Analysis of black rice and some other cereal grains for protein, sugar, polyphenols, antioxidant and anti-inflammatory properties

Abstract

Cereal grains are the most consumed source of food for mankind. This study analyzed the nutritional status, polyphenol content, antioxidant, and anti-inflammatory activity of black rice and other commonly consumed cereal grains such as brown rice, white rice, barley, and wheat. For this, dried seed samples were grounded and extracted with 70 % ethanol. Among the grains, black rice was found rich in nutritional components like protein (15.81 ± 1.03%), free amino acid (2.69 ± 0.21%), and total sugar (4.61 ± 0.05%) content. However, barley was found rich in reduced sugar content (2.65 ± 0.03%). A functional component like polyphenol content (226.70 mg/g extract) was found to be the maximum in black rice. Black rice also showed high antioxidant activity where a small amount of black rice extract scavenged both 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (IC50, 99.73 μg/mL) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (IC50, 204.60 μg/mL) free radicals. Anti-inflammatory activity analysis by inhibiting nitric oxide (NO) production revealed that black rice extracts had a higher level of inhibition (15.56 ± 1.05%) against NO production. So, nutritionally rich, and functionally potent black rice might be added or incorporated with our food items as a functional ingredient to uplift the nutritional status, antioxidant, and anti-inflammatory properties of food.

Keywords

• Cereal grains
• Black rice
• Protein
• Sugar
• Antioxidant
• Polyphenol