Impact of dry- and hydro-thermal treatments on swelling power, water absorption and water solubility on red-rice flours

Filli Pratama

Abstract


The impact of dry- and hydro-thermal treatments on swelling power (SP), water absorption (WA) and water solubility (WS) of red-rice flour (RRF) were investigated. The dry-thermal treatment was conducted at RRF’s moisture content (mc) of 10%, and the hydro-thermal treatment was performed at the mc of 25%. There were two heating methods applied on RRF: oven (80oC) and autoclave (121oC) heating. The exposure duration was 8, 10 and 12 hours in an oven-heating; 15 and 30 minutes in an autoclave-heating. Results showed that exposure durations, moisture content and theirs interaction had significant effect on SP and WS of RRF for the autoclave-heating. WA and WS increased with longer exposure duration to heat, and at a higher heating temperature. WA of RRF (40.34%) at 8 hr of exposure duration increased to 51.43% after 12 hr of exposure duration (for dry-thermal treatment) and 45.36% to 50.76% for hydro-thermal treatment. Modification of RRF by hydro-thermal treatment in an autoclave gave better physical properties than that of heating in an oven with higher values on SP and WA, and lower value of WS

Keywords


red rice, dry and hydro thermal, swelling power, water absorption, water solubility

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