Comparison of amygdalin and benzaldehyde levels in California almond (Prunus dulcis) varietals
Almonds (Prunus dulcis), are characterized into three flavor phenotypes: bitter, semi-bitter and sweet. Amygdalin is a cyanogenic diglucoside responsible for bitterness in almonds. Studies have shown that amygdalin can hydrolyze to release benzaldehyde, which is the key component of almond aroma. In this study, the amygdalin and benzaldehyde content of fourteen sweet cultivars of almonds from four growing regions in California were determined. Solid-phase extraction and ultra high-pressure liquid chromatography coupled with electrospray triple-quadrupole mass spectrometry (UHPLC-(ESI)MS/MS) were used to determine the amygdalin content in the raw almond kernels. Headspace solid phase microextraction (HS-SPME) coupled with a gas chromatography mass spectrometry (GC/MS) was used to determine the benzaldehyde concentration in raw almond kernels. Saturated salt water was added to the sample to improve the extraction of benzaldehyde in the headspace. Results indicated that the mean concentration of both amygdalin and benzaldehyde are significantly different (p<0.0001) among the fourteen cultivar. Furthermore, a positive correlation was found between the amygdalin and benzaldehyde concentrations among the 14 cultivars. Although 'Nonpareil' cultivars is considered the premier snacking almond, 'Aldrich' has significantly higher concentrations of benzaldehyde in the headspace, the key contributor of the almond aroma.
Luo, K.K., Kim, D.A., Mitchell-Silbaugh, K.C., Huang, G. and Mitchell, A.E. (2018). Comparison of amygdalin and benzaldehyde levels in California almond (Prunus dulcis) varietals. Acta Hortic. 1219, 1-8
sweet almond, non-bitter almond, gas chromatography, liquid chromatography, flavor