期刊：
Journal of Food Biochemistry,2023年2023 ISSN：0145-8884
通讯作者：
Zhou, H
作者机构：
[Liu, Yan; Liu, Chengguo; Zhou, Hui; Luo, Jie; Lei, Wenping; Chen, Qi] Hunan Agr Univ, Coll Food Sci & Technol, Changsha, Hunan, Peoples R China.;[Tang, Xia] Royal Grp Hunan Ushi Dairy Co Ltd, Changsha, Hunan, Peoples R China.
通讯机构：
[Zhou, H ] H;Hunan Agr Univ, Coll Food Sci & Technol, Changsha, Hunan, Peoples R China.
摘要：
Exopolysaccharides (EPS) of lactic acid bacteria (LAB) has gained special interests in the dairy industry due to their health-promoting properties and contribution to the rheology of fermentation milk products. In the present study, an EPS designated as EPS-NS1905E was partially purified and characterized secreted from L. plantarum NS1905E. The EPS-NS1905E had an average molecular weight of 2.658 x 10(5) Da and was composed of glucose, arabinose, rhamnose, mannose, and galactose in an approximate molar ratio of 58.83 : 17.4 : 6.31 : 5.86 : 2.74. The FTIR spectroscopy showed the prevalence of carboxyl and hydroxyl groups. The EPS-NS1905E had a thermal stability and exhibited higher viscosity in the NaCl solution and low acidity conditions (pH 2-4). Furthermore, the EPS-NS1905E possessed strong scavenging abilities against DPPH radicals (96%). The addition of EPS-NS1905E in skim milk significantly shortened the fermentation time of yogurt, and the water-holding capacity (WHC) and viscosity of yogurt were improved during storage. The results indicated that the EPS-NS1905E has great potential for use as a food additive in the food industry.
摘要：
In this study, Rhizopus oryzae HC-1, a food-grade fungal isolated from sufu, was utilized for solid-state fermentation (SSF) of soybeans, to investigate its effect on metabolites composition and antioxidant activity. Results revealed that SSF notably enhanced the total phenolics content (TPC), total flavonoids content (TFC), aglycone isoflavones, and antioxidant capacity of soybeans. The increase in aglycone isoflavones was attributed to the action of secreted beta-glucosidase. The fermented soybean (FSB) with strongest antioxidant activity was further investigated by UPLC-MS/MS-based untargeted metabolomics analysis and in vitro human gut microbiota modulation effect by colonic fermentation. A total of 176 and 114 metabolites differed significantly between non-fermented soybean (NSB) and FSB in positive-and negative-ion modes, respectively. FSB and NSB had a beneficial modulation effect on the microbiota community structure. Additionally, colonic fermentation of both FSB and NSB for 24 h resulted in a higher relative abundance of beneficial bacteria Bacteroides compared to the control group, and FSB showed a greater modulation effect. Thus, SSF with R. oryzae HC-1 was found to significantly improve the metabolite profile, antioxidant activity and human intestinal microbiota modulation effect of soybeans, potentially offering novel functional or nutraceutical ingredients for the food and pharmaceutical industry.
摘要：
Although Litsea cubeba essential oil (LCEO) is widely used for against fungi, antifungal mechanism of it is not fully understood. In the study, antifungal potential and mechanism of LCEO on Colletotrichum scovillei, the main pathogen fungi caused pepper anthracnose, were studied. Results of gas chromatograph-mass spectrometry (GCMS) showed that citral (67.37%) and D-Limonene (11.72%) were the major components of LCEO. LCEO was effective in inhibiting germination of C. scovillei spores, and the minimum inhibitory concentration (MIC) was 0.60 mg mL -1. To determine influence of LCEO on cell membrane integrity and permeability of C. scovillei, SEM observation, OD260 nm (nucleic acids), OD280 nm (proteins), extracellular electric conductivity, cell membrane permeability (propidium iodide, PI), cell wall integrity (calcofluor white, CFW), malondialdehyde (MDA) content and ergosterol content were analyzed. Spores exposed to LCEO were partly deformed, collapsed, shrunken and shriveled. The OD260 nm, OD280 nm and the extracellular electric conductivity of LCEO treatment group increased by 2.0, 1.5 and 1.2 times, respectively, at 12 h after treatment of LCEO (0.6 mg mL-1). Besides, high accumulation of MDA content indicated that LCEO significantly enhanced membrane lipid peroxidation. Moreover, LCEO induced a decrease in ergosterol content of C. scovillei. These findings suggest that LCEO exhibited potent inhibitory activities against C. scovillei, and the cell membrane permeability and cell wall integrity of C. scovillei treated by LCEO were significantly destroyed.
