Journal of Ready to Eat Food | April-June, 2016 | Volume 03 | Issue 02 | Pages 25-27 © 2016 Jakraya JOURNAL OF READY TO EAT FOOD Journal homepage: www.jakraya.com/journal/jref ORIGINAL ARTICLE Effect of Soaking and Steaming Time on Milling Quality of Paddy Pramod Rai 1 , Md. I. A. Ansari 1 and Gajendra Prasad 2 1 Department of Agricultural Engineering, Birsa Agricultural University, Kanke, Ranchi-834006, India. 2 Department of Agricultural Engineering, Assam University, Silchar-788011, Assam, India. *Corresponding Author: Md. I. A. Ansari Email: irfan26200@yahoo.com Received: 18/06/2016 Revised: 22/06/2016 Accepted: 29/06/2016 Abstract Rice is one of the most important staple foods in the world. One of the major problems of the rice industry is breakage of kernels during milling. Parboiling is an excellent means of improving milling quality of paddy. It is carried out by soaking, steaming followed by drying. Long grain paddy (pusa-1121) was taken for experimental study. Soaking of paddy was done at 60ºC for different duration of 6, 9 and 12 hours. Steaming of soaked paddy was done at a pressure of about 7 kg/cm 2 for different duration of 60, 90 and 120 second. The soaked and steamed paddy was dried at 45ºC to a final moisture content of 12 % (w. b.) in lab model dryer. Milling of dried paddy was done by using lab model (Satake) rubber roll dehusker. After milling, head rice and broken rice was separated by using grading cylinder. The milling characteristics of paddy were determined in terms of percentage head rice ratio (HRR). Keywords: Paddy, Soaking, Steaming, Drying, Milling. 1. Introduction Rice is considered as a staple food for nearly one-half of the world’s population. One of the major problems of the rice industry is breakage of kernels during milling. Breakage in rice kernels occur because of fissures in rice kernel (Sharma and Kunze, 1982). These fissured grains are more susceptible to insect and microbial attacks. Fissuring can occur in the field prior to harvest, or during harvesting, processing, and storage. Many researchers observed that much breakage in rice may occur because the rice kernels have previously been weakened by stress cracks (fissures) caused by rapid moisture adsorption or desorption during harvesting, handling and/or processing. Improper drying and tempering processes can be a major cause of fissuring (Sharma and Kunze, 1982). As the cooking quality of broken rice is very poor, the market price with broken grains is much less than that of whole grains (Li et al., 1999). The ultimate goal of the rice industry is to achieve maximum head rice ratio (HRR) from the milling process. HRR is the current standard to assess commercial rice milling quality, and is defined as the weight percentage of rough rice that remains as head rice (kernels that are at least 3/4 of the original kernel length) after complete milling. HRR reduction decreases the value of rice since broken kernels are typically worth half the value of head rice. Kunze and Hall (1965) stated that a rice kernel with two or three cross-sectional fissures has lost its commercial value. Parboiling process has long been established as an excellent means of reducing the breakage of rice that would otherwise affect the milling quality in comparison to milling of raw paddy. In general, the parboiling process consists of three stages: soaking the cleaned raw paddy to saturation moisture content, gelatinization of starch by adding heat to the moist kernels through steaming, and drying the product to moisture content suitable for milling or storage. Parboiling produces the physical, chemical and organoleptic modifications in rice with economic and nutritional advantages. The advantages are, higher head yield with less broken, easier shelling of paddy, increased resistance to insects, firmer cooked texture, less solid loss during cooking, better retention of nutrition like proteins, vitamins and minerals and higher oil content in bran (Velupillai et al., 1989). During the processing of parboiling, the paddy attains moisture content (MC) of about 50-60 % (d. b.). The soaked and steamed paddy is dried for storage or milling. The commercial dryers used for drying of agricultural products, use the heated air, which is circulated around the product for removal of moisture. The most important parameter during milling is HRR which is used to define the quality of milled rice in their sale price. The transaction price of rice has been strongly correlated to the size and shape and cleanliness of the rice. The price of head rice is almost double or triple as compared to that of the broken ones.