RICE PUFFING IN RELATION to ITS VARIETAL CHARACTERISTICS and PROCESSING CONDITIONS

Abstract

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.

Optimum conditions of rice puffing - review

“…The extent/degree of starch gelatinisation as obtained by varying the intensity of the hydrothermal treatment with different steaming pressures and periods was correlated with Brabender hot paste peak viscosity values, and their effects on the ER of puffed rice produced were also studied (CHANDRASEKHAR & CHATTOPADHYAY 1991).…”

“…Samples of 12 paddy varieties consisting of short, medium, and long types including some traditionally known well puffing varieties were chosen and collected for studying the variety characteristics (CHANDRASEKHAR & CHATTOPADHYAY 1991). Their varieties were dried in shade to 12-13% moisture content (wb), cleaned and stored in metal containers till further use.…”

“…Sodium chloride (NaCl) and calcium chloride (CaCl 2 ) were used as additives (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% by weight) to study their effects on the puffing quality of rice (CHANDRASEKHAR & CHATTOPADHYAY 1991). Each salt was added to the parboiled milled rice sample in the form of saturated solution and the mixture was thoroughly mixed before drying to the moisture content required for puffing (10.5-11% w.b.).…”

“…The standard model Brabender amylograph (Brabender OHG, Duisburg) was used to measure the peak viscosities of parboiled rice samples showing their extents/degrees of starch gelatinisation (CHANDRASEKHAR & CHATTOPADHYAY 1991). Rice was ground to pass through the 40 mesh screen of No.…”

“…Each salt was added to the parboiled milled rice sample in the form of saturated solution and the mixture was thoroughly mixed before drying to the moisture content required for puffing (10.5-11% w.b.). CHANDRASEKHAR and CHATTOPADHYAY (1991) puffed salted and dried samples in hot air at about 250°C in the continuous heated air fluidised bed puffing machine developed for this purpose (CHAN-DRASEKHAR & CHATTOPADHYAY 1988).…”