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In this study, six types of amino acids (Ala, Phe, Glu, Gly, Ser, and Lys) were combined with glucose to produce Maillard reaction products (MRPs) named G-Ala, G-Phe, G-Glu, G-Gly, G-Ser and G-Lys. The effect of MRPs on bread staling was evaluated through texture and sensory analyses during storage. Furthermore, the study comprehensively analyzed the anti-staling mechanisms of MRPs by examining moisture content, starches, and gluten network changes. The results indicated that G-Gly and G-Glu delayed bread staling, with G-Gly showing the most significant effect. Compared with control, the staling rate and starch crystallinity of G-Gly bread decreased by 24.07% and 7.70%, respectively. Moreover, G-Gly increased the moisture content (3.48%), weakly bound water mobility (0.77%), and α-helix content (1.00%) of bread. Component identification and partial least squares regression further confirmed the aldonic acid, heterocyclic acids and heterocyclic ketones in MRPs inhibit water evaporation, gluten network loosening, and starch degradation, thereby delaying bread staling. [Display omitted] • Glucose-derived Maillard reaction products (MRPs) might enhance bread anti-staling. • Adding MRPs to bread enhanced sensory quality and texture, reducing staling rate. • MRPs restrained the starch retrogradation by retarding the starch crystallinity. • MRPs-enriched bread presented stabler gluten networks and higher α-helices content. • Heterocyclic ketones, aldonic and heterocyclic acids of MRPs inhibited bread staling. [ABSTRACT FROM AUTHOR]

• pH-shifting was effective in reducing lectin allergy combining with autoclaving. • More hydrophobic exposures were confirmed in refolding process of pH-shifting. • β-turn increased and random coil decreased after the combining treatment. • Lectin aggregation was observed after autoclaving and enhanced with low pH treated. • Flexible structure and exposure of enzyme cutting sites improved digestibility. Combined effects of pH-shifting and an autoclaving cycle (121 °C, 15 min) on red kidney bean lectin (RKBL) were investigated using intrinsic and extrinsic fluorescence, UV, FTIR, DSC, SEC, dot-blot analysis and in vitro digestibility. Spectroscopic studies suggested that the protein refolding was stable after 3 h incubation with the hydrophobic exposure after pH-shifting, and hydrophobicity was significantly increased with the formation of more looser structure, which would influence the structural stability of known epitopes. In details, the increase of β-turn and reduction of random coil was related with the lower denaturation enthalpy, while the protein aggregation was also observed in acidic treated samples after autoclaving. Lower antigenicity and good digestibility suggested the exposure of enzyme cutting sites, and confirmed the effectivity of pH-shifting prior to the autoclaving. Then the results would be beneficial to the development of hypoallergenic kidney bean foods. [ABSTRACT FROM AUTHOR]

Highlights • Lectin of black turtle bean were incubated in acidic buffers for various times. • A steady state of lectin tertiary structure was formed by low pH treatment for 8 h. • Low pH treatment could cause structure alterations significantly and dissociation. • Allergenicity and digestibility of lectin were reduced by low-pH induced process. Abstract Lectin was incubated in corresponding acidic buffers (pH 1.0–3.5) for a certain period (0.5, 1, 2, 4, 8, 12 and 24 h) at 25 °C. Low-pH induced changes in structure, allergenicity and in vitro digestibility of lectin from black turtle bean (Phaseolus vulgaris L.) were investigated in the present study. Results indicated that the alteration in structure was a progressive unfolding process mainly depending on pH environment, and the treated lectin attained a stable state at 8 h. Electrophoretic, dynamic light scattering (DLS) and size exclusion chromatography (SEC) analyses suggested that lectin monomers appeared in the solutions of pH < 2.0. Differential scanning calorimetry (DSC) confirmed that thermal stability of lectin weakened in low pH environments. Furthermore, ELISA and in vitro digestion assay showed allergenicity and digestibility significantly decreased with the structural alterations. These results showed low-pH treatments have great potential to reduce the damage of legumes protein consumption. [ABSTRACT FROM AUTHOR]

• Pre-germination was used to improve the nutritional value of brown glutinous rice. • Antagonism between ultrasound treatment and CaCl 2 stress was explored in soaking. • Both CaCl 2 and ultrasonic treatments improved GABA production during germination. • Energy metabolism, lipid metabolism and protein hydrolysis were enhanced. • Low-frequency ultrasound with salt stress would short the germinated time. In order to fortify γ-aminobutyric acid (GABA) of brown glutinous rice (BGR), pre-germination strategy was employed, and effects of low-frequency (28 kHz) ultrasound treatment combined with CaCl 2 stress on the sprout length, germination rate, morphology, color, water, total polyphenol content (TPC), starch, protein, GABA contents and relevant metabolites were investigated. The germination rate would be inhibited under CaCl 2 concentration ≥ 2.0 % during 24 h soaking without ultrasound treatment, and no significant difference was also observed combined with 9 h ultrasound treatment. Ultrasound treatment was beneficial to water absorption, TPC enrichment, energy metabolism, lipid metabolism and protein hydrolysis. Higher contents of GABA (3.29 folds), pyruvic acid (7.63 folds), glycerol (4.88 folds), glutamate (2.02 folds) and glucose (1.32 folds) were obtained due to the antagonistic effect between the 30 w ultrasound treatment and 2.0 % CaCl 2 stress at the 9 h pre-germination, and energy, lipid and protein metabolomic pathways were all involved in the GABA accumulation. [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]

