Different Cooking Methods Reduce Antioxidant Levels in Vegetables
Vegetables, especially green vegetables, are good for our health. But how these healthy foods are cooked affects the benefits to be gained from 5-7 serves a day.
Health authorities around the world are encouraging people to get into the habit of eating good amounts of greens and other vegetables every day to maximise the benefits from their health-protective properties.
In summer, eating sufficient vegetables is easy – just make salad a part of every meal. But cooked vegetables have a place on the menu too, and in cooler weather, salad isn’t always desirable.
The trick is to cook the vegetables to maximise their antioxidant content.
Spanish Researchers Investigate Best Methods to Cook Greens
There is a range of ways to cook vegetables, and an enthusiastic cook will try several to vary the finished dishes. But which is the healthiest method?
To answer this question, researchers at Spain’s University of Murcia and University of Complutense examined how various cooking methods affected antioxidant activity by analyzing six methods of cooking vegetables.
What’s more, although green vegetables are among the highest in terms of antioxidants, the researchers didn’t stop with them, but tested 20 vegetables all up.
Vegetable Cooking Methods Affect Antioxidant Levels
The Spanish researchers tested six different ways of cooking the vegetables, and analyzed the antioxidant levels before and after cooking. They tested boiling, pressure-cooking, baking, microwaving, griddling (cooking on a flat metal surface with no oil) and frying.
They looked at how artichoke, asparagus, beetroot, broccoli, Brussels sprouts, cauliflower. carrot, celery, eggplant, garlic, green beans, leeks, maize, onions, peas, peppers, spinach, Swiss chard and zucchini coped with the different cooking methods, and reported their findings in the Institute of Food Technologists’ Journal of Food Science.
Griddling and Microwaving Best Ways to Cook Vegetables
The researchers showed that griddling and microwaving protected antioxidants best of all the cooking methods. Boiling was the most destructive method, followed by pressure cooking. Boiling was severely destructive to the antioxidants in zucchinis, cauliflower and peas.
As one researcher, A. M. Jiménez-Monreal, commented: “water is not the cook’s best friend when it comes to preparing vegetables.”
Green Beans and Garlic Keep High Antioxidant Levels
Some vegetables truly are ‘super foods’. Green beans, garlic and beetroot kept their antioxidant levels unchanged through all forms of cooking except boiling and pressure cooking. Surprisingly artichoke performed even better, maintaining its high antioxidant content even after being boiled.
Some cooking methods actually increased the antioxidant levels of certain vegetables. Celery, carrots and green beans all showed gains in usable antioxidants after cooking, so long as they weren’t boiled to death! In fact, celery improved its antioxidant levels in every method save boiling,
Frying Has a Place in Cooking Vegetables
This research doesn’t mean that all vegetables served at every meal must be microwaved or griddled. There is a place for variety in cooking and presenting food to make it appetising and enjoyable.
Stirfrying – frying quickly in a small amount of oil, so the vegetables are just cooked, or still crunchy – is a good alternative to other methods. And the ‘super veggies’ can cope with most cooking styles.
Broccoli, however, although a ‘super food’ in terms of its antioxidant powers, is easily ruined by the wrong cooking methods. Stick to quick microwaving, griddling or stirfrying, so it’s barely cooked.
“Our findings have identified the best methods for cooking vegetables while retaining their radical-scavenging activity and antioxidant activity with its health-related properties,” the researchers wrote.
“Depending on the vegetable in question, griddling and microwave cooking produced the lowest losses, while pressure-cooking and boiling led to the greatest losses; in general, frying occupies an intermediate position. In short, water is not the cook’s best friend when it comes to preparing vegetables.”