Viabilitas Bakteri Asam Laktat Yoghurt Sinbiotik dengan Penambahan Maltooligosakarida dari Ubi Jalar Ungu selama Penyimpanan pada Suhu Dingin

Abstract

Purple sweet potato contains a high amount of starch, which can be utilized to produce maltooligosaccharides. These maltooligosaccharides can act as prebiotics and serve as a substrate for lactic acid bacteria, thereby enhancing their viability. This study was aimed to evaluate the effect of storage duration at cold temperatures on the physical, chemical, sensory qualities, and the viability of lactic acid bacteria in synbiotic yoghurt with added maltooligosaccharides derived from purple sweet potato. The research design used was a non-factorial Completely Randomized Design (CRD) with a single factor of storage duration (P): (0 days; 7 days; 14 days; 21 days; and 24 days). The results showed that storage duration had a highly significant effect (P<0.01) on pH, titratable acidity, anthocyanin content, total lactic acid bacteria, viscosity, aroma hedonic score, taste hedonic score, viscosity hedonic score, and overall acceptance hedonic score, and had a non-significant effect (P<0.05) on color index (°Hue) and color hedonic value. The total lactic acid bacteria increased up to 14 days of storage but declined after 21 days. On day 28 of storage, the total lactic acid bacteria was 8.23 Log CFU/mL (1,7 × 10⁸ CFU/mL). The shelf life of yoghurt under cold storage was estimated using a regression equation between storage duration and total acidity. The maximum allowable total acidity of 2% was used as the shelf life limit, resulting in a shelf life of 16 days.