chapter  4
Chemistry of Waxes and Sterols
Pages 26

I. Chemistry of Waxes ................................................................................................................ 99 A. Introduction...................................................................................................................... 99 B. Properties and Characteristics of Waxes ....................................................................... 100

1. Physical Properties of Waxes ................................................................................. 100 2. Chemical Properties of Waxes ............................................................................... 101 3. Properties of Important Naturally Occurring Waxes.............................................. 102

C. Isolation, Separation, and Analysis of Natural Waxes .................................................. 102 1. Isolation .................................................................................................................. 103 2. Separation ............................................................................................................... 103 3. Analysis .................................................................................................................. 105

D. Biosynthesis of Natural Waxes ..................................................................................... 105 II. Chemistry of Sterols.............................................................................................................. 106

A. Introduction.................................................................................................................... 106 B. Biosynthetic Origins of Sterols...................................................................................... 107

1. Cholesterol Biosynthesis......................................................................................... 107 2. Biosynthesis of Plant Sterols .................................................................................. 111

C. Regulation of Sterol Biosynthesis in Animals............................................................... 112 D. Cholesterol Metabolism................................................................................................. 114 E. Chemistry of Vitamin D and Related Sterols ................................................................ 115 F. Analysis of Sterols ......................................................................................................... 118

1. Extraction of Sterols ............................................................................................... 118 2. Isolation of Sterols.................................................................................................. 119 3. Characterization of Sterols...................................................................................... 120

References ..................................................................................................................................... 121

The term waxes commonly refer to the mixtures of long-chain apolar compounds found on the surface of plants and animals. By a strict chemical definition, a wax is the ester of a long-chain acid and a long-chain alcohol. However, this academic definition is much too narrow both for the wax chemist and for the requirements of the industry. The following description from the German Society for Fat Technology [1] better fits the reality:

Wax is the collective term for a series of natural or synthetically produced substances that normally possess the following properties: kneadable at 208C, brittle to solid, coarse to finely crystalline,

even slightly above melting point, not tending to stinginess, consistency and solubility depending on the temperature and capable of being polished by slight pressure.