The chemical complexity of food provides for the interactions of different classes of biomolecules. These, in turn, can lead to desirable or undesirable consequences. Presentations in this sesssion are centered around the reactions of proteins/peptides with other biomolecules (water, flavors, carbohydrate and lipids). The effects on structure and function of the component reactants (that is, protein/peptide and other molecule classes) are significant and can help explain the basis for quality loss in food. In particular, the speakers will address interactions of proteins/peptides with the following: (1) polysaccharides, and the effects on emulsion stability and encapsulation; (2) tannins, and the impacts on volatility and aroma intensity in solution; (3) water, and control of ice-crystal growth; and (4) lipid oxidation products, and the concurrent loss of redox stability and potential loss of heme iron. The specific examples elucidated in these talks will provide the basis for understanding the potential effects of similar reactions in other food products.