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Maillard reaction products formed from whey protein isolate (WPI) and sugar have been shown to have an anti-inflammatory effect in vitro. Here, we incubated WPI and galactose (GWA) in an aqueous solution at 65°C for 24 h to produce a glycated conjugate, which was then fermented using Lactobacillus gasseri 4M13 to obtain the fermented product (F-GWA). We demonstrated that F-GWA had an anti-inflammatory effect on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. It reduced both LPS-stimulated nitric oxide production and LPS-stimulated increases in the gene expression levels of tumor necrosis factor-α and cyclooxygenase-2 in a dose-dependent manner. Furthermore, F-GWA inhibited the LPS-induced phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase, members of the mitogen-activated protein kinase family. The glycation process was evaluated by measuring fluorescence intensity and the furosine concentration during the Maillard reaction to form GWA. The protein modifications of WPI were analyzed using MALDI-TOF tandem mass spectrometry. We found that the combination of the Maillard reaction and L. gasseri 4M13 fermentation increased the prebiotic properties of GWA as well as organic acid production, compared with the nonreacted WPI and galactose., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Objective: The objective of this study was to investigate the impact of supplementation with fermented Maillard-reactive whey protein (F-MRP) on natural killer (NK) cell activity, circulating cytokines, and serum protein levels., Methods: A randomized, double-blind, placebo-controlled study was conducted on a sample of 80 participants without diabetes or obesity. Over an 8-week study period, the F-MRP group consumed 6 g of powder containing 4.2 g of F-MRP each day, whereas the placebo group consumed the same amount of maltodextrin. For each participant, NK cell activity was evaluated based on the ratio of effector cells (E; peripheral blood mononuclear cells, PBMCs) to target cells (T; K562 cells) at E : T ratios of 10 : 1, 5 : 1, 2.5 : 1, and 1.25 : 1., Results: Body mass index (BMI) and NK cell activity under all assay conditions were significantly increased in the F-MRP group at the 8-week follow-up visit compared with the values at the baseline, whereas the placebo group showed significant reductions in NK cell activity (at an E : T ratio of 5 : 1), serum albumin, and pre-albumin at the 8-week follow-up visit compared with the values at the baseline. When comparing the changes between the placebo and F-MRP groups, the increases in NK cell activity under all assay conditions and serum interleukin (IL)-12 in the F-MRP group were greater than those in the placebo group after adjusting for baseline values. There were also significant differences in pre-albumin and insulin-like growth factor (IGF)-1 between the two groups; the change in (Δ) IL-12 was positively correlated with both Δpre-albumin (r = 0.435, P = 0.006) and ΔNK cell activity at an E : T ratio of 10 : 1 (r = 0.571, P < 0.001) in the F-MRP group., Conclusion: Daily consumption of F-MRP enhanced NK cell function, which was positively associated with ΔIL-12. Moreover, ΔIL-12 was positively correlated with Δpre-albumin.

Whey protein concentrate (WPC), which contains α-lactalbumin and β-lactoglobulin, is utilized widely in the food industry. The Maillard reaction is a complex reaction that produces Maillard reaction products (MRPs), which are associated with the formation of antioxidant compounds. In this study, the hepatoprotection activity of MRPs of WPC against oxidative stress through the nuclear factor-E2-related factor 2 (Nrf2)-dependent antioxidant pathway in HepG2 cells was examined. Glucose-whey protein concentrate conjugate (Glc-WPC) was obtained from Maillard reaction between WPC and glucose. The fluorescence intensity of Glc-WPC increased after 7 d compared to native WPC, and resulted in loss of 48% of the free amino groups of WPC. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of Glc-WPC showed the presence of a high-molecular-weight portion. Treatment of HepG2 cells with Glc-WPC increased cell viability in the presence of oxidative stress, inhibited the generation of intracellular reactive oxygen species by tert-butyl hydroperoxide (t-BHP), and increased the glutathione level. Nrf2 translocation and Nrf2, reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H)-quinone oxidoreductase 1 (NOQ1), heme oxygenase-1 (HO-1), glutamate-L-cysteine ligase (GCL)M and GCLC mRNA levels were increased by Glc-WPC. Also, Glc-WPC increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK). The results of this study demonstrate that Glc-WPC activates the Nrf2-dependent pathway through the phosphorylation of ERK1/2 and JNK in HepG2 cells, and induces production of antioxidant enzymes and phase II enzymes.

This study examined the effects of Maillard reaction products (MRP) and MRP fermented by lactic acid bacteria on antioxidants and their enhancement of cardiovascular health in ICR mouse and rat models. In previous in vitro studies, the selected lactic acid bacteria were shown to significantly affect the activity of MRP. The expression of genes (e.g., superoxide dismutase, catalase, and glutathione peroxidase) related to antioxidant activity was upregulated by Maillard-reacted sodium caseinate (cMRP), and cMRP fermented by Lactobacillus fermentum H9 (F-cMRP) synergistically increased the expression of catalase and superoxide dismutase when compared with the high-cholesterol-diet group. Bleeding time, the assay for determination of antithrombotic activity, was significantly prolonged by Maillard-reacted whey protein concentration (wMRP) and wMRP fermented by Lactobacillus gasseri H10 (F-wMRP), similar to the bleeding time of the aspirin group (positive control). In addition, the acute pulmonary thromboembolism-induced mice overcame severe body paralysis or death in both the wMRP and the F-wMRP groups. In the serum-level experiment, cMRP and F-cMRP significantly reduced the serum total and low-density lipoprotein cholesterol levels and triglycerides but had only a slight effect on high-density lipoprotein cholesterol. The levels of aspartate transaminase and alanine transaminase also declined in the cMRP and F-cMRP intake groups compared with the high-cholesterol-diet group. In particular, F-cMRP showed the highest reducing effects on triglycerides, aspartate transaminase, and alanine transaminase. Moreover, the expression of cholesterol-related genes in the F-cMRP group demonstrated greater effects than for the cMRP group in the level of cholesterol 7 α-hydroxylase (CYP7A1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), and low-density lipoprotein receptors compared with the high-cholesterol-diet group. The protective role of cMRP and F-cMRP in the high-cholesterol group may have been the result of an antioxidative defense mechanism that regulated cholesterol synthesis and metabolism. Therefore, F-cMRP and cMRP have the potential to play preventive and therapeutic roles in the management of cardiovascular disease., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to determine the dual effect of Maillard reaction and fermentation on the preventive cardiovascular effects of milk proteins. Maillard reaction products (MRP) were prepared from the reaction between milk proteins, such as whey protein concentrates (WPC) and sodium caseinate (SC), and lactose. The hydrolysates of MRP were obtained from fermentation by lactic acid bacteria (LAB; i.e., Lactobacillus gasseri H10, L. gasseri H11, Lactobacillus fermentum H4, and L. fermentum H9, where human-isolated strains were designated H1 to H15), which had excellent proteolytic and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities (>20%). The antioxidant activity of MRP was greater than that of intact proteins in assays of the reaction with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and trivalent ferric ions; moreover, the effect of MRP was synergistically improved by fermentation. The Maillard reaction dramatically increased the level of antithrombotic activity and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) inhibitory effect of milk proteins, but did not change the level of activity for micellar cholesterol solubility. Furthermore, specific biological properties were enhanced by fermentation. Lactobacillus gasseri H11 demonstrated the greatest activity for thrombin and HMGR inhibition in Maillard-reacted WPC, by 42 and 33%, respectively, whereas hydrolysates of Maillard-reacted SC fermented by L. fermentum H9 demonstrated the highest reduction rate for micellar cholesterol solubility, at 52%. In addition, the small compounds that were likely released by fermentation of MRP were identified by size-exclusion chromatography. Therefore, MRP and hydrolysates of fermented MRP could be used to reduce cardiovascular risks., (Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)