BIOACTIVE AND TECHNOLOGICAL POTENTIAL OF INDIGENOUS PALM WINE YEASTS FOR SUSTAINABLE FUNCTIONAL BEVERAGE DEVELOPMENT

Introduction: The increasing global demand for functional foods has intensified the search for indigenous microorganisms capable of producing bioactive compounds without adversely affecting food quality. Traditional fermented beverages constitute valuable reservoirs of diverse yeasts possessing desirable technological and probiotic attributes. Palm wine, a naturally fermented beverage widely consumed in West Africa, harbours a rich diversity of indigenous yeasts that remain largely underexplored for functional food applications. Characterizing these yeasts provides opportunities to develop novel starter cultures for sustainably conferring bioactivity on fermented beverages.

Objectives: This study aimed to isolate indigenous yeasts from Nigerian palm wine and evaluate their technological and probiotic characteristics in order to identify multifunctional strains for the development of bioactive fermented beverages.

Methodology: Nine freshly tapped palm wine samples collected in Ibadan, Nigeria, were analysed for yeast diversity. A total of 160 yeast isolates were obtained and screened for extracellular enzyme production, including protease, esterase and lipase. Twenty isolates producing at least two enzymes were further evaluated for tolerance to fermentation-associated stresses, namely ethanol (10–15%), sodium metabisulphite (50–200 mg/L) and glucose (10–40%). Principal Component Analysis was employed to select the most technologically promising strains. Selected isolates were subsequently assessed for probiotic characteristics, including survival under acidic conditions, bile salt tolerance, simulated gastrointestinal transit, autoaggregation, cell surface hydrophobicity and antioxidant activity, using the DPPH radical scavenging assay. The most promising isolate was identified through ITS gene sequencing.

Results: Sixty yeast isolates (37.5%) exhibited extracellular enzymatic activities, demonstrating substantial technological diversity. Four strains (YIJ361, MOA252, MAP163 and YOA252) displayed superior tolerance to fermentation-associated stresses and were selected for functional evaluation. All four strains survived acidic conditions (pH 2.5–3.5), tolerated 0.3–0.5% bile salts and maintained more than 70% viability during simulated gastrointestinal digestion. The strains demonstrated appreciable cell surface hydrophobicity and autoaggregation after 24 hours ranged from 87.12% to 95.82%, while antioxidant activities varied from 5.36% to 23.55% DPPH radical scavenging. Molecular characterization identified the most promising multifunctional strain as Saccharomyces cerevisiae MAP163.

Discussion: The combined technological robustness, extracellular enzymatic activities and probiotic characteristics of the selected isolates highlight their capacity to generate bioactive metabolites while withstanding food fermentation and gastrointestinal conditions. These multifunctional attributes support their application as indigenous starter cultures capable of enhancing fermentation performance and the functional quality of plant-derived beverages.

Conclusions: Nigerian palm wine represents an important source of multifunctional indigenous yeasts with considerable technological and bioactive potential. Saccharomyces cerevisiae MAP163, together with the other selected strains, offers promising prospects for developing sustainable, non-dairy functional beverages enriched with naturally occurring bioactive compounds. The findings further reinforce the importance of traditional fermented foods as reservoirs of microorganisms with significant biotechnological and health-promoting potential.