期刊：
International Dairy Journal,2023年137:105504 ISSN：0958-6946
通讯作者：
Ren, F.;Luo, J.
作者机构：
[Luo, Jie; Guo, Mengyuan; Wang, Pengjie; Zhang, Yan; Ren, Fazheng] China Agr Univ, Coll Food Sci & Nutr Engn, Beijing Adv Innovat Ctr Food Nutr & Human Hlth, Beijing 100083, Peoples R China.;[Luo, Jie; Sheng, Zhaoyue] Hunan Agr Univ, Coll Food Sci & Technol, Changsha 410114, Peoples R China.;[Zhang, Xiaoying] Inner Mongolia Yili Ind Grp Co Ltd, Innovat Ctr, Hohhot 010000, Peoples R China.;[Zhang, Ying] Inner Mongolia Yili Ind Grp Co Ltd, Cheese Business, Hohhot 010000, Peoples R China.;[Szeto, Ignatius Man-Yau; Wang, Yilun] Inner Mongolia Yili Ind Grp Co Ltd, Yili Maternal & Infant Nutr Inst, Hohhot 010000, Peoples R China.
通讯机构：
[Fazheng Ren; Jie Luo] B;Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China<&wdkj&>College of Food Science and Technology, Hunan Agricultural University, Changsha 410114, China<&wdkj&>Beijing Advanced Innovation Centre for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China<&wdkj&>Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Government, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
摘要：
The functionality changes of processed cheese analogue with stretchability during refrigerated storage (0 e60 d) at 4 degrees C were explored and the possible mechanisms were investigated. The results showed that stretchability, meltability, and free oil release of the cheese analogue decreased during refrigerated storage, and stretch length decreased from > 270 cm to 130.63 +/- 8.24 cm after refrigerated storage. Furthermore, the pH 4.6-soluble nitrogen fractions, soluble calcium and phosphorus, and the fraction of bound water of the cheese analogue significantly increased during refrigerated storage, while the b -casein and the fraction of free water decreased. The microstructure results showed that the whey channel disappeared while the proteins were swollen and squeezed and deformed the fat globules over refrigerated time. In conclusion, the functionality changes of the cheese analogue during refrigerated storage occurred under the compound effects of proteolysis and hydration of protein as well as disso-lution of bound calcium.(c) 2022 Elsevier Ltd. All rights reserved.
摘要：
To enhance the understanding of enzymatic hydrolysis and to accelerate the discovery of key bioactive peptides within enzymatic products, this research focused on elastin as the substrate and investigated the variations in peptide profiles and the production of key bioactive peptides (those exceeding 5% of the total) and their impacts on the biological activity of the hydrolysates. Through the application of advanced analytical techniques, such as stop-flow two-dimensional liquid chromatography and ultra-high-performance liquid chromatography-tandem mass spectrometry, the research tracks the release and profiles of peptides within elastin hydrolysates (EHs). Despite uniform peptide compositions, significant disparities in peptide concentrations were detected across the hydrolysates, hinting at varying levels of bioactive efficacy. A comprehensive identification process pinpointed 403 peptides within the EHs, with 18 peptides surpassing 5% in theoretical maximum content, signaling their crucial role in the hydrolysate's bioactivity. Of particular interest, certain peptides containing sequences of alanine, valine, and glycine were released in higher quantities, suggesting Alcalase(®) 2.4L's preference for these residues. The analysis not only confirms the peptides' dose-responsive elastase inhibitory potential but also underscores the nuanced interplay between peptide content, biological function, and their collective synergy. The study sets the stage for future research aimed at refining enzymatic treatments to fully exploit the bioactive properties of elastin.
