Abstract
Background: The polyphenol oxidase (PPO) responsible for the enzymatic browning of fruits and vegetables, has been involved in the undesirable brown discolouration of food products that resulted in negative effects on colour, taste, and nutritional value. This is a generally undesired process and needs to be prevented in food technology. Objective: The present work was carried out to evaluate the effect of chemical and thermal treatments on browning inhibition of eggplant fruit (Solanum melongena L.). Materials and Methods: A screening of PPOs activities from eggplant was carried out. The physicochemical characteristics and thermal stability of main PPOs activities were determined in order to develop methods of anti-browning. Results: Dopamine oxidase and pyrocatechol oxidase activities were the most active main eggplant fruit PPO activities. Maximal PPO activity was found at 30°C, pH 7.0 for dopamine and 25°C, pH 6.6 for pyrocatechol. The enzymes were stable and retained almost all of their catalytic activity at their optimum temperature (30 and 25°C) for 120 min and their pH stability was in the range of 5.0 - 7.0. Polyphenol oxidases (dopamine oxidase and pyrocatechol oxidase) remained their full activity in the presence of ion Na+, Cu2+, Pb2+ (1 mM) but were inhibited strongly by the ion Fe2+ and Pb2+ (5 mM). On the other hand, the ion K+, Ba2+ and chemical agents, EDTA, citric acid have virtually no effect on dopamine oxidase and pyrocatechol oxidase activities. Energy for inactivation (Ea) obtained using dopamine and pyrocatechol were 30.8 kJ/mol and 7.1 kJ/mol from respective substrates. Conclusion: Ascorbic acid was a better inhibitor where 82.32% of PPOs inhibition was achieved. At 65°C, their D-values ranged from 44.72 to 72.72 min. Hence, heat treatment at 65°C for 30 min reduced browning of eggplant fruit. These data regarding the properties of PPO should enhance understanding of the browning reaction in eggplant and lead to the development of techniques for controlling this undesirable process.
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Claims 13
Claim · model-written summary
Dopamine oxidase and pyrocatechol oxidase were the most active eggplant fruit PPO activities.
- Taxon
- eggplant
Solanum melongenae0 - Organ / stage
- fruite0
- Outcome
- Dopamine oxidase and pyrocatechol oxidase activitiese0
- Direction
- most activee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dopamine oxidase and pyrocatechol oxidase activities were the most active main eggplant fruit PPO activities.”
Claim · model-written summary
Dopamine oxidase activity was maximal at 30°C and pH 7.0.
- Taxon
- eggplantSolanum melongenat0
- Gene
- dopaminee0
- Outcome
- PPO activitye0
- Direction
- Maximale0
- Value
- 30°C, pH 7.0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximal PPO activity was found at 30°C, pH 7.0 for dopamine and 25°C, pH 6.6 for pyrocatechol.”
t0“Violet Eggplant”
Claim · model-written summary
Pyrocatechol oxidase activity was maximal at 25°C and pH 6.6.
- Taxon
- eggplantSolanum melongenat0
- Gene
- pyrocatechole0
- Outcome
- PPO activitye0
- Direction
- Maximale0
- Value
- 25°C, pH 6.6e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximal PPO activity was found at 30°C, pH 7.0 for dopamine and 25°C, pH 6.6 for pyrocatechol.”
t0“Violet Eggplant”
Claim · model-written summary
The enzymes retained almost all catalytic activity for 120 min at optimum temperatures.
- Taxon
- eggplantSolanum melongenat0
- Outcome
- catalytic activitye0
- Direction
- retainede0
- Qualifier
- for 120 mine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The enzymes were stable and retained almost all of their catalytic activity at their optimum temperature (30 and 25°C) for 120 min and their pH stability was in the range of 5.0 - 7.0.”
t0“Violet Eggplant”
Claim · model-written summary
PPO pH stability ranged from 5.0 to 7.0.
