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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.

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Rate constants and activation parameters are reported for the substitution reactions of nickel(II) ion with pyridine, 2,2'-bipyridine, 1,10-phenanthroline, and 2,2',2"-terpyridine, mainly in acetonitrile and dimethyl sulfoxide as solvents. In addition, similar data are reported for terpyridine in methanol and ethylene glycol and for bipyridine in ethanol-water and tert•butyl alcohol-water mixtures. In dimethyl sulfoxide substitution by pyridine appears to proceed by an Id mechanism in which solvent exchange is rate limiting (as in water), but with the multidentate ligands at ordinary temperatures the possibility exists that the rate-controlling step is ring closure. There is some evidence that near 120°nickel(II) ion in dimethyl sulfoxide loses its ability to discriminate among the four ligands. In acetonitrile the unexpected result is obtained that the enthalpy and entropy of activation for substitution by the multidentate ligands, particularly phenanthroline, are much lower than for pyridine. In alcohol-water mixtures pronounced minima in the enthalpy and entropy of activation occur at the same solvent compositions at which the medium is known to possess maximum structure.