Effect of Preheating Whey Protein Concentrate on the Stability of Purple Sweet Potato Anthocyanins

Shuo Zhang; Guowei Deng; Fang Wang; Haiyan Xu; Jiagen Li; Jialei Liu; Dengfeng Wu; Shitao Lan

doi:10.3390/polym15153315

Effect of Preheating Whey Protein Concentrate on the Stability of Purple Sweet Potato Anthocyanins

Polymers (Basel). 2023 Aug 6;15(15):3315. doi: 10.3390/polym15153315.

Authors

Shuo Zhang¹, Guowei Deng¹, Fang Wang¹, Haiyan Xu², Jiagen Li¹, Jialei Liu³, Dengfeng Wu¹, Shitao Lan¹

Affiliations

¹ Sichuan Provincial Key Laboratory for Development and Utilization of Characteristic Horticultural Biological Resources, College of Chemistry and Life Sciences, Chengdu Normal University, Chengdu 611130, China.
² College of Life Sciences, Sichuan Normal University, Chengdu 610101, China.
³ Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.

Abstract

Anthocyanins (ANs) have strong antioxidant activities and can inhibit chronic diseases, but the instability of ANs limits their applications. The conservation of preheating whey protein concentrate (WPC) on the stability of purple sweet potato ANs was investigated. The retention of ANs in WPC-ANs was 85.88% after storage at 25 °C for 5 h. WPC-ANs had higher retention of ANs in heating treatment. The retention rates of ANs in WPC-ANs exposed to light and UV lamps for 6 h were 78.72% and 85.76%, respectively. When the concentration of H₂O₂ was 0.50%, the retention rate of ANs in the complexes was 62.04%. WPC-ANs' stability and antioxidant activity were improved in simulated digestive juice. The WPC-ANs connection was static quenching, and the binding force between them was a hydrophobic interaction at one binding site, according to the fluorescence quenching spectroscopy. UV-visible absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR) analysis further indicated that the secondary structure and microenvironment of amino acid residues in WPC can be impacted by the preheating temperature and preheating times of WPC. In conclusion, preheating WPC can successfully preserve the stability of purple sweet potato ANs by binding to them through a non-covalent interaction.

Keywords: anthocyanins; interaction; preheating temperature; preheating time; stability; whey protein concentrate.

Grants and funding

This work was supported by the Project of Science and Technology Ministry of Sichuan Province (Grant No. 2022NSFSC1643); and the Undergraduate Innovation and Entrepreneurship Training Program supported by the Ministry of Education (grant number S202214389140).