Genetic relationships among 18 Turkish hazelnut ( Corylus avellana L.) cultivars were investigated using randomly amplified polymorphic DNA (RAPD), intersimple sequence repeat (ISSR), and amplified fragment length polymorphism (AFLP) markers. Twenty-five RAPD primers, 25 ISSR primers, and eight AFLP primer pairs generated a total of 434 polymorphic marker loci. The three marker systems were able to differentiate the cultivars. Genetic similarity index values ranged from a high of 0.96 for ‘Kan’ and ‘UzunMusa’ to a low of 0.73 for ‘Yassi Badem’ and ‘Kalinkara’. The genetic relationships were presented as an unweighted pair group method with arithmetic average (UPGMA) dendrogram and a three-dimensional principal coordinate analysis (PCoA) plot. The UPGMA dendrogram showed two main clusters, while PCoA analysis showed three groups. Cultivar-specific markers were produced by all marker systems for 10 cultivars. This study demonstrates the usefulness of molecular markers for identification of hazelnut cultivars.

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.

This research was conducted to determine the chemical traits of Ordu Levant hazelnuts that were dried with sun–drying [on concrete ground (CG), grass ground (GG)], or in drying machine (DM) during 24 months of storage (2014-2016) at 20-25 °C and 70-90% relative humidity. Drying process continued 39 h for CG and GG, and 23 h for DM. Sun–drying were performed in similar sunshine and environmental conditions. Nut quality traits in protein, lipid, moisture contents, water activity, free fatty acids (FFA), peroxide value (PV), rancimat value (RV), and amount of aflatoxin were investigated during storage. The lowest FFA (0.35%, oleic acid) was recorded for GG, and the lowest PV (0.35 meqO₂ kg^–1 ) was recorded for CG. In addition, DM method contained much more RV (3.87 h) than those dried by CG and GG. After 24 months of storage, kernel FFA (0.38%, oleic acid) and RV (3.59 h) were lower than the acceptable limit values after storage (0.40% and 3 h, respectively). In conclusion, in–shell hazelnuts can be stored at an ambient temperature for 24 months without there being any significant changes in chemical traits. Overall, DM appears to be a promising strategy for hazelnut drying.

This study was conducted to determine the effects of different drying methods of sun-dried (grass and concrete ground) machine drying on chemical properties of Levant quality hazelnut in coastal region (Ordu, Turkey) during storage. In conventional drying, only solar energy was used and the drying time was about 50-58 h (concrete ground and grass ground, respectively), and in the drying machine it lasted about 30 h. After the drying and storage time, while the highest rancimat value (5.73 h) and the lowest peroxide value (0.27 meqO2kg-1) were found in the drying machine and the concrete ground gave the lowest free fatty acid (0.04 %). At the end of the storage period, the lowest free fatty acid and peroxide value were determined on concrete ground (0.29 %) and on drying machine (0.00 meqO2kg-1), respectively. In addition, total aflatoksin and aflatoxin B1 were not detected in any drying methods during storage. As a result, the drying machine was more effective than the other two drying methods for nut quality and preservation. In addition, it has been observed that hazelnuts can be stored for 24 months without significant change in nut quality in room conditions.