Impact of vacuum cooking and boiling, and refrigerated storage on the quality of galega kale (Brassica oleracea var. acephala cv. Galega)

- The quality of cooked kale depends on the cooking method and conditions.
- Boiling causes lower losses of soluble solids and vitamin C than vacuum cooking.
- Vacuum cooking in autoclave induced the lowest antioxidant capacity, bioactive compounds and colour changes.
- Losses during storage are higher in autoclaved than in the water bath treated kales.
- Vacuum cooking could ensure a longer shelf-life of kales.

Physicochemical parameters, bioactive compound contents and antioxidant capacity were evaluated and compared in fresh samples of Galega kale and samples cooked by boiling and different vacuum cooking procedures. The effect of refrigerated storage for 21 days was also studied in relation to the different vacuum cooking treatments. The impact on chemical and quality parameters depended on the cooking method used. Boiling caused lower loss of soluble solids and vitamin C than vacuum cooking. Vacuum cooking in an autoclave led to greater retention of antioxidant capacity, total phenolics, chlorophyll and colour. In general, losses during storage were higher in kale samples cooked by the vacuum cooking method in an autoclave than in those cooked by the same method in a water bath. The study findings demonstrate that vacuum cooking could be used as an alternative to conventional methods of cooking kale.