Pasting Behavior of Rice: A New Method of Viscography

ABSTRACT Brabender viscograms of 45 rice varieties, belonging to eight distinct property profiles, were determined at several slurry concentrations each. The conventional criteria, viz. peak viscosity ( P ), breakdown and setback, obtained at an arbitrarily fixed slurry concentration, did not provide useful information. For each rice variety there was a P value below which the breakdown was zero but rose progressively above it, as well as another P value at which the setback was zero but became positive below and negative above it. These two critical P values were fairly characteristic of the rice type: e.g. the zero‐set‐back P value rose from about 350 B.U. for rice varieties of Group VIII (waxy) to 3500 B.U. for those of Group 1 (some dwarf indica ). But the most useful test criterion was the‘relative breakdown,’i.e. breakdown/(breakdown + setback). Its value, at a P value of 1000 B.U., rose from about 3% for Group I to 300% for Group VIII. The three mutual ratios of the peak, hot‐paste and cold‐paste viscosities provided other useful distinguishing criteria. These viscogram indices were closely related to the total and insoluble amylose contents of the samples.