Food College, Shihezi University, Shihezi, Xinjiang, 832000, PR China.
J Food Sci. 2021 Mar;86(3):824-833. doi: 10.1111/1750-3841.15643. Epub 2021 Feb 15.
A chickpea protein isolate (CPI) was oxidized using peroxyl radicals derived from 2,2'-azobis (2-amidopropane) dihydrochloride (AAPH), and the structural and foaming properties of the oxidized CPI were evaluated. The oxidation degree of protein was determined by measuring carbonyl content, dimer tyrosine content, free thiol content, and total thiol content. The structural changes of oxidized protein were evaluated by surface hydrophobicity, endogenous fluorescence intensity, Fourier transform infrared spectroscopy, SDS-PAGE, and amino acid content changes. Compared with the control group (0 mmol/L AAPH), moderate oxidation (0.04 mmol/L AAPH) led to the formation of a soluble protein with flexibility, which could improve the foaming properties of the protein (foaming capacity and stability increased by 25.50% and 6.38%, respectively). Over-oxidized (25 mmol/L AAPH) protein exhibited improved foaming capability, but its foam stability was reduced owing to the formation of insoluble aggregates. The results indicate that oxidation can change protein conformation, and the protein structure can affect the foamability of the CPI. PRACTICAL APPLICATION: CPI is a protein supplement food. Protein oxidation can occur during processing and storage, thereby affecting protein function. In this study, we evaluated how peroxy free radicals affect the structure, solubility and foaming properties of CPI, and clarified the mechanism between them. It has been found that peroxy free radicals can accelerate the oxidation of proteins and have a significant effect on foaming. Therefore, the degree of oxidation should be controlled to improve the quality of CPI.
一种鹰嘴豆分离蛋白（CPI）使用 2,2'-偶氮双（2-脒基丙烷）二盐酸盐（AAPH）衍生的过氧自由基进行氧化，评估了氧化的 CPI 的结构和起泡性能。通过测定羰基含量、二酪氨酸含量、游离巯基含量和总巯基含量来确定蛋白质的氧化程度。通过表面疏水性、内源荧光强度、傅里叶变换红外光谱、SDS-PAGE 和氨基酸含量变化来评估氧化蛋白质的结构变化。与对照组（0 mmol/L AAPH）相比，适度氧化（0.04 mmol/L AAPH）导致形成具有柔韧性的可溶性蛋白质，从而可以改善蛋白质的起泡性能（起泡能力和稳定性分别提高了 25.50%和 6.38%）。过度氧化（25 mmol/L AAPH）的蛋白质表现出改善的起泡能力，但由于形成不溶性聚集体，其泡沫稳定性降低。结果表明，氧化可以改变蛋白质构象，并且蛋白质结构可以影响 CPI 的起泡性。实际应用：CPI 是一种蛋白质补充食品。在加工和储存过程中可能会发生蛋白质氧化，从而影响蛋白质的功能。在这项研究中，我们评估了过氧自由基如何影响 CPI 的结构、溶解度和起泡性能，并阐明了它们之间的机制。已经发现过氧自由基可以加速蛋白质的氧化，并对起泡有显著影响。因此，应控制氧化程度以提高 CPI 的质量。
