Clean-label smoothies with apple and carrot pomaces: rheology and antioxidant stability

Abstract

Smoothies are thick blended beverages made from fruits, vegetables, and additional ingredients such as yogurt, rice beverages, or honey. In this study, smoothies with different formulations were developed using whey, a by-product of the cheese industry, together with a rice beverage as a plant-based alternative for the growing vegan and lactose-free market. In this study, clean-label smoothies were formulated using a commercial rice beverage, liquid whey, and a 50 : 50 blend of rice beverage and whey. Each of these liquid bases was further enriched with 5% (w/w) apple or 5% (w/w) carrot pomace powder. The impact of the formulations on viscosity was evaluated, along with their effect on total phenolic compounds and antioxidant properties before and after in vitro gastrointestinal digestion. The viscosity of carrot pomace-based smoothies was approximately five times higher than that of apple pomace formulations. Smoothies made with whey exhibited higher initial total phenolic content and antioxidant activity (through DPPH and FRAP assays). However, their post-digestion bioaccessibility was significantly reduced, likely due to protein–polyphenol interactions and lower pH. In contrast, rice beverage-based smoothies demonstrated greater retention of antioxidant capacity after digestion, especially those containing carrot pomace. These findings emphasize the importance of matrix effects on the bioaccessibility of functional compounds and suggest that rice beverage-based formulations with fruit/vegetable pomaces may be preferable for developing functional beverages with improved post-digestive bioactivity.