl alcohol (PVA) as film-forming materials with the addition of bromocresol purple and methyl red. The effect of substrate composition on the structure, physical properties and detection performance of indicator films was investigated, and the application in shrimp freshness monitoring was also evaluated. The Fourier transform infrared (FTIR) spectroscopy results indicated strong compatibility among the film components and the rheological studies exhibited the strongest intermolecular force when the MC-to-PVA ratio was 3:1 (m/m). The introduction of MC could enhance the properties of PVA effectively, and the film with a MC-to-PVA ratio of 3:1 (m/m) had the highest tensile strength (65.36 ± 4.29) MPa and the strongest hydrophobic properties with a water contact angle of (57.30 ± 0.81)° as well as the best light and water vapor barrier performance. All the indicator films prepared in this study could response to pH change and showed good color stability. Furthermore, when it was applied to monitor shrimp freshness under refrigeration (4 ℃), on the fourth day, the color of the indicator film with the best properties changed from reddish brown to purple brown, indicating less fresh. On the eighth day, pH and total volatile basic nitrogen (TVB-N) content were 7.73 ± 0.01 and (60.90 ± 7.00) mg/100 g, respectively, and the color turned black, indicating severe spoilage. The film color was significantly different in response to various freshness degrees, and color difference was significantly correlated with pH and TVB-N content (P < 0.05 or 0.01). Considering the indicator film could produce color change discernible to naked eyes in response to different spoilage degrees, the freshness of preserved shrimps could be graded according to the film color. Therefore, the indicator film is promising for monitoring the freshness of food products in real time.

Sour rot, caused by Geotrichum citri-aurantii, is one of the most devastating diseases of harvested citrus fruit. Nonetheless, there are currently no efficient fungicides available to control this disease. In this study, ammonium carbonate as a generally recognized as safe compound was evaluated for its antifungal activity against the pathogen and the possible mechanism of its action was investigated. The results showed that ammonium carbonate could inhibit spore germination, germ tube elongation and mycelial growth of G. citri-aurantii in vitro in a dose-dependent manner, completely inhibiting spore germination and mycelial growth at a concentration of 0.8 g/L. Further analysis revealed that ammonium carbonate inhibited spore activity, powerfully repressed mycelial respiration, altered the permeability of cell membrane as indicated by propidium iodide (PI) staining, and gradually increased the leakage of intracellular ions, proteins and nucleic acids, thus leading to the functional loss of hyphal cells. In vivo experiment demonstrated that 20 g/L ammonium carbonate could effectively decrease lesion diameter in Valencia oranges artificially inoculated with a spore suspension at 1 × 106 spores/mL, 20 μL and reduce disease incidence. These results suggested that ammonia carbonate could be a potential alternative to fungicides to control sour rot in citrus fruit.

Objective: To explore the effect of Penicillium expansum infection on the membrane permeability and membrane phospholipid metabolism of apple fruits. Methods: ‘Red Delicious’ apple fruits were used in this study. Changes in cell membrane permeability, key enzyme activities involved in membrane phospholipid metabolism, and substrate and product contents were measured in the junction between diseased and healthy parts of apples inoculated with P. expansum. Results: There was no obvious change in the lesion diameter of fruit in the early stage of infection by P. expansum (before 2 days), and the lesion diameter and cell membrane permeability of fruit increased significantly in the late stage of infection (after 2 days). The activity of phospholipase A2 (PLA2), phospholipase C (PLC) and phospholipase D (PLD), and the content of phosphatidic acid (PA) in infected fruits increased continuously, while the contents of phosphatidylcholine (PC) and phosphatidylinositol (PI) significantly decreased. Significant variation in the contents of PC, PI and PA occurred between the infected and control groups at the late stage of infection. In addition, the content of unsaturated fatty acid increased rapidly at the early stage of infection, and on the second day of infection, the contents of oleic acid, linoleic acid and linolenic acid were 31.58%, 55.57% and 43.67% higher than those in the control group, respectively. The content of saturated fatty acid increased significantly at the late stage of infection, and on the sixth day, the contents of palmitic acid and stearic acid were 49.46% and 43.39% higher than those in the control group, respectively. The unsaturation degree of fatty acids in the infected group was higher than that in the control group at the early stage but lower at the late stage of infection. The correlation analysis indicated that there was a very significantly positive correlation between cell membrane permeability and the activity of PLA2, PLC and PLD, as well as palmitic acid, stearic acid and PA contents. A highly significantly negative correlation was found between cell membrane permeability and PC and PI contents. Conclusion: P. expansum infection can activate phospholipase, promote the degradation of phospholipid and the release of fatty acids, and destroy the integrity of the cell membrane in apple fruit. The rapid release of unsaturated fatty acids at the early stage of infection may be related to disease resistance.

