Ozone treatment increase the whiteness of soy protein isolate through the degradation of isoflavone

Junyou Li; Yunqi Chen; Dan Wang; Lijun Yin; Chenyan Lv; Jiachen Zang; Guanghua Zhao; Tuo Zhang

doi:10.1016/j.foodchem.2024.141665

Ozone treatment increase the whiteness of soy protein isolate through the degradation of isoflavone

Food Chem. 2024 Oct 17;464(Pt 2):141665. doi: 10.1016/j.foodchem.2024.141665. Online ahead of print.

Authors

Junyou Li¹, Yunqi Chen¹, Dan Wang², Lijun Yin³, Chenyan Lv¹, Jiachen Zang¹, Guanghua Zhao³, Tuo Zhang⁴

Affiliations

¹ College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
² Institute of Agri-food Processing and Nutrition, Beijing Academy of Agriculture and Forestry Science, Beijing Key Laboratory of Fruits and Vegetables Preservation and Processing, Key Laboratory of Vegetable Postharvest Processing, Ministry of Agriculture and rural affairs, Beijing 100097, China.
³ College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China; Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
⁴ College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China; Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.. Electronic address: [email protected].

PMID: 39427465
DOI: 10.1016/j.foodchem.2024.141665

Abstract

The color of soy protein isolate (SPI) influences the appearance of products such as tofu and soymilk, consequently impacting consumer preferences. Typically, whiter-colored SPIs were more favorite. However, products currently manufactured in the industry predominantly exhibit a yellowish hue. In our study, the incorporation of gaseous ozone into the production process of SPI notably improved its appearance on color. Simultaneously, a reduction in the isoflavone content enriched in SPI due to ozone treatment was observed, suggesting a potential mechanism for improving the whiteness of SPI. In addition, we discovered that the introduction of ozone for different times oxidized ozone-sensitive sulfhydryl groups, tryptophan, and tyrosine in proteins, thereby affecting the protein structure. This finding was determined through the analysis of free sulfhydryl groups, disulfide bonds, SDS-PAGE electrophoresis, FTIR, and endogenous fluorescence spectroscopy of SPIs. Meanwhile, the ozone treatment did not induce protein aggregation or alter its functional properties.

Keywords: Color mechanism; Ozone; Soy isoflavones; Soy protein isolate; Structure and functional properties.