- Steaming vegetables
- Stir-frying vegetables
- Oven-baking vegetables
- Other methods of cooking vegetables
- Recommended cooking methods for vegetables
- Find out about Frozen vegetables
- Find out about Canned vegetables
- Cooking with Asian vegetables
Cooking Recommendations for Optimum
Taste & Nutrition
Cooking changes the colour, texture, taste and the nutritional content of vegetables.
- Colour: Heat breaks down enzymes and stabilises proteins, making green colours more vibrant
- Nutrients: Water leaches out water-soluble vitamins like Vitamins B and C, and water-soluble phytonutrients like the purple colour in purple cabbage, or beetroot. Adding oil to a stir-fry, or dressing, makes fat-soluble vitamins and phytonutrients more easily absorbed by us, like beta-carotene in carrots (which makes Vitamin A in our body)
- Texture: The combination of heat and time makes vegetables softer and easier to eat and digest.
- Flavour: Flavours change, as some components of fresh, ‘green’ flavour are lost due to heat, sugars can caramelise (go brown) producing new flavours, or bitter flavours can become more dominant.
- Over-cooking vegetables:
- makes green vegetables go even darker and less vibrant
- leaches even more nutrients out
- makes them softer and mushier
- can remove all the typical flavour that we expect from fresh vegetables.
Based on a lot of scientific evidence, we have produced a list of the recommended optimum cooking methods for the best taste and nutritional benefits from all the vegetables featured on Veggycation. You can see this by clicking here, or by searching on each vegetable from the Veg Lovers or Growers & Industry pages.
Here is some more information about the top 3 recommended cooking methods to get the best taste and nutritional benefits from vegetables:
What: Steaming uses the heat from boiling water vapour to cook vegetables.
How to: You can use a wok and bamboo steamer, an electric steamer, or a steam insert in a pan to steam vegetables.
Timing/Method: After the water starts boiling, add vegetables to the steamer and steam for a maximum of 3 minutes. Longer leads to mushy, limp vegetables, & greater loss of nutrients.
Benefits: Rapid cooking and very low water contact leaves vegetables brightly coloured, crunchy and tasting great, and minimises loss of water soluble vitamins like Vitamin C.
Which vegetables to steam: most vegetables can be cooked by steaming, check out the complete list of vegetables and their optimum cooking methods for best flavour and nutritional content by clicking here.
What: Stir-frying uses high contact heat with pan, a small amount of oil, and sometimes a small amount of water to cook vegetables.
How to: You can use a wok or a fry-pan to stir-fry vegetables.
Timing/Method: Heat pan on high, add oil and when hot, add vegetables*. Keep vegetables moving with a heat-proof spatula. Stir-fry for 2 mins, add a small amount (1-2 tablespoons) of water, place lid over wok/pan and leave for 1 min. Cooking time: a maximum of 3 minutes. Longer leads to mushy, limp vegetables, & greater loss of nutrients.
Benefits: Rapid cooking and very low water contact leaves vegetables brightly coloured, crunchy and tasting great, and minimises loss of water soluble vitamins like Vitamin C. The addition of oil makes fat-soluble vitamins and phytonutrients more available to your body.
Which vegetables to stir-fry: many vegetables can be cooked by stir-frying, not just Asian vegetables. Check out the complete list of vegetables and their optimum cooking methods for best flavour and nutritional content by clicking here.
*Prepare vegetables so that they cook in the same amount of time, i.e. chop harder vegetables like carrots into smaller pieces than ‘softer’ vegetables like green beans or leafy greens. OR, add harder vegetables first, and ‘softer’ vegetables later in the cooking time.
What: Oven-baking uses hot air and a small amount of oil to cook vegetables.
How to: You can use a conventional or fan-forced oven, or a combined microwave/oven on oven setting to bake vegetables.
Timing/Method: Prepare vegetables by cutting into large chunks, and toss them in a small amount of oil. For whole baked potatoes, carefully push a metal skewer right through the potato and remove it again, to make a hole for steam to escape. Place veg on oven tray and into oven at 160°C (fan forced) or 180°C until soft (20-45 mins depending on cut size).
Benefits: Oven-baking is great for vegetables like root and starchy vegetables and potatoes, making the energy and fibre available, and caramelising the sugars to make them taste great. Although the heat reduces some vitamins, the lack of water maintains others. The addition of oil makes fat-soluble vitamins and phytonutrients more available to your body.
Which vegetables to oven-bake: Check out the complete list of vegetables and their optimum cooking methods for best flavour and nutritional content by clicking here.
Microwaving: There's not a lot of consistent scientific information on the impact of microwaving on vegetable nutrients. Keep the amount of water and time used minimal.
