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Effects of the Functional Properties of Corn, Cassava and Potato Starches on the Physical, Sensory and Whey Separation Properties of Soy Yoghurt

O. E. Agwo
I. L. Princewill-Ogbonna
C. M. Adinnu
U. C. Igwillo


Yoghurt is a probiotic food produced from the action of acid-forming bacteria on milk and consumed due to its many nutritional and health benefits. Stabilizers play a key role in yoghurt production. Starch stabilizers were produced from a yellow variety of maize grains, TMS 419 cassava roots and orange-flesh potatoes. Soymilk was processed from soybeans using the hot water extraction method at the ratio of 250 g:1 litre. Three different
yoghurt samples were produced from the soymilk fermentation at 44 C for 10 hours using the stabilizers without
flavour. The corn-stabilized, cassava-stabilized and potato-stabilized yoghurts were coded XOX, YOY and ZOZ respectively. The functional properties of the starches and their effects on the physical, sensory and whey separation properties of soy yoghurts were evaluated. There was variation in the evaluated functional properties of the starches with cassava starch standing out. There was a significant difference (p<0.05) in the physical properties of the soy yoghurt samples. The cassava-stabilized soy yoghurt had the highest acidity (4.66 pH) and total solid content (18.03%) but the least titratable acidity value (0.42%). The potato-stabilized yoghurt was the least acidic (4.92 pH) but had the highest total titratable acidity value (0.51%). The corn-stabilized yoghurt had the least total solid content (17.49%). ZOZ had the highest score for all the sensory parameters evaluated, followed by XOX. No significant difference existed (p>0.05) in their appearance, mouthfeel and sweetness, while significant difference existed in their sourness, texture, after-taste and general acceptability. ZOZ had the highest acceptability of 7.95+1.10, followed by XOX with 6.65+1.53. YOY did not exhibit syneresis while XOX and ZOZ separated at the serum: water ratio of 70:40ml and 70:30ml, respectively. This research upholds that cassava starch is a reliable stabilizer in soy-yoghurt production.