The effect of microwave and roasted processing on the fatty acid composition of oils extracted from stone pine (Pinus pinea) nuts

Abstract

Crude oil, crude ash, crude protein and crude fibre contents of pine (Pinus pinea) nuts were determined as 50.8% and 48.7%; 3.1% and 2.7%; 24.8% and 23.3%; and 7.6% and 8.8%, respectively. In addition, peroxide values, acidity, density and refractive index values of both samples were established as 1.21 meqO2/kg and 1.87 meqO2/kg; 1.47% and 1.33% (oleic acid); 0.924 g/cm(3) and 0.921 g/cm(3); and 1.471 and 1.463, respectively.

Mineral contents of pine nuts were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Among the minor elements determined, Ni, Cd and Pb were found in lower concentrations. Macronutrient mineral contents of pine nuts were determined as Ca, K, Mg and P. The potassium contents of the nuts were found to be 7987.6 mg/kg and 8067.7 mg/kg for Balikesir and Kahramanmaras pine nuts, respectively, and were followed by P, Mg and Ca elements. Pinus nut oils are rich in unsaturated fatty acids.

The oleic acid contents of microwave roasted pine nuts samples ranged from 50.53% to 52.78% for Kahramanmaras and Balikesir provinces, respectively, corresponding to linoleic contents ranging from 38.48% to 38.50%.

However, pine nuts roasted by conventional heating contained 52.05% and 53.29% oleic acid and 38.83% and 37.59% linoleic acids. Oleic acid content of Balikesir pine nuts roasted by microwave heating was found to be lower compared with conventional heating.