Metabolomic profile of pomegranate cider-like beverages started by different yeast species

This study aimed to assess the differences, in terms of physico-chemical characteristics, antioxidant properties and flavour profile, among four pomegranate cider-like beverages (PCB), produced starting from two pomegranate juices, fermented by either commercial Saccharomyces cerevisiae or a non-conventional, autochthonous strain of Hanseniaspora valbyensis. Although both starters were able to drive the fermentation of pomegranate juices, H. valbyensis reached higher cell densities four days earlier than S. cerevisiae. After fermentation, PCB were subjected or not to a clarification treatment (centrifugation or filtration) and matured for additional seven days. In the mature PCB, filtration caused a stronger decrease in yeast cell density compared to centrifugation. As for elemental composition, K and Ca increased during fermentation, whereas Fe and Cu decreased. A strong reduction of Cu, Zn, as well as Fe and Ni, was observed in clarified mature PCB. The use of H. valbyensis led to a more rapid consumption of monosaccharides, higher acetic acid and lower ethanol concentrations compared to S. cerevisiae. The final profile of Volatile Organic Compounds (VOCs) was reached after three and seven days of fermentation with autochthonous and commercial yeast, respectively. After maturation, PCB obtained with H. valbyensis kept more complex VOCs profile, compared to S. cerevisiae. The panel test on centrifuged PCB did not result in any significant difference. The antioxidant activity of PCB was always high and not affected by fermentation, type of starter, and maturation. This study paves the way for better understanding fermentation capability and impact of H. valbyensis on food quality.