Inactivation of Peroxidase from Fuji Apples by Heat and Chemical Treatments

가열 및 화합물에 의한 후지 사과 Peroxidase의 활성억제

As a basic research for inhibition of enzymatic browning of apples during dehydration or processing, peroxidase was extracted from Fuji apples to investigate heat inactivation, and chemical inhibition. Peroxidase showed the highest activity at $35^{\circ}C$ and pH 5.5 using substrates of p-phenylenediamine and $H_2O_2$. The thermal inactivation followed biphasic kinetics to have activation energy (Ea) of 48.2kcal/mol and z value of $11.2^{\circ}C$ for the heat labile fraction and Ea of 36.3kcal/mol and z value of $14.9^{\circ}C$ for the heat resistant fraction. Browning by peroxidase was completely inhibited at the concentrations of 10mM for sodium diethyldithiocarbamate and potassium metabisulfite and 1mM for L-cysteine and ascorbic acid.

사과의 건조, 가공 중의 갈변을 방지하기 위한 기초 조사로서 후지 사과로부터 추출한 crude peroxidase의 열불활성화와 갈변 저해제의 저해 효과 등을 조사하였다. Peroxidase의 최적 pH와 온도는 p-phenylenediamine과 $H_2O_2$를 기질로 하였을 때 각각 5.5와 $35^{\circ}C$이었고, 열불활성화 반응은 biphasic으로 heat labile fraction의 $E_a$와 Z값은 각각 48.2kcal/mol 과 $11.2^{\circ}C$, heat resistant fraction의 $E_a$와 Z값은 각각 36.3kcal/mol과 $14.9^{\circ}C$이었다. Peroxidase에 의한 갈변은 sodium diethyldithiocarbamate와 potassium metabisulfite는 10mM에서, L-cysteine과 ascorbic acid는 1mM에서 현저하게 저해되었다.