Effects of Short-Chain and Long-Chain Inulin on the Quality of Probiotic Yogurt Containing L actobacillus rhamnosus

Abstract

This study investigated the effects of adding short-chain and long-chain inulins on the growth of Lactobacillus rhamnosus and the physicochemical and sensory properties (appearance, structure-texture, odor and taste) of probiotic yogurt during cold storage. The inulin-supplemented yogurt batches were compared with control batches of unsupplemented yogurt and L. rhamnosus-inoculated yogurt. The inulins were incorporated at 2% w/w in the yogurt mixtures that were inoculated with L. rhamnosus and mixed cultures of Streptococcus thermophilus and L. delbrueckii ssp. bulgaricus. The contents of organic acids (lactic, citric, acetic, propionic, formic and butyric) profile were determined using high-performance liquid chromatography. The results indicated that the viability of L. rhamnosus (6.71 log10 cfu/g) in probiotic yogurt was enhanced by the presence of short-chain inulin (RSI). Consequently, yogurt with short-chain inulin (RSI) received higher scores for odor, taste and overall acceptance than did yogurt containing long-chain inulin (RLI). However, the chain lengths of the inulins did not significantly affect the consistency, product appearance or the organic acid profile. Practical Applications Inulin is a natural component of some fruits and vegetables and widely used in functional foods for its nutritional benefits. In addition to its health promoting properties, as a dietetic fibre and as a prebiotic ingredient inulin has technological properties, as a low-calorie sweetener, fat substitute and texture modifier. Inulin also promotes healthy probiotic bacteria grown in the colon and enhances calcium absorption and immune functions. This study provided information on the effects of short-chain and long-chain inulin on the properties of probiotic yogurt containing Lactobacillus rhamnosus.