Enhancing Low-Fat Probiotic Yogurt: The Role of Xanthan Gum in Functionality and Microbiological Quality

Abstract

The objective of this study was to determine the effect of XG addition on low-fat yogurt (LFY) properties. Pasteurized skimmed buffalo milk (SBM) was heated to 95 ± 2 °C for 16 s, cooled to 40 ± 1 °C, and then divided into six treatment lots. The treatments included the following: T1 (control), T2 (0.2% XG), T3 (0.4% XG), T4 (0.6% XG), T5 (0.8% XG), and T6 (1% XG). A proportion of 2% of a mixed starter culture from Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB), and Bifidobacterium bifidum (BB) in the ratio 1:1:1 was added. Yogurt was manufactured following the standard manufacturing protocol. Chemical composition and texture were determined at fresh time, while water-holding capacity (WHC), viscosity, and syneresis % were determined at 0, 7, 14, and 21 days of storage. Total bacterial counts (TBC), lactobacilli, streptococci, and bifidobacteria counts were determined at 0, 7, 14, and 21 days of storage. Sensory analysis was performed immediately upon the cooling stage (time zero) and then after 14 and 21 days of storage. The experiment was performed in trice. The results obtained showed that the addition of XG in LFY significantly (p < 0.05) decreases the pH, total protein (TP), and ash, and significantly (p < 0.05) increased the total solids (TS). Additionally, the addition of XG led to a significant (p < 0.05) increase in hardness, WHC, and viscosity; however, syneresis significantly (p < 0.05) decreased. The addition of higher amounts of XG led to a significant (p < 0.05) decrease in the TBC and led to a significant (p < 0.05) increase in counts of ST, LB, and BB during the first two weeks of the storage period. Sensory evaluation revealed that increasing the XG concentration up to 0.8% increased the product’s acceptability among panelists; however, further increasing the concentration to 1% had a detrimental impact on its acceptability. To conclude, this study showed that XG can be used as a stabilizer in the manufacturing of LFY as well as a prebiotic for starter culture and improve the quality of LFY.