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| Format: | Artículo científico |
| Sprache: | en |
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Sociedad Mexicana de Nutrición y Tecnología de Alimentos
2004
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| _version_ | 1866812531335495680 |
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| author | M. A. da Silva Vasconcelos |
| author_facet | M. A. da Silva Vasconcelos |
| contents | Characterization of polyphenol oxidase of soursop (Annona muricata L.) fruit and a comparative study of its inhibition in enzyme extract and in pulp M. A. da Silva Vasconcelos P. S. Bora H. J. Holschuh Química Soursop Annona muricata Enzyme inhibition Polyphenol oxidase Crude enzyme extract containing polyphenoloxidase (PPO) was obtained from ripe soursop (Annona muricata L.) fruit by extraction with0.2 M phosphate buffer (pH 7.5) containing 0.5 M NaCl, followed by precipitation with 20, 40, 60 and 80% saturation of ammonium sulfate anddialysis against distilled water at 4ºC. The maximum PPO activity was observed in the protein fraction obtained with 60% ammonium sulphatesaturation. The effect of pH (3 to 8.8), temperature (20 to 60ºC) and chemical inhibitors (ascorbic acid, EDTA and SO2) at several concentrations onthe PPO activity was studied. The optimum pH and temperature for PPO activity were 7.5 and 32ºC, respectively. Among chemical inhibitors,ascorbic acid and SO2 were almost equally effective, but EDTA showed very small inhibitory effect. 61.9 and 71.5% inhibition of PPO was achievedusing 0.28 mM and 0.84 mM concentrations of ascorbic acid, while for 55.4 and 70.2% inhibition 0.78 mM and 2.34 mM concentrations of SO2were needed. Heating the enzyme extract at 70, 80, 90 and 95ºC for 6 s reduced 15.2, 49.5, 84.8 and 95.1% PPO activity, respectively. At the naturalpH of pulp (4.3), SO2 at concentration of 3.9 mM reduced specific activity of PPO from about 60 to about 8.4 U/mg protein in partially-purifiedenzyme extract (PPEE), while the specific activity of 22.5 U/mg protein was retained in the pulp. Heating PPEE at 80ºC at pH 4.3 (natural pH ofpulp) for about 14 s decreased specific enzyme activity from 60.0 to about 11.0 U/mg and heating during 8 min decreased to 9.0 U/mg protein 2004 artículo científico 1135-8122 https://www.redalyc.org/articulo.oa?id=72440407 en http://www.redalyc.org/revista.oa?id=724 Ciencia y Tecnología Alimentaria application/pdf Sociedad Mexicana de Nutrición y Tecnología de Alimentos Ciencia y Tecnología Alimentaria (México) Num.4 Vol.4 |
| format | Artículo científico |
| id | redalyc_72440407 |
| language | en |
| publishDate | 2004 |
| publisher | Sociedad Mexicana de Nutrición y Tecnología de Alimentos |
| spellingShingle | Characterization of polyphenol oxidase of soursop (Annona muricata L.) fruit and a comparative study of its inhibition in enzyme extract and in pulp M. A. da Silva Vasconcelos Química Soursop Annona muricata Enzyme inhibition Polyphenol oxidase Characterization of polyphenol oxidase of soursop (Annona muricata L.) fruit and a comparative study of its inhibition in enzyme extract and in pulp M. A. da Silva Vasconcelos P. S. Bora H. J. Holschuh Química Soursop Annona muricata Enzyme inhibition Polyphenol oxidase Crude enzyme extract containing polyphenoloxidase (PPO) was obtained from ripe soursop (Annona muricata L.) fruit by extraction with0.2 M phosphate buffer (pH 7.5) containing 0.5 M NaCl, followed by precipitation with 20, 40, 60 and 80% saturation of ammonium sulfate anddialysis against distilled water at 4ºC. The maximum PPO activity was observed in the protein fraction obtained with 60% ammonium sulphatesaturation. The effect of pH (3 to 8.8), temperature (20 to 60ºC) and chemical inhibitors (ascorbic acid, EDTA and SO2) at several concentrations onthe PPO activity was studied. The optimum pH and temperature for PPO activity were 7.5 and 32ºC, respectively. Among chemical inhibitors,ascorbic acid and SO2 were almost equally effective, but EDTA showed very small inhibitory effect. 61.9 and 71.5% inhibition of PPO was achievedusing 0.28 mM and 0.84 mM concentrations of ascorbic acid, while for 55.4 and 70.2% inhibition 0.78 mM and 2.34 mM concentrations of SO2were needed. Heating the enzyme extract at 70, 80, 90 and 95ºC for 6 s reduced 15.2, 49.5, 84.8 and 95.1% PPO activity, respectively. At the naturalpH of pulp (4.3), SO2 at concentration of 3.9 mM reduced specific activity of PPO from about 60 to about 8.4 U/mg protein in partially-purifiedenzyme extract (PPEE), while the specific activity of 22.5 U/mg protein was retained in the pulp. Heating PPEE at 80ºC at pH 4.3 (natural pH ofpulp) for about 14 s decreased specific enzyme activity from 60.0 to about 11.0 U/mg and heating during 8 min decreased to 9.0 U/mg protein 2004 artículo científico 1135-8122 https://www.redalyc.org/articulo.oa?id=72440407 en http://www.redalyc.org/revista.oa?id=724 Ciencia y Tecnología Alimentaria application/pdf Sociedad Mexicana de Nutrición y Tecnología de Alimentos Ciencia y Tecnología Alimentaria (México) Num.4 Vol.4 |
| title | Characterization of polyphenol oxidase of soursop (Annona muricata L.) fruit and a comparative study of its inhibition in enzyme extract and in pulp |
| topic | Química Soursop Annona muricata Enzyme inhibition Polyphenol oxidase |
| url | https://www.redalyc.org/articulo.oa?id=72440407 |