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Polyphenoloxidase from guava ( Psidium guajava L.)
Author(s) -
Augustin M. A.,
Ghazali Hasanah M.,
Hashim Hasimah
Publication year - 1985
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740361209
Subject(s) - psidium , chemistry , browning , ascorbic acid , acetone , enzyme , hydrochloride , chromatography , sodium , allium , cysteine , polyacrylamide gel electrophoresis , biochemistry , food science , botany , biology , organic chemistry
Polyphenoloxidase (PPO) was isolated from guava ( Psidium guajava L., cv. Kampuchea). Purification by acetone precipitation and dialysis of the Amicon concentrate resulted in 4.9‐fold and 17.2‐fold purification of the dialysed crude extract respectively. Polyacrylamide gel electrophoresis indicated that PPO had a molecular weight in the region of 120000–140000. The pH optimum of the enzyme was found to be 7.2. Heat inactivation studies showed that heating for 1.1, 3.5, and 10.1 min at 75, 65 and 55°C respectively caused a 50% loss in enzymic activity. The enzyme‐catalysed browning reaction was significantly inhibited in the presence of sodium metabisulphite, L‐cysteine hydrochloride and ascorbic acid.