Effect of hazelnut roasting on the oil properties and stability under thermal and photooxidation

Abstract

The roasting process plays a key role in hazelnut oil production. The optimal roasting conditions for Delisava and Kara Fındık hazelnut cultivars were studied using response surface methodology (RSM). The maximum oil content and minimum values of peroxide value (PV), conjugated diene (K232), conjugated triene (K270) values of Delisava and Kara Fındık hazelnut cultivars were used to estimate the production of high-quality oils. The optimal roasting temperature and time for Delisava and Kara Fındık hazelnuts were 114.24 °C for 27.21 min and 123.43 °C for 22.12 min, respectively. Optimal oils were subjected to accelerated oxidation tests (Schaal oven test at 60 °C) and photooxidation at daylight. Under thermal conditions, Kara Fındık oil possesses higher oxidative stability than Delisava oil according to PV, K232 and K270 values. Under photooxidation conditions, an opposite trend was noted when Kara Fındık oil exhibited lower oxidative stability in comparison with Delisava oil.