Comparison of Enzymatic and Biochemical Characteristics in Early Split and Intact Hulls of Pistachio

Penetration of spores of Aspergillus fungi to pistachio kernel was facilitated by Occurrence of Early splitting in pistachio which it provides suitable condition for fungal growth and considerable amount of aflatoxin in pistachio mass will be produced. It is hull that is exposed to any biotic and abiotic stresses; therefore, the growth of hull cells and its flexibility has an important role in the resistance of hull against these stresses. In order to investigation of enzymatic and biochemical characteristics related to the flexibility of hull, intact and early split samples were transported to the laboratory at harvest time. Phenylalanine ammonia-lyase and peroxidase activity, lignin, phenolic compound, total protein content and soluble and bound calcium and magnesium were measured. On the base of results, increased Phenylalanine ammonia-lyase and peroxidase activity and wall--bound phenols were observed in early split hull compared with those of the intact hull. Also soluble calcium and magnesium decreased in early split hull compare to intact hull. As a result, decreasing in peroxidase activity and wall bound phenolic compound and bound calcium was caused increasing in elasticity of intact cell wall hull that it increased hull elasticity against shell pressure.