Development of shelf life indicators for baby leaf spinach and rocket (VG08166)

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Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.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?

Shelf life was an issue of critical importance in babyleaf spinach because it related directly to freshness, a quality that consumers valued highly in their buying decisions.

Breeders were expected to produce varieties with good shelf life characteristics and growers were expected to supply crops to the market and to processors with a long shelf life, to reach consumers in good condition. However, no techniques were available to help breeders or growers to reliably assess shelf life characteristics of new babyleaf spinach varieties or of crops in production.

The project identified the relative importance of damage during harvesting and processing on shelf life, the reasons for babyleaf spinach failing shelf life, and the length of time spinach could be successfully stored under ideal growing and storage conditions for summer- and winter-grown crops. The project also identified and evaluated a range of tests that could be used to predict shelf life by plant breeders or growers. Useful tests included specific leaf area, leaf colour, leaf respiration rate, chlorophyll, leaf thickness, plant height, total leaf area, amount of leaf damage and leaf apex tearing.

The most useful indicators of shelf life needed to be fine-tuned and adopted as predictive tests both for in-field use, and as breeding selection tools for shelf life. More work needed to be done on determining the effect of high nitrogen availability and planting density on the shelf life of spinach under different seasonal conditions.

Two significant areas of research remained to be completed. First, the development of reliable tests that growers could use to predict what the shelf life of a crop that was in the ground would be once it was harvested, when it had been affected by adverse conditions during growth. Second, actions that could be applied to adversely affected babyleaf crops before harvest to restore the shelf life to an acceptable level needed to be evaluated under conditions known to induce poor shelf life, i.e. summer in southern Australia.