Impact of the gamma and electron beam irradiations on yeast-spot disease fungal agent and physicochemical attributes of hazelnut (Corylus avellana L.)

Abstract

In this study, the effects of gamma irradiation (GMI) and electron beam irradiation (EBI) on the yeast spot fungus Eremothecium coryli isolated from hazelnuts and the physicochemical features of irradiated hazelnut samples were evaluated. Results demonstrated that GMI doses ≥2 and EBI doses ≥4 effectively removed E. coryli from artificially contaminated hazelnuts and reduced the contamination by 5 log CFU/g. GMI and EBI at higher doses resulted in an increment in malondialdehyde content (MDA) and a change in the profile of fatty acids. Both treatments caused an enhancement in total phenolic content (TPC) and antioxidant activity in the DPPH assay but declined antioxidant activity in the ABTS assay at a dose of 6 kGy. L*, a*, and b* color indices were changed, and the surface color of the hazelnuts became darker. Total protein solubility (TSP) and protein profile of the samples were affected by GMI and EBI. Higher doses of GMI and EBI reduced the hardness of the hazelnuts and led to a more fragile texture. The overall acceptability of the samples was adversely affected by GMI, but it was not affected by EBI treatment. Hence, GMI (≥2 kGy) and EBI (≥4 kGy) have the potential to be applied as a fungal disinfection method; lower doses (≥2 kGy) of both treatments can sustain desirable physicochemical attributes and sensory characteristics of hazelnuts.