Structural unfolding of soy protein isolate (SPI) as induced by holding (0, 0.5, 1, 2, and 4 h) in acidic (pH 1.5−3.5) alkaline 10.0−12.0) pH solutions, followed refolding (1 at 7.0, was analyzed. Changes emulsifying properties treated SPI were then examined. The pH-shifting treatments resulted a substantial increase surface hydrophobicity, intrinsic tryptophan fluorescence intensity, disulfide-mediated aggregation, along with the exposure tyrosine. After processes, adopted molten...

Maize zein was hydrolyzed for 0.5−5 h by alcalase or papain. Protein solubility increased (P < 0.05) with the degree of hydrolysis (DH) and higher alcalase-hydrolyzed than papain-hydrolyzed zein. The hydrolysates both enzymes consisted mostly small peptides amino acids nondetectable 15% acrylamide gel electrophoresis. Alcalase-hydrolyzed exhibited a stronger antioxidant activity zein, as indicated peroxide thiobarbituric acid-reactive substance values in liposome-oxidizing system. Zein...

The objective of the study was to assess antioxidant potential alcalase-treated zein hydrolysate (ZH) during a two-stage (1 h pepsin → 0.5−2 pancreatin, 37 °C) in vitro digestion. Sephadex gel filtration and high-performance size exclusion chromatography were used separate ZH into fractions. amino acid composition, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+•) 1,1-diphenyl-2-picrylhydrazyl (DPPH•) free radical scavenging activity, reducing power, Cu2+ chelation ability...

Soy protein isolate (SPI), β-conglycinin (7S), and glycinin (11S) were subjected to pH-shifting treatments, that is, unfolding at pH 1.5 or 12.0 followed by refolding 7.0, induce molten globule structures. Treated samples analyzed for solubility, thermal stability, aggregation in 0, 0.1, 0.6 M NaCl solutions 2.0−8.0. The pH12 shifting resulted drastic increases (up 2.5-fold) SPI solubility the 6.0−7.0 range, especially 0 NaCl. pH1.5 had a generally lesser effect on solubility. 11S exhibited...

The dose-dependent effects of gallic acid (GA; at 0, 6, 30, and 150 μmol/g protein) on chemical changes gelling properties oxidatively stressed porcine myofibrillar protein (MP) in vitro digestibility the gels were investigated. incorporation GA suppressed lipid oxidation carbonyl formation but promoted loss thiol amine groups, destabilization tertiary structure, aggregation, cross-linking. potential (storage modulus) MP was increased by nearly 50% with 6 30 GA, corresponding to enhanced...

Integration of gallic acid (GA) and its derivative epigallocatechin gallate (EGCG; 20, 120, 240 μmol/g, protein basis) into whey isolate (WPI) at room temperature pH 3.0 7.0 was investigated. At 7.0, both phenolics caused significant structural changes EGCG induced greater digestibility WPI. Total sulfhydryl in WPI decreased from 28.6 to 7.6 μmol/g surface hydrophobicity declined by nearly 50% with 7.0. Similar but less appreciable were produced GA 3.0. Isothermal titration fluorescence...

Protein hydrolysates were prepared by limited alcalase hydrolysis (0.5, 1, and 6 h, corresponding to degrees of 0.72, 1.9, 2.3, respectively) heat-coagulated potato protein. The characterized for peptide composition, ferric reducing/antioxidant power (FRAP), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity, Fe2+- Cu2+-chelation capacity. Hydrolyzed intact proteins formulated (4%, w/w) into beef patties determine in situ antioxidant efficacy....

The objective of the study was to investigate role emulsified fat (lard) and oil (peanut oil) in rheology microstructure porcine myofibrillar protein (MP) gels. Heat-induced composite gels were prepared from 2% MP with 0% 15% pre-emulsified lipids at 0.6 M NaCl, pH 6.2. Dynamic rheological testing upon temperature sweeping (20 80 degrees C 2 C/min) showed substantial increases G' (an elastic modulus) sols/gels addition emulsions. Gel hardness markedly enhanced (P < 0.05) by incorporating...

ABSTRACT: Native and heated soy protein isolate was hydrolyzed with 3 purified (pepsin, papain, chymotrypsin) crude (Alcalase®, Protamex TM , Flavourzyme ) proteases. The hydrolysates were incubated (37 °C, 1 h) a liposome‐oxidizing system (50 μM FeCl /0.1 mM ascorbate, pH 7.0) to test antioxidant activities by determining the concentrations of TBARS. Degree hydrolysis SPI ranged from 1.7 20.6%. Both nonhydrolyzed decreased TBARS (by 28 65%), except for papain‐hydrolyzed samples. Samples...

ABSTRACT Myofibrils, oxidized with FeCl 3 /H 2 O /ascorbate, exhibited an increase in carbonyls and amines, SH→SS conversion, peptide scission, myosin polymerization, a decrease thermal stability gel‐formation ability. Amino‐acid side chains of whey‐protein isolates (WPI) soy‐protein (SPI) were also modified during oxidation, but the WPI or SPI was not significantly altered. Oxidation increased elasticity gel that gel. Similarly, oxidation promoted interactions myofibrils WPI, resulting &gt;...

Alcalase-treated zein hydrolysate (ZH) was separated by gel filtration, ultrafiltration, and reversed-phase HPLC, the scavenging activities for 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), 1,1-diphenyl-2-picrylhydrazyl (DPPH•), superoxide anion (O2•−) radicals of different peptide fractions were measured to establish antioxidant efficacy. Results showed that ability stabilize water-soluble free (ABTS•+) ZH components insensitive size, whereas against ethanol-soluble...