Effect of soil moisture stress from flowering to grain maturity on functional properties of Sri Lankan rice flour

Functional properties of flour from rice variety BG 250 (short-season) and BG 359 (long-season) exposed to soil water stress from flowering to grain maturity were investigated. Protein content was reduced in both varieties but lipid was reduced only in BG 359 in response to soil moisture stress. AAM content decreased in BG 250 but unaffected in BG 359. Water stress increased swelling power, onset of pasting, peak viscosity, granular breakdown, gel hardness, and cohesiveness in both varieties. Gelatinization temperatures in both varieties were unaffected by water stress, while gelatinization enthalpy was increased in BG 359 but unchanged in BG 250. A double endotherm (type I and type II) appeared in AM–lipid complex in all the flour samples. Type I AM–lipid complex was reduced in BG 359 in response to water stress. Only a single endotherm appeared in the re-formed AM–lipid complex in gelatinized starch. The magnitude of the ΔH of re-formed AM–lipid complex was reduced in BG 359 in response to soil moisture stress, but unaffected in BG 250. Water stress decreased AP retrogradation in BG 359 while it was unaffected in BG 250.