Effect of blanching on storage stability of hazelnut meal

Influence of blanching on storage stability of hazelnut meal was investigated under accelerated storage conditions. Meals were obtained from unblanched and blanched hazelnut kernels, and stored at a relative humidity of 60% at 30C for 50 days. Total free fatty acid content, concentrations of individual free fatty acids, peroxide value and oil stability index were measured in the hazelnut meal samples during storage. No significant difference was found between peroxide values of the samples, however, the values of both samples increased during storage time. The concentrations of free fatty acids increased because of the activity of lipase in both meals, but the levels were lower in the blanched sample. Oil stability index of the unblanched sample was lower than that of the blanched sample. Blanching treatment was found to improve the oxidative stability of hazelnut meal, possibly because of partial inactivation of deteriorative enzymes. PRACTICAL APPLICATIONS Hazelnut meal is a product obtained from hazelnut which is used as an ingredient in various food products. Hazelnut meal is more prone to degradation and quality loss during storage via oxidation compared with the whole counterpart. Stability of whole hazelnut has been studied to a great extent in the literature, but there is a scarcity of information regarding stability of processed hazelnut. In addition, there is no information in the literature about the amount of individual free fatty acids in hazelnut where the amounts of total free fatty acids have been reported extensively. This study provides data for quality and stability of hazelnut meal during storage which could be used by the food industry.