How does one determine the nutritional content of food?!
Answers: I just asked this in the chemistry section & got 1 answer that didn't really answer my question. Also, someone tried to ask this before, but no one really understood what they were trying to ask. What I want to know is, what is the exact process for finding the caloric content of, say, an apple (or any foodstuff)? I don't mean where do you look it up. I mean in the1st place, what do they do to find these values? How do they know what vitamins, minerals, amount of fiber/carbs, etc. are in there?
All these tests are run in the laboratory originally. Calories for example are determined with a bomb calorimeter. Vitamins are usually analyzed for using HPLC or another form of chromatography. Minerals are calculated using an ashing process. And individual mineral can be done by wet chemical methods or spectrometry. Protein can be done by several methods the first was by Kejdahl (sp?) and fiber by chemical destruction. There are whole books written on analysis of foodstuffs. The most complete is the AOAC methods book. It is used as the official referee in legal disputes.
PhD Food Chemistry and Nutrition