Effect of Chloride Iron in Soaking Water for Altering Parboiled Rice Quality

Abstract

Parboiling of rice is an ancient traditional process of Asian countries and it reduces the level of grain breakage and increase in head yield of rice during milling. Generally, parboiling process consists of three major steps i.e. soaking of cleaned paddy up to saturation moisture content, gelatinization of rice starch by adding heat to the moist kernels through steaming, and drying the product to moisture content suitable for milling or storage. Parboiling is also improved nutritive and some sensory qualities of rice. The market demand of the parboiled rice depends on its quality parameters such as kernel broken grain percentage, head rice yield, kernel whiteness and hardness (texture). Even though many factors contributing in quality of parboiled rice, soaking water quality, soaking procedures and steaming procedures were impart effect on quality of parboiled rice. It can be observed, quality of parboiled rice varies from place to place in Sri Lanka although, parboiling treatments are similar. Underground water is the main water source used for soaking of paddy in parboiling. It was observed that lot of chemical such as CaC03, Cl irons; N03 and Fluoride irons are soluble in ground water available in dry zone of Sri Lanka where most of rice mills are located. Hence this research study mainly focused to evaluate, effect of chlorine in soaking water to alter quality of parboiled rice such as kernel whiteness, texture/hardness, broken grain percentage and head rice yield percentage. Results revealed that chlorine iron concentration of the soaking water significantly affects only for changing of rice kernel hardness (texture) in parboiled rice and also it does not change other rice quality parameters. And also effect of chlorine iron concentration in soaking water die not show any clear pattern for changing of rice kernel texture/hardness in parboiled rice.