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Peroxidase from jackfruit: Purification, characterization and thermal inactivation
Yi-Ming Tao1, Song Wang1, Hui-Liu Luo1
1College of Biotechnology, Guilin Medical University, Guilin 541004, People's Republic of China.
International Journal of Biological Macromolecules
|April 8, 2018
Summary
Jackfruit bulb peroxidase (POD) was purified and characterized. This enzyme is most active with o-phenylenediamine (OPD) substrate and shows reduced activity upon heating, impacting antioxidant properties.
Area of Science:
- Biochemistry
- Enzymology
- Food Science
Background:
- Peroxidase (POD) enzymes are crucial in various biological processes and have potential industrial applications.
- Understanding the properties of POD from unconventional sources like jackfruit can reveal novel enzymatic characteristics.
- Heat stability is a critical factor influencing enzyme functionality in food processing and preservation.
Purpose of the Study:
- To purify and characterize peroxidase (POD) from jackfruit bulb.
- To determine the kinetic properties and optimal conditions for the purified jackfruit POD.
- To investigate the effect of heat treatment on POD activity and the associated antioxidant properties of jackfruit extracts.
Main Methods:
- Enzyme purification using ammonium sulfate precipitation, hydrophobic interaction, and gel filtration chromatography.
- Determination of kinetic parameters (Km, Vmax) using different substrates like guaiacol, gallic acid, and o-phenylenediamine (OPD).
- Enzyme characterization including optimal pH, temperature, thermal inactivation kinetics, and effects of various ions and chemicals. Analysis of antioxidant activity (FRAP, ABTS) and total phenolics in heat-treated extracts.
Main Results:
- Purified jackfruit POD is a dimer (104 kDa) with optimal activity at pH 5.5 and 55-60°C.
- o-Phenylenediamine (OPD) was identified as the most suitable substrate.
- Heat treatment (80-90°C) significantly reduced POD activity, leading to decreased ferric-reducing antioxidant power, ABTS radical scavenging activity, and total phenolics.
Conclusions:
- Jackfruit bulb POD is a stable enzyme under specific conditions but sensitive to high temperatures.
- The study provides valuable insights into the biochemical properties of jackfruit POD and its potential limitations in thermal processing.
- Understanding the thermal lability of POD is crucial for optimizing jackfruit processing to retain its valuable antioxidant components.
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