Development of a pigmented soju-like beverage using natural colorants from sweet potatoes (Ipomoea batatas L.)

Abstract

Purple-fleshed sweet potato (PFSP) is known for its high anthocyanin content, which not only enhances the color of food products and beverages but also provides nutrients, particularly antioxidants. Due to the safety of purple sweet potato’s anthocyanin (PSPA), it is currently being positioned as an alternative to synthetic pigments. One of the widely known alcoholic beverages today is Soju, a Korean clear distilled liquor. Therefore, this study aimed to develop a pigmented soju-like beverage by utilizing yellowfleshed sweet potato (YFSP) for alcohol production with PFSP as the color source. During the fermentation, the total soluble solids (TSS), pH, and alcohol content were analyzed. Additionally, total monomeric anthocyanin pigment (TMAP) content and sensory properties were measured during the steeping process. Results showed a decrease in TSS and pH of YFSP due to yeast activity, while alcohol content increased during fermentation. Steeping for 6 days resulted in higher TMAP, TSS, and alcohol content, lower pH values, and sensory attributes were more acceptable. In conclusion, the study successfully developed a naturally colored soju from sweet potatoes. These findings can contribute to the manufacture of soju with unique product qualities.