Résumé :
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Viscosity properties of wheat starch and flour measured by the Rapid Visco Analyser (RVA) were characterised by RVA running conditions and varietal difference. RVA variables including starting temperature of measurement, heating rate and final cooling temperature were found to be the must important factors determining RVA viscosity properties. Starting temperature mostly affected peak time, peal; viscosity, breakdown and setback viscosity for starch, and peak time and breakdown for flour. Heating rate influenced peak time, peak viscosity, holding strength and final viscosity for starch, and peak time, peak viscosity, breakdown and holding strength for flour. Setback viscosity for starch and flour was determined by final cooling temperature. Discrimination of wheat varieties was greatest with the following RVA running profile: starting temperature of 50 degrees C, heating rate of 20 degrees C/min and final cooling temperature for both starch and flour of 43 degrees C. This profile also showed clear classification of wheat varieties tested and accordingly good prediction for softness of cooked white salted noodles.
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