The Effect of Inulin and Sucrose Addition on the Number of Colonies L. acidophilus and B. bifidum in the Soyghurt After the Freeze-Drying Process

Abstract

The freeze-dried soyghurt generally will be last much longer. However, the reduction of L. acidophilus and B. bifidum (LAB) colonies during the freezedrying process could be occurred and it could be minimized by adding inulin as a prebiotic and sucrose as a cryoprotector. This research aimed to determine whether or not the colonies number in freeze-dried soyghurt with the SNI and to analyze the effect of inulin and sucrose addition to the growth of the LAB in the freeze-dried soyghurt. This experimental laboratory study with pretest-posttest design consists of 1 negative control group, 1 group of soyghurt, and 4 groups of soyghurt with the addition of 10% sucrose and 0.5%, 1%, 3%, 5% inulin. The bacterial growth was calculated using the TPC method. All data were tested using the Saphiro Wilk test, followed by the Kruskal Wallis and Mann Whitney Post Hoc test. The conclusion of this research was that the number of colonies in each experimental groups decreased after the freeze-dried process and only the group of soyghurt without any additions did not meet the standard of SNI. Statistical tests showed a significant distinction between groups, giving a conclusion that the addition of inulin and sucrose gave a better incretion of the LAB significantly. 10% sucrose and 3% inulin was the best combination which has 2.34 × 1029 CFU/ml as the highest TPC. It means that the higher of sucrose and inulin addition to the soyghurt, does not guarantee the number of LAB colonies inside will also be higher.