Abstract
Flavor instability resulting from beer storage and oxidation is the most important quality-related problem in the brewing industry. This study evaluated the influence of adding 80% ethanolic extract of Moringa stenopetala leaf to lagered beer at 400, 600, and 800 ppm concentrations for 30-, 60-, and 90-day storage time at room temperature. The effect of physicochemical properties of the beer incorporated with leaf extract of Moringa stenopetala (LEMS) was evaluated using the American Society of Brewing Chemists method of analysis. Sensory acceptability of the beer treated with LEMS was evaluated using nine hedonic scales over a period of storage time. Original gravity (11.06-11.08), apparent extract (3.68-3.77), pH (4.23-4.40), vicinal diketone (0.07-0.09), and alcohol content (4.76-4.81) were not altered by the incorporation of LEMS at any level of treatment and over a period of storage time. The beer color (8.88-9.70 EBC), bitterness (13.62-15.56 bitterness unit), calcium ion (44.18-52.04 ppm), and foam stability (201.5-246.5) of beer increased with increasing LEMS concentration, but a significant haziness reduction (1.23-0.63) was observed. However, the storage time decreased both haziness and foam stability of LEMS-incorporated beer. The incorporation of LEMS at an optimum level kept its quality for 90 days better than the usual antioxidant (potassium metabisulfite) added in beer. The sensory analysis also supported the beer treated with 600 ppm of LEMS as the best overall acceptability. The result indicates a promising use of LEMS as a functional ingredient in beer to reduce beer oxidation probability and keep its freshness for a period of storage time.