Growth kinetics and fermentation properties of autochthonous yeasts in pineapple juice fermentation for starter...

Autochthonous yeasts associated with pineapple fermentation were isolated and their fermentation behaviours were investigated for development of specific culture in pineapple winemaking. Autochthonous yeast isolates, Saccharomycodes ludwigii and Hanseniaspora uvarum, were selected due to their generated products of alcohol and 2-phenylethyl acetate, respectively. The fermentation kinetic parameters of selected autochthonous yeasts as single and co-cultures in chaptalized pineapple juice were investigated comparing to commercial Saccharomyces cerevisiae. The ethanol production rate of S'codes ludwigii (0.104%(v/v)/h) during the initial stage of fermentation was relatively slower compared to those of S. cerevisiae (0.129%(v/v)/h) but increased during middle through final stages with similar ethanol content to the commercial S. cerevisiae (~12%(v/v)). In pineapple juice, fructose was firstly assimilated, S'codes ludwigii (K = 0.405) and S. cerevisiae (K = 0.552), while glucose was secondly used, S'codes ludwigii (K = 0.281) and S. cerevisiae (K = 0.217) for first-order kinetic model. In co-cultures, the two isolated strains displayed synergistic behaviours during fermentation. S'codes ludwigii supported the growth of H. uvarum so that it generated more desirable volatile organic compounds (VOCs) at an early stage. Interestingly, the VOCs could not be produced in co-cultures of H. uvarum with the commercial strains. Then, S'codes ludwigii further completed the alcoholic fermentation through final stage. The fermentation performances of co-cultured autochthonous yeasts demonstrated a new approach for successful pineapple winemaking over S. cerevisiae. In addition, growth kinetics and fermentation behaviour, as observed in this study, could be a key information in development of potential substrates and strains for future alcoholic fermentation.