Computational study on the Maillard reactions of glucose and galactose with lysine.

CONTEXT: Milk has nutrient-rich but thermal sensitive matrix that undergoes varying degrees of Maillard reaction (MR) at heating conditions. The MR mainly occurs between lysine residues (Lys) and lactose composed of glucose (Glc) and galactose (Gal), which are abundantly sourced from dairy products. In the present study, the MRs of Glc and Gal with Lys at the initial and intermediate stages have been investigated theoretically using density functional theory (DFT) to simulate the gaseous and aqueous phases. Reaction mechanisms have been proposed, and relative energy changes of different steps were calculated according to the total mass balance. The calculations reveal that both Nα- and Nε-amine groups of Lys can react with the carbonyl functional group of Glc and Gal with the similar potential energy profiles, and Gal is more reactive than Glc. However, the barrier in Nε-channel is lower than in Nα-channel, indicating a faster reaction rate through the former channel compared with the latter. The 5-hydroxymethyl-2-furfural (HMF) and derivative are formed under 3-deoxysone route in the intermediate stage. The calculation results are helpful for proposing a reasonable MR mechanism and suggesting possible control methods of the MRs. METHODS: In this study, different levels of DFT calculations have been conducted to investigate the mechanisms and favorability of generating MR products in Glc-Lys and Gal-Lys models at initial and intermediate stages in the gaseous and aqueous conditions. In order to elucidate the molecular models from the perspectives of chemistry and geometry, DFT calculations were performed by the mean of B3LYP functional at basis sets of 6-311 + + G (d, p) and 6-311 + + G (2df, 2p) with optional solvation settings. To examine the solvation effect, the study further constructed models with solvent H2O and calculated in wB97XD functional with 6-31 + G (d) basis set. All computations were carried out Gaussian 09 suite of quantum chemistry software.

Metabolomics study on fermentation of Lactiplantibacillus plantarum ST-III with food grade proliferators in milk.

Milk is a naturally complex medium that is suitable for the growth of most lactic acid bacteria. Unfortunately, Lactiplantibacillus plantarum ST-III grow poorly in milk without supplementation. To solve this problem, we use fresh pineapple and mung beans juice to develop an edible proliferator for L. plantarum ST-III. Our comparative analysis of metabolomics changes before and after fermentation reveals that amino acids and dipeptides are the most consumed compounds, with other substances including nucleotides and vitamins, implying the mechanism of proliferation. Combining the KEGG metabolic pathway analysis, substances that may promote the growth of L. plantarum ST-III in milk were screened. To explore which component of the proliferator is required for L. plantarum ST-III cultivate, we supplemented with several combinations of molecules aforementioned in milk. The simulation addition experiment results of L. plantarum ST-III in milk show that if any additions are missing, the concentration of viable bacteria is lower. Only when it contains all additives can the highest concentration of viable bacteria be obtained. Compared with the control, the fold change of the viable bacteria is about 32. Thus, it proves that milk primarily lacked available amino acids, dipeptides, uracil, xanthine, nicotinamide, and manganese for the growth of L. plantarum ST-III.

Effect of Lacticaseibacillus casei LC2W Supplementation on Glucose Metabolism and Gut Microbiota in Subjects at High Risk of Metabolic Syndrome: A Randomized, Double-blinded, Placebo-controlled Clinical Trial.

Metabolic syndrome (MetS) is a global epidemic complex and will cause serious metabolic comorbidities without treatment. A prevention strategy for MetS development has been proposed to modulate gut microbiota by probiotic administration to improve intestinal dysbiosis and benefit the host. Lacticaseibacillus casei LC2W has exhibited positive effects in preventing colitis and anti-hypertension in vivo. However, the effect of L. casei LC2W on subjects at high risk of MetS is unknown. Here, a randomized, double-blinded, placebo-controlled study was conducted on 60 subjects with high risk of MetS, and the hypoglycemic and hypolipidemic activity and possible pathways of L. casei LC2W were inferred from the correlation analysis with gut microbiome composition, function, and clinical phenotypic indicators. The results showed that oral administration of L. casei LC2W could exert significant benefits on weight control, glucose and lipid metabolism, inflammatory and oxidative stress parameters, and SCFA production, as well as modulate the composition of gut microbiota. The relative abundance of Lacticaseibacillus, Bifidobacterium, Dorea, and Blautia was enriched, and their interaction with other gut microbes was strengthened by oral administration of L. casei LC2W, which was beneficial in ameliorating gut inflammation, promoting glucose and lipids degradation pathways, thus alleviated MetS. The present study confirmed the prevention effects of L. casei LC2W towards MetS from aspects of clinical outcomes and microflora modulation, providing an alternative strategy for people at high risk of MetS.Trial registration: The study was proactively registered in ClinicalTrial.gov with the registration number of ChiCTR2000031833 on April 09, 2020.

Lactiplantibacillus plantarum ST-III and Lacticaseibacillus rhamnosus KF7 Enhance the Intestinal Epithelial Barrier in a Dual-Environment In Vitro Co-Culture Model.

Intestinal barrier hyperpermeability, which is characterised by impaired tight junction proteins, is associated with a variety of gastrointestinal and systemic diseases. Therefore, maintaining intestinal barrier integrity is considered one of the effective strategies to reduce the risk of such disorders. This study aims to investigate the potential benefits of two probiotic strains (Lactiplantibacillus plantarum ST-III and Lacticaseibacillus rhamnosus KF7) on intestinal barrier function by using a physiologically relevant in vitro model of the intestinal epithelium. Our results demonstrate that both strains increased transepithelial electrical resistance, a measure of intestinal barrier integrity. Immunolocalisation studies indicated that this improvement in barrier function was not due to changes in the co-localisation of the tight junction (TJ) proteins ZO-1 and occludin. However, we observed several modifications in TJ-related genes in response to the probiotics, including the upregulation of transmembrane and cytosolic TJ proteins, as well as TJ signalling proteins. Gene expression modulation was strain- and time-dependent, with a greater number of differentially expressed genes and higher fold-change being observed in the L. plantarum ST-III group and at the latter timepoint. Further studies to investigate how the observed gene expression changes can lead to enhanced barrier function will aid in the development of probiotic foods to help improve intestinal barrier function.

Recent Studies and Applications of Hydrogel-Based Biosensors in Food Safety.

Food safety has increasingly become a human health issue that concerns all countries in the world. Some substances in food that can pose a significant threat to human health include, but are not limited to, pesticides, biotoxins, antibiotics, pathogenic bacteria, food quality indicators, heavy metals, and illegal additives. The traditional methods of food contaminant detection have practical limitations or analytical defects, restricting their on-site application. Hydrogels with the merits of a large surface area, highly porous structure, good shape-adaptability, excellent biocompatibility, and mechanical stability have been widely studied in the field of food safety sensing. The classification, response mechanism, and recent application of hydrogel-based biosensors in food safety are reviewed in this paper. Furthermore, the challenges and future trends of hydrogel biosensors are also discussed.