Antioxidant, nutritional and physicochemical quality of yoghurt produced from milk- based fermentation mix enhanced with food spices

Abstract

Utilization of natural additives, which could meet the growing need for ‘clean label’ and value addition with respect to diseases prevention and health promotion in humans, is a current interest in the yoghurt industry. In this study, yoghurt recipes derived from standard milk -based fermentation mix enhanced with African black pepper (ABP), Turmeric, or Cloves extracts were evaluated for antioxidant, nutritional and physico-chemical quality. Each fermentation mix was pasteurized; inoculated with 0.5% industrial starter culture containing Streptococcus thermophillus and Lactobacillus delbrueckii subsp. Bulgaricus (1:1); and then allowed to ferment in fermentation tank for 9 hours at 40OC. The results revealed that, clove- enriched yoghurt recipe exhibit the strongest antioxidant capacity as indicated by significant increase (p < 0.05) in total phenolics, total flavonoids, Total Antioxidant Capacity (TAC), DPPH radical scavenging activity, nitric oxide radical scavenging activity, Ferric ion reducing power (FRAP), and inhibition of lipid peroxidation but also reduced apparent viscosity and organoleptic properties. Similarly, ABP increased the antioxidant characteristics, with increased protein content and gel viscosity. Turmeric extracts significantly increased (p < 0.05) the calcium content and reduced syneresis. In conclusion, fermentation of milk-based mix containing ABP extract resulted in yoghurt which combines improved antioxidant characteristics with increased protein and enhanced techno-functionality.