사과주(酒)의 효소(酵素)에 의(依)한 갈변(褐變)을 조사하기 위하여 갈변(褐變)과 관련된 polyphenol성(性) 물질 및 polyphenol oxidase 활성 band의 변화를 사과주(酒) 제조기간동안 조사한 결과는 다음과 같다. Total phenol 의 감소율은 $SO_2$ 처리에 의해서 현저히 둔화되었고, catechol의 산화(酸化)는 온도(溫度)와 pH가 높아짐에 따라 촉진되었으나, pH 5.0 이하에서는 $4^{circ}C$에서 산화(酸化)가 일어나지 않았다. Polyacrylamide gel 전기영동으로 사과에는 Rm값이 각각 0.21, 0.30, 0.41, 0.51인 a, b, c, d 4 개의 polyphenol oxidase활성을 가진 band가 관찰되었다. 이들중 a, c 2 개의 band는 발효(醱酵) 5 일째까지 계속 관찰되었으며, 발효(醱酵) 6 일째부터는 c band만 관찰되었다. 이 band는 $60^{circ}C$, 30분간(分間)의 살균(殺菌) 처리 후에도 계속 남아있었다.
To examine enzymatic browning of apple wine, changes of active bands of polyphenol oxidase (EC 1.10.3.1) as well as polyphenol substances related to browning of apple wine were investigated during wine brewing. The decrease of total phenol was remarkably inhibited by the addition of sodium metabisulfite. In the meantime, auto-oxidation of catechol in a model system increased proportionally as the reaction pH and temperature increased. Catechol oxidation, however, was not detected at $4^{circ}C$ below pH 5.0. Polyacrylamidegel electrophoretic patterns showed that the apple (Jonathan) indicated 4 bands with polyphenol oxidase activity, designated a, b, c and d whose Rm were 0.21, 0.30, 0.41 and 0.51, respectively. Among these, 2 bands, a and c remained until 5th day fermentation and only c band after 6th day fermentation. After pasteurization of apple wine at $60^{circ}C$ for 30min, c band also remained.
