CASEIN HYDROLYSATE .2. FUNCTIONAL-PROPERTIES OF PEPTIDES

Acid casein was continuously modified using immobilized (IM-) trypsin, chymotrypsin and Rhozyme-41. The objective was bulk production of hydrolysates with desirable functional attributes. The degree of modification was controlled by regulating the flow rate through an IM-enzyme bioreactor at 4-degrees-C. Polyacrylamide gel electrophoresis indicated little change in the major caseins. C18 reverse phase high performance liquid chromatography (HPLC) on the other hand showed the formation of large amounts of peptides only at the highest level of treatment. C-8 HPLC, following the selective extraction of peptides by membrane filtration, showed small amounts of peptide mixtures even in the least treated samples. The emulsifying properties of the casein was markedly improved by modification. IM-Rhozyme-41 gave up to a 3.2-fold increase in the emulsifying activity, whereas emulsion stability was improved using IM-trypsin. Oil holding capacity of the preparations was best when IM-trypsin was used even though all the enzymes tested improved it markedly. The solubility and thermostability of all levels of treatments were far better than those for the control.