Development of functional probiotic yogurt from buffalo milk supplemented with red beetroot (Beta vulgaris L.) as an antioxidant, natural colorant, and starter growth stimulant

The physicochemical, sensorial, and probiotics viability properties of supplemented probiotic yogurt with beet juice (BJ) at various ratios (0–5)% in fresh and stored yogurts were determined. 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (%) and minerals content of BJ-yogurts were increased. The color aspects (ΔE) were improved with the increasing of BJ. BJ-yogurts at 1 and 3 % were color-stable when stored in the refrigerator (5 ± 1 °C) for 9 days. The syneresis reached of 42.9, 43.0, 43.5, and 43.5 mL for control, 1 %, 3 %, and 5 % BJ, respectively in stored yogurts for 12 days. Moreover, the probiotic yogurt viability in BJ-yogurts treatments was found to be higher (p < 0.05) than control which recorded of 7.0 ± 0.08, 7.22±0.04, 7.34±0.002 log cfu/mL for streptococci, lactobacilli, and bifidobacteria counts respectively in 5 % BJ treatment, on the other hand, in control recorded of 6.76±0.07, 7.11±0.06, 6.66±0.030 log cfu/mL for streptococci, lactobacilli, and bifidobacteria counts respectively; indicating that BJ had a stimulating effect on the additive starter. Fresh yogurts with 1 % BJ had superior sensorial scores than other treatments, and generally maintained desirable organoleptic attributes for up to 9 days. This study provides a nutritious, low-cost, stable, and attractive colored yogurts from buffalo milk without negative impact on physiochemical qualities.