Cooking methods are no longer a preference as one of them may be better than the others in terms of preserving nutrients and antioxidant level. A study published by Institute of Food Technologists (IFT) found that cooking with no oil, steaming and microwaving maintain the highest nutrient levels. If you think cauliflower is best when boiled, you may be cooking the wrong way!
Vegetables contain pectin - a cell wall that breaks down with heat. Thus, when you're cooking leafy greens, pectin releases cell bonds - causing the veggies to soften. This breakdown process also causes vitamins to 'evaporate' soon, especially when boiled.
Cooking method matters, whether you steam, microwave, fry or boil. Other factors such as the type of vegetables, the time and temperature make a big difference on how many nutrients you obtain. A study in the University of Murcia experimented with various methods of cooking that might have an impact on the antioxidant levels. There are 6 cooking methods tested, which are, pressure cooking, boiling, frying, griddling, and microwaving.
The research found that cauliflower lost its antioxidant when boiled or microwaved. It goes the same with boiled peas and zucchini. Whereas beets, green beans, and garlic still conserve the nutrients after any cooking method. Celery, tomatoes and carrots were said to increase the antioxidant levels after they're cooked.
The journal report showed that frying is the worst when it comes to conserving nutrients. The high heat is responsible for the loss of antioxidant property in vegetables. The next one would be boiling because the nutrient loss may be up to 50 percent or less. Steaming is the best way to avoid the antioxidant loss and it is much similar to microwaving.
Rui Hai Liu, food science professor at the Cornell University told the Washington Post that some foods produce a high level of nutrients when cooked because they become more absorbable by our body. Some of those vegetables are:
- Tomato
Tomatoes when fried or baked, can release lycopene - a property that lowers down cancer risk.
- Spinach
The greens contain oxalic acid that actually block the calcium and iron absorption but it breaks down when cooked at high temperature. This means cooking reduces the oxalate that enables our body absorbs the nutrients better.
- Carrots
Carrots conserve the highest nutrient when boiled before slicing. Food Chemistry reported that boiling boosts carotenoid up to 14% and frying boosts it up to 13 percent.
