Characterising the flavour phenotypes of almond (Prunus dulcis Mill.) kernels

Abstract

To determine the chemical basis of almond flavour phenotypes, non-bitter, semi-bitter, and bitter kernels from 101 almond trees, all derived from a common maternal parent, were evaluated for flavour using three approaches: (1) sensory analysis (i.e., by taste); (2) amygdalin quantitation (using High Performance Liquid Chromatography); and (3) non-targeted analysis of volatile metabolites released on maceration (by Solid Phase Micro-Extraction, Gas Chromatography-Mass Spectrometry, and Chemical Sensor). Tasting identified three categories of flavour (non-bitter, semi-bitter, and bitter) that were also distinguishable on the basis of chemical analyses, and by a chemical sensor using principal component analysis. Highly significant correlations were found between amygdalin content and the taste panel's score for 'marzipan', and also between the taste panel's scores for sweet and overall taste preference. Non-targeted metabolite analysis identified benzyl alcohol and 2,3-butanediol as potentially important flavour components of almond, for the first time.