Isolation and thermostability of peroxidase isoenzymes from apple cultivars Gala and Fuji

• Published in: Food chemistry Vol. 87; no. 4; pp. 601 - 606
• Main Authors: Valderrama, P, Clemente, E
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2004; Elsevier
• Subjects: Apple; Biological and medical sciences; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Isoenzymes; Isolation; Mallus comunis; Peroxidase; Thermostability; Mallus comunis; Thermostability; Isolation; Apple; Peroxidase; Isoenzymes; Fruit; Enzyme; Isozyme; Thermal stability; Peroxidases; Oxidoreductases; Cultivar
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2004.01.014

Extracts of soluble peroxidase and ionically-bound peroxidase were obtained from the peel and pulp of apples ( Mallus comunis), cultivars Gala and Fuji, using 100 mM sodium phosphate buffer and pH 6.0 and 7.0 for pulp and peel of Gala cultivar, respectively and pH 5.5 for the pulp and the peel of cultivar Fuji. Then the enzymatic activity of peroxidase (POD) was determined in both extracts, soluble fractions and ionically-bound. Electrophoresis results shows similar compositions for the anionic and cationic isoenzymes in both cultivars. The molecular weights and p I values of the isolated isoenzymes from the Fuji cultivar were: two anionic, A 1 and A 2 (38, 28 kDa and p I 4.4; 5.0, respectively) and three cationic C 1, C 2 and C 3 (40, 34, 26 kDa and p I 8.0, 8.3, 9.0, respectively). From the Gala cultivar, also, two anionic isoenzymes were isolated A 2 and A 4 (28, 26 kDa and p I 5.0 and 5.7, respectively) and three cationic isoenzymes C 1, C 2 and C 3 (40, 34, 26 kDa and p I 8.0, 8.3 and 9.0, respectively). The cationic isoenzymes were more heat-stable under the heat treatments at 65, 70, 75 and 80 °C in both cultivars.