Interaction of preheated whey protein isolate with rose anthocyanin extracts in beverage model system: Influence on color stability, astringency and mechanism.

Preheating proteins have the potential to improve anthocyanin stability. Our aim was to investigate the effect of preheated whey protein isolate (WPI) on the color stability and astringency of the beverage model system in the presence of rose anthocyanin extracts (RAEs), and to explore the mechanism of interaction between preheated WPI and RAEs. The secondary structure, particle size and transparency of WPI were obviously changed by preheating. WPI preheated at 100°C  (WPI100) could effectively improve the color stability of RAEs in the beverage model system. Importantly, the WPI100-RAEs in the beverage model system exhibited the smallest particle size and the weakest astringency effect. In addition, different preheated WPIs could interact with RAEs non-covalently, and the interaction forces are hydrogen bonding and van der Waals forces, among which WPI100 had the strongest binding ability to RAEs. These results will provide a new insight into the development of protein-anthocyanin beverages.

Influence of Sweeteners (Sucrose, Sucralose, and Stevia) on Bioactive Compounds in a Model System Study for Citrus-Maqui Beverages.

Recently, new formulations of beverages with low sugar and high bioactive compound contents are being demanded because of their association with metabolic health. However, the sweeteners' influences on the bioactive compounds remain underexplored. In this sense, this work aims to evaluate the interactions between different bioactive compounds such as flavonoids, vitamin C, and sweeteners (sucrose, stevia, and sucralose) in a functional citrus-maqui beverage. For this purpose, the phytochemical behavior was studied, in model system solutions, during one-month storage at 4 °C. The results obtained corroborated previous descriptions of the interactions between these compounds. However, when studying the bioactives in the model solutions, the loss of flavanones in the citrus solution increased up to 29%, while anthocyanin losses decreased to 27%. The vitamin C losses ranged from 100% (beverage) to 46% (ascorbic acid solution). Regardless, an influence of the sweeteners was observed. Sucrose reduced the anthocyanin and flavanone losses in both model solutions and the beverage, while sucralose increased flavanone loss. Finally, all sweeteners increased vitamin C degradation (up to 75%) when compared to the model solution. In conclusion, sweeteners added to beverages should be taken into account, depending on the bioactive compounds that should be preserved during storage.