Citrus Essential Oils as Modulators of Lactic Acid-Fermented Wort-Based Beverage Characteristics

Abstract

Increasing interest in functional non-dairy beverages has led to the development of fermented cereal-based products with improved bioactive properties. This study evaluated the influences of lemon, orange, and mandarin essential oils (0.01–0.05%) on fermentation, phenolic contents, antioxidant activities, and sensory properties of wort-based beverages fermented with Lacticaseibacillus casei ssp. rhamnosus Oly. The applied concentrations did not suppress bacterial growth, although fermentation proceeded slightly more slowly. In all samples, viable cell counts remained above 11 log CFU/mL. Fermentation contributed to the preservation or even enhancement of phenolic compounds at the lowest and highest oil concentrations and generally increased antioxidant activity, as determined by the FRAP assay. CUPRAC, DPPH, and ABTS results also indicated changes associated with microbial transformation of phenolic constituents and their interactions with citrus essential oils. Sensory assessment demonstrated improved aroma and taste compared with the control, and the highest sensory ratings were obtained for beverages supplemented with 0.04% lemon, 0.02% orange, and 0.02% mandarin essential oil. Among the tested formulations, the beverage containing 0.02% orange essential oil provided the most favorable combination of sensory quality and functional characteristics.