Journal of the Korean Society of Food Science and Nutrition (한국식품영양과학회지)

The Korean Society of Food Science and Nutrition (한국식품영양과학회)
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Some Properties of Polyphenol Oxidase from Apple (Jonathan) and Thermal Stability of the Active Bands

홍옥(紅玉) Polyphenol Oxidase의 일반적(一般的) 성질(性質) 및 활성(活性) Band의 열안정성(熱安定性)

  • Chung, Ki-Taek (Department of Food Science and Technology, College of Agriculture, Kyungpook National University) ;
  • Seo, Seung-Kyo (Department of Food Science and Technology, College of Agriculture, Kyungpook National University) ;
  • Song, Hyung-Ik (Department of Food Science and Technology, College of Agriculture, Kyungpook National University)
  • 정기택 (경북대학교 농과대학 식품가공학과) ;
  • 서승교 (경북대학교 농과대학 식품가공학과) ;
  • 송형익 (경북대학교 농과대학 식품가공학과)
  • Published : 1984.11.30
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Abstract

As a basic research for inhibition of enzymatic browning of apple wine, polyphenol oxidase (EC 1.10.3.1) from apple (Jonathan) was extracted, partially purified, and some properties of the enzyme and changes o( active bands by heat treatment were investigated. Optimum conditions for the enzyme reaction were pH6.5 and temperature of $30^{\circ}C$, and o-diphenol was the main substrate for the enzyme. Approximately 35% and 15% of initia lpolyphenol oxidase activity remained after heating at $60^{\circ}C$ and $70^{\circ}C$ for 1 hour, respectively. About 0.5mM of the inhibitor such as sodium metabisulfite, cysteine and ascorbic acid was required for effective inhibition of the enzyme reaction. However, EDTA was found to be a very poor inhibitor. Ethanol did not affect the enzyme activity. The number of active bands of polyphenol oxidase from apple(Jonathan) was found to be four, but two bands and one band were observed after heating at $60^{\circ}C$ and $70^{\circ}C$ for 1 hour, respectively, which showed a significant difference in thermal stability among active bands.

사과주(酒)의 효소적(酵素的) 갈변(褐變)에 대한 기초(基礎) 연구(硏究)의 일환으로, 홍옥에서 polyphenol oxidase(EC 1.10.3.1)을 추출(抽出), 조정제(粗精製)하여 그 일반적(一般的) 성질(性質) 및 열처리(熱處理)에 따른 polyphenol oxidase 활성(活性) band의 변화(變化)를 조사(調査)한 결과(結果)는 다음과 같다. 홍옥 polyphenol oxidase의 최적(最適)pH는 6.5, 최적온도(最適溫度)는 $30^{\circ}C$였으며, 주(主) 기질(基質)은 o-diphenol이었다. 열(熱)에 대한 안정성(安定性)은 $60^{\circ}C$와 $70^{\circ}C$에서 1시간(時間) 처리후(處理後)에도 잔재활성(殘存活性)이 각각(各各) 35%, 15% 정도였다. Sodium metabisulfite, cysteine 및 ascorbate 는 0.5 mM에서 거의 완전히 효소활성(酵素活性)을 저해(沮害)하였으나 EDTA는 저해효과(沮害?果)가 아주 약하게 나타났다. 또한 알콜은 polyphenol oxidase의 활성(活性)에 아무린 영향(影響)을 미치지 않았다. 홍옥 polyphenol oxidase의 활성(活性) band는 4개로 관찰(觀察)되었고, $60^{\circ}C$ 및 $70^{\circ}C$에서 1시간(時間) 동안 발효액(醱酵液)을 열처리(熱處理)한 후(後)에는 각각(各各) 2개 및 1개의 활성(活性) band가 관찰(觀祭)되었다. 그러므로 각(各) band는 열(熱)에 대한 안정성(安定性)이 크게 차이(差異)가 있음을 알 수 있었으며, 또한 각(各) band의 열안정성(熱安定性)과 효소(酵素)의 열안정성(熱安定性) 성적과는 거의 일치(一致)되었다.

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