Optimization of processing conditions for preparation of gluten free biscuits from two TEFF (Eragrostis tef) varieties

Abstract

The demand for gluten-free foods is certainly increasing. Because of this, interest in teff has been increasing noticeably due to its very attractive nutritional profile and its gluten-free nature. The limited knowledge of teff processing challenges faced making teff-based food products adapted for international consumers. This study aims to develop teff based biscuits as an alternative food source for gluten intolerant people. Optimization of three independent variables, baking temperature (174,180 and 186o C), baking time (4, 8 and 12 minutes), and biscuit thickness (4.5, 5.5 and 6.5 millimeter) were taken as important factor to determine physical and nutritional quality of biscuits. There were twenty combinations of biscuit baking temperature, time, and thickness from each variety of teff using CCD with the aid of Design-Expert software to get best quality teff biscuit. The major response variables of physicochemical properties at different baking condition were analyzed. The moisture, protein, ether extract, fiber, ash, carbohydrate, and gross energy in the biscuit samples were found in the range of 4.15 to 6.98%, 14.59-18.94%, 13.50-14.80%, 3.72-4.08%, 3.38 to 3.74 %, 51.88-60.25%, and 414.22-422.15Kcal/100g respectively for both tested teff varieties. Results showed that baking temperature and time were the most important factors that significantly affected (p<0.01) water rehydration capacity, biscuit hardness, water activity, bulk density, protein, moisture content, carbohydrate and gross energy. Biscuit diameter, thickness, ash, fat, fiber, and mineral were not significantly affected by interaction of baking conditions. Based on all parameters with exception of sensory analysis the best treatment combination of temperature, time, and biscuit thickness; 174o C, 9 min, and 4.5mm thick for both Kuncho and Keyetena based biscuit was selected. Acceptability was also assessed using a 5-point Hedonic scale. Compared with two varieties, biscuits made from Kuncho teff got better overall acceptability but in terms of most of chemical and physical properties almost they are the same except mineral composition. When both teff compared, biscuit made from keyetena teff contains highest calcium and iron content and lower sensory score and Kuncho teff got better sensory acceptability. Generally result of this study confirmed the possibility of production of gluten free teff based biscuit as an alternative food source for gluten intolerant consumers.