Effect of the use of starches of three cassava varieties (Bankye Hemaa, Agra and Abraboba), as a thickener, on the physico-chemical, functional, sensory properties and consumer acceptability of yoghurt

Abstract

Yoghurt is a popular probiotic food rich in micronutrients but suffers from a thickness loss referred to as syneresis. To reduce this adverse sensory effect, the starches of three new cassava varieties, Abrabopa, AGRA and Bankye Hemaa, were used as thickening agents in the preparation of yoghurt. The starches were characterized by assessing their pH, moisture, colour, water absorption and binding capacities, swelling power and capacities and pasting characteristics. These three samples were incorporated at rate of 2.5, 5.0 and 7.5 %, to prepare three types of yoghurt, from fully-skimmed, partially-skimmed and whole milk. The pH, viscosity, syneresis, back extrusion properties and sensory properties of the yoghurt samples stored at 6+1 oC were monitored over a period of 21 days. Whilst there were significant differences (p < 0.05) in the swelling power and indices. However, the water binding values of the starch samples from all three varieties were comparable. The cooked paste viscosity values ranged from 512.5 BU (Bankye Hemaa), 550 BU (Abrabopa) to 620 BU (CRI-CRI-CRI- AGRA). When used in preparing the yoghurt, the whole milk yoghurt, with Abrabopa starch at 5.0 % inclusion, gave the highest consistency (28.7 N.s) and cohesiveness (-2.1 N), whilst fully-skimmed milk yoghurt with AGRA starch, at 7.5 %, gave the lowest consistency (7.5 N.s) and cohesiveness (-0.4 N). These results correlated well with those of the sensory scores, which gave the best taste, mouthfeel and sourness scores to yoghurt prepared from whole milk in which Abrabopa cassava starch at 7.5 % had been incorporated and stored up to the 14 day. The starch of Abrabopa cassava variety therefore adequately prevented syneresis in yoghurt