The effect of some pre-roasting treatments on quality characteristics of pumpkin seed oil

Abstract

In this study, the pumpkin seed oils used were obtained from roasted and unroasted seeds of the two varieties called “Nevşehir Çerçevelisi” and “Ürgüp Sivrisi”, belonging to the species Cucurbita pepo. Oil extraction, from seeds subjected to three different pretreatments (unsalted, dry salted and wet salted) before roasting and sun-dried unroasted seeds, was carried out by means of a screw press. Pumpkin seed oils were analyzed for quality and antioxidant characteristics. The p-anisidine, peroxide and TBARS (thiobarbutiric acid reactive substances) values of oils obtained from sun-dried unroasted seeds and roasted seeds after wet salting process were lower than the other sample groups (p < 0.05). The obtained oils were rich in Zn, Fe, Mg, Se, Ca, K and Na minerals, and palmitic, stearic, oleic and linoleic fatty acids. In the oils, β + γ tocopherols content ranged from 131.78 to 881.77 mg/kg oil, δ-tocopherol content ranged from 3.22 to 8.67 mg/kg oil. Total phenolic matter content ranged from 1.35 to 3.62 mg gallic acid equivalent (EAG)/g. ABTS+ radical scavenging activity of the oils obtained from sun-dried-unroasted seeds and roasted seeds after wet salting process was determined higher than the other oil samples (p < 0.05).

Keywords

• pumpkin seed oil
• tocopherol
• total phenolic content
• antioxidant activity
• fatty acid