Q. What is meant by unsaturation or saturation of oils and fats?

When it is said that a triglyceride is saturated it means that in its molecule the carbon chain is bound in its maximum capacity to hydrogens, i.e., there are no triple or double bonds between carbons. These saturated molecules are generally solid fats at normal temperature.

Unsaturated triglyceride molecules are those in which there are triple or double bonds between carbons and so they do not accomplish their maximum capacity of hydrogenation. These unsaturated molecules in general are oils, liquid at normal temperature.

The terms unsaturated or saturated refer then to the saturation of the carbonic chain by hydrogen atoms.