MadSci Network: Physics |
Hi, Anna. The length of time a food is in a microwave oven certainly is correlated to moisture loss in that food, but a general relationship - other than saying that the longer the time, the greater the moisture loss - is difficult to state. There are so many parameters, besides time. that will also influence the moisture loss. You asked for some key words to head your thoughts and searches in the right direction. Some ideas to pursue are: depth of food, ability to conduct heat, composition of food (one item or several parts to it), density, wattage of the MW oven, surface area, exposure (is food in a covered container or sitting on a paper towel), free water versus bound water (probably not with the result you would expect). There are two ways to look at your question regarding the influence on the concentration of water in the food. Are you looking at the change in overall moisture content in the food before and after microwaving? Or, are you looking at how the water concentration patterns change within the food itself? (At first microwaves drive moisture out from just under the surface of the food so the concentration in the center is stable for a time. Then the moisture is driven from the center out.) Special microwave ovens are often used in laboratories to quickly determine the moisture content in foods. (Older methods with more traditional types of lab ovens could take several hours of drying time.) A number of companies supply these lab microwave ovens and often provide a lot of useful information about the technology on their web sites. If you are interested in more, try checking out http://www.cemx.com Carol Crouse Food Technologist The Food Chain Ltd.
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