An integrated laboratory experiment for the determination of main components in different food samples

An integrated laboratory experiment was designed for introducing biochemistry students to basic static biochemistry to deepen their understanding on the properties and analysis of biomolecules such as total carbohydrates, lipid, protein, and protein-constituent amino acids. Food represents a very important source of biomolecules of technological and functional interest; therefore, 15 types of food samples were selected to demonstrate the analysis of basic composition of these biomolecules. In this experiment, students learnt testing the total carbohydrates of all the food samples using 3,5-dinitrosalicylic acid (DNS) method, while performing acid hydrolysis. Then, lipid extraction was done using Soxhlet extraction method in order to determine the crude lipid concentration in different samples. After this, the students learnt testing crude protein content of these samples by using Kjeldahl method, and amino acid analysis was performed using HPLC. From the experiments, students grasped the concept and advantages of these methods and deepened their understanding on compositional analysis of different food samples. This laboratory exercise can be included into any college-level biochemistry courses and gives hands-on experience to the students for conducting scientific research in the field of life sciences, food science, and other bio-related fields.