Determination of Some Antinutritional Factors and Heavy Metals in Sesame Oil, Raw and Peeled Sesame (sesamum indicum L.) Seed of two Varieties Cultivated in Iran

Sesame is one of the most consumed oilseeds that despite being rich in mineral salts, contains some anti-nutritional compounds that are limiting nutrients to the body. Therefore, the aim of this study was to investigate some of the antinutritional compounds (oxalate and phytate) and heavy metals (lead and cadmium) in sesame oil, raw and peeled sesame seed (Sesamum indicum L.) of two varieties; Dashtestan 2 and Darab 14; Cultivated in Iran.

Sesame seed samples were collected from Seed and Plant Certification and Registration Institute in Karaj, iran. Oxalate and phytate were determined using High Performance Liquid Chromatography (HPLC) methods and Pb, Cd, Ca, Mg, Fe, Zn and Mn were determined using atomic absorption spectrophotometry (AAS).

The lead content of all samples is higher than the maximum permissible level and their cadmium content is below the maximum permissible standard in Iran. The Darab variety contains more phytic acid and the Dashtestan variety has higher oxalic acid content. Most of the minerals in the samples are calcium. The oil extracted from the raw sesame seeds lacks phytic acid and contains about 2.5 mg/Kg oxalic acid.

The raw sesame seeds have some anti-nutritional compounds that significantly reduces by peeling, while the amount of these compounds in sesame oil is much lower than the standard Iranian and Codex. Therefore, it is better to evaluate its quality before using raw sesame seeds.