Hanseniaspora valbyensis-bioprocessed pomegranate seeds to produce a novel food ingredient

Pomegranate by-products are valuable sources of nutritionally important compounds. The aim of this study was to develop a large-scale consumption food, added with fermented pomegranate matrices, to be able to meet consumer’s needs, in terms of nutrition and sustainability. To this aim, chemical composition, antioxidant activity, and microbiota of pomegranate matrices were analysed. Hanseniaspora valbyensis yeasts dominated (order of magnitude: 5 Log CFU/g) the matrices. Among four representative strains of H. valbyensis able to ferment pomegranate matrices, we selected S-L1, because it caused the highest increase in mineral content in seeds (e.g., ca. 162 mg of K/100 g of seeds fermented with S-L1 vs. ca. 104 mg of K/100 g of unfermented seeds). Then, we tried to design a granola snack supplemented with pomegranate seeds flour. In detail, we compared three theses of granola: G-FS, supplemented with fermented seeds flour; G-US, supplemented with unprocessed seeds flour; G-C, conventional granola (control). Compared to G-C, the use of pomegranate seeds flour increased antioxidant activity of the snack (ca. 60% DPPH. scavenging activity vs. ca. 40 % activity of G-C). The expected contents of calcium, iron, potassium, and zinc were higher in G-FS and G-C, compared to G-US, while lower energetic values are expected for the two fortified granola snacks. Fermentation of seeds with H. valbyensis S-L1 also contributed to significantly improve the overall acceptability of fortified granola snack (score on 1-9 scale: 6.3), making it more similar to the control (7.5) and more appreciated than granola containing unprocessed seeds (4.9). The results of this study could be of interest for food industries searching for novel foods, with added value in terms of nutritional quality and sustainability.