Impact of ionizing radiation on cake from Brazilian macadamia nut (Macadamia integrifolia) after oil extraction

Abstract

Macadamia oil extraction is commonly performed by cold pressing. This process presents low extraction yields, generating partially defatted meal as a byproduct. To take advantage of their important nutritious components, we propose to use the cake after lipid extraction as a food ingredient following the elimination of potentially hazardous microbiological contamination. Food irradiation is a mature, effective, broad spectrum and residuefree technology that can play an important role in food safety and food security. This study presents the impact of gamma irradiation on the residual cake from Brazilian macadamia pressing. An absorbed dose of 5 kGy reduced yeasts, molds and aerobic mesophilic bacteria below admissible maxima. The concentration of important elements like Ca, Se, Mg or Mn appeared higher in the cake than in the nut itself as measured by instrumental neutron activation analysis (INAA).