Proper packaging of foods is of particular importance for inhibiting the growth and reproduction of harmful microorganisms in foods during storage, delaying the quality deterioration and extending the shelf life. Chitosan-coated antimicrobial polyethylene (PE) bilayer films incorporated with hops extract were prepared in this study to investigate the effects of different concentrations of hops extract on the surface structure, physical properties and antibacterial activity of the films. Furthermore, the release behavior of hops extract from the films was investigated in simulated food systems (ethanol solutions at 10%, 50%, and 95%, V/V) at different temperatures (4, 25 and 35 ℃). The results showed that the addition of hops extract especially at 0.2 g/100 mL increased the water resistance and UV barrier capacity of the film and imparted good antioxidant and antimicrobial activity to it. Under the same conditions, the release percentage of hops extract increased with increasing its concentration, and the release amount similarly increased with increasing temperature and ethanol concentration, which indicates that the chitosan-coated antibacterial PE bilayer films could be used for the packaging of high-fat foods. Moreover, the antibacterial films not only overcome the poor water resistance of single-layer edible films, but also had antibacterial effects while PE packaging films do not have.

In this paper, inclusion complexes of tea polyphenol (TP) with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) were prepared by the co-precipitation method with different molar ratios (1:0.5, 1:1 and 1:2) of HP-β-CD to TP. Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to analyze the structure of TP and its inclusion complexes. The results showed that HP-β-CD/TP inclusion complexes were successfully prepared, and the one with HP-β-CD:TP molar ratio of 1:2 had the strongest antioxidant activity in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. Further, different concentrations (0, 0.1, 0.5 and 1.0 mg/mL) of this inclusion complex were used to immerse ovine tripe, which was then stored at 4 ℃ for up to seven days, in order to explore its effect on myofibrillar protein (MP) oxidation during the storage period. The results showed that the inclusion complex could significantly inhibit the increase in the carbonyl content, surface hydrophobicity and turbidity and the decrease in the total sulfhydryl content, free amino content and solubility of MP from ovine tripe (P < 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that the TP/ HP-β-CD inclusion complex had an inhibitory effect on MP degradation which increased with increasing concentration up to 1 mg/mL. Therefore, the interaction with the HP-β-CD/TP inclusion complex can effectively delay the denaturation and degradation of MP, and inhibit the deterioration of the functional properties of ovine tripe.

Objective: To prepare a biodegradable antimicrobial packaging material from polybutyrolactam (PA4) by casting method for use as a sausage casing. Methods: The mechanical properties, water and oxygen barrier properties, heat shrinkage, tear resistance, overall migration and antibacterial properties of the PA4 film as well as its potential in preserving pork sausages were evaluated in comparison to a commercially available nylon composite casing and a commercially available collagen casing. Results: The PA4 sausage casing had a tensile strength of 84.42 MPa, an elongation at break of 73.34%, and an oxygen permeability coefficient of 2.448 × 10-16 cm3·cm/(cm2·s·Pa), which indicates high oxygen barrier capacity. Besides, with the antibacterial ingredient chitosan, the casing film had good antibacterial performance, and its antibacterial performance value was 3.13 (lg(CFU/cm2)). At 4 ℃, the storage period of pork sausages stuffed in this casing was 28 days. Conclusion: The comprehensive performance of the PA4 sausage casing was close to that of the commercially available nylon composite casing and significantly better than that of the commercially available collagen casing. The PA4 sausage casing can be applied to low-temperature meat packaging and is promising for application in the field of meat packaging.

