Pharmaceutical Analysis

Chapter 1

Analysis of Food Components

CRUDE PROTEIN ANALYSIS (NITROGEN DETERMINATION)

• Nitrogen is a commonly occurring element in most foods in the form of proteins as organically bound nitrogen.
• Other nitrogen compounds are present in minor proportions which are non-proteins such as nucleic acids, alkaloids, nitrogen, lipids, pigments, vitamins and stimulants.
• The labelling of food regulations 1970 given specifications for proteins at least 12% calorie content is provided by proteins present in foods.
• The crude protein is determined by the following:
  1. Kjeldahl method: macro and semi-micro
  2. Formal titration
  3. Colorimetric method
  4. Other methods
  1. Kjeldahl method: This method involves first heating the sample with conc. H₂SO₄ in a long necked digestion ...