Enhanced Functional, Sensory, Microbial and Texture Properties of Low-Fat Set Yogurt Supplemented With High-Density Inulin

The influence of high-density inulin addition at different concentrations upon the yogurt characteristics and on the growth of the lactic acid bacteria of low-fat yogurt during cold storage at 5 °C for 14 days was investigated. High-density inulin was incorporated into milk containing 0.1% of milk fat at 0, 1, 2 and 3%, this inulin-supplemented yogurt samples were compared with control samples (3.2% of milk fat without supplementation) whereas all treatments were inoculated with mixed cultures of Streptococcus thermophilus and Lactobacillus delbrueckiissp. bulgaricus. The chemical composition, pH, titratable acidity, acetaldehyde, apparent viscosity in addition to microstructure properties, texture profile analysis and sensory properties were measured during the storage. Yogurt pH values and titratable acidity was not influenced by the addition of different ratios of inulin, while the addition of high-density inulin (1 and 2%) positively affected the acetaldehyde formation resulted in higher concentration than the low-fat without additives, as well as yogurt apparent viscosity which increased with inulin addition till 2% and was comparable to full-fat yogurt. The viability of L. delbrueckiissp. bulgaricus was enhanced by the addition of 1 and 2% of inulin, while the addition of 3% had negative effect. However, no effect was noted in case of Streptococcus thermophiles viability. The results indicated that the addition of inulin had significantly improved the rheological properties and microstructure. Consequently, low-fat yogurt with 1 and 2% inulin received higher scores for sensory and overall acceptance than did low-fat yogurt without inulin.