PENGARUH PENAMBAHAN JENIS PATI DAN TEPUNG KULIT ARI KEDELAI HITAM (Glycine max (L) Merril) TERHADAP KARAKTERISTIK FISIKOKIMIA SOYGURT

Soygurt is a fermented soy milk product developed as an alternative to vegetable-based yoghurt. However,
soygurt products have weaknesses in terms of thin texture, low viscosity, and tend to experience syneresis
due to lack of protein matrix stability. These problems trigger the need for innovation in the formulation of
additional ingredients that can improve the physicochemical quality of soygurt. This study aims to analyze
the effect of adding types of starch (cassava starch, arrowroot, and ganyong tubers) and black soybean
skin flour on the physicochemical and microbiological characteristics of soygurt, and to determine the best
combination that produces optimal product quality. This study used a two-factor factorial Randomized
Block Design (RBD), namely the type of starch (0%, cassava, arrowroot, ganyong) and the concentration
of black soybean skin flour (0% and 1%). The parameters tested included pH, total titratable acid (TAT),
protein content, viscosity, total lactic acid bacteria (LAB), color, and organoleptics. The results showed
that ganyong starch significantly increased viscosity (8.73 cP), arrowroot starch produced the highest
protein content (3.92%), and cassava starch gave the highest total LAB (8.9×10⁸ CFU/mL). Meanwhile,
the addition of 1% bran increased TAT (2.7%) but decreased viscosity and protein. The combination of
starch and bran types had a significant effect on the physicochemical quality of soygurt. The combination
of arrowroot starch and without bran was the best treatment with a balance between texture, nutritional
value, and microbiological activity that met the standards of probiotic yoghurt.