Pineapple Wines Obtained from Saccharification of Its Waste with Three Strains of Saccharomyces cerevisiae

This work aims to report on the processing of pineapple (Ananas comosus) peel and core into quality wines by combining physical and enzymatic treatments of waste and alcoholic fermentation of the pineapple must with three strains of Saccharomyces cerevisiae (TT, AW, EM2) at three different temperatures (25C, 20C, 15C). The main parameters of the alcoholic fermentation (yeast growth, ethanol production and sugar consumption) were monitored; the fixed and the volatile compounds of pineapple wines were characterized by means of HPLC and GC-MS techniques. Results outlined that the highest levels of ethanol, i.e., more than 7 and 8% vol/vol, were reached in 96 h when the fermentation was carried out at 20 and 25C with AW and TT strains, respectively. Differently, the fermentation at 15C with EM2 achieved the highest ethanol concentration (7.60% vol/vol) after 120 h and maintained higher levels of citric and malic acid. Accordingly, as the ethanol increases a simultaneous decrease in simple sugars was observed: glucose fell faster than fructose and reached concentrations below 1 g/L after 120 h of fermentation. Significantly different aroma profiles were measured in the wines by changing temperature and strain of S.cerevisiae: the fermentation with AW at 20C produced the highest concentration of acetate and ethyl esters that increased the fruity character of pineapple wine, whilst varietal aroma was enhanced by both fermentations at 25C and 15C with TT and EM2, respectively. However, no variations in pH and acidity during fermentation and very low levels of acetic acid in any pineapple wine sample stressed the aptitude to human consumption of pineapple wines obtained from pineapple waste under this study. Practical ApplicationsOutcomes of the study are important to the industry and highlighted the feasibility of processing tropical fruit waste to obtain added value food products. Furthermore, the results of this work updated the small amount of information published to date on the processing of pineapple waste (or of other tropical fruits) into food grade products, and on the volatile compounds of pineapple wine. As a consequence, the process of conversion of pineapple waste into wine when properly scaled-up may be transferred to industries that are located either in tropical areas, or in developing countries where the waste is not utilized yet.