Enhanced Probiotic Activity, Physicochemical and Sensory Properties of Set-Yoghurt Incorporated with Asparagus officinalis Inulin
Author(s): Weerasingha WVVR, Jayasumana MTLK, Chandrasiri KAKL, Wimalasiri KMS*
Inulin extracted from Asparagus officinalis roots was evaluated for its effect on physicochemical, microbiological and sensory quality attributes of set-yoghurt during refrigerated storage of 21 days. Set-yoghurt was developed with 1%, 2%, 3% (w/w) inulin levels andan authenticated control was carried out without inulin. Commercial starter cultures containing Bifidobacterium bifidum, Lactobacillus bulgaricus ssp. bulgaricus and Streptococcus thermophiles were used as probiotic bacteria. The yield of inulin powder from A. officinal is roots were 15.28% (w/w). Inulin incorporated yoghurt showed higher (p>0.05) viable cell counts throughout the entire storage period and the highest viable cell counts were observed in yoghurt with 3% inulin. Average viable cell counts of B. bifidum (~8.90 log cfu/mL) and L. bulgaricus ssp. bulgaricus (~8.96 log cfu/mL) had more or less similar counts while S. thermophilus (~9.11 log cfu/mL) had the highest (p>0.05) cell counts. Different inulin levels had no effect (p>0.05) on acidification of set-yoghurts. Set-yoghurt produced with 2% inulin resulted low syneresis, improved sensory attributes with proven prebiotic effect. Inulin powder extracted from A. officinalis root tubers could be effectively utilized as a prebiotic source in set-yoghurt.