Addition of inulin to probiotic yogurt: Viability of probiotic bacteria (Bifidobacterium bifidum) and sensory characteristics

Abstract

The objective of this work was to study the effect of different concentrations of inulin (0.2, 0.4, and 0.6%) on the viability of probiotic bacteria (Bifidobacterium bifidum) and sensory characteristics of probiotic yogurt. The yogurt was manufactured with Lactobacillus delbruckii ssp. bulgaricus (Lb), Streptococcus thermophilus (St), and Bifidobacterium bifidum (Bb). Raw milk was received, heated to 90°C, and divided into 4 aliquots portions. All portions were inoculated with 5.11 log cfu of Lb and St combined and 5 log cfu of Bb per kg of milk. The first portion was utilized as control (T1) while 0.2, 0.4, and 0.6% of inulin were added to the second (T2), third (T3), and fourth (T4) portions, respectively. All treatments were incubated at 40°C until a pH of 4.6 was reached. Subsequently, the yogurt was cooled and stored at 4°C for 16 days. Titratable acidity, total bacterial count (TBC), Bb count, yeast count, mold count, and sensory evaluation were determined during the storage. The results showed that the addition of inulin and the storage period have significant effects (p .05) in the sensory evaluation of all treatments. We conclude that inulin can be utilized in the manufacturing of probiotic yogurt as a prebiotic, which, inturn, enhances the growth of Bb and increase the shelf-life.