Process improvements for preserving peak freshness in broccoli (2) (VG14062)

What was it all about?

Despite broccoli’s image as a healthy, nutritious and flavoursome vegetable, sales can be constrained by the product’s quality at the retail outlet, and disappointing storability after purchase.

Following earlier project VG13086, this investment examined some of the factors that could increase or decrease the retail freshness of broccoli including harvest time, delay before cooling, cooling method and packaging materials. Researchers also tested a novel method of reducing yellowing of broccoli.

The research found that delays in cooling and temperature fluctuations during transport have the potential to greatly reduce broccoli freshness at retail. It seems likely that poor postharvest temperature management is a key factor in the observed variability in retail quality and short storage life after purchase.

The work found that vacuum cooling immediately after harvest and hydrocooling can retain quality and increase the weight of harvested broccoli. It also found leaving harvested broccoli in the field, rather than transporting the produce straight to the packing shed, can increase weight loss by up to six per cent.

Timing of harvest was also identified as a crucial factor in broccoli quality – the greatest gains in weight during cooling were observed in produce harvested at 6am, with the smallest increase at 4pm (though broccoli was sweetest at this time).

The project also conducted trials of SmartFresh, an in-box treatment that was shown to reduce yellowing and extend shelf life. More information can be found in this levy-funded  Vegenotes edition.