通讯机构：
[Weiguo Wu; Luyan Liao] A;Authors to whom correspondence should be addressed.<&wdkj&>College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China
关键词：
pickled Brassica napus;fermentation salt concentration;free amino acids;volatile flavor components
摘要：
This study aimed to elaborate on the role of salt concentration on pickled Brassica napus leaf and stem (BLS); it also contributed to the development of low-salt and healthy Brassica napus products in the harvest period. Five sets of pickled BLS samples were prepared, and the physicochemical parameters, free amino acids (FAAs), and the volatile flavor components (VFCs) were analyzed after fermentation. Results showed that some antioxidants, FAAs, and VFCs underwent dynamic changes during fermentation. Nitrite increased with an increase in the salt concentration used for fermentation. Pickled BLS contained a wide range of FAAs; a total of 23 were detected, which might be used as a source of amino acid supplementation. The VFCs were analyzed via headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography and mass spectrometry (GC-MS). A total of 51 VFCs were tentatively identified. The contribution to flavor could be expressed by the relative odor activity value (ROAV). Salt is one of the important factors affecting the quality of vegetable fermentation. Therefore, for large-scale pickled BLS production, a key issue is to balance the low salt concentration and high fermentation quality. Under the action of salt and microorganisms, the fresh BLS fermented via dry pickling, which not only improved its FAAs and VFCs, endowed the production with a unique flavor, but also prolonged the shelf life.
摘要：
Steam explosion (SE), as a high-efficient and environment-friendly pretreatment technology, was applied to pretreat the grape pomace. The results showed that SE increased the yield of free phenolics and flavonoids, but decreased the yield of bound phenolics and flavonoids. The content of total phenolics from grape pomace was much higher than that of total flavonoids. SE significantly decreased the contents of total monomeric antho-cyanins and non-extractable proanthocyanins. (-)-Epicatechin and catechin were the most abundant ingredients in free extracts. After SE, most phenolic acids and flavonoids in the free extracts showed an increasing trend, while it is opposite in the bound extracts. SE increased the antioxidant activity of free extracts, but decreased the antioxidant activity of the bound extracts. SE can convert insoluble dietary fiber (IDF) into soluble dietary fiber (SDF) from grape pomace, and increase the oil-holding capacity (OHC) and sodium nitrite binding capacity (SNBC) of SDF. It can be concluded that an optimal SE condition at 1.2 MPa for 1 min could maximally increase the release of the phenolic compounds and enhance the antioxidant capacity; and the optimal SE condition for the extraction, OHC and SNBC of SDF in grape pomace was at 0.8 MPa for 3 min.
通讯机构：
[Xingbo Shi] L;Laboratory of Micro & Nano Biosensing Technology in Food Safety, Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China
摘要：
In this study, a ratiometric fluorescence-based colorimetric sensor was developed for the portable analysis of antioxidant capacity (AOC) using a smartphone. The sensor used carbon dots (CDs) and o-phenylenediamine (OPD) as fluorescence signal substrate and manganese dioxide nanosheets (MnO2 NSs) as a fluorescence quencher, a catalyst of the substrate. Without a target, MnO2 NSs effectively quench the fluorescence of the CDs via inner filter effect and could catalyze the oxidization of nonfluorescent OPD, forming a yellow fluorescent product (ox-OPD). With a target, MnO2 NSs were destructed into Mn2+, resulting in the loss of the fluorescence quencher and catalytic function. The fluorescence of the CDs was recovered, and the fluorescence of the ox-OPD decreased. The fluorescence color change of the system from yellow to blue was further digitized using a smartphone via the red-green-blue (RGB) analysis. Choosing glutathione as the proof-of-concept target, the two readout modes of the fluorescence spectra and RGB analysis achieved the detection limits of 1.84 and 8.33 mu M, respectively. Ratiometric fluorescence exhibited precise and reliable detection owing to the built-in self -cali-bration function, while the colorimetric readout via a smartphone realized the portable determination. This proposed strategy shows a great potential application in assessing the AOC of food samples and controlling food quality.
摘要：
As a common raw material of industrial products, bisphenol A (BPA) is widely used in the production of food contact materials, and there is a high risk of exposure in food. However, BPA is a well-known endocrine disruptor and poses a serious threat to human health. Herein, a fluorescent sensing platform of BPA based on enzymatic oxidation-mediated fluorescence quenching of silicon nanoparticles (SiNPs) is established and used to the detection of BPA in food species. The SiNPs are prepared with a facile one-step synthesis and emit bright green fluorescence. BPA can be oxidized by horseradish peroxidase (HRP) and hydrogen peroxide (H(2)O(2)) to form a product which can quench the fluorescence of SiNPs through electron transfer. There is a good linear relationship between the fluorescence intensity and BPA concentration in the range of 1-100μM. Therefore, a fluorometry of BPA is established with a low limit of detection (LOD) of 0.69μM. This method has been applied to the determination of BPA in mineral drinking water, orange juice, and milk with satisfactory results. The fluorescent sensor of BPA based on SiNPs has favorable application foreground in the field of food safety analysis.
