Fruit by-products as potential prebiotics and promising functional ingredients to produce fermented milk

Recently, fruit by-products (FBP) have started to be explored due to their prebiotic potential associated with considerable amounts of dietary fibers and polyphenols. These compounds possess anti-inflammatory activity and can reduce dysbiosis, which is characterized by alterations in the composition and function of the gut microbiota and thus may reduce the onset or progression of several diseases. Therefore, the consumption of FBP must be encouraged. Among food products, fermented milk is a potential candidate for carrying FBP. In this scenario, this review discusses the prebiotic potential of FBP and their anti-inflammatory activity and brings a unique contribution, as it highlights fermented milk as a food carrier for FBP. Therefore, the technological application of FBP as a new ingredient to improve the nutritional and functional values of fermented milk, probiotic viability, and the effects of their addition on the physical and sensory characteristics of fermented milk are topics extensively covered in this review. Moreover, we described the chemical composition of FBP, focusing on polysaccharides and bioactive compounds, their obtention methods and potential adverse effects related to their consumption. Finally, limitations and future directions are outlined to deepen the understanding of FBP and to stimulate their use, to prove their prebiotic potential and to optimize their incorporation into fermented milk.