Differential Protein constituents and physicochemical characteristics of some rice varieties in Sindh Pakistan

Abstract

In recent years many new rice cultivars have been introduced in the market in terms of greater yield, increased resistance to diseases and insects, greater tolerance of climate and soil conditions. Despite all these characteristics, the nutritional needs of the common man are being neglected. While the better protein and amylose/amylopectin content of rice can have a significant positive impact on public health. Materials and Methods: To find out the better rice variety in term of nutritional and cooking quality fourteen rice varieties, procured from Nuclear Institute of Agriculture (NIA) Tandojam, Sindh, Pakistan were analyzed for the morphological & physicochemical properties. 1000 grains weight, Length, Breadth, Elliptic factor was determined for grain types and the proximal chemical analysis such as total protein, amylose-amylopectin ratio and content of different protein fractions were obtained. Results: Non-Basmati rice cultivars were significantly different (p<0.05) from Basmati rice cultivars in physical dimensions grain length and breadth. In both Basmati and Non -Basmati rice varieties weight of 1000 seeds / g is positively correlated to breadth and negatively correlated to elliptic factor while, breadth was negatively correlated to elliptic factor in all varieties. 1000 grain weight of Non- Basmati (18.7-21.9) over Basmati (14.0-21.8) determines the quality characteristics and density of rice cultivar. The highest amylose/ amylopectin ratio was observed in Shadab while the lowest was in Mahak rice variety. The highest protein value was found in an aromatic Basmati rice variety jajai-77 (9.7% ± 0.01) & the lowest (6.86% ± 0.02) in Non-Basmati variety IR-8. Conclusion: The study reveals that rice varieties under study showed a significant difference from medium to long grain size as well as in their protein and amylose content. High protein and Low amylose content gives desirable feature to Basmati rice due to soft texture on cooling for longer time period, which is definitely preferred over Non- Basmati rice varieties with high amylose content.