摘要：
The maturity of tobacco leaves plays a decisive role in tobacco production, affecting the quality of the leaves and production control. Traditional recognition of tobacco leaf maturity primarily relies on manual observation and judgment, which is not only inefficient but also susceptible to subjective interference. Particularly in complex field environments, there is limited research on in situ field maturity recognition of tobacco leaves, making maturity recognition a significant challenge. In response to this problem, this study proposed a MobileNetV1 model combined with a Feature Pyramid Network (FPN) and attention mechanism for in situ field maturity recognition of tobacco leaves. By introducing the FPN structure, the model fully exploits multi-scale features and, in combination with Spatial Attention and SE attention mechanisms, further enhances the expression ability of feature map channel features. The experimental results show that this model, with a size of 13.7 M and FPS of 128.12, performed outstandingly well on the task of field maturity recognition of tobacco leaves, achieving an accuracy of 96.3%, superior to classical models such as VGG16, VGG19, ResNet50, and EfficientNetB0, while maintaining excellent computational efficiency and small memory footprint. Experiments were conducted involving noise perturbations, changes in environmental brightness, and occlusions to validate the model’s robustness in dealing with the complex environments that may be encountered in actual applications. Finally, the Score-CAM algorithm was used for result visualization. Heatmaps showed that the vein and color variations of the leaves provide key feature information for maturity recognition. This indirectly validates the importance of leaf texture and color features in maturity recognition and, to some extent, enhances the credibility of the model. The model proposed in this study maintains high performance while having low storage requirements and computational complexity, making it significant for in situ field maturity recognition of tobacco leaves.
摘要：
The study aimed to compare the effects of crystalline L-lysine and L-glutamate (CAA), Lys-Glu dipeptide (KE) on the growth and muscle development of grass carp (Ctenopharyngodon idellus), and related molecular mechanisms. Five experimental diets (CR, 0.5% CAA, 1.5% CAA, 0.5% KE, 1.5% KE) containing Lys and Glu as free (Lys and Glu, CAA) dipeptide (Lys-Glu, KE) forms were prepared, respectively. A total of 450 juvenile grass carp with an initial weight of 10.69 ± 0.07g were randomly assigned to 15 cages, and 5 treatments with 3 replicates of 30 fish each for 61days of feeding. The results showed that the group of 0.5% KE exhibited the best growth performances according to the indicator's weight gain rate (WGR) and specific growth rate (SGR), although no statistically significant occurred among all groups; diet supplemented with 0.5% CAA significantly elevated the condition factor (CF) and viscerasomatic index (VSI) of juvenile grass carp. Diet supplemented with different Lys and Glu co-forms at different levels promoted the muscle amino acid content compared with those of CR group. Comparing with the CR group and other groups, the hardness of 0.5% CAA group significantly increased, and the springiness of 0.5% KE group excelled. Both the muscle fiber diameter and density of 0.5% KE group showed significant difference with those of the CR group, and a negative correlation between them was also observed. To uncover the related molecular mechanism of the differences caused by the different co-forms of Lys and Glu, the effect of different diets on the expressions of protein absorption, muscle quality, and antioxidation-related genes was analyzed. The results suggested that comparing with those of CR group, the dipeptide KE inhibited the expressions of genes associated with protein metabolism, such as AKT, S6K1, and FoxO1a but promoted PCNA expression, while the free style of CAA would improve the FoxO1a expression. Additionally, the muscle development-related genes (MyoD, MyOG, and Myf5) were significantly boosted in CAA co-form groups, and the expressions of fMYHCs were blocked but fMYHCs30 significantly promoted in 0.5% KE group. Finally, the effect of different co-forms of Lys and Glu on muscle antioxidant was examined. The 0.5% CAA diet was verified to increase GPX1a but obstruct Keap1 and GSTP1 expressions, resulting in enhanced SOD activity and reduced MDA levels in plasma. Collectively, the different co-forms of Lys and Glu influenced the growth of juvenile grass carp, and also the muscle development and quality through their different regulation on the protein metabolism, muscle development- and antioxidative-related genes.
