Evaluation of White Hibiscus-Black Tea Blends in Kombucha Production: Chemical Composition and Sensory Properties

Abstract

Enid Adiegwu, Ken Hurley, Renata Carneiro, and Sean O'Keefe ACADEMIC ABSTRACT The increasing demand for healthy beverage options is one of the reasons driving the positioning of kombucha as a popular choice, prompting interest in exploring innovative ingredient combinations. Our study aimed to assess the impact of replacing black tea with white hibiscus at 100%, 50%, and 0% replacement levels on the physicochemical properties and consumer perception of the kombucha. Three kombucha tea formulations—100% black tea, 100% white hibiscus, and a 50% black tea:50% white hibiscus (50% BT:50% WH) blend—were produced and analyzed in triplicate for pH, total titratable acidity (TTA), ethanol content, and sugar concentrations (sucrose, glucose, and fructose). Sensory analysis was conducted with untrained volunteers (N=97) who rated overall liking, color, aroma, and taste liking of the kombuchas (9-point hedonic scale), described the samples using a check-all-that-apply (CATA) list of descriptors, and answered a willingness-to-pay (WTP) question (price per 473 mL; range = $0.00 - $4.00). Correspondence analysis (CA) and penalty lift analysis of the CATA descriptors associated the 100% black tea kombucha with positive attributes, such as sweet, floral, fruity, and refreshing, while negative attributes, including fermented, vinegary, astringent, bitter, sour, and tartness, were more closely associated with the 100% white hibiscus kombucha and its blend. A two-way ANOVA, at a significance level of alpha = 0.05, revealed highly significant differences in the main effects of tea type and fermentation time on the pH (p < 0.001), TTA (p < 0.001), ethanol (p < 0.01), sucrose (p < 0.001), fructose (p < 0.001), and glucose (p < 0.001). The 100% WH was found to have high levels of residual sugars, indicating sluggish fermentation. One-way ANOVA revealed significant differences in overall liking (p < 0.001), color liking (p < 0.001), aroma liking (p = 0.00445), flavor liking (p = 0.00445), mouthfeel liking (p = 0.00445), and WTP (p < 0.001) of the kombucha among all the general panelists. A subgroup of 18 frequent kombucha drinkers did not find a statistical difference in the overall liking, color liking, flavor liking, aroma liking, and mouthfeel liking attributes of the three kombuchas. Our findings demonstrate that white hibiscus can be used as an ingredient in kombucha production and recommend optimizing white hibiscus replacement for targeted consumer segments.