Impact of mango and pomegranate peels supplementation on quality characteristics of yoghurt with or without whey powder.

Abstract

2 Abstract: Set yoghurt was prepared from buffalo's milk standardized to 3% fat and supplemented with 2% skim milk powder (SMP), why powder (WP), pomegranate peel powder (PPP), mango peel powder (MPP), WP+PPP (1:1) and WP+MPP (1:1). Survival of lactic acid bacteria, some chemical, functional properties and sensory quality of yoghurt samples were evaluated. There were non significant differences in dry matter and fat content among all treatment. Significant differences were observed in lactose, protein, ash, acidity diacetyl and acetaldehyde contents in all treatment of yoghurt. Yoghurt supplemented with PPP, MPP, WP+PPP and WP+MPP were rich with crude fibers and antioxidant contents. Supplementation the yoghurt with 2% PPP or MPP led to significant decrease in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp bulgaricus in resultant yoghurt compared with yoghurt supplemented with 2% WP and SMP. Extracts of PPP and MPP showed a high cytotoxic effect towards HePG2 (liver), HCT116 (colon) and MCF7 (breast) cells line. Yoghurt samples supplemented with WP+PPP and WP+MPP recorded higher flavor, appearance and overall scores than that of samples supplemented with PPP and MPP, respectively. So, addition of 1% WP in supplemented milk yoghurt with 1% PPP or MPP lead to significant increase in flavor score and enhance a sensory quality of yoghurt product compared with yoghurt samples supplemented with 2% PPP or MPP. It could be concluded, that mango or pomegranate peels powder should be incorporated with whey powder when used as ingredients in functional yoghurt.