Optimization of Baking Temperature, Time and Thickness for Production of Gluten Free Biscuits from Keyetena Teff (Eragrostis tef) Variety

Abstract

The demand for gluten-free foods is certainly increasing. Teff was becoming popular crop noticeably due to its very attractive nutritional profile and gluten-free nature. This study aims to develop Teff biscuits as an alternative food source for gluten intolerant people. Optimization of three independent variables, baking temperature (174,180 and 186°C), baking time (4, 8 and 12 min), and biscuit thickness (4.5, 5.5 and 6.5 ml) were taken as important factor to determine physical and nutritional quality of biscuits. There were twenty combinations created by Central Composite Design with the aid of Design-Expert software to get best quality Teff product. Moisture, protein, ether extract, fiber, ash, carbohydrate, and gross energy in biscuit samples were found in the range of 4.20-6.98%, 14.59-18.14%, 13.63-14.80%, 3.93-4.08%, 3.38 to 3.65%, 52.4-60.25%, and 414.22-422.15 Kcal/100 g respectively. Results showed that baking temperature and time were the most important factors that significantly affected (p <0.01) rehydration ratio, 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 were; 174°C, 9 min, and 4.5 mm. Biscuits sensory score shows variation in terms of colour and crispness. Biscuits baked at low temperature slighter thickness got better overall acceptability. Generally, result of this study confirmed that the possibility of production of gluten free Teff based biscuit as an alternative food source for gluten intolerant or tolerant consumers.