內(nèi)容: Nature fermented dry-cured hams may be contaminated by ochratoxin A (OTA) due to the colonization of OTA-producing fungi. Yeast plays essential roles in the formation of the special flavor of ham as well as the potential to retard OTA biosynthesis. In this study, the yeast diversity of Panxian hams fermented from 1 year to 2 years was investigated, revealing a total of 9 yeast genera. The dominant genus switched from Debaryomyces hansenii to Yamadazyma triangularis, while the yeast diversity increased with the prolongation of the fermentation period. Notably, Yarrawia lipolitica GZPX-3Y-1 was identified as a biocontrol yeast strain that can effectively inhibit the OTA biosynthesis up to 82% in OTA-producing modeling media and 55% in ham media when cocultivated with a previously identified OTA producing fungi from Panxian ham, specifically Aspergillus niger A-8. The double-plate methods experiment unveiled that Y. lipolitica GZPX-3Y-1 can only inhibit the growth of A. niger A-8 under the anoxic conditions. Characteristics of Y. lipolitica GZPX-3Y-1 were explored, showing its ability to grow at wide range of temperature (18–33 ℃) and pH levels (pH 3–12). Additionally, it exhibited tolerance to high salt conditions (8%) and demonstrated lipolysis ability without hemolytic ability. These findings indicate the great potential of Y. lipolitica GZPX-3Y-1 to be applied in the fermentation of Panxian ham as a biocontrol strain.

內(nèi)容: Deoxynivalenol (DON), the most common mycotoxin in the world, poses serious health hazards to both humans and animals and causes significant economic losses to the food and feed industry. An intriguing method for DON detoxification involves enzymatic cascade catalysis by pyrroloquinoline quinone-dependent alcohol dehydrogenase (DADH) and aldo-keto reductase (AKR13B3). However, the poor catalytic activity of AKR13B3 has limited its usefulness. Here, structure-guided steric hindrance engineering, computer-assisted protein engineering, and combinatorial mutagenesis were carried out to increase the catalytic efficiency of AKR13B3. The best mutant in this project was M28S/S65V, which outperformed wild-type AKR13B3 in terms of catalytic efficiency (kcat/Km) and specific activity by factors of 44.07 and 41.65, respectively. Kinetic parameter determination revealed that the enhanced catalytic efficiency of M28S/S65V toward 3-keto-DON was attributed to the decreased Km and increased kcat values. Moreover, the engineered enzyme was applied to degrade DON in contaminated corn steep liquor, for a 90.62% removal rate. Structure-based computational analysis provided insights into the enhanced catalytic efficiency of M28S/S65V, which was attributed to the enlarged substrate-binding pocket and reshaped pocket with a favorable hydrophilic attack distance. The results provide a reference for improving the catalytic activity of an enzyme toward non-native bulky substrates and pave the way for the development of enzymes as detoxification agents to mitigate DON in the food and feed industry.

內(nèi)容: Delaying skin-aging through diet is a hot research topic in recent years, but the anti-aging effects of fish gelatin and related mechanisms are not well understood. In this study, we prepared edible fish gelatin from the swim bladder of Cynoscion acoupa using three different processing methods, namely dried (DCM), soaked (SCM) and instanted (ICM), to investigate its anti-aging effects and mechanisms on D-galactose induced skin aging in mice, as well as its effects on the gut microbiota. The results demonstrated that fish gelatin significantly increased water content, collagen, hyaluronic acid (HA) and hydroxyproline (Hyp) content, and skin integrity of mice skin, as well as enhanced the antioxidative ability and anti-inflammatory capacity of the skin. In terms of protein and mRNA expression levels in skin tissue, CMs treated with different treatments can up-regulate the expression of epidermal growth factor receptor (EGFR) and tissue inhibitor of metal protease 1 (TIMP1), down-regulating the expression of matrix metalloproteinase 1 (MMP1) and matrix metalloproteinase 3 (MMP3), and increase the expression of collagen type III alpha 1 chain (COL3A1) and collagen type I alpha 2 chain (COL1A2). CMs attenuated the D-galactose-mediated inhibition collagen expression by stimulating the transforming growth factor beta (TGF-β)/Smad signaling pathway, thereby maintaining collagen matrix homeostasis. In addition, we revealed that CMs reversed gut microbiota by increase the abundance of intestinal flora. In conclusion, we demonstrated that CMs, especially for ICM, as an effective dietary supplement, have potential anti-aging and skin health benefits.