The effect of high relative humidity (HRH) storage on reducing chilling injury of green pepper fruits and its relationship with changes in the antioxidant system were investigated. Fresh green peppers were stored at 4 ℃ in a dry-fog humidity controlled cold room with 96%–99% RH or a common low relative humidity (LRH) cold room with 70%–75% RH for up to 15 days. Every three days during the storage period, changes in chilling injury, quality attributes and antioxidant system parameters were examined. The results showed that HRH storage significantly delayed the increase in chilling injury index, relative electric conductivity and percentage mass loss and the decrease in fruit firmness, and maintained higher levels of chlorophyll, ascorbic acid, total phenolics and total flavonoids. Meanwhile, HRH storage significantly increased the activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, maintained higher scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical, and decreased the accumulation of superoxide anion and hydrogen peroxide. These results suggested that HRH storage could reduce chilling injury of green pepper fruits by maintaining higher antioxidant activity and inhibiting the detrimental effects of reactive oxygen species (ROS).

In order to study the major types of non-enzymatic browning reaction occurring during the storage of boiled lotus sprout and the pattern of changes in the main related substances, two packaging bags with different oxygen permeability were used to store boiled lotus sprout in vacuum for up to 60 days. The results showed that the higher oxygen permeability through packaging materials resulted in higher browning degree of lotus sprout. The relationship between the causal factors of browning and the changes in the color parameters of lotus sprout packaged in the material with high oxygen permeability was explored by principal component analysis (PCA) combined with correlation analysis. The first principal component (PC1) contributed 77.746% of the total variance, reflecting the relationship between the color and the causal factors of browning. The major factors causing browning were ascorbic acid, total phenol, threonine and glutamic acid contents, indicating that polyphenol autoxidation, oxidative decomposition of ascorbic acid, and the Maillard reaction contributed to non-enzymatic browning of boiled lotus sprout. Polyphenol autoxidation was the most important non-enzymatic browning reaction.

This work studied the effect of ozone treatment at a flow rate of 15 g/h combined with closed packaging on the physicochemical properties (color, wet?gluten content, gluten index, protein subunit distribution and falling number), gelatinization properties and stability (reducing sugar content, sedimentation value and total number of colonies) of wheat (cv. Gaoyou 2018) harvested in 2018 during storage. The results showed that compared with the control group, ozone treatment for 15 min slowed down the decrease in the gelatinization temperature of wheat starch. At the end of the 70-day storage period, L* and whiteness values in the treated sample increased, protein aggregates/subunits degraded, peak viscosity, breakdown and reducing sugar content declined, sedimentation value enhanced, the reduction rate of bacteria reached 94.68%. Nevertheless, there was no significant difference in final viscosity, gluten index, wet gluten content or falling number. Ozone treatment combined with closed packaging could significantly delay wheat quality deterioration, especially in terms of total number of colonies, reducing sugar content and sedimentation value. Therefore, ozone treatment is a green and effective method to retard wheat quality deterioration during storage.

An edible packaging material with good performance was prepared using whey protein isolate (WPI) as a film-forming substrate with the addition of bamboo leaf antioxidant (BLA) and sodium caseinate (SC). The effects of film-forming material composition, pH, and glycerol concentration on the film physical properties such as tensile strength at break, elongation at break, water vapor transmission rate, and light transmittance were investigated. The results showed that the tensile strength and elongation at break of the film with a BLA:SC:WPI ratio of 1:1:10 (m/m) and glycerol concentration of 0.04 g/mL formed at pH 8–9 were 18.4 MPa and 32.8%, respectively, water vapor transmission rate 10.86 g/(m2·d), and light transmittance 90.2%, indicating good physical properties of the film. Fourier transform infrared (FTIR) spectral analysis showed good compatibility between the film-forming materials. Scanning electron microscopic (SEM) analysis showed that the surface of the film was smooth, and the cross section was regular and uniform. When applied to actual samples (dried squid), the prepared edible film showed good antimicrobial and antioxidant effects. This study provides a reference for the development of edible films.

