Composition and properties of partially hydrolyzed sunflower protein isolates
Ukrainian Food Journal
Keywords: Sunflower Protein Isolate Hydrolysis Proteases Introduction. Partial enzyme hydrolysis of proteins is common method of modification of their functional properