Originally Posted by RBG09
A lot of people may disagree with me on this, but I actually think one of the best ways to prepare vegetables is to heat them quickly inside the microwave. There is a lot of fear over microwave cooking, but when you consider the small amount of time you have to have vegetables in there to heat them up, you're probably losing LESS nutrients than with other cooking methods that require you to heat them longer. Just think about it - if the main cause of lost nutrients is heat damage and transmission into water, wouldn't a microwave, which is the fastest, and requires very little water, be a really good method? That's the way I look at it.
Possibly but there are few more factors to consider. The amount of nutrients that migrate from solid part of vegetables to the cooking water, probably has little to do with the amount of water you are cooking the vegetables in, or whether the vegetables are sitting in the water or on a platform above it. To support this claim, I did the following experiment. I cooked same kind and same amount of vegetables in small amount of water (1/3 cup), and in large amount of water (2/3 cup), then tasted the water. The water from the vegetables cooked in smaller amount of water, had a much stronger taste than the water from the vegetables cooked in the larger amount of water, suggesting that more nutrients do not leave the vegetables, if they are cooked in a larger amount of water. Most likely the same amount of nutrients leave the vegetables, either way. However the time did have a great effect on the taste of the water. The longer I cooked, the stronger the water tasted.
I have read that temperature effects nutrient loss. Higher temp, more loss. However water will not go more than a hair above 100 degrees C (its boiling point) and steam from boiled water is about the same temp. Water that is gently simmering is the same temp as water that is rapidly boiling. From what I can tell, the food in a "slow cooker" is kept at just about the boiling point of water. It is not kept at a lower temperature than that. That is why "slow cooking" is a "slow cooker" is a misnomer, and is really just longer cooking
. One way to increase water temp is to put the water under pressure, use a pressure cooker. The temperature of the water under pressure (and any steam that occurs) may reach 120 degrees C. You will probably not have much greater nutrient loss due to pressure cooking, because the cooking time is shorter, making up for the slightly higher temperature. However certain nutrients may show faster acceleration of decompostion, as you raise temperature, than other nutrients. The big change is not between pressure cooking and regular steaming or boiling, but between cooking in water and cooking in oil. Temp of oil is much higher than temp of water. 200 degrees C or more, as compared to 100.
Microwaving also raises water temp (of the water inside the vegetables) slightly higher than ordinary boiling of water over a flame. However this may possibly be compensated for, by the shorter cooking time. All in all, I think microwaving is about the same as steaming or boiling. It does appear that if I cook vegetables in the same amount of water, those cooked in the microwave (inside a plastic container with a cover, with holes in the top to allow steam to escape) have less strongly tasting water. This is moot, if you consume the water
. If you cook in a coverd plastic container, make sure the cover
The main disadvantage of microwaving in plastic is that more toxic substances enter the food - toxic substances are leached from the plastic. The gov regulators say if the container is microwavable, the amount is negligable. I am skeptical. I would suggest microwaving in pyrex glass or ceramic containers.
Stainless steel allows only a small amount of iron and nicke to enter food. The iron is at non-toxic levels (our bodily iron requirements exceed the amount leached from the steel). Nickel is also at a very safe level. You should avoid scrubbing the pots with abrasive scrubbers, or if you do, wash them with detergent and water afterwards, and rinse very very thoroughly. You should gnerally not need to use abrasives on stainless steel after steaming or boiling. Only after frying, does food stick.
Boiling and steaming cook by raising the natural water inside vegetable, to the same temperature as the water they are steamed or boiled in. This causes cell walls to break down, and nutrients, and flavoring substances, to leave the vegetables, and go into the water. Microwaves cook by causing the natural water inside vegetables, to boil (you should never microwave dehydrated food, as this will both decrease the life of the oven, and cause excessive microwave leakage from the oven). This brings the vegetables to the same temperature that immersing them in boiling water or steam brings them to, and has the same effect, except that when boiling water or steam, the temp of the vegetables rises, from the outside first, then after a time the vegetable piece gets hotter toward the center. Microwaves penetrate vegetable pieces, and the outside and center of the vegetable pieces get hot at about the same time. This is why they cook faster in a microwave oven. Both the outside and the inside are cooked for about the same length of time. With boiling or steaming, the outside of the veg piece ends up being cooked for a longer time than the inside. This can be mostly avoided, made negligable, by cutting into small pieces before cooking. Microwaving allows you the luxury of not having to cut vegetable pieces as small. To me that is not a big deal as I dice vegetables very fast using a chef's knife and cutting board. Cleaning these after dicing vegetables is a matter of wiping the board with a damp cloth and rinsing the knife off under running water for a moment, then drying and putting in a wooden knife holder (to protect the knife edge). Quality stainless steel knives, with houshold use, only need to be sharpened once a month or so. While it does require a bit of know-how, timewise, this is a matter of running a whetstone over the knife edge, a few times, then cleaning the knife.
When you bake in a conventional oven the air in the oven gets much higher in temp than the temp of boiling water, however, the water inside the vegetable you are cooking will not
get any higher. Only the dried out edge of the veg will get higher in temp. Animal flesh, on the other hand because it contains so
much fat, can get a bit higher in temperature, as the fat will reach higher temp than water will reach, and as the water inside the flesh boils away, the dry solids of the flesh reach the temperature of the fat. We are talking about 200 degrees C, or about the same temperature as the air in the oven, 150 to 200 degrees C.