These are fatty acids which do not contain double bonds. They do not exhibit addition reactions, and their iodine values are nil. Generally, the presence of saturated fatty acid makes the fat solid. They are built up on acetic acid, which is the first member of the series. General formula for saturated fatty acids is…

Saturated fatty acids do not contain double bonds, while unsaturated fatty acids contain one or more double bonds, whereas saturated fatty acids do not contain double bonds. Saturated and unsaturated fatty acids are equally present in the natural lipids. If fatty acids contain one double bond, they are known as monounsaturated and if they contain…

Most of the fatty acids that occur in natural lipids are of even carbons (14C–20C). Among the odd chain fatty acids, propionic acid (3C) and valeric acid (5C) are well known.

Fatty acids are divided into three types:

Fatty acid is an important constituent of fat. It is a monocarboxylic acid with a hydrocarbon chain. The length of the chain may vary from 2 to 34 carbon atoms. It is obtained by the hydrolysis of fats by acids, alkalis, or enzymes. Almost all the fatty acids found in nature have straight chain and even…

Significance: The importance of waxes in plants and animals is that they serve as protective agents. The waxy coating on the surface of plants prevents excessive loss of moisture. The waxy coating over fruits like apple and citrus fruits prevents them from drying and from being infected with fungi and bacteria. In birds, the presence of…

Waxes are esters of fatty acids with alcohol other than glycerol. One such alcohol is cholesterol. They are insoluble in water but soluble in fat solvents. They are not easily hydrolysed like fats or digested by lipases. Therefore, they are of no value nutritionally.

Definition: Acetyl number is defined as the number of milligram of KOH required to completely neutralise the acetic acid obtained by saponification of 1 gm of fat after it has been acetylated. (The treatment of fat or fatty acid mixture with acetic anhydride results in acetylating of all alcoholic OH groups.) Example: Butter: 17–35   Coconut…

Definition: Reichert–Meissl number is defined as the number of 0.1 N KOH required to completely neutralise the soluble volatile fatty acids distilled from 5 gm of fat. Example:   Butter:    25–30 Significance: RM number is useful in testing the purity of butter since it contains a good concentration of volatile fatty acids. Butter has RM number in the range of…

Definition: Polenske number is defined as the number of millilitres of 0.1 N KOH required to neutralise the insoluble fatty acids (those which are not volatile with steam distillation) obtained from 5 gm of fat. Example: The Polenske number is usually negligible or very low in pure ghee.