Shelf life determination of two palm wine varieties and its effect on biochemical properties and enzyme production.

Abstract

In palm wine, the available complex microbiota plays very vital roles in the general attributes of the beverage as well as the significance of the various metabolites generated. This research focused on evaluating the biochemical properties of the palm wine obtained from two different varieties of oil palm (Elaeis guineensis) and its potential enzyme activity, as well as assessing the effect of the changes that occur during the keeping time. The biochemical contents (alcohol, total titratable acid, reducing sugar, and pH) were evaluated every 2 h over a period of 144 h. The palm wine varieties were also analyzed for cellulase and amylase production. There was an increase in ethanol for both varieties from 7.29±0.02% (1 h) to 14.82±0.02 (144 h) for variety 1, and from 8.35±0.01% (1 h) to 16.32±0.03% (144 h) for variety 2; the TTA increased with keeping time from 2.25±0.03% (1 h) to 4.42±0.03% (144 h) for variety 1, and from 2.35±0.02% (1h) to 5.01±0.04 (144 h) for variety 2. Reducing sugar decreased from 476.58±0.04 mg/L (1 h) to 42.84±0.75 mg/L (144 h) for variety 1, while variety 2 decreased from 238.18±0.05 mg/L (1 h) to 43.73±0.63 mg/L (144 h). The pH of the palm wine also experienced a decrease for variety 1 from 5.2±0.06 at 1 h to 2.8±0.17 at 144 h, while the variety 2 decreased from 4.8±0.17 at 1 h to 2.8±0.1 at 144 h. There was a reduction in the sugar content with the accumulation of alcohol, which occurred in both varieties, and a drop in the pH due to an increase in organic acids. The palm wine varieties were screened for cellulase and amylase activity, with the highest amylase yield for varieties 1 and 2 at 0.62 U/ml and 0.21 U/ml, respectively on the first day, while that of cellulase was observed at 48 h (0.34 U/ml) for V1 and at 1 h (0.2 U/ml) for V2. The result of this current study proves the importance of the microbial consortium in fresh palm wine as well as its potential as a source of enzyme production, and also shows that these parameters are affected by the keeping time.