Effect of drying methods on long term storage of hazelnut

Abstract 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.