CHAPTER ONE
INTRODUCTION
1.1  Background to the Study Rice is the staple food of about half of the world population supplying more than 21% of total calorie requirement for those people and about 76% of South East Asians. In Thailand, rice provides about 41% of total daily energy intake (FAOSTAT, 2015). Food consumption patterns from the Malaysian adult nutrition survey revealed that cooked rice was consumed by 97% of the population twice daily (NARC, 2015). Malnutrition and chronic diseases are widespread in most of the developing countries where white rice is the main staple food (Dipti et al., 2012) while many researchers have reported that brown rice contained the essential nutrients like iron, zinc, thiamine, niacin, vitamin E, dietary fiber, protein and carbohydrate. Furthermore, bioactive constituents such as γ- oryzanols, tocotrienols, polyphenols have also been identified from brown rice. In addition, some varieties of brown rice were found to be low in glycemic index (GI) and evidences have shown that low glycemic index (GI) food has many health benefits such as control type II diabetes (Greenwood et al., 2013), prevent coronary heart diseases (Hallfrisch et al., 2003), obesity and cancers. However, GI of rice were reported to be affected by various factors like variety, geography, method of processing conditions, nature of the starch, cooking method, presence of fiber, and other nutrients content such as fat and protein. Hence, brown rice has potential to reduce the prevalence of malnutrition and chronic disease (Anderson et al., 2009). In Nepal, rice is the most important and prestigious food crop and is grown as high as 3,050 m above the sea level (NARC, 2015). It is grown over 1.4 million ha, with the productivity of 2.56 t/ha. It contributes nearly 20 % to the agricultural GDP and provides more than 50% of the total calorie requirement of the Nepalese people (NARC, 2015). Several varieties of white rice have been developed in the country, however, only a very few are available as commercial brown rice in the stores. In this article, we discuss the nutritional composition of brown rice and losses during milling and the health benefits of brown rice over milled rice. Brown rice is whole grain rice with intact bran layer and the inedible outer hull removed. It is the unmilled rice containing the pericarp, the seed coat and nucellus, the germ or embryo, and the endosperm (Ajimilah et al. 2004). The dark color of brown rice is due to the bran layer and is rich in vitamins like thiamine, niacin, pyridoxine, and minerals like manganese, phosphorus, and iron. Although brown rice contains several vitamins and minerals, it is only consumed by a limited number of health conscious and nutritionally aware people, probably due to its longer cooking time, instability during storage, strong bran flavor, and undesirable texture (Babu et al., 2009). Mostly, the brown rice production in Nepal is done locally in the villages using traditional equipment called dhiki, a special de-husking instrument made generally of wood. After threshing, paddy is dehulled using dhiki, generally operated by one or two persons using foot. In Nepal, the commercial brown rice production has started in one industry with a total production of less than 50 M ton (Personal Communication, September 11, 2016), compared to a total import of more than 3000 M ton from India in 2015. Commercially, brown rice is obtained after the de-husked grains are graded, color-sorted, and damaged or broken grains removed from the mixture. This results in considerable loss resulting in only around 65-70% recovery of the total paddy (Personal Communication, September 11, 2016). However, the recovery of brown rice depends on the quality and variety of paddy used. The brown rice recovery ranged from 78.6 % in Mithila variety compared to 82.6% in Radha 4 variety (NARC, 2015). Further detailed investigations are required to obtain the production and consumption data of brown rice in Nepal.