內(nèi)容: How to reduce peanut allergies has always been a main food safety concern. Plant polyphenol complex peanut sensitizing protein was proposed as a new desensitization strategy. Gallic acid (GA), as a natural plant polyphenol, has anti-inflammatory and immunomodulatory effects. Therefore, the aim of this study was to investigate the effect of GA on peanut protein (PP) sensitization under high moisture extrusion conditions. The contents of free sulfhydryl groups and disulfide bonds in the PP-GA complex were determined, and the structure of the complex was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy. The results showed that with increasing GA content, the number of free sulfhydryl groups increased while the number of disulfide bonds decreased. The secondary structure of PP-GA showed that the random coils and β-turns were transformed to α -helices and β-sheets. A BALB/c mouse model was also established, wherein Al(OH)3 was used as an adjuvant when the complex was administered via intraperitoneal injection, and the mice showed mild allergic symptoms and a decreased immune organ index. In addition, the serum levels of specific antibodies (immunoglobulin E (IgE), immunoglobulin G1 (IgG1), and immunoglobulin G2a (IgG2a)), cytokines (interleukin-5 (IL-5), interleukin- 13 (IL-13), and interferon gamma (IFN-γ)) and histamine were reduced. In summary, this study proved that GA can relieve the sensitization of PP induced by high moisture extrusion.

內(nèi)容: Whole wheat flour is a food raw material rich in macronutrients, but its application in baking industry is limited due to the existence of a large amount of insoluble dietary fiber in bran. In order to make full use of this resource, we first screened twelve cellulase-producing strains, and then extracted soluble dietary fiber (SDF) from whole wheat flour after fermentation with 3 strains of Aspergillus sp. and 2 strains of Bacillus sp., respectively. The effects of different strains on nutritional characteristics, SDF yield, structure improvement, and antioxidant activity of whole wheat flour were compared. The results showed that fermentation of whole wheat significantly increased the yield of SDF, the content of nutritive active substances, and improved the physicochemical structure and antioxidant activity of SDF in vitro. Scanning electron microscopy (SEM), X-ray diffraction and liquidity characteristics show that the fermentation to make whole wheat SDF has more porous microstructure and crystallinity of lower molecular weight. Fourier transform infrared spectrum showed that there were differences in functional group types between soluble dietary fiber in control group (C-SDF) and soluble dietary fiber in the fermentation group (F-SDF). These changes together improved the hydration performance and antioxidant activity of whole wheat SDF, including water holding capacity, oil holding capacity, cholesterol adsorption, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and hydroxyl radical scavenging, and lipase activity inhibition. Bacillus sp. SH and Aspergillus oryzae Y21 are ideal strains for fermentation of improved whole wheat, which has the potential of antioxidant properties while improving nutritional properties and food quality.

內(nèi)容: Herein, a novel label-free electrochemical immunosensor was fabricated via immobilizing specific anti-β-lactoglobulin (β-LG) antibodies (Abs) onto an integrated electrode of gold nanoparticles (AuNPs)/Prussian blue (PB)/cubic Ia3d structured mesoporous carbon (CMK-8). This immunosensor allowed for the quantitative detection of the major milk allergen β-LG. CMK-8 with excellent electrical conductivity and uniformly adjustable pore structure was modified on the glassy carbon electrode (GCE) and served as the sensitive substrate for the electro-polymerization of PB, forming the redox-active layer. AuNPs were subsequently electrochemically deposited on PB/CMK-8/GCE to improve the electrical conductivity and utilized as the connector for Abs immobilization. During β-LG detection, the Abs-modified AuNPs/PB/CMK-8/GCE exhibited a significant reduction in differential pulse voltammetry current signal when exposed to β-LG, displaying an inverse dose-dependent relationship. The developed electrochemical immunosensor demonstrated good detection performance for β-LG, with a wider linear range of 0.01–100 ng/mL and a lower detection limit of 4.72 pg/mL. Meanwhile, the sensor exhibited remarkable repeatability, reproducibility, stability and anti-interference capabilities, which was further applied to detect β-LG in dairy food, achieving satisfactory recoveries (89.2%–98.8%) and lower relative standard deviation (￡ 3.1%). Therefore, this innovative electrochemical method for food allergen detection holds great potential application in food safety determination and evaluation.

內(nèi)容: Microbial growth causes lamb spoilage. This study explored the spoilage ability of Latilactobacillus sakei, Serratia proteamaculans and Hafnia proteus in vacuum-packed raw lamb, including growth ability, degradation of protein and lipid, and change of volatile organic compounds (VOCs) profile, meanwhile screened the key VOCs produced by the targeted strains with meat background excluding, finally confirmed the volatile spoilage marker of vacuum-packaged lamb by comparing with our previous work. The results showed that L. sakei, S. proteamaculans and H. proteus had excellent growth ability. L. sakei inoculated group significantly reduced the pH value, showed higher trichloroacetic acid-soluble peptides content, and excellently degraded sarcoplasmic and myofibrillar proteins. About free amino acids, L. sakei significantly degraded serine, arginine and aspartic acid, while S. proteamaculans and H. proteus significantly degraded serine and lysine. In addition, L. sakei had the strongest effect on promoting free fatty acid production, followed by S. proteamaculans and finally H. proteus. Evaluating from various indicators, the co-culture of the three strains did not have any effect. The key volatiles produced by L. sakei were 1-hexanol, acetic acid and hexanoic acid, S. proteamaculans produced 1-hexanol and acetoin, and H. proteus produced 1-hexanol, acetic acid and acetoin. In the end, 1-hexanol, hexanoic acid and acetoin were proven to be spoilage markers for vacuum-packaged and chilled lamb. This study can provide fundamental information for inhibiting and rapid identification of spoilage in vacuum-packaged lamb.

