Antibiotics can be classified in diff erent ways.
Antibiosis is a process in which one organism may destroy another to survive. The term antibiotic was first of all introduced by Vuillemin in 1889. ‘Antibiotic is a chemical substance produced by or derived from living cells which are capable, in small concentrations, of inhibiting the life process or even destroying the microorganisms.’
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…
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.
Definition: Iodine number is defined as the number of grams of iodine absorbed by 1 gram of fat. Example: Human fat: 65 – 69 Butter: 25–40 Coconut oil: 7 – 10 Significance Iodine number measures the degree of unsaturation of fatty acids in the fat. The iodine number for solid fats is lesser than that…