Nuke Your Veggies for Healthiest Antioxidant Value

by Susan Davis on 19/05/09 at 8:34 am

Who Knew?

A new study testing various cooking methods puts to rest the rumor and speculation about whether boiling or microwaving vegetables provides better nutritional value, especially when it comes to preserving the highest level of antioxidants.  Antioxidants are the healthy compounds in fruits and vegetables that are thought to slow down or prevent cancer and other diseases.  They are one of the reasons we’ve been encouraged to eat several servings of fruits and vegetables daily.

The new study was published by the Chicago-based Institute of Food Technologists and was conducted under the auspices of Dr. A. M. Jimenex-Monreal of the University of Murcia in Spain. The research team examined how six different cooking methods affected 20 vegetables.  The cooking methods used were boiling, microwaving, frying, griddling, pressure-cooking and baking.

The vegetables tested were artichokes, asparagus, beets, broad beans, broccoli, Brussels sprouts, carrots, cauliflower, celery, corn, eggplant, garlic, green beans, leeks, onions, peas, peppers, spinach, Swiss chard and zucchini.

The vegetables were purchased on five different occasions in a local supermarket and came from different lots.

The consensus was that microwaving or griddling (heating vegetables on a heavy skillet without oil) did the best job of preserving antioxidant activity in almost all the vegetables, with the exception of corn, which lost about 35 percent of its free-radical scavenging capacity after microwaving.

Boiling and pressure-cooking generally caused the greatest loss of antioxidant capacity, with frying landing squarely in the middle.

Cauliflower and exhibited the highest antioxidant loss after boiling or microwaving,  peas after boiling, and zucchini after boiling or frying.  Green beans, beets and garlic were found to keep their antioxidant levels after most cooking treatments.

The vegetables that increased their antioxidant levels after all cooking methods were celery, carrots and green beans (except green beans after boiling).

The artichoke was the only vegetable that kept its high antioxidant level during all the cooking methods

“In short, water is not the cook’s best friend when it comes to preparing vegetables,” the researchers say.

The full study may be accessed through the Journal of Food Science, April 2009, Volume 73, Issue 3.