Effect of pH-shifting treatment on structural and heat induced gel properties of peanut protein isolate

• Published in: Food chemistry Vol. 325; p. 126921
• Main Authors: Li, Junguang, Wu, Mengmeng, Wang, Yuntao, Li, Ke, Du, Juan, Bai, Yanhong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 30.09.2020
• Subjects: Gel properties; gels; heat; hydrophobicity; moieties; particle size; peanut protein; Peanut protein isolate; pH-shifting; protein aggregates; protein isolates; solubility; Structure; water holding capacity; pH-shifting; Peanut protein isolate; Structure; Gel properties
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2020.126921

•The gel strength (GS) of PPI10 gel were significantly increased.•The water holding capacity (WHC) of PPI10 gel was significantly enhanced.•PPI10 has larger solubility and increased free sulfhydryl content.•PPI10 has smaller particle size and increased surface hydrophobicity.•PPI2 or PPI12 lost its gel ability due to the formation of large protein aggregates. Modifying proteins with new methods to improve their functional properties is essential to extend their application in food related field. In this study, the effect of pH-shifting treatment on structural and heat induced gel properties of peanut protein isolate (PPI) were investigated. PPI was subject to different pH conditions (pH 2, pH 4, pH 10, and pH 12) for 1 h, then adjusted back to pH 7 and they were marked as PPI2, PPI4, PPI10, and PPI12, respectively. It was found that the breaking force (BF) and water holding capacity (WHC) of PPI10 gel were significantly improved due to the decreased particle size, increased solubility, free sulfhydryl group content and surface hydrophobicity of PPI10. While PPI2 or PPI12 lost their gel ability due to the formation of large protein aggregates. These results indicated that pH-shifting treatment might be a convenient and economical method to prepare PPI with different gel and structural properties.