HPLC–DAD profiling of a phenolic extract from Moroccan sweet Basil and its application as oxidative stabilizer of sunflower oil

Abstract

Lipid oxidation is the major chemical phenomenon leading to the deterioration of edible oils by the diminution of their organoleptic and nutritional qualities. This study was aimed at profiling a phenolic extract from sweet Basil cultivated in Morocco and to investigate its possible protective effect against the oxidative process in sunflower edible oil as a natural alternative to synthetic antioxidants. The extract provides significant prevention of sunflower oil peroxidation after storage at 37 °C for 60 days. However, the effect was relatively less than that exerted by the BHA. Against, the phenolic extract significantly decreased the peroxidation value of oil after heating at 370 °C/5 h; the effect was comparable to that of BHA. Besides, the extract protects sunflower oil against oxidation induced by copper ion, but this activity remains statistically lower than that exerted by the BHA. Moreover, the DPPH radical scavenging activity of the phenolic extract is less than that recorded by the BHA. This extract inhibits also the oxidative bleaching of β-carotene relatively less than BHA. The extract contains 153.19 ± 1.05 mg/g total phenol. The HPLC analysis showed that the extract contains eight phenolic acids (caftaric acid, gallic acid, chlorogenic acid, caffeic acid, chicoric acid, rosmarinic acid, carnosic acid and p-hydroxybenzoic acid) and two flavonoids (rutin and luteolin-7 glucoside). In conclusion, we suggest that the phenolic Basil extract is a good source of natural antioxidants that might be exploited in edible oil preservation.