HUMAN NUTRITION

Detailed explanation-1: -In this, test the given sample to be tested is rubbed between the folds of filter paper. The appearance of translucent spot confirms the presence of fats in the given sample. Note: If there is a presence of translucent spot then the presence of fats is confirmed.

Detailed explanation-2: -Fats and oils have higher boiling points so at room temperature they cannot absorb enough heat to evaporate. When fat or oil is place on a sheet of paper, it diffracts light. The diffracted light can pass from one side of the paper to another side and produces a translucent spot.

Detailed explanation-3: -A translucent spot test is also a preliminary test for the lipids, which is characterized by a translucent and greasy spot. The lipid will not wet the filter paper, unlike water. The lipids will form a greasy or translucent spot due to their greasy texture, and penetrate the filter paper.

Detailed explanation-4: -A positive result for a lipid will result in an evenly distributed oily stain remaining on paper after 15 minutes. Water will completely evaporate, and nonlipid substances mixed with water will leave a circular stain.