Chapter 7 General Discussion
11. Conclusion
This project has improved the understanding of avocado ripening physiology and the interactive effects of production location, maturity, low temperature storage and modified humidity packaging. This is important for future design of optimal storage and shipping protocols. Previously, various aspects of avocado fruit physiology have been studied, but not in a comprehensive manner which takes into account important interactions of pre- and postharvest conditions which impact on final fruit quality at consumer level. Using some of the important parameters measured, it has also been possible to demonstrate the potential for NIR spectroscopy as a valuable tool in the avocado industry for non-destructive and possibly orchard or packline prediction of quality outcomes, and thereby allowing the packer or marketer to better target logistic requirements and sales opportunities.
Beyond the obvious recommendation for improved postharvest management to better maintain fruit quality, a model explaining fruit ripening is postulated. There are many factors which contribute to ripening and fruit quality which still need to be investigated, so this model is not complete, but lays the foundation for further research into avocado ripening physiology.
It is envisioned that as NIR technology improves and is used more extensively in the avocado industry, non-destructive sampling will provide a window into fruit to allow a greater understanding of how these factors influence ripening. Once calibration models are developed for each factor of interest, many more samples can be analysed repeatedly, at a much faster rate and lower cost, to provide more conclusive answers. It is hoped that some of the results from this research, particularly NIR, will be used commercially in the near future.
The paradigm that avocados cannot be stored below 5°C without developing chilling injury has again been shown to be incorrect. South African ‘Hass’ avocados can be successfully stored at 1°C. The use of modified humidity packaging provides a means of limiting metabolism during cold storage, particularly for fruit stored at 5.5°C and may offer a viable commercial postharvest treatment. Semi-commercial testing including fruit from different production areas, maturities and a number of seasons is required before these treatments are used commercially.
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