Frying: Keep cooking times short, and minimise the amount of oil added. Drain on paper towel prior to serving.
BBQ'ing: A great way to enjoy vegetables like capsicum, corn and potatoes. Brush with oil and keep cooking times short.
Slow-cooking: Because slow-cookers take a long time, and there is usually a lot of water present, the vegetables end up mushy and over-cooked. However, most of the liquid is generally eaten too, so nutrients can still be OK overall.
Boiling: Although most people still boil vegetables, it's not recommended as a lot of water is used, which leaches water-soluble vitamins, and it's very easy to over-cook boiled vegetables.
A note on washing and peeling vegetables: All vegetables should be washed prior to eating or cooking. Although traditionally many vegetables like carrots, parsnips and potatoes are peeled before cooking, try leaving the peel on. We don't think you'll notice the difference much, and the extra fibre is great for your body. Try things like:
- Oven-baked potato wedges (peel on) instead of chips
- Leave the peel on when steaming potatoes for mash, or potato salad
- Leave the peel on when grating carrots to make coleslaw, or when preparing them for cooking
- Oven bake beetroot with the peel on, then rub (using rubber gloves to stop your hands going pink) the skins off and enjoy hot or cold.
The first step of freezing involves a blanching step, which is effectively a cooking step, thus there is always some loss of nutrients, particularly heat sensitive and water-soluble compounds. Steam blanching is preferable to methods that involve vegetables being immersed in water. Boiling frozen vegetables is particularly detrimental. If using frozen vegetables, it is best to use cooking methods with minimal or no water and keep cooking time to a minimum.
DO NOT thaw frozen vegetables prior to cooking, as this reduces many vitamins dramatically.
- Vitamin C: Freezing is better than canning in terms of Vitamin C retention. Nutrient retention in frozen vegetables can be better than fresh veg stored in ambient or refrigerated storage.
- B vitamins: The blanch step results in significant losses.
- Carotenoids (fat-soluble): Small losses of beta-carotene on cooking frozen broccoli, with microwaving having greatest loss. In frozen red capsicum, boiling caused greatest loss. Losses on blanching and freezing occurred for broccoli (22-48%), carrots (10-36%) and green beans (5%) while for corn it increased. Lycopene relatively stable during processing.
- Vitamin E (fat-soluble): Small losses of vitamins on cooking frozen broccoli by boiling, with higher losses in steamed and microwaved. For frozen red capsicum, greatest losses were with steaming and microwaving, and boiling led to a slight increase. Thermal processing may release Vitamin E.
- Minerals: Inconsistent results, because levels are so dependent on processing techniques and water mineral content.
- Anti-oxidant activity: Cooking frozen vegetables - microwaving resulted in no loss of activity of peas or spinach, short boiling time resulted in a small loss, but overcooking resulted in a significant loss. Many vegetables showed minimal loss of antioxidant activity after 8 months of frozen storage.
Canning is generally more detrimental than freezing in particular for water soluble nutrients because they leach into the canning liquid.
- Vitamin C: Major loss with canning - in many cases seems to be proportional to absolute Vitamin C content: the higher the level of Vitamin C, the greater the % loss.
- B vitamins: Significant loss of thiamin with thermal processing. Rates of degradation vary between vegetables. Riboflavin generally only small losses. Vitamin B6 loss of 57-77% in many vegetables, but increased in tomato. Niacin is relatively stable, with losses often less than 10%. Folate losses vary from 0 up to 30%. There is loss of folate into the canning liquid.
- Carotenoids (fat-soluble): On a wet weight basis there is little or no change in carotenoids (pro Vitamin A), and Lycopene is relatively stable during processing.
- Vitamin E (fat-soluble): Thermal processing may release Vitamin E which is still present in canned vegetables, sometimes at higher levels than fresh or frozen, but there are very few studies.
- Minerals: Inconsistent results, because these are so dependent on processing techniques and water mineral content.
- Anti-oxidant activity: Inconsistent results: In one study, canned vegetables showed a more pronounced loss of activity than frozen compared with fresh. In another, losses were less than for freezing. Canned vegetables showed minimal loss of anti-oxidant activity after 18 months of storage.
Recipes for Asian vegetables:
Asian Style Omelette
Kale and Chinese
Cabbage Stir Fry
Vegetable and Chicken
|Cabbage, white or green||yes||yes|
|Mushrooms, Swiss brown||yes||yes||yes||yes||yes||yes||yes|
|Mushrooms, white button||yes||yes||yes||yes||yes||yes||yes|
|Peas, snow (pod)||yes||yes||yes|
|Pumpkin, golden nugget||yes||yes||yes||yes||yes|
|Pumpkin, Queensland blue||yes||yes||yes||yes||yes|
|Tomatoes, standard red||yes||yes||yes|