Gill Stannard

Thursday, November 24, 2005

To Steam or to Zap?

Recently the microwave oven turned 60 years old. Fancy that! I remain in a minority (only 10%) of Australian homes that does not have one. I have heard all the arguments for owning one. The marvels of reheating food, warming a heat pack or cooking vegetables in a flash. But the texture of food cooked in this way has never seemed quite right to me and really, how long does it take to steam a bowl of vegetables?

In the last few years science has been supporting my suspicions that this invention may not be the best thing since sliced bread, nutritionally speaking. Or perhaps, considering the state of the humble loaf these days it is more accurate to say nutrients in microwaved food are going the way of those found in sliced bread! An in depth study in 2003, published in the Journal of the Science of Food and Agriculture tested for the goodies in brocolli when cooked in a variety of ways. For nutritionists and science buffs, the study looked at phenolic compounds. These flavanoids and other compounds are handy markers of the beneficial chemicals in the much touted ‘anticancer’ famous brocolli.

So what did Vallejo and his team find? Using the amount of phenols in raw broccoli as a base line, they then cooked the vegetable by pressure cooking, boiling, steaming and microwaving. While steaming came out on top as preserving all but about 11% of the immune boosting antioxidants, zapping it in the microwave lost a whopping 97% flavanoids.

Do the maths, just how much more microwaved broccoli do you need to eat, to get the equivalent phenolic content as steamed broccoli? (Tell me in comments if you wish).

The take home message from this study is clearly eating your veggies raw or steamed is the way to go.

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