Quality and sensory properties of maize flour cookies enriched with soy protein isolate

This study was carried out to assess the quality and sensory properties of maize flour cookies enriched with soy protein isolate with the aim of encouraging the use of soy beans in producing value-added products. Soy protein isolate was produced from soy beans and then incorporated at 5, 10, 15, 20, 25 and 30% levels in maize flour. The results revealed that substitution of maize flour with soy protein isolate significantly (p ≤ 0.05) increased the protein from 8.69 ± 0.19 to 29.11 ± 0.34 while the moisture, crude fibre, fat and sugar contents of the cookies from the composite flour decreased as the percentage of soy protein isolate in the blends increased from 8.76 ± 0.22 to 6.96 ± 0.13, 3.81 ± 0.07 to 2.87 ± 0.02, 2.63 ± 0.06 to 1.69 ± 0.01, 9.41 ± 0.24 to 8.45 ± 0.13 and 6.21 ± 0.20 to 4.98 ± 0.11 respectively. The calorific value of the cookies decreased from 468 ± 1.59 to 383 ± 1.01 cal/100 g as the percentage of soy protein isolate increased in the cookies. Sensory evaluation results showed that the colour, texture, taste and overall acceptability changed significantly (p ≤ 0.05) with increase in soy protein isolate in the composite flour. The optimum substitution level with soy protein isolate was 20%. Above this, the product consumer acceptability decreases.