Evaluation of secondary metabolites, nutraceutical potential and amino acid profile of fresh dates (Phoenix dactylifera) alcoholic beverage

Abstract

The present study comprehensively investigated the fermentation process of fresh dates pulp to alcoholic beverage, analyzing various aspects including physicochemical properties, nutraceutical potential, amino acid composition, color properties, sensory evaluation, and microbial load. Over the fermentation period, the alcohol content of the beverage reached 8.79%, suggesting it is an off-dry wine. Total Soluble Solids (TSS) decreased from an initial 24.17°Brix to 5°Brix. The pH level dropped from 7 to 3.9, and the titratable acidity increased from 0.15 to 0.22%. The nutraceutical potential of the alcoholic beverage displayed dynamic transformations, with total phenolic content (TPC) decreasing from 23 to 9 mg GAE mL−1, while total flavonoid content (TFC) increased significantly (p < 0.05). Amino acid analysis revealed distinct concentrations, with alcoholic beverage exhibiting higher levels of essential amino acids due to fermentation. Color analysis showed a shift towards reddish hues, and a progression towards a more yellowish color during fermentation. Sensory evaluation indicated a non-significant difference (p > 0.05) between the alcoholic beverage and juice in terms of color, but the alcoholic beverage scored higher in appearance, flavor, texture, taste, mouthfeel, and overall acceptability.Microbial load increased from an initial 5–6 log CFU mL−1 to 8–9 log CFU mL−1 after 5 days, indicating the occurrence of alcoholic fermentation. Kinetics study was also performed for different quality parameters. This is the first study provides a comprehensive understanding of the multifaceted changes occurring during the fermentation process, offering valuable insights for winemakers and researchers. Graphical Abstract: (Figure presented.)