Heat treatment effect on whey protein-epigallocatechin gallate interaction: A fluorescence spectroscopic analysis.

This study aimed to examine the interaction mechanism of polyphenol protein in a heat-treated aqueous solution system using epigallocatechin gallate (EGCG) and whey protein (WP) as raw materials. Further, we hypothesized the binding characteristics of these two compounds. The results were as follows: The quenching mechanism between WP and EGCG was characterized as static quenching. As the temperature increased, the binding constant and the binding force between EGCG and WP both increased. The number of binding sites (denoted as n) between WP and EGCG was approximately 1. Hence, WP provided a single site to bind to EGCG to form a complex. The main binding modes between WP and EGCG were hydrophobic and electrostatic interactions, and they were spontaneously combined into complexes (ΔG < 0). This study provided a basis for the interaction between WP and EGCG under different heating conditions and their combination mode.

Encapsulation of a Desmodium intortum Protein Isolate Pickering Emulsion of ß-Carotene: Stability, Bioaccesibility and Cytotoxicity.

Owing to their excellent characteristics, Pickering emulsions have been widely used in the development and the application of new carriers for embedding and for delivering active compounds. In this study, ß-carotene was successfully encapsulated in a Pickering emulsion stabilized using Desmodium intortum protein isolate (DIPI). The results showed that the encapsulation efficiencies of ß-carotene in the control group Tween 20 emulsion (TE) and the DIPI Pickering emulsion (DIPIPE) were 46.7 ± 2.5% and 97.3 ± 0.8%, respectively. After storage for 30 days at 25 °C and 37 °C in a dark environment, approximately 79.4% and 72.1% of ß-carotene in DIPIPE were retained. Compared with TE, DIPIPE can improve the stability of ß-carotene during storage. In vitro digestion experiments showed that the bioaccessibility rate of ß-carotene in DIPIPE was less than that in TE. Cytotoxicity experiments showed that DIPI and ß-carotene micelles within a specific concentration range exerted no toxic effects on 3T3 cells. These results indicate that DIPIPE can be used as a good food-grade carrier for embedding and transporting active substances to broaden the application of the protein-based Pickering emulsion system in the development of functional foods.