Effects of cross-linked inulin with different polymerisation degrees on physicochemical and sensory properties of set-style yoghurt

Abstract

This work investigated effects of cross-linked inulin with different degrees of polymerisation (DP, average = 7 and 15) on physicochemical and sensory properties of set-style yoghurt. Compared with set-style yoghurt made with native inulin (average DP = 4 and 11), yoghurts with cross-linked inulin had higher acidity and lower syneresis values, with a shelf-life of 14 days. Supplementation of cross-linked inulin with higher DP resulted in enhanced firmness and adhesiveness of yoghurts. In addition, bacterial counts showed that yoghurts with cross-linked inulin exhibited longer retention of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus cell viability than that with native inulin. Sensory evaluation indicated that yoghurt with cross-linked long-chain inulin received higher scores for overall acceptability than other samples. However, different types of inulin did not significantly affect odour and colour of set-style yoghurt. Consequently, cross-linked inulin prepared can be exploited as a prebiotic to prolong shelf-life of yoghurt.