BEST INCLUSION RATE OF PURPLE YAM “Kinampay” (Dioscorea alata L.) POWDER IN YOGHURT

Abstract

The study was conducted to develop a technology for the supplementation of yoghurt with purple yam powder (PYP) as a potential source of prebiotic and determine its effect on the properties of the product. Five inclusion rates of gelatinized PYP were used: 0% (Control), 2% (T1), 3% (T2), 4% (T3) and 5% (T4). Higher acidity level was observed in T1, T2, T3, and T4 compared to control throughout 1, 7 and 14 days of storage. No significant differences were observed in terms of fat, protein, moisture and total solids. Yoghurt supplemented with gelatinized PYP showed a higher viable cell count of Lactobacillus delbrueckii subsp. bulgaricus compared with the unsupplemented yoghurt. This indicates the positive influence of gelatinized PYP on the growth of the bacteria due to its prebiotic properties. Sensory characteristics of yoghurt enriched with 2% gelatinized PYP (T1) had higher overall acceptability and sensory scores in terms of aroma, sourness, sweetness, texture, body and consistency, and flavor than the control, T2, T3, and T4. The results show that the best inclusion rate of gelatinized PYP in yoghurt is 2% and supplementation with purple yam boosts the characteristics of yoghurt as functional food.