Salinity alters the protein composition of rice endosperm and the physicochemical properties of rice flour

BACKGROUND: Salinity is one of the major threats to production of rice and other agricultural crops worldwide. Althoughnumerous studies have shown that salinity can severely reduce rice yield, little is known about its impact on the chemicalcomposition, processing and sensory characteristics of rice. The objective of the current study was to investigate the effect ofsalinity on the pasting and textural properties of rice flour as well as on the protein content and composition of rice endosperm.RESULTS: Rice grown under saline conditions had significantly lower yields but substantially higher protein content. Theincrease in protein contentwas mainly attributed to increases in the amount of glutelin,with lesser contributions from albumin.Salinity also altered the relative proportions of the individual peptides within the glutelin fraction. Flours obtained from ricegrown under saline conditions showed significantly higher pasting temperatures, but lower peak and breakdown viscosities.Rice gels prepared from the flour showed significantly higher hardness and adhesiveness values, compared to the freshwatercontrols.CONCLUSION: Salinity can significantly affect the pasting and textural characteristics of rice flour. Although some of the effectscould be attributed to changes in protein content of the rice flour, especially the increased glutelin level, the impact of salinityon the physicochemical properties of rice is rather complex and may involve the interrelated effects of other rice componentssuch as starch and lipids.