Evaluation of Micronutrient and Sensory Properties of Composite Yoghurts

Composite yoghurt was produced from blend of cow milk, soymilk and tigernut. The proportions of cow milk, milk extracts from soybean and tiger nut were varied resulting in five formulations. Yoghurt was produced from five formulations; their micronutrient analyses and sensory evaluation was determined. Cow milk in a ratio of 100: 0% (sample A1), Cow milk + Tiger nut milk 50:50%-(sample A2 ), Cow milk +Soybean milk 50:50%- (sample A3 ), Tiger nut + Soymilk-(sampleA4 ), and Cow milk + Soybean milk+ Tiger nut milk50:25:25%- (sample A5 ). The objective of the study was to determine the mineral and vitamin content of yoghurt prepared from extracts of tigernut and soybean milk. The 5 milk samples were analysed for minerals (Mg, Ca, Fe, K) and vitamins (A, B12 , C, E) using UV-visible spectroscopy. Data were subjected to analysis of variance (ANOVA) where appropriate and means separated by Duncan’s multiple range test (DMRT) at 0.05% significant level. The various milk extracts used in making yoghurt were investigated in a completely randomized design model using Cow milk (A1 ) as control, 50% Cow milk + 50% Tiger nut milk (A2 ), 50% Cow milk + 50% Soybean milk (A3 ), 50% Tiger nut + 50% Soymilk (A4 ), and 50% Cow milk + 25% Soybean milk+ 25% Tiger nut milk (A5 ). Sensory evaluation of the yogurt was conducted using a five-point hedonic scale. It involved the participation of 40 panellists which comprised of staff of NAERLS, Ahmadu Bello University: Zaria. Each individual evaluated seven sensory characteristics (appearance, taste, colour, flavour, consistency, sweetness and thickness). A 9-point hedonic scale was used to evaluate the organoleptic parameter of the sensory characteristics. The result of the nutrients and vitamin analysis showed that sample A4  had the highest amount of Mg and vitamin A (40%), while sample A5  was richest in Ca, Fe and vitamin C (30%) However, yogurt made from sample A1  and A3  had similar sensory qualities (60%) compared to yoghurt from other samples except samples (40%). Yoghurt prepared from sample A2 and A3 had the overall acceptability score (80%) as such could be successfully used in production of yoghurt characterized for good health and nutritional properties. The result of the study observed that the enriched yoghurt with soybean milk produced is sweeter and nutritionally superior in all the quality attributes than the conventional yoghurt. Thus, this enriched yoghurt can be used to produce yogurt which would be acceptable in the market.