Concealed damage (CD) results in a brown to black discoloration that occurs in almond kernels only after roasting. CD can result in a very bitter off-flavor, lower consumer acceptance, and possibly lower nutritional value due to degradation of amino acids and lipids. Moreover, there is concern that almonds with CD are more susceptible to lipid oxidation and rancidity. CD is initiated when in-hull nut kernels are exposed to a warm and moist environment (e.g. rain, stockpiling). To date, CD cannot be detected by screening methods and the mechanism by which this color forms is unknown. Herein, UHPLC-(ESI)QTOF MS/MS was used to profile the chemical composition of CD and non-concealed damage (NCD) almonds to evaluate the effect of moisture, and storage time on the composition of non-volatiles in almonds. Non-targeted (e.g. amino acid metabolism library) and data mining (unknown analysis) approaches were employed. Thirteen amino acid-related metabolites were tentatively identified with CD development in almonds.  Principle component analysis on non-targeted and data mining analysis demonstrated clear separation in CD/NCD almonds. These approaches can be used to evaluate the general chemical composition of CD and NCD almonds to provide distinguishing chemical markers associated with the development of CD.

UHPLC-QTOF MS approaches for chemical verification of concealed damage in raw almonds

248th National Meeting (2014)

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