Investigating the Effect of Glucoamylase Enzyme Treatment and Continuous Ultrasound Application on Quality Characteristics and Aflatoxins Degradation of Hazelnut Paste by Box-Behnken Response Surface Design

Aflatoxins (AFs) are toxic secondary metabolites of filamentous fungi which can reduce the quality of several food commodities like hazelnut and hazelnut products. For the AFs, the data were fitted to polynomial response models using multiple regression analysis, resulting in high coefficients of determination (R² values ranging from 0.8917 to 0.9674) for each type of aflatoxins. The optimal conditions for achieving maximum degradation percentages for total aflatoxins (AFT) and AFB1 were determined to be US power of 80W, enzyme treatment of 2.5 U g sample, and 20 min of US application for 12.5 µg kg AFT conditions after graphical and numerical optimizations. The optimum conditions resulted in 44.33% and 45.58% degradation for AFT% and AFB1 respectively, with predicted values of 43.93% and 44.17% for AFT% and AFB1. The data exhibited that, enzyme treatments were not significant for degradation for AFB1% and AFT%, whereas significant for AFB2 and AFG2. Depending on the initial AFT concentration, more than 50% degradation rate was achieved by current design parameters. Study results indicated that US treatment can alter certain quality parameters of hazelnut paste, including changes in aroma, a decrease in browning index, and a slight increase in peroxide value.