Effect of Preparation Methods of Yeast Protein Isolate on Emulsifying Capacity

Abstract

The previous methods for recovery of yeast proteins and reduction of the nucleic acid content resulted in low yields of the protein and impairment of the desirable functional characteristics. In this paper, emulsifying properties of yeast protein isolates prepared with three different methods (yeast protein isolate I, II and III) were studied in comparison with those of a soy protein and a caseinate at various pH's, ionic strengths and lecithin contents (%). The emulsifying capasity of the yeast protein isolate I prepared by the method of authors were far superior to those of the soy protein and caseinate, especially in acidic and alkaline region. However, yeast protein isolate II and III prepared by the previous method gave low emulsifying capacity, which was similar to those of the soy protein or caseinate. From these results, it was suggested that emulsifying properties of the yeast protein isolate was largely influenced by the preparation methods of the protein.