Effect of drying on the chemical composition of Çakıldak (cv) hazelnuts during storage

Abstract

The hazelnut (Corylus avellana L.) is one of the most popular tree nuts in the world. The proper selection of drying methods is necessary to prevent oil oxidation which will influence the overall nut quality during storage. The aim of this study was to determine the effects of sun drying (SD) and artificial dryingied (AD) on the chemical traits of hazelnuts during long–term storage. Protein, lipid and moisture contents, water activity, fatty acid composition, sum of fatty acids, and oil oxidation properties were determined over 24 months’ storage (2015–2017) at 20–25 °C and 70–90% relative humidity. The results showed that monounsaturated fatty acids (MUFA) was the main fatty acid group (81.55–83.38%) followed by polyunsaturated (PUFA; 10.39–11.57%) and saturated fatty acids (SFA; 5.75–6.60%). The samples dried by AD had more SFA (5.86%) and MUFA (83.11%) than the SD samples. At the end of storage, the lowest free fatty acid, and peroxide value (0.52%–1.45 meqO2·kg-1, respectively), and the highest oleic/linoleic acidity ratio (7.76) were found from AD. Therefore, AD appears to be more promising for hazelnut drying.