Cassava and yam starches used as thickener in yoghurt

Abstract

Chemically modified starches are usually employed as thickeners to ensure a desired effect in different food products. In order to offer fully natural products there is a demand for non modified starches which provide desired textural attributes over a larger temperature range. Yam starches have been shown to have promising functional properties as thickeners but have not been as yet fully exploited commercially. This investigation focused on the use of starch isolated from different yam and cassava cultivars as thickeners in yoghurt. Three yoghurt samples at 1 %, 2 % and 3 % of starch were prepared. And then the samples were analysed for a preference test. Another sensory evaluation was carried out with a trained panel of 18 panelists on yoghurt attributes such as: colour, consistency, texture and smoothness. Finally the level of spontaneous syneresis in undisturbed yoghurt was determined. According to their preference 86 % of the panelists selected the very thick yogurt sample as their first choice, 53 % of the panelists selected the least thick yogurt sample as their 2nd choice and 64 % made the less thick yogurt as their 3rd choice. Spontaneous syneresis of yogurt after 7 days at 4°C were 0 % for the both 1 % of starch, 1.05± 0.86 for 2 % of cassava starch , 8.66 ± 0.62 for 2 % of yam starch, 6.09 ± 3.42 for 3 % of yam starch. Due to the high structural strength of the swollen granules, natural yam and cassava starches can be used as an alternative to some types of chemically modified starches. Yam and cassava starches therefore have a high potential as thickening agents in foods