Variability of oil content and its physicochemical traits from the main almond [Prunus dulcis Mill. DA Webb] cultivars grown under contrasting environments in north-eastern Morocco

Abstract To produce nut virgin oils at a large scale, mechanical extractions have become widely accepted to obtain nut oils of higher quality without chemical residues. Little is known about kernel oil from the commercially grown almond cultivars in Morocco obtained by press extraction. This work was set up to evaluate effects of different environments on almond oil content (OC) and related quality traits, namely polyphenols (PP), saturated (SFA), monounsaturated (MUFA), polyunsaturated fatty acids (PUFA), and oleic/linoleic (O/L) ratio. To this end, the main cultivars were compared across various sites belonging to northern (typical Mediterranean climate) and the eastern Morocco (hot Mediterranean climate) over three growing seasons (2016–2018). Virgin oil achieved via mechanical press showed high quality as demonstrated by lower records of routinely measured parameters (acid value, peroxide value, and UV absorption coefficients K232 and K270) on one hand and higher records of PP and O/L on the other hand. Cultivars of longer fruit development period (FDP) such as ‘Marcona’ displayed higher OC, while ‘Tuono’ and ‘Fournat de Brezenaud’ (shorter FDP) presented the best record of PP. 2016 (the driest season) had the best scores of OC and PP. Eastern Morocco (relatively hot and dry) showed higher OC, PP, PUFA, but lower MUFA and, therefore, lower O/L. In conclusion, drier environments could enhance OC and foster the accumulation of more PP, PUFA but lower MUFA with a decreased oil stability.