Effect of Inulin and Bif. longum ATCC15708 and on Some Properties of Low Fat Flavored Stirred Yoghurt

Abstract

This study was carried out to investigate the effect of inulin as a source of dietary fiber and  Bifidobactrium longum ATCC15708 on some properties of low fat flavored yoghurt as well as folic acid production.  Four treatments namely: T1 low fat yoghurt (control), T2 (control inoculated with Bif. longum and yoghurt starter 1:1), T3 (T2+ 2 % inulin and flavored with vanilla) and T4 (T2+ 2 % inulin flavored with strawberry juice) were manufactured. Addition of inulin had non significant effect on pH value and acetaldehyde content in the fresh samples, while it increased the viscosity of fresh (T3) vanilla yoghurt as compared to control yoghurt (T1). During storage, the corresponding values were significantly increased in all treatments. The syneresis index in vanilla yoghurt was decreased as compared to other treatments, while it was increased in case of strawberry yoghurt either in fresh or stored samples. The growth of Bif. longum in fresh yoghurt and during storage as well as folic acid content were improved as a result of fortification with inulin. Fresh strawberry stirred yoghurt (T4) was highly accepted followed by T3, T2 and T1 resp. All organoleptic attributes scores were gradually decreased in all treatments during storage. Inulin had a high antioxidant activity, phenolic and flavonoids content.