Optimization of okara, wheat and red teff blending Ratios for better physico-chemical, and sensory Properties of cookies

Abstract

Okara is a by-product of soy milk processing and it is often underutilized because of knowledge gap and undesired sensory quality related with soyabean products. Inline with this, the present study was initiated to assess the potential of incorporating okara in bakery products to produce value added product. The cookies were made with mixture of red teff, wheat and okara flours blended in different proportions. Sixteen composite flours were prepared using D-optimal mixture Design with three ingredients in the ranges of 20-40%, 10-20%, and 40-50% for red teff, wheat and okara flours. Standard procedures were used to analyze proximate compositions, anti-nutritional factors (phytate and tannin), mineral composition, physical properties and sensory quality of cookies made from the flours. High ratio of okara in the blend increased fat, fiber, protein, gross energy, mineral contents of cookies. But an increse in wheat and red teff flour increased the carbohydrate value. The breaking strength, diameter and thickness of cookies were significantly (p<0.05) different as compared with control. The red teff and wheat, wheat and okara, and red teff with okara were showed highly significant effect on spread ratio. The higher proportion of okara flour in the blend reduced the physical characteristics of the cookies due to the dilution of the gluten network. The mineral contents (Zn, Ca, and Fe) were significantly (p<0.05) different and cookies prepared from more portion of okara and red teff have good mineral content than the control. Interms of anti- nutritional contents cookies made with high concentration of okara flour significantly different in tannin content but cookies made from different composite flour were non significance in phytate content. Control cokkies samples were superior in terms of colour, aroma, taste and crispness but none significsntly different in terms of overall acceptability of cookies made from teff 30-40%, wheat 17-20% and okara 43- 50%. Optimized mix ratios were 35-40%, 15-18% and 47-50% for Teff, Wheat and Okara flours respectively. At this optimum mix the ranges for protein were 15.4-18.56%, carbohydrate 45.11- 57.45%, fat 14.8-18.2%, energy 409.88-416.2 kcal/100gm, fiber 7.4-8.9 %, Iron 6.66-7.3 mg/100g, Calcium16.6-18mg/100gm, Zinc 2.66-2.88 and overall acceptance received hedonic ratings 3.32-4.55 were obtained. The results from this study revealed addition of okara improved the nutrient content and other functional properties than discarding as a waste from soya milk processing.