- Taxon
- eggplantSolanum melongenat0
- Outcome
- pH stabilitye0
- Value
- 5.0 - 7.0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“their pH stability was in the range of 5.0 - 7.0”
t0“Violet Eggplant”
Claim · model-written summary
Na+, Cu2+ and Pb2+ at 1 mM preserved full PPO activity.
- Taxon
- eggplantSolanum melongenat0
- Treatment
- ion Na+, Cu2+, Pb2+ (1 mM)e0
- Outcome
- full activitye0
- Direction
- remainede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Polyphenol oxidases (dopamine oxidase and pyrocatechol oxidase) remained their full activity in the presence of ion Na+, Cu2+, Pb2+ (1 mM)”
t0“Violet Eggplant”
Claim · model-written summary
Fe2+ and Pb2+ at 5 mM strongly inhibited PPO.
- Taxon
- eggplantSolanum melongenat0
- Treatment
- ion Fe2+ and Pb2+ (5 mM)e0
- Outcome
- were inhibited stronglye0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were inhibited strongly by the ion Fe2+ and Pb2+ (5 mM).”
t0“Violet Eggplant”
Claim · model-written summary
K+, Ba2+, EDTA and citric acid had virtually no effect on PPO activities.
- Taxon
- eggplantSolanum melongenat0
- Treatment
- ion K+, Ba2+ and chemical agents, EDTA, citric acide0
- Outcome
- dopamine oxidase and pyrocatechol oxidase activitiese0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ion K+, Ba2+ and chemical agents, EDTA, citric acid have virtually no effect on dopamine oxidase and pyrocatechol oxidase activities.”
t0“Violet Eggplant”
Claim · model-written summary
Dopamine substrate gave inactivation energy of 30.8 kJ/mol.
- Taxon
- eggplantSolanum melongenat0
- Compound
- dopaminee0
- Outcome
- Energy for inactivation (Ea)e0
- Value
- 30.8 kJ/mole0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy for inactivation (Ea) obtained using dopamine and pyrocatechol were 30.8 kJ/mol and 7.1 kJ/mol from respective substrates.”
t0“Violet Eggplant”
Claim · model-written summary
Pyrocatechol substrate gave inactivation energy of 7.1 kJ/mol.
- Taxon
- eggplantSolanum melongenat0
- Compound
- pyrocatechole0
- Outcome
- Energy for inactivation (Ea)e0
- Value
- 7.1 kJ/mole0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy for inactivation (Ea) obtained using dopamine and pyrocatechol were 30.8 kJ/mol and 7.1 kJ/mol from respective substrates.”
t0“Violet Eggplant”
Claim · model-written summary
Ascorbic acid inhibited PPO by 82.32%.
- Taxon
- eggplantSolanum melongenat0
- Treatment
- Ascorbic acide0
- Outcome
- PPOs inhibitione0
- Direction
- inhibitione0
- Value
- 82.32%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ascorbic acid was a better inhibitor where 82.32% of PPOs inhibition was achieved.”
t0“Violet Eggplant”
Claim · model-written summary
At 65°C PPO D-values ranged from 44.72 to 72.72 min.
- Taxon
- eggplantSolanum melongenat0
- Outcome
- D-valuese0
- Value
- 44.72 to 72.72 mine0
- Qualifier
- At 65°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At 65°C, their D-values ranged from 44.72 to 72.72 min.”
t0“Violet Eggplant”
Claim · model-written summary
Heating at 65°C for 30 min reduced eggplant fruit browning.
- Taxon
- eggplantSolanum melongenae0
- Treatment
- heat treatment at 65°C for 30 mine0
- Outcome
- browning of eggplant fruite0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heat treatment at 65°C for 30 min reduced browning of eggplant fruit.”
The same questions in other papers
citric acid · physiology: enzyme activity · Solanum melongena (eggplant)Positive and negative results
2 in the opposite direction
- positive
- positive
ascorbic acid · disease · Solanum melongena (eggplant)Results agree
2 papers in the same direction as this paper
- positive
- positive
heat · disease · Solanum melongena (eggplant)Positive and negative results
6 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
4 papers more in this group
See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.