Biochemical characterization of red rice cultivar from Thatta, Pakistan

Abstract

Rice is one of the basic diet constituents of many people around the globe. There are different colored varieties of rice like black, red, brown (due to anthocyanin pigment). Colored rice pigments possess antioxidant activities. Red rice is a specific variety of rice grown in different parts of the world including the Thatta district of Sindh, Pakistan. This study was conducted to analyze the biochemical properties of the red rice cultivar of Thatta. Red rice grain samples collected from Thatta were subjected to phenol extraction to estimate the free and bound fraction of phenols. Results revealed a higher fraction of bound phenol in all the cultivars (78% of bound phenol content). Phenolic compounds not only protect plants from toxic effects, pests, and pathogens but also have different applications in medicines and cosmetics. Gas chromatography coupled mass spectrometry (GC-MS) identified several volatile compounds in red rice grains. A total of 18 compounds were identified out of which 5 belong to the ester group and the rest of the compounds belong to the amide group with the higher proportion of amides in all the samples as compared to esters. N-(Trifluoroacetyl)pyrrolidine was detected as the major compound among all samples. SDS-PAGE was used to determine the protein profile of red rice grains. Results obtained from SDS-PAGE of the rice grains showed a similar pattern of proteins in rice cultivars. Few polymorphic bands that could be used to distinguish the cultivars were also detected. Major bands were commonly present in all the cultivars indicating that genes coding these proteins are conserved.