The Bioactivity of Byproducts from the Blackberry (Rubus fruticosus) Juice Industry

The blackberry (Rubus fruticosus) is a red fruit with great potential as a functional food thanks to its composition, which is rich in antioxidants. This work focused on the study of two byproducts of blackberry (skins and seeds) after juice production, with the aim of characterizing them and studying their bioactivity. The phenolic composition and antioxidant capacity of the products, determined by ABTS, as well as their colonic fermentation fractions, were analyzed. In addition, their genotoxicity and effect on the intestinal microbiota were evaluated after in vitro gastrointestinal digestion and fermentation. Blackberry byproducts, namely skin and seeds, are rich in phenolic compounds, especially the skin, which is rich in anthocyanins and presents an antioxidant capacity that makes it potentially usable as a functional ingredient. All the fermented samples present in vitro genoprotective activity and a modulation effect on the intestinal microbiota, promoting the growth of Bifidobacterium and Lactobacillus and reducing the abundance of the Clostridia XIVa cluster and Faecalibacterium prausnitzii. A similar effect was observed for the skin and seeds. The results provide insights into the digestive properties and health benefits of blackberry byproducts after consumption.