HTM 2700 Lecture Notes - Lecture 6: Isoelectric Point, Peptide, Georgian Lari

• School: University of Guelph
• Department: Hospitality and Tourism Management
• Course: HTM 2700
• Professor: Alison Crerar

Document Summary

The point where the amino acid (a protein molecule) no longer has an electrical charge. The like charges of the protein are no longer repelling each other, which makes them unstable. Protein molecules are then attracted to each other and form hydrogen bonds with each other creating larger molecules. Each protein has a different iep (ph value) where the negative charges are neutralized around the protein molecule. When proteins are no longer colloidally dispersed they precipitate out of colloidal dispersion. Proteins in food exist at a ph different than their iep. Therefore, they exist as stable colloidal dispersions. E. g. milk has a ph of 6. 5-6. 7. Casein proteins in milk have an iep of ph 4. 6. Proteins are sensitive to changes in: ph - least stable at their iep, temperature. Also decreases (e. g. freezing: mechanical action - beating of egg whites. Any of the above results in: denaturation and possibly, coagulation.