TABLE OF CONTENTS All food is of animal, plant or microbial origin. As such, the original living organism manufactures and uses many chemicals that will not be required by another organism that uses it as a food. Most of these are completely innocuous at the levels consumed, having no role in or effect on human nutrition. Some have specific properties that maintain the structure and composition of the food (e.g. pectin in fruit). Others, as described above, are actually beneficial to human health. Others that may cause health problems, we have learned to deal with. A common example of this is the lectins in kidney beans; these have to be rendered harmless by soaking and vigorously boiling the beans before eating them. A more extreme example is puffer fish, a delicacy in Japan, which must be prepared in a precise fashion as it contains a lethal toxin. Others we just live with like the dozens of compounds in onions that make us cry. This chapter describes some examples of these groups of compounds and looks at how food manufacturing is affected by them.
The majority of flavour chemicals have no role in nutrition at all (although some nutrients such as sugars do contribute to flavour), but they do actually help to persuade us to eat the food that we need to eat, and are therefore quite important! Of course, at times, they may persuade us to eat things that perhaps we could do without (at least in the volumes...