In order to explore the effect of exogenous 24-epibrassinolide (EBR) treatment on preventing chilling injury (CI) and the possible underlying mechanism in baby ginger rhizome, ‘Zhugen’ ginger rhizomes were treated with EBR for 30 min, sun-dried and then stored at 4 ℃ for up to 25 days. Changes in CI index, firmness, relative electric conductivity, the contents of hydrogen peroxide (H2O2), malondialdehyde (MDA) and total phenolics, and enzyme activities associated with reactive oxygen species (ROS) and phenolic metabolism were analyzed regularly during the storage period. Results showed that 10 μmol/L EBR treatment distinctly alleviated CI symptoms during cold storage. At the end of storage, CI index and total color difference (ΔE) in the EBR-treated group were 51.8% (P < 0.05) and 48.1% (P < 0.01) as compared to the control group, respectively, and firmness was 38.6% higher than that in the control group (P < 0.01). Relative electric conductivity, MDA content and H2O2 content in EBR-treated group were decreased by 24.6%, 10.5% and 24.8%, respectively (P < 0.05 or 0.01), compared to the control group. The enzyme activities involved in ROS metabolism including superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were increased by 9.0%, 35.7% and 33.2% (P < 0.01), respectively, indicating that EBR can maintain cell membrane integrity and suppress the accumulation of ROS. Meanwhile, total phenolic content and phenylalanine ammonia lyase (PAL) activity were 38.5% and 24.8% higher in the EBR-treated group than in the control group, but polyphenol oxidase (PPO) activity was 17.3% lower than that in the control at the end of storage. Correlation analysis demonstrated that CI index was significantly positively correlated with ΔE, relative electric conductivity, MDA content, SOD, PAL and PPO activity (P < 0.01), but significantly negatively correlated with firmness, CAT and APX activity (P < 0.05 or 0.01). These results suggest that EBR could enhance chilling tolerance of baby ginger rhizome by regulating enzyme activities related to ROS and phenolic metabolism and ameliorating ROS-induced oxidative damage.

In order to study the effect of short-wave ultraviolet (UV-C) treatment on the color and physiological quality of green pepper, different doses of UV-C were used to treat green pepper to get the best treatment dose. Green bell peppers were treated with short-wave ultraviolet (UV-C) at a dose of 0.25 kJ/m2 to explore the changes in sensory quality, total chlorophyll, carotenoid, flavonoid and total phenol contents, and peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO), phytoene synthase (PSY) and lycopene-β-cyclase (LCYB) activities during subsequent storage at room or cold temperatures. The results showed that UV-C treatment significantly improved the appearance of green bell peppers, slowed down the degradation of chlorophyll, and reduced the activities of PSY and LCYB at room temperature, affecting the synthesis of carotenoid, inhibiting the increase in carotenoid and flavonoid contents and consequently delaying green bell peppers from turning red. In addition, compared with the control group, UV-C treatment reduced PPO activity, effectively delayed browning, induced the synthesis of phenolics, and enhanced the activities of POD, CAT and APX leading to improved antioxidant capacity. To sum up, UV-C treatment could delay green bell peppers from turning red, maintain the physiological quality during storage, and extend effectively the shelf life of green bell peppers, which will provide a theoretical basis for the postharvest preservation of green bell peppers.

The influence of short-wave ultraviolet (UV-C) irradiation at a dose of 3.0 kJ/m2, 10 g/L chitosan coating and their combination on physiological indices of fresh-cut Chinese yam at different storage times was investigated in order to explore the effect of these treatments on preserving the quality of fresh-cut Chinese yam and the underlying mechanism. The results showed that compared with the control group, UV-C irradiation could promote the accumulation of phenolics and flavonoids, enhance antioxidant capacity and reduce oxidative damage. Chitosan coating maintained the quality of fresh-cut Chinese yam for a long time by inhibiting respiration, reducing the permeability of the cell membrane, and decreasing lipid peroxidation in the cell membrane. On day 12 of storage, UV-C irradiation, chitosan coating and their combination reduced the respiration intensity by 15.7%, 21.3% and 23.6%, reduced the total number of bacterial colonies by 24.6%, 18.5% and 30.8%, increased the total phenol content by 13.3%, 16.7% and 22.2%, and enhanced the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity by 17.5%, 9.6% and 20.2% respectively when compared with the control group. Therefore, both treatments especially their combination was effective in preserving the quality of fresh-cut Chinese yam. This study is meaningful for the preservation of fresh-cut fruits and vegetables.

