Induction of superoxide anion radical-scavenging capacity in an argan press cake-suspension by fermentation using Lactobacillus plantarum Argan-L1

The argan tree, Argania spinosa, is only endemic to south-western Morocco. Oils from the argan tree are not only edible, but also used for hair-conditioning, dermocosmetic, and pharmaceutical purposes. The mechanical press method yields approximately 43% argan oil, and a residue, which is called the argan press cake (APC). To elucidate the usefulness of the APC, the effects of fermentation using the bacteria Lactobacillus plantarum Argan-L1, which is isolated from argan fruits, on the in vitro antioxidant properties of a 5% w/v APC-suspension (APC-S), were determined. The main sugar in the APC-S was sucrose, which was converted to lactic acid in the fermented APC-S (F-APC-S). Although the fermentation slightly reduced the phenolic compound content and Fe-reducing power, there was a notable rise in the superoxide anion (O2−) radical scavenging capacity in the F-APC-S. From the results obtained for the ultrafiltered fractions, it can be said that the increase in the O2− radical-scavenging capacity might be due to the presence of <3 kDa compounds, including lactic acid and protein-related compounds. These results suggest that the F-APC-S, which had retained polyphenols and saponins, generated lactic acid and peptides, and thus, Argan-L1 can be used to prepare functional food and cosmetic materials.