Abstract

Concealed Damage (CD), as defined by the almond industry, is a brown discoloration of the kernel interior which is only detectable after the nuts are roasted. High moisture in raw almonds is the key factor in the development of CD. Hence, drying temperatures in the range 45°C – 95°C were used to determine if drying could be used to decrease the incidence of CD and the effect of drying in the quality of raw almond with CD. Dried samples were analyzed for volatiles (HS-SPME-GC/MS), reducing sugars, and Amadori compounds. Drying temperatures below 65°C decreases the visual sign of CD up to 40% while drying temperatures above 75°C increases the visual sign of CD up to 100%. No significant differences were found for reducing sugar and Amadori compounds. After drying and under accelerated storage conditions, volatile compounds were related with lipid oxidation (alcohols, aldehydes and ketones). Drying above 85°C volatile corresponding to Maillard reaction were found (pyrrole, phenylacetaldehyde). Our results demonstrate that raw almonds that have been exposed to moisture damage and then dried reduce the visual sign of CD. However, almond contains significant levels of volatile compounds related with lipid oxidation that may present quality defects and may influence shelf-life and flavor.