The Effect of Adding Kimpul Starch (Xanthosoma sagittifolium) into Set Yoghurt with Different Incubation Time on the Chemical, Microbiological and Microstructural Quality

The purpose of this study was to know interaction between addition of kimpul starch (Xanthosoma sagittifolium) and different incubation time on pH value, protein content, total of Lactic Acid Bacteria (LAB), Total Plate Count (TPC), exopolysaccharide and microstructure of set yoghurt. This study used factorial experiment (4x4) and Completely Randomized Design (CRD) with 3 replications. First factor was addition of kimpul starch with various concentration (T0 =0%. T1= 1%, T2= 2% dan T3=3%). Second factor was different incubation time at room temperature (±23^oC) during (L1= 24 hour, L2= 32 hour, L3= 40 hour, L4= 48 hour), and continued with Duncan’s New Multiple Range Test (DMRT). The observed variables were pH value, protein content, total of LAB, TPC, exopolysaccharide production and microstructure. The result of interaction between addition of kimpul starch and adjustment of incubation time was not significantly different (T>0.05) on pH, protein content, total of LAB, TPC and exopolysaccharide. The addition of kimpul starch was highly significant different (T<0.01) on protein content, total of LAB, TPC, and exopolysaccharide, but it was significant different (T<0.05) on pH. The adjustment of incubation time was highly significant different (T<0.01) on pH, protein content, total of LAB, TPC and exopolysaccharide. In conclusion, the best quality of set yoghurt combined from the addition of 3% kimpul starch and 24-hour incubation can improve the structure of set yoghurt in microstructure.