Cereal Chem 64:337-342   |  VIEW ARTICLE

Varietal Differences in Quality Characteristics of Puffed Rices.

C. P. Villareal and B. O. Juliano. Copyright 1987 by the American Association of Cereal Chemists, Inc. 

Varieties differing in amylose content (AC) and final gelatinization temperature (GT) were used to study the most suitable rices for three methods of producing puffed rice. Puffed rice was prepared from both parboiled and boiled milled rice by heating the dried milled rice in oil at 210-220 C and by heating raw milled rice in a puffing gun. Among the nine rices parboiled for 10 min at 100 C, waxy and low-AC rices gave higher puffed volume than higher AC nonwaxy rices; after parboiling at 127 C, most intermediate- and high-AC rices gave as high a volume expansion on puffing as waxy and low-AC rices. Puffed rice Instron hardness was lower for the more expanded products parboiled at 127 C than at 100 C. By boiling milled rices in excess water, volume expansion on puffing similarly improved for most samples, particularly the intermediate-GT rices, from 3.3-5.1 after 10 min of boiling to 4.8-5.8 after complete cooking (13-22 min). Thus, after complete starch gelatinization (similar water uptake), nonwaxy rice gave volume expansion as high as waxy rice. Expansion ratio on heating in a puffing gun for 3-7 min to 11.3 kg/cm2 pressure or 200- 210 C was higher for waxy milled rice than for nonwaxy rice, corresponding to 81-97% drop in gel viscosity. Protein content was negatively correlated with expansion ratio of puffed rices. Minimal losses of lysine, cysteine, and tryptophan in the puffed products were observed.