**2. Compositional distinctiveness of rice bran**

The composition of rice bran differs with the variety of rice, geographical conditions and processing methods. Rice bran, the outer layer of the rice grain, accounts for 8–10% of the total weight of the grain; however, it contains most of the nutrients: carbohydrates (34–62%), lipids (15–20%), protein (11–15%), crude fiber (7–11%) and ash (7–10%). In particular, rice lipids and bioactive components are concentrated in rice bran [6, 7]. Fatty acids such as palmitate (21– 26%), linoleate (31–33%) and oleate (37–42%) are predominant in rice bran. In addition, due to its high content of polyunsaturated fatty acids, rice bran is considered a healthy food [7, 8]. Significant quantities of bioactive compounds such as γ‐oryzanol, tocotrienol, tocopherol and α‐sitosterol as well as dietary fibers such as α‐glucan, pectin and gum have been found in rice bran [9, 10]. Specifically, γ‐oryzanol, the main antioxidant present in rice bran, has a 10‐times higher antioxidant activity than tocopherol, while tocotrienol has 40–60 times greater antiox‐ idant activity than tocopherol. However, the proportions of these phytochemicals vary with the type of rice cultivar [11]. In addition, rice bran contains 4‐hydroxy‐3‐methoxycinnamic acid (FA), which has photoprotective and antioxidative effects [12–14].

The health information website SelfNutritionData (http://nutritiondata.self.com) reports that one cup of crude rice bran provides 88 calories and that 28 g of rice bran contains 5.8 g of fat, 1.2 g of which is saturated and 4.2 g of healthy unsaturated fatty acids. According to Walter Willett, a nutritionist from Harvard University (https://www.hsph.harvard.edu/walter‐ willett), heart health is directly related to the ratio of unsaturated to saturated fatty acids in the diet. In addition, one cup of rice bran delivers 13.9 g of carbohydrate and 3.7 g of protein, which is 7% of our daily requirement and a single serving of rice bran delivers more than half of our daily nutritional requirements of thiamine, niacin and pyridoxine.
