Aromatic potential, quality and antioxidant activity of saffron grown in Morocco

Abstract

Saffron is a spice derived from the flower of Crocus sativus L., which has a special aroma, colour and odour influencing positively its economic value. In this context, ten saffron ecotypes were screened for their biochemical composition and antioxidant activity. The samples were also analysed using GC-MS and LC-MS to determine their content of volatile and phenolic compounds, respectively. The results revealed statistically significant differences among samples based on moisture (9.09%-11.23%), total phenols (31.62-62.71 mg EAG/g), total flavonoids (23.02-40.02 mg ER/mg), total carotenoids (66.12-155.05 μg/g), picrocrocin (88.99-121.53), crocin (137.44-228.39) and safranal (26.56-53.04). The radical scavenging activity ranged from 17.09% to 29.53% for DPPH assay, and oscillated from 0.128 mmol AAE/g to 0.239 mmol AAE/g for ABTS test, while the ferric reducing antioxidant potency (FRAP) varied from 0.974 to 1.989 mmol Fe²⁺/g. Gas chromatography-mass spectrometry (GC-MS) analysis identified 66 volatile compounds, among which the Safranal and Isophorone were the most abondant. The ES1 from Taliouine recorded a very distinct volatile composition compared to the others ecotypes with 22 authentic volatile compounds. Moreover, liquid chromatography- mass spectrometry (LC-MS) analysis revealed 14 phenolic compounds with picrocrocin and crocin were found to be the major compounds. The principal component analysis classified the investigated ecotypes into two mean distinctive sets with ES1 and ES9 were distinguished as a single items. The α-pinene, β-pinene, limonene, anethole, acetic acid, ketoisophorone, isophorone, safranal, thymoquinone, total flavonoids, FRAP and total carotenoids, are the main discriminant variables. The two-dimensional analysis of the clustered heatmaps divided showed a relatively similar patterns as the principal component analysis (PCA) and confirmed the singularity of the sample ES1 based on its particular volatile profile dominated mainly by α-terpinyl acetate, methyleugenol, copaene, anethole, limonene, methyl-cyclopentane, which were not identified in the other samples even at minor levels. These findings herein found revealed the high quality of Moroccan saffron, which is very important for the species breeding and valorization.