Reduction of amygdalin in apricot kernels by immersion in ethanol solution

Abstract

Apricot seeds are removed during food processing and discarded as waste. The apricot kernel within an apricot seed contains the cyanogenic glycoside, amygdalin. Since amygdalin generates harmful hydrogen cyanide upon hydrolysis by emulsin, an enzyme found in apricot kernels or β-glucosidase in the human body, it is necessary to remove amygdalin in order to make apricot kernels edible. Thus, we immersed the apricot kernel in ethanol solutions of various concentrations, and examined which concentration reduced amygdalin the most efficiently. As a result, amygdalin was most efficiently reduced in ethanol solution concentrations ranging from 10% to 30%. Moreover, in order to clarify the reduction mechanism of amygdalin in apricot kernels by ethanol solution immersion treatment, we assessed the rate of elution from apricot kernels and the rate of amygdalin hydrolysis in ethanol solutions. As a result, the maximum rates of hydrolysis and elution were observed in the 20% and 50% solutions, respectively. From these results, enzyme degradation and elution of amygdalin from apricot kernels were considered to be important factors in the reduction of amygdalin. Moreover, we established a method for reducing the hydrogen cyanide generated by hydrolysis of amygdalin.