Study of Physicochemicals Characteristics and Antioxidant Capacity of Cork Oak Acorns (Quercus suber L.) grown in Three Regions in Tunisia

This study focuses on the valorization of the Tunisian cork oak acorns in minerals, bioactive compounds and antioxidants. It involved the study of physico-chemical characteristics of acorns from Quercus Suber L, of three Tunisian northern regions: Sejnen, Nefza and Ain Drahem. The kernels and hulls of acorns were analyzed for their antioxidant capacity using DPPH free radical scavenging activity. The total phenolics, flavonoid and carotenoid contents were measured using standard methods. The multi-elemental analysis was performed by atomic emission spectrometry with inductively coupled plasma (ICP). Acorns exhibit a degree of organic matter and moisture varies according to the region and part of the studied plant. The ICP analysis shows the abundance of cork oak acorns in calcium, magnesium and especially in potassium (6.942 g.kg-1). Kernels have higher polyphenol contents (66 - 77 mg GAE.g-1). The radical scavenging activity of methanol extracts of cork oak acorns shows that the Sejnan kernels have significant antiradical activity with an IC50 in the order of 6.94 µg.mL-1. Analysis of sugars in the fruits by HPLC revealed the presence of fructose, galactose, sucrose and maltose. This plant can be used as an inexpensive source of natural antioxidants and mineral supplements of food.