Mechanism of improving interfacial hydration characteristic of high‐denatured peanut protein induced by cold plasma

Abstract

AbstractHigh‐denatured peanut protein (HPP), obtained from high‐temperature pressed peanut meal, is limited in the food industry applications due to poor hydration characteristics. The ionic force generated by the cold plasma (CP) was used to activate the surface groups of HPP for generating the interfacial chemical force binding with water molecules, in which the high‐speed shear homogenization (12,000 r/min, 15 min) was as a pretreatment to enhance the accessibility for CP. The content of soluble protein increased from 0.22 ± 0.005 to 1.02 ± 0.03 mg/ml with a CP treatment power of 70 W for 2 min. Meanwhile, CP treatment facilitated the transition of weakly bound water to strongly bound water, therefore, the hydration property was improved. The tertiary, secondary, and apparent structure in HPP stretched after CP treatment. Besides, NH4+ ions in CP excited state improved the flexibility of HPP. Some hydrophilic groups such as COOH, CO, C═O, and OH formed via hydrogen bond to HPP surface was the primary reason for the increased hydration property, which was related to an increase of oxygen on the surface of protein. The increased interfacial hydration property of proteins provides the possibility for the preparation of preparation of functional films, gels, and nutrition agents.Practical applicationsCold plasma (CP), as a nonthermal and surface processing technology, has drawn great attention during the processing. The amount of free radicals, high‐energy electrons, ions, and ultraviolet radiation generated by CP modified the surface structure of the materials, which avoided thermal denaturation and pollution, and had high efficiency. This study indicated that CP treatment enhanced the interfacial hydration characteristic of the high‐denatured peanut protein extracted from peanut meal via analyzing the changes of structure, functional property, as well as chemical bonds, which was beneficial for the preparation of functional films, and gels for drug and nutrition delivery.