Effect of harvest date of Argania spinosa fruits on Argan oil quality

• Argan fruits were collected during 4 months, with progressing ripening degrees.
• No change noted on kernel oil acidity, peroxide value, fatty acid composition.
• Harvest date acts on extinction coef., tocopherols, phospholipids, induction period.
• Ripe fruit oil (July) shows the highest oxidative stability for industrial use.

Virgin Argan oil is a prized specialty oil produced by cold-pressing kernels of Argania spinosa fruits, and increasingly used in cosmetics. This work was aimed at studying the influence of fruit maturity – through harvest date – on the chemical composition of oil, in order to determine the optimal harvesting period. For this purpose, Argan fruit samples were collected at different ripening degrees. Oil quality was assessed by determining key analytical parameters: acidity, peroxide value, extinction coefficients (K270 and K232), fatty acid composition, phospholipid and tocopherol contents. In addition, the oxidative stability was measured by the Rancimat method. Argan oil obtained over the investigated period presented a rather stable chemical composition and met the standard. But owing to the higher content of tocopherols and phospholipids found in the oil from fruits collected in July (mid-summer, end of ripening period), this last sample presented the best oxidative stability. This brings an improved preservation upon storage, which is a suitable characteristic for industrial use. Therefore the stage of ripening (harvest date) is to be considered, and there is a preferred time for fruit collection in view to preparing high quality Argan oil.