Effect of high pressure processing on avocado slices

• First significant study demonstrating effect of HPP on ethylene and CO2 production rates
• HPP of avocado slices largely did not deactivate polyphenol oxidase or peroxidase.
• Despite the microstructure changes structural properties may be reasonably retained after HPP.
• Colour changes of HPP-treated avocado slices were not visually significant.

While the commercial benefits of high pressure processing (HPP) on pulp products (e.g. guacamole) are known, little information is available on HPP of whole avocado tissue. We examined HPP effects on the quality, physiology, biochemistry and microstructure of avocado slices. Flesh colour was affected, with L (lightness) and C (chroma) values decreasing after some treatments, although these changes were not obvious visually. HPP (> 300 MPa) dramatically reduced respiration rates and ethylene production 1 h after treatment, and particularly after 17 h at 20 °C. Treatment resulted in some peroxidase (POD) activity reduction, particularly at higher pressures, while polyphenoloxidase (PPO) activity was generally increased. HPP (600 MPa) induced changes in the cell wall structure, disruption of the cellular network and coalescence of oil vesicles. HPP treatment of avocado slices provides potentially beneficial reduced respiratory activity, without obvious colour changes — a solid foundation for examining shelf life quality implications.Industrial relevance
• This work outlines underpinning science that may have commercial relevance in the future.
• It is not directly relevant to HPP industries in the immediate future.
• The effect of HPP on respiration rate and ethylene production is useful to industry in their understanding of the physiology of horticultural products after HPP.