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Kinectics of calcium diffusion and associated physical changes in papaya fruit
Nayara Cantarino Barbosa1, Isamara Reis Gomes1, Sérgio Henriques Saraiva2
1Laboratory of Food Technology, State University of Northern Rio de Janeiro (UENF), Campos dos Goytacazes, Rio de Janeiro, Brazil.
Summary
Postharvest calcium chloride treatments enhance papaya firmness and slow peel color change. The fruit peel acts as a barrier, affecting calcium diffusion kinetics into the pulp.
Area of Science:
- Horticultural Science
- Food Science
- Mass Transfer
Background:
- Calcium treatments are vital for postharvest papaya quality preservation.
- Understanding calcium diffusion mechanisms and kinetics in papaya pulp is crucial but underexplored.
Purpose of the Study:
- To characterize calcium diffusion parameters in 'Golden' papaya after postharvest calcium chloride immersion.
- To investigate the influence of calcium concentration and immersion time on diffusion kinetics and fruit quality.
Main Methods:
- Employing a transient diffusion model fitted with the Freundlich isotherm to determine calcium concentration at the fruit surface.
- Measuring calcium diffusivity in papaya peel and pulp layers.
- Assessing pulp firmness and peel color changes after storage.
Main Results:
- The peel acts as a significant diffusion barrier, exhibiting lower diffusivity (2.9 × 10⁻⁹ m² s⁻¹) compared to the outer pulp (2.4 × 10⁻⁷ m² s⁻¹).
- Optimal pulp firmness was achieved with 60-minute immersion in ≥1% Ca²⁺ solutions.
- Immersion in 1% Ca²⁺ for ≥30 minutes delayed peel color changes during 12 days of storage.
Conclusions:
- Calcium diffusion kinetics are influenced by the peel's resistance to mass transfer.
- Calcium chloride treatments effectively improve postharvest papaya quality, enhancing firmness and retarding senescence.
- Optimized immersion parameters can be established for effective postharvest calcium application in papayas.
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