Antioxidant, Nutritional, and Physicochemical Quality of Yoghurt Produced from a Milk-Based Fermentation Mix Enhanced with Food Spices

Utilization of natural additives, which could meet the growing need for ‘clean label’ and value addition with respect to disease prevention and health promotion in humans, is a current interest in the yoghurt industry. In this study, yoghurt recipes derived from a standard milk-based fermentation mix enhanced with African black pepper (ABP), turmeric, or cloves extracts were evaluated for antioxidant, nutritional and physicochemical qualities. 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 a fermentation tank for 9 hours at 40 °C. The results revealed that the clove-enriched yoghurt recipe exhibits the strongest antioxidant capacity, as indicated by a 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 it also exhibits 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, the fermentation of a milk-based mix containing ABP extract resulted in yoghurt which combines improved antioxidant characteristics with increased protein and enhanced techno-functionality.