SOAKING
Gelatinization is process by which starch granules change to a gelatinous or jelly form, filling voids and cementing fissures in grain. Soaking time can be reduced by first subjecting paddy to a vacuum for a few minutes or by soaking it under pressure in hot water. Rice soaked in water at ambient temperature (20-30°C) will take 36 to 48 hours to reach 30 per cent moisture content. In hot water (60-65°C), it will takes only two to four hours. If soaking time is too long, part of rice dissolves in water, seed begins to germinate, and starch fermentation occurs. Water temperature and length of soaking time affect solubility of substances in rice as well as colour, smell, and taste. mineral content, sulphides and pH of soaking water also affect results of process. During cold soaking, starch fermentation occurs because of respiration of paddy grains and release of carbon dioxide. Fermentation can cause an off-flavour and can lead to excessive development of fungi and or micro organisms in paddy. During hot water soaking (60-65°C), grain absorbs moisture faster and reaches a moisture level of 30-35 per cent in two to four hours depending on variety. Respiration and fermentation are restricted. shortest period of soaking time is achieved by maintaining a constant water temperature. This requires continuous recirculation and reheating of water. Hot soaking keeps grain at a higher temperature which will reduce steaming time needed to complete process. After soaking is completed, water is drained with moisture around 30 per cent for eir cold or hot soaked paddy. amount of water required for soaking paddy is about 1.3 times weight of paddy.