Identification best method of processing for rice string hopper flour with optimum quality characteristics

Abstract

The busy life styles of Sri Lankans demand traditional food items on instant preparation category. Therefore this study was conducted to identify best processing method for string hopper flour with it’s promised quality characteristics as demanded by the peoples. Various processing conditions and treatments were tested to identify best processing conditions. Deferent preheater temperature(3 5°C, 60°C, 70C°, 80°C, 85°C), different water amounts (1000ml, 15Q0ml,2000ml/50kg of rice) in deferent soaking time (30min.,45min., 60min.) was tested to identify gelatinization effect. The roasting effect on gelatinization is tested at several temperature levels (,60°C, 70C°, 80°C, 90°C) for different times(2min., 5min., 10min.,15min. ). Chemical treatments were given using vinegar, citric acid, sodium carbonate, sodium bicarbonate, calcium carbonate, calcium bicarbonate, hydrogen peroxide, phosphoric acid at the range of 0.01-0.2% . The plate milling, hammer milling and there combinations were used to check effect milling. Different kind of parboiled rice were also used in the preparation of rice flour for string hopper. Sensory tests were conducted in comparison of parboiled rice flour with two commercial available rice flour mixtures (Type I and Type III) to evaluate the functional properties of string hoppers. Temperature in the range of 70 - 80°C found to be the best preheater temperature for string hopper flour manufacturing process; and with 2-5 min. and 70-80°C found to be the ideal time temperature combination during roasting. Hydrogen peroxide and phosphoric acid in the range of 0.01- 0.2 % given good texture and colour. Results revealed that flour prepared using parboiled rice could able to make dough with cold water while maintaing required quality characteristics. A combination of parboiled rice and water spray is the most efficient and cheapest method to prepare string hopper. The sensory evaluation related that there is a significant difference of functional properties (e.g. colour, smell, texture, taste, appearance and overall quality) between three samples. All of functional properties of parboil rice flour was best than type I flour. Hydration capacity about 3.2-4.0 level suitable for string hopper preparation.