This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

The flesh of avocado fruit contains approximately 8-24 per cent oil for fruit harvested in the commercial harvest season. Some procedures for extracting the oil produce high oil yields, but the oil loses its characteristic flavour, colour and health benefits. “Extra virgin” or “coldpressed” oils are extracted using more “gentle” procedures so that much of the colour, flavour, and specific “health-promoting” compounds of the fresh fruit are retained. These include “good” (mono-unsaturated fatty acids) oils, Vitamin E, plant pigments (antioxidants providing disease protection), plant sterols, fibre and Vitamin B6.

Commercial production of extra virgin avocado oil commenced in New Zealand in 2001, and in Brisbane, Australia in 2004. Several factors can affect the efficiency of oil extraction, and also oil quality, and these factors need to be well understood to develop a viable avocado oil industry. This project investigated the oil yield from the main avocado cultivars from some of the major production regions in Australia and New Zealand through the harvest season and from a range of growers over two seasons. Oil quality (content of some health-promoting compounds) was also studied in some samples.

In Australia and New Zealand, both dry matter and oil content increased as the fruit matured. In New Zealand, these tended to reach a maximum in about January, but this varied in Australia because of the larger differences in growing climate. Maximum oil yield (laboratory-based extraction) varied from about 10 per cent in early season fruit, to about 29 per cent in late season fruit with some regional differences. Commercial extraction using cold-pressed techniques resulted in lower yield comparatively, but the results suggest commercial yields of 25 per cent could be possible for harvested fruit later in the season. There was little difference in maximum oil yield from fruit of the same maturity from Australia or New Zealand, suggesting similar commercial potential in both countries. However, New Zealand growers generally harvest for fruit with higher potential yield, so that commercial viability in New Zealand may be higher. This factor may change if the Australian industry changes its minimum fruit maturity level.

One of the key challenges for an avocado processing industry in Australia and New Zealand is consistency of fruit supply, particularly of fruit with adequate oil yield and fruit quality. This will be the major factor determining long-term commercial viability.