Effect of different doses of nitrogen on protein profiling, pasting and quality attributes of rice from different cultivars.

Effect of different level (60, 120 and 180 kg N/ha) of nitrogen (N) application on protein profiling, pasting and cooking quality characteristics of milled rice from different paddy cultivars was evaluated. N dose showed positive correlation with protein content and negative correlation with L*, whiteness and amylose content. N application significantly affected the protein profile, textural and pasting properties of different cultivars. All the cultivars expect PR120 and PAU201, showed an increase in the amount of accumulation of 60 kDa polypeptide with increase in N application. Accumulation of prolamines (16 and 14 kDa) and polypeptides of 38 and 35 kDa increased in all the cultivars. Size exclusion chromatography revealed decrease in low molecular weight subunits and increase in medium molecular weight subunits in all the cultivars upon N application. However, high molecular weight subunits increased in IET21214 and decreased in PR120 and PAU20 upon N application. N application resulted in increase in glutelins and decrease in peak and breakdown viscosity. PAU201 and PR120 showed lower AAC due to low accumulation of 60 kDa granule-bound starch synthase (GBSS), in response to N application. Gumminess and hardness of cooked rice increased with the increase in N dose and the increase was significant at 60 kg N/ha.