內(nèi)容: Trehalose is an autophagy-promoting disaccharide, which can improve and delay chronic diseases like neurodegenerative diseases and atherosclerosis, but its bioavailability is severely restricted by endogenous trehalase in mammals. Trehalase inhibitor is a promising and effective way to enhance trehalose bioavailability by preventing trehalose from hydrolyzing. However, previously reported trehalase inhibitors still face safety of long-term use and promiscuous inhibition on intestinal glycosidases. This study carried out a high-throughput virtual screening through molecular pool-based molecular docking combined with in vitro inhibition experiments to screen trehalase inhibitors naturally derived from foods. Out of 1 769 small molecules, which include 115 analogs of trehalose, natural monosaccharides, disaccharides, trisaccharides, imidazoles and their derivatives, as well as 20 natural amino acids and their 400 dipeptides, isomaltose, α-isomaltulose, and isomaltitol exhibited the best inhibitory activities, beyond as traditional sweetener and prebiotic. Best of all, isomaltose showed the half maximal inhibitory concentration (IC50) and inhibition constant (Ki) values on trehalase of 5.59 and (2.176 0 ± 0.343 1) mmol/L, respectively. Moreover, isomaltose was resistant to the simulated digestive environment and did not affect intestinal glycosidases such as α-glucosidase and glucoamylase, making it a reliable edible candidate for a trehalase inhibitor. This study provides new insights into the virtual screening-based identification of new food-derived trehalase inhibitors for enhanced integrity and bioavailability of orally administered trehalose, especially repurposing a prebiotic for another new use as trehalase inhibitor.

內(nèi)容: Fermented sour soup is a unique traditional sour food of the Miao and Dong ethnic groups in China. However, due to the commonly used traditional fermentation, the unstable fluctuation of microbial community often leads to some unpleasant inherent off-flavours in rice sour soup. In this study, the microbial composition and volatile flavour components of off-flavour and normal rice sour soup were examined by high-throughput sequencing and headspace solid-phase microextraction coupled with gas chromatographymass spectrometry. Then, based on Pearson correlation coefficients, the correlations between fungi and bacteria and those between core microorganisms and key volatile flavour components were investigated. The dominant fungal genera included Candida, Dekkera, Pichia, Rhizopus, and Issatchenkia, whereas the dominant bacterial genera included Lactobacillus, Pectinatus, Bifidobacterium, Pseudomonas, and Acetobacter. Compared to normal rice sour soup, off-flavoured rice sour soup contained the significantly increased relative abundance of Candida and the significantly decreased relative abundance of Dkkera. In addition, 80 volatile flavour compounds detected in off-flavoured rice sour soup, mainly including esters, acids, and alcohols, were different from those detected in normal rice sour soup. Especially, some substances were only detected in off-flavoured rice sour soup, such as 1-hexanol (68–207 μg/kg), butyric acid (20–92 μg/kg) and heptanoic acid (12–45 μg/kg), which might be the main source of off-flavours. These results provide new ideas and strategies of removing or abating odour from fermented rice sour soup.

內(nèi)容: Edible mushroom polysaccharides demonstrate a range of bioactivities and have been investigated as potential adjuvant therapies for cancer treatment. Our prior research found Lactariks hatsudake Tanaka polysaccharide (LHP) effective against hepatocellular carcinoma, but the mechanisms remain unclear. This study aims to clarify the anti-cancer molecular mechanisms by examining the effects on specific signaling pathways through in vivo and in vitro analyses. Animal studies showed that LHP significantly inhibited the growth of transplanted liver cancer without toxicity. Histological and immunohistochemical analyses revealed that LHP increased nuclear cohesion in tumor cells and altered the expression of key regulatory proteins such as protein kinase B (Akt), nuclear factor κB (NF- κB), caspase-3, p21, and p53. These findings suggest that LHP’s anticancer effects involve promoting apoptosis and disrupting the cell cycle. At the cellular level, assays such as 3-(4,5- dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl) -2- (4-sulfophenyl) -2H-tetrazolium (MTS), flow cytometry, and transwell invasion confirmed that LHP inhibited cancer cell proliferation and induced apoptosis. Polymerase chain reaction and Western blot assays revealed that LHP intervention reduced cyclin-dependent kinase 4 activity by upregulating p53 and p21, leading to cell cycle arrest and inhibited cell proliferation. LHP also promoted apoptosis by altering Bcl-2-associated X protein, B-cell lymphoma 2, and cleaved caspase-3 levels. Moreover, LHP could affect the Akt, NF-κB, and mitogen-activated protein kinase signaling pathways to exert anticancer effects. These findings underscore the potential of LHP as a novel and multifaceted therapeutic agent. Furthermore, the elucidation of LHP-related mechanisms offers a crucial theoretical foundation for developing innovative and effective treatments for hepatocellular carcinoma. Additionally, this supports its potential development as a functional food or adjuvant therapy for cancer, which holds significant implications and application prospects in both the food and medical fields.