• Two-step protocol with 70–80% (v/v) ethanol recover more prolamins from kidney beans. • MS data showed the composition diversity of prolamins from various kidney beans. • Seven prolamins were clustered into three main groups related to seed coat colors. • LSKB, BSKB, and RKB extractions have higher hydrophobicity and better OAC. • Hydrophobicity was related to the compositions and structures of prolamins. Ethanol protocol, two-step protocol and enzymatic extraction were used to extract prolamins from seven kidney beans (P. vulgaris L.) compared with Osborne protocol. 70–80% (v/v) ethanol concentrations were beneficial to the extraction, and two-step protocol was conducive to higher prolamin content. Varied protein subunits were observed in electrophoresis profiles, and further differences in composition were identified by LC-MS/MS while potential functions were annotated. Stronger hydrophobicity was found with prolamins enrichment from light speckled kidney bean (LSKB), black speckled kidney bean (BSKB), and red kidney bean (RKB), which was negative correlation with α-helix content based on the principal component analysis (PCA). The crude prolamins from the two kinds of white kidney beans possessed higher sulfhydryl and exhibited better water holding capacity (WHC), while higher oil absorption capacity (OAC) was observed in LSKB, BSKB, and RKB. Compared with zein, kidney bean prolamins could be used as food packaging materials due to hydrophobicity. [ABSTRACT FROM AUTHOR]

• Low pH-shifting was used in black turtle bean protein isolate treatment. • Protein isolates were adjusted to neutral from pH 3.0, 2.0, 1.5, 1.0 incubations. • Protein was unfolded with exposure of buried hydrophobic residues after treatment. • Hydrophobic functionalities were improved, with decrease of hydrophilic properties. • Lower hemagglutination and immunoreactivity were obtained with better digestibility. Low pH-shifting was firstly applied in the black turtle bean (Phaseolus vulgaris L.) protein isolate treatment by acidic (pH 1.0–3.0) buffer incubation for 8 h, then was adjusted to pH 7.2 and kept 3 h for protein stabilizing. Mild loss of secondary structure was confirmed in the protein isolate after low pH-shifting treatment by CD and FT-IR analyses. Intrinsic fluorescence, UV spectra, surface hydrophobicity, SH content and SDS-PAGE analyses indicated the protein conformation was unfolded with the exposure of much more buried hydrophobic residues, which would result in the enhancement of emulsifying properties, foaming properties and fat holding capacity, and lead to the reduction of solubility and water holding capacity. Furthermore, lower immunoreactivity was observed by the ELISA, and improved digestibility was found in in vitro digestion assay. Our results suggested the low pH-shifting treatments would broaden the application of bean protein isolate with better hydrophobic processing functions and safety. [ABSTRACT FROM AUTHOR]

• Effects of pH and heating on BKBL IgE-binding capacity were characterized by RSM. • IgE-binding capacity reduction was related with the structural change of BKBL. • Low-pH incubated BKBL was a bit resistant to structural alterations during heating. • Combination of pH and heating was effective to reduce IgE-binding capacity of BKBL. Combined effects of pH and thermal treatments on black kidney bean lectin (BKBL) were investigated by response surface methodology (RSM). Low-pH (1.0, 2.0, 3.0) incubation decreased hemagglutination activity (HA) and IgE-binding capacity, but the activities would be restored when the lectin was treated by pH shifting to 7.2. Conformational structure analyses indicated that low-pH induced protein unfolding and pH-shifting treatment resulted in a limited structural rearrangement. Mild heating, such as 60 °C for 3 min, slightly increased the HA and IgE-binding activities of pH shifted BKBL, but no obvious effects in the pH 1.0 incubated BKBL. High-temperature and long-time treatment might induce the protein aggregation, further decreased HA and IgE-binding capacities. RSM results showed both IgE-binding capacity and HA were the lowest under the combination of pH 1.0 incubation with 80 °C heating for 15 min or pH shifting from 1.0 to 7.2 with 100 °C heating for 10 min. [ABSTRACT FROM AUTHOR]

• Protein extracted at pH 9.0 had lower glucosinolates, phytic acid and sinapine. • Protein extracted at pH 9.0 had lighter colour and lower D-amino acid content. • Protein obtained at pH 4.5 had the lowest glucosinolates, phytic acid and sinapine. • Water/oil absorption, foaming and emulsifying features decreased as pH decreased. • The α-polypeptide of cruciferin and napin showed gastric digestive resistance. Cold-pressed rapeseed meal with high protein content (38.76% protein dry weight basis) was used to prepare rapeseed protein isolates (RPIs) by alkaline extraction (pH 8.0, 9.0, 10.0, 11.0, 12.0 and 13.0) and acid precipitation (pH 3.0, 3.5, 4.0, 4.5, 5.0 and 5.5). The protein with an intact structure and the highest yield (65.08%) was obtained at extraction pH 9.0 and precipitation pH 4.5, accompanied by the lowest D-amino acid content, the lightest colour and the lowest contents of glucosinolates (2.85 mmol/kg), phytic acid (1.05 mg/g) and sinapine (0.68 mg/g). Additionally, water/oil absorption, foaming and emulsifying capacities decreased with decreasing precipitation pH, while the solubility showed the reverse trend. During gastric simulation digestion, the α-polypeptide of cruciferin and napin in the RPIs showed digestive resistance. Overall, pH regulation might be an effective method to isolate high quality RPIs for use in the food processing industry. [ABSTRACT FROM AUTHOR]