Effects of heat treatment and pH on the physicochemical and emulsifying properties of coconut (Cocos nucifera L.) globulins

• Published in: Food chemistry Vol. 388; p. 133031
• Main Authors: Ma, Jingrong, Chen, Haiming, Chen, Weijun, Wu, Jilin, Li, Zengqing, Zhang, Ming, Zhong, Qiuping, Chen, Wenxue
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.09.2022
• Subjects: Coconut globulins; Cocos; Emulsifying Agents - chemistry; Emulsifying properties; Emulsions - chemistry; Globulins - chemistry; Heat treatment; Hot Temperature; Hydrogen-Ion Concentration; Physicochemical properties; Protein structure; pH; Heat treatment; Coconut globulins; Protein structure; Physicochemical properties; Emulsifying properties
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2022.133031

•The emulsifying properties of CG were improved by heating at 90 ℃.•The aggregates linked by covalent bonds are good for the emulsion stability.•The flexibility of CG at pH 3 led to better emulsifying properties.•The low solubility led to the poor emulsifying properties of CG at pH 5. The present study aimed to assess the effects of heat treatment (70–90 °C) and pH (pH 3–11) on the physicochemical, structural, and emulsifying properties of coconut globulins (CG). The results revealed that the emulsifying property was improved with increasing temperature due to the denaturation degree of CG. CG had a better emulsifying property at pH 3 but showed the worst emulsifying property at pH 5 due to its lowest solubility, surface hydrophobicity, and absolute value of zeta potential. The best emulsifying stability was detected at pH 11 with 90 °C heating. SDS–PAGE indicated that the formation of aggregates cross-linked by covalent bonds was the main reason for the better emulsion stability at pH 3 and pH 11 with 90 °C heating. The secondary structure showed that CG had more α-helix and β-turn contents as well as fewer β-sheet contents at pH 3 and pH 11 with 90 °C heating.