Δ12/Δ15 fatty acid desaturases (FADS12/15) play an important role in the synthesis of polyunsaturated fatty acids, and are the key enzymes involved in the fatty acid metabolism pathways in living organisms. The probiotic effect of fatty acids in fermented foods has become a hot topic in the field of functional lipids, and it is of significance to research the application of FADS12/15 in the regulation of fatty acid synthesis. This review gives an overview of FADS12/15 and the fatty acid metabolism pathways in which they are involved, as well as six different sources of FADS12/15 including plants, animals, bacteria, yeasts, molds and algaes, and it summarizes recent studies on the application of FADS12/15 in fermented foods. The objective of this review is to provide the fundamental theory and novel ideas for researchers and manufacturers to apply FADS12/15 in the fermented food industry.

Polyphenols are one of the most important secondary metabolites in Camellia oleifera seeds, which are closely related to the quality, color and oxidative stability of Camellia oleifera seed oil. However, these compounds are greatly affected by extraction conditions, identification methods and processing technologies. In order to obtain further understanding of its chemical properties and potential utilization, in this paper, the current status of research on polyphenol compounds in Camellia oleifera seed oil is reviewed, with respect to 1) the relationship between polyphenols and antioxidant properties, 2) the routine and innovative methods to extract and identify polyphenols from the oil, 3) the influence of cultivars, oil production techniques, refining and pretreatment methods on the oil’s polyphenol content, and 4) the role of polyphenols in improving its oxidative stability under appropriate processing conditions. Previous studies can provide a theoretical basis for retaining and regulating polyphenols in Camellia oleifera seed oil under moderate processing conditions and for developing natural, healthy and nutritious Camellia oleifera seed oil products.

Caffeoylquinic acids are major plant secondary metabolites with many biological activities such as antioxidant, antibacterial, anti-inflammatory, anti-tumor, anti-viral, blood glucose-regulatory, blood lipid-regulatory, blood pressure-regulatory, and hepatoprotective effects. However, they have low oral bioavailability. In this review, we summarize recent advances in the biological activity of caffeoylquinic acids and the technologies for improving their bioavailability such as nanoparticle encapsulation, liposome preparations, phospholipid complexes, emulsion delivery systems and cyclodextrin inclusion, in order to provide a theoretical basis for studies on caffeoylquinic acids and rational development and utilization of this resource.

In recent years, the widespread use of pesticides has caused increasingly serious food safety problems and agricultural ecological environmental problems throughout the world. The traditional methods for the detection of pesticide residues generally require large expensive instruments and professionals, which greatly limits their application in resource-limited areas. Therefore, it is highly important to develop user-friendly, rapid and sensitive methods for pesticide residue detection. One such method is the nanomaterial-based optical aptasensor, which is generally recognized as a powerful tool for the detection of pesticide residues. In this review, the latest progress in the application of nanomaterial-based optical aptasensors for the detection of pesticide residues is presented and the major challenges in this field are summarized. Finally, an outlook on future development is proposed with the aim of stimulating further research into developing novel biosensors for pesticide residue detection.

Salmonella is one of the most common foodborne pathogens, and the traditional methods for Salmonella detection include biochemical identification following isolation and culture, immunoassay, and nucleic acid analysis, which, despite having high reliability, have low detection limits and are tedious and time-consuming. The biosensor is a new technology for rapid detection of Salmonella integrating biology, chemistry, optics and other technologies. This review presents a comparison of the traditional methods for Salmonella detection, and it focuses on describing the optical and electrochemical biosensors based on nanomaterials and aptamers. Finally, we conclude with an outlook on the future development of biosensors for Salmonella detection.

Anthocyanins are one of the most common and widely distributed flavonoids in various plant tissues and naturally occur in the form of glycosides. They are the main water-soluble pigments present in many plants and are widely applied owing to their safety, potent antioxidant properties and biological activities against various chronic diseases. However, due to their structural characteristics, anthocyanins have poor stability and low bioavailability and also possess high hydrophilicity, largely limiting their application in lipophilic matrices. The solubility, stability and antioxidant capacity can be improved through the chemical and physical modification of anthocyanins. This paper reviews and compares the methods used to modify anthocyanins and the properties of the modified products, which will provide references for further studies on the thermostability, lipophilicity and biological activity of anthocyanins and their applications in the food, pharmaceutical and other industries.