Evaluation of Quality Characteristics of Soy Fortified Wheat-Cassava Composite Bread

Abstract

Preliminary studies of proximate composition, physical characteristics and sensory properties of bread formulated from blends of Soy protein isolate (SPI), High Quality Cassava Flour (HQCF) and wheat flour (WF) were carried out. Soy protein isolate and HQCF were used to replace wheat flour at 10, 15 and 20%. Proximate, physical characteristics were carried out using standard analytical procedures. The developed bread samples were subjected to sensory analyses using a 9- point Hedonic scale. Data obtained were subjected to Analysis of Variance ANOVA and means separated by Duncan Multiple Range test. Results showed that the 20% soy protein isolate fortified samples improved protein content of the bread sample (16.54%) than that of 15% fortified samples. It ranged from 4.69-16.54%. There was a significant increase in all the soy protein isolate fortified samples compared to the control sample that was not fortified with soy protein isolate. The soy protein fortified bread samples had higher loaf weights than the cassava bread. It ranged from 262.5g -287g, while a significant reduction (p<0.05) existed in the loaf volume and specific loaf volume of the soy fortified bread with increased level of soy protein isolate and cassava flour inclusion. It ranged from 600 -1000 cm3 and 2.23 -3.73cm3/g respectively. The mean sensory scores obtained revealed that all the fortified bread samples had acceptable loaf appearance, crust colour, crumb colour, texture and taste significantly comparable to those of non fortified bread. However, there was a slight significant difference in the overall acceptability of the fortified bread (6.80 and 6.40) to those of non fortified samples with the highest score of 7.13. Thus, composite blends of soy protein isolate and wheat flour up to 15% could be adopted as a means of supplementation without significant impairment of overall acceptability.