BIOCHEMICA L CHANGE S I N PROTEIN S AN D LIPID S DURIN G STORAG E O F HEA T PROCESSE D GROUNDNU T (A rachi s hypogaea , L. )

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Date
1988
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MPKV, UNIVERSITY LIBRARY RAHURI
Abstract
The present investigations were undertaken to study the influence of heat treatments and storage on the changes in quality of proteins and oil of groundnut kernels. The groundnut kernels (cv.C-1-2) of freshly harvested produce were subjected to roasting (160°C for 30 min) and frying (2 min in boiling groundnut oil) treatments and stored up to 150 days at ambient (27 +2 C) and cold temperature (5 + 2°C) in sealed polythene bags . The samples were analysed after every 30 days for different quality parameters. The heat treatments reduced the moisture content markedly and increased the protein by about 4 percent and oil by about 2 percent in the kernels. Both roasting and frying treatments and, storage significantly increased the soluble proteins and decreased the methionine and tryptophan contents in the kernels. The heat treatments however, significantly decreased the pepsin hydrolysis of residual proteins. The heat treatments and storage also significantly affected the saponification value, acid value and iodine value of the kernel oil . There was an increase in both saponification value and acid value while a decrease in iodine value due to these treatments. The changes in saponification and iodine value due to heat treatments and storage were however, not of significant order. The acid value was, however, found to increase gradually during storage of raw and heated kernels up to 120 days and rapidly thereafter. The heat treatments were found to induce detrimental changes in the quality of storage proteins and oil of the kernels and decreased their shelf-life. The frying treatment exhibited more pronounced detrimental effects on the quality of the proteins and oil as compared to roasting. The storage of raw and heated kernels at 5 + 2 C was found to be beneficial in minimizing the deteriorative changes in the kernels. Further, investigations on the standardization of time and temperature of the heat treatments and, storage conditions to minimize the undesirable changes and, to increase the shelf-life of heat processed groundnut kernels are essential.
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