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United States Department of Agriculture

Agricultural Research Service

Research Project: CONTROL MECHANISMS FOR MYCOTOXIN PREVENTION IN PEANUTS AND THEIR ROTATION CROPS

Location: Peanut Research

Title: Determination of the Nature of Spotting in Blanched Peanuts

Authors
item Sobolev, Victor
item Dorner, Joe
item Butts, Christopher
item Sanders, Timothy
item Whitaker, Thomas

Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 2007
Publication Date: January 9, 2008
Citation: Sobolev, V., Dorner, J.W., Butts, C.L., Sanders, T.H., Whitaker, T.B. 2008. Determination of the Nature of Spotting in Blanched Peanuts . American Peanut Research and Education Society Abstracts.

Interpretive Summary: none required.

Technical Abstract: The peanut spotting is a big problem responsible for significant loss by the peanut industry. The cause of the spotting has been identified in the lab as being due to infection by fungi. Secondary fungal metabolites and peanut stilbene phytoalexins were not involved in the spot formation. The nature of spotting has not been fully characterized, but suggested as being due to a non-enzymatic browning. Significant changes in sugars and proteins upon peanut blanching contribute to the spotting. Compounds that produced orange, green, and blue fluorescence have been isolated from spotted peanuts and analyzed by HPLC-MSn. Those are colorless low-molecular weight compounds that could be considered early indicators of browning. Isolated colored compounds had very complex composition and were similar to compounds yielded from the Maillard reaction. Preliminary data indicated that the brown color of the spots is formed in part by high-molecular weight melanoidin polymers generated by condensation of heterocyclic subunits. Structural elucidation of the pigmented components is crucial for the determination of the nature of spotting. The peanut industry will benefit from knowledge of the exact chemical cause of spotting because further specific actions may be taken to prevent the problem.

Last Modified: 4/17/2014
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