RICE PUFFING IN RELATION to ITS VARIETAL CHARACTERISTICS and PROCESSING CONDITIONS

The effect of rice varietal characteristics, namely, length (L): breadth (B), ratio, amylose and protein contents and processing conditions namely, extent/degree of hydrothermal treatment, degree of milling and percentage of salt addition to rice, on puffing quality were studied in detail. the L:B ratio of varieties tested showed a positive correlation (r = 0.69) with expansion ratio (ER) of puffed rice produced. Total amylose and hot water insoluble amylose contents revealed a definite pattern of relationship, with ER showing predicted peaks at 28.5% total amylose (db) and 13.5% insoluble amylose (db) for highest ER. Protein content showed a negative relationship (r =−0.79) with ER. A new method for determining extent/degree of starch gelatinization, based on Brabender hot paste peak viscosity value (viscosity of 15% slurry retained at 95°C for 20 min.) was used in this study. Normal parboiled and pressure parboiled rice having 425 BU and 240 BU peak viscosities produced highest ER of 7.5 and 9.7% respectively. A 6% milling (minimum) and a 2% salt (NaCl/CaCl2) addition during preconditioning of rice resulted in maximum ER.