Effective Bioassay for Vinegar Production Using African Star Apple (Chrysophyllum albidum G. Don) by Enzymatic Catalysis and Acetic Bioconversion

Abstract

The present study aims to valorize the neglected and underutilized fruits of Chrysophyllum albidum in vinegar production through enzyme catalysis and acetic bioconversion. To do this, Chrysophyllum albidum juice was extracted from ripe fruits by using a pectinolytic enzyme (Pectinex Ultra SP-L) at a concentration of 1ml.kg-1. The extracted juice was first subjected to alcoholic fermentation using yeast strains of Saccharomyces cerevisiae in anaerobic conditions, and secondly to an acetic fermentation using strains of Acetobacter spp. isolated from unpasteurized cider vinegar. Results obtained indicated that the use of the pectinolytic enzyme significantly improves (p<5%) the yield of juice extraction. The highest extraction yield (89.21%) is obtained with an incubation temperature of 60°C for 120 minutes. The monitoring of kinetic parameters during the fermentation processes indicated a significant variation (p<5%) of the pH, the acidity, the density and the Brix of the musts during the bioprocesses. Vinegars produced had a pH of 3.83±0.12 and a relatively low acetic acid content (5.17±0.23 %), characteristic of vinegars for food use, in accordance with European standards. The production of vinegar from Chrysophyllum albidum fruit, using fast, less expensive and easily applicable processes, presents a very interesting solution to reduce postharvest losses, and could make available on national and international markets, a new bioproduct with high added value.