Formulation, Optimization and Characterization of Dietary Cookies from Blends of Corn, Peanut, Sweet Potato and Soybean

Abstract

Traditionally wheat is used for cookies production but the harsh climatic conditions in the tropical regions is not conducive for the growth of wheat. There are locally grown crops that can be used to produce high quality cookies that meet consumer’s dietary requirements. The aim of this study was to develop, characterize, and optimize the formulation and some production processes of dietary cookies from blends of corn, peanut, sweet potato and soybean. A four-component, constrained, randomized, combined, D-optimal mixture-process experimental design; with 34 randomized experimental runs, was employed. The formulation design constraints were: roasted corn flour (20% - 70%), defatted peanut meal (10% - 30%), blanched soybean (10% - 30%), and sweet potato extract/gel (5% - 20%). The four major components comprise 95% of the total mixture. Other minor components of the formulation, which were kept constant throughout the experimentation, were: sugar (1 %), baking powder (0.8 %), baking fat (0.2 %), and water (3 %). The processing parameters investigated were: baking temperature (1200C - 1800C) and baking time (10min – 25min). The formulated dietary cookies were analyzed and evaluated for the proximate properties, physicochemical properties and sensory characteristics using standard procedures. The result of the dietary cookies optimization gave optimal formulated dietary cookie with overall desirability index of 0.531, based on the set optimization goals and individual quality desirability indices. The optimal cookie was obtained from 22.744% roasted corn, 26.589% defatted peanut, 25.666% blanched soybean, 20.0% sweet potato extract/gel, 1380C baking temperature, and 25 minutes baking time. The quality properties of this optimal cookies are 14.071% moisture content, 25.699% crude protein, 4.957% crude fibre, 16.033% fat content, 34.388% carbohydrate, 7.234% ash content, 386.440 Kcal/100g energy value, 381.514 mg/100g potassium, 80.0 mg/100g calcium, 3.789 mg/100g iron, 0.552 mg/100g zinc, 75.088% digestibility, 20.566 D/T spread ratio, 0.657 g/cubic cm bulk density, 1.695g breaking strength, and overall acceptability of 5.96, based on 9-point hedonic scale. The result of the study showed that the formulated dietary cookies was of high quality and that improving nutritional quality of cookies is possible through composite formulation. It is recommended that further study be carried out on formulation of nutritionally improved dietary cookies using other nutritionally rich roots and legumes. Enrichment of cookies with these protein-rich sources will result in cookies with improved nutrient quality that meets the consumer’s dietary needs.