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Vegetable oils with different unsaturated degrees (corn > peanut > olive > palm > coconut) and corresponding enzymatic hydrolysis-thermal oxidation (ENTH) oils were added into D-xylose and L-cysteine Maillard reaction (MR) system, respectively, for potential meaty aroma production. Results indicated that coconut oil and palm oil had lower peroxide, p-anisidine, total antioxidant values, and malondialdehyde content after ENTH and MR. Corn, peanut, and olive oils after ENTH could significantly promote MR because they caused the lower pH, higher reactants depletion, and higher browning degree in the water phase separated from the oil-Maillard reaction system. Additionally, the volatiles were mainly formed from oil phase. Corn, peanut, and olive oils were beneficial to volatiles formation in the oil-MR system due to fatty acid oxidation, especially oleic acid and linoleic acid. Meanwhile, compared to raw oils, adding ENTH oils to the MR system could reduce the content of oxygen, nitrogen, and sulfur-containing heterocycles., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Effects of Maillard reaction products derived from 1 to 3 kDa soybean peptides (MRPF3) on aging ICR mice were investigated. Seven animal groups were established for 5 weeks, including one normal group and six D-galactose (1000 mg kg -1 /day) treated groups. Aging control was D-galactose + saline solution, and positive controls were D-galactose + ascorbic acid (Vc) (400 mg kg -1 /day) and oligofructose (400 mg kg -1 /day), respectively, while the test groups are D-galactose + high (800 mg kg -1 /day), medium (400 mg kg -1 /day) and low (200 mg kg -1 /day) doses of MRPF3. Compared with the aging controls, food intake, body weights and organ indexes returned to normal after feeding with MRPF3, and the color of feces as well as the fluorescence intensity of urine increased. The content of malondialdehyde (MDA) in the liver significantly decreased with the intake of MRPF3, and the activities of SOD and GSH-Px and the total antioxidant capacity of serum significantly increased. The abundance ratio of Bacteroidetes and Firmicutes significantly decreased in MRPF3 groups, and the abundance of Lactobacillus significantly increased, while potentially pathogenic bacteria such as Porphyromonadaceae significantly decreased. Our results showed that MRPF3 might offer a potent retardation potential for aging., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Maillard reaction products (MRPs) were obtained by using the xylose and soybean peptide system through a 2 h heating at pH of 7.6. Cysteine addition and thermal treatment at 80, 100, 120 and 140 °C were investigated via E-nose and E-tongue, free amino acids (FAA) and GC-MS analyses of MRPs. Afterwards, the combined effects were performed using the partial least square regression (PLSR). Results suggested that MRPs without cysteine addition (XSs) had stronger browning intensity, and the cysteine would be beneficial to the pH reduction with heating temperature increasing. PLSR analysis revealed that MRPs with cysteine addition heated at 140 °C (XSC-140) showed the lowest bitterness, and XS-100 had the highest umami and saltiness. Both bitter and umami FAA increased with the addition of cysteine, and more furans and nitrogen-containing compounds formed in the XSs brought caramel-like flavor, while XSCs exhibited meat-like flavor attributed to sulphides generation., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The low-temperature roasting of sesame oil has become increasingly popular because of its nutritional benefits; however, the flavor is reduced. In order to improve the quality of sesame oil without exogenous addition, sesame meal was hydrolyzed and further used to prepare Maillard reaction products (MRPs) while protease hydrolysis (PH) and glucoamylase-protease hydrolysis (GPH) were used, and their respective Maillard products (PHM and GPHM) were added in the oils for reducing sugar and total sugar content determination, free amino acid determination, and color and descriptive sensory analysis, as well as electronic nose, SPME-GC-MS, odor activity value, and oxidative stability analyses. Results showed that the MRPs could be produced using the enzymatically hydrolyzed sesame meal without exogenous addition, and the oil flavor blended with GPHM (GPHM-SO) was significantly (p < 0.05) improved with the best sensory quality. The composition of pyrazines (119.35 μg/mL), furans (13.95 μg/mL), and sulfur substances (6.25 μg/mL) contributed positively to sensory properties in GPHM-SO, and 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, and 2,3-dimethylpyrazine were characterized as the key flavor compounds with odor activity values of 7.01, 14.80, and 31.38, respectively. Furthermore, the oxidative stability of the oil was significantly improved with the addition of MRPs, and the shelf life of GPHM-SO was predicted to be extended by 1.9 times more than that of the crude oil based on the accelerated oxidation fitting analysis. In general, the MRPs derived only from sesame meal can enhance the flavor and oxidative stability of sesame oil and can be applied in the oil industry. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Rapeseed peptide and d -xylose were used to develop Maillard reaction products. • Reaction with or without cysteine and various temperatures were considered. • High temperature promoted the formation of browning products and volatiles. • Cysteine addition was favor to generation of sulfur-containing compounds. • Furans and nitrogen oxides could be produced without cysteine. Abstract Rapeseed peptide was used to produce flavor enhancer via heating with d -xylose at various temperatures (80–140 °C) at reaction pH 7.4 for 2 h with or without l -cysteine (RXC or RX). Effects of temperatures and l -cysteine on the Maillard reaction products (MRPs) were investigated by the determinations of pH, color, free amino acids (FAA), and volatile compounds, as well as E-nose and E-tongue analyses. Partial least square regression (PLSR) method was further applied to explore the correlations. Results suggested that pH decreased more significantly in RXCs, and a more dark brown color was observed in RXs with the increase of heating temperatures. The lowest bitterness MRPs were obtained by heating at 140 °C with cysteine (RXC-140), while the highest umami and saltiness sample was found in RX-100. Bitter and umami FAAs were present in greater amounts at higher temperatures with cysteine. Furthermore, RXC showed a meat-like flavor due to the generation of sulfur-containing compounds, and more furans and nitrogen-containing compounds were detected in RX, along with a caramel-like flavor. [ABSTRACT FROM AUTHOR]

Four peptide fractions PF1 (>5 ;kDa), PF2 (3–5 ;kDa), PF3 (1–3 ;kDa), PF4 (<1 ;kDa) were isolated from soybean hydrolysate using the ultrafiltration method. Then, d -xylose and l -cysteine were reacted with specific peptide solution at 120 ;°C for 2 ;h, and the molecular weight distribution (MWD), pH, colour, browning intensity, DPPH radical-scavenging activity, free amino acids and sensory characteristics of corresponding Maillard reaction products (MRPF1, MRPF2, MRPF3 and MRPF4) were evaluated, respectively. Peptides with low molecular weight showed higher contribution to the changes of pH, colour and browning intensity during Maillard reaction. The DPPH radical-scavenging activity of PF4 was significantly improved after Maillard reaction. Aroma volatiles and PLSR analysis suggested MRPF3 had the best sensory characteristics with higher contents of umami amino acids and lower of bitter amino acids, therefore it could be deduced that the umami and meaty characteristics were correlated with the peptides of 1–3 ;kDa. [ABSTRACT FROM AUTHOR]

• SPI was modified by low pH shifting with hydrophobicity enhancement. • SPI-SPSS conjugates were easily obtained by Maillard reaction. • Submicro particles were formed by heating self-assembly reaction. • Improvement of hydrophobicity of SPI could promote submicron gelling properties. In the present study, the soybean protein isolate (SPI) was treated by pH shifting process, as the protein was incubated in low pH solutions (pH 1.5–3.5) for 12 h, following neutralized to pH 7.0 and held for 4 h, which resulted in a conformation unfolding/refolding confirmed by the fluorescence spectra and a substantial increase in α-helix content revealed by circular dichroism (CD) spectra, along with the increased exposure of hydrophobic and sulfhydryl groups. In addition, the heat-induced gelation process and enhanced gel strength of pH 3.0 and 3.5 shifted SPIs were observed. Maillard reaction was then applied and the glycosylated SPI was further applied to the sub-micron gel particles formation. Results showed that low-pH shifting obviously improve the glycosylation ability of SPI as the conjugation degree and browning degree were enhanced. The sub-micron gel particles with core–shell structure and the average sizes of 100–250 nm were formed via heating self-assembly reaction and confirmed through Z-average of particle size, meanwhile, the increasing stability of gel particles in the solution was determined by Zeta potential analysis, suggesting that the improvement of hydrophobicity and glycosylated ability of SPI could promote gelling properties. Hence, the protein modification stage of pH shifting process would provide a great potential application in the formation of nano- or microscale gel particles. [ABSTRACT FROM AUTHOR]