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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Blanching on Peanut Shelf Life

Authors
item Sanders, Timothy
item Adelsberg, Gordon - NCSU
item Hendrix, Keith
item Mcmichael, Jr, Robert - NCSU

Submitted to: American Peanut Research and Education Society Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 11, 1997
Publication Date: N/A

Technical Abstract: Blanched peanuts are required in many manufacturing operations and the blanching process, in conjunction with color sorting, is effective in removing damaged/discolored seed often associated with aflatoxin contamination. Although blanching is often a necessary processing step, the general peanut industry consensus is that significant shelf life reduction occurs as a result of the process. To evaluate the effect of blanching on peanut shelf life, virginia-type peanuts were exposed to nine heating protocols consisting of three heating times (30, 45, and 60 min) factorially paired with three final temperatures (76.6, 87.8, and 98.9 C achieved from 32.2 C over six heating zones). Lipoxygenase activity in peanuts decreased with increasing time and temperature of heating. Blanched peanuts from each protocol and unblanched controls were stored at 30 C and ambient relative humidity over a 28-wk period. Blanched peanuts from all protocols had similar or better storage stability than unblanched peanuts as determined by oil stability index (OSI) and peroxide value (PV). OSI was ca. 10 hr for blanched and unblanched peanuts and did not change significantly over the storage period. PV's for blanched peanuts from the nine protocols varied from 0.2-0.8 and were significantly different from the PV of 1.3 for unblanched peanuts. Descriptive sensory analysis of roasted peanuts which had been stored as blanched from each protocol or unblanched indicated no significant differences in intensity of roasted peanutty and painty descriptors.

Last Modified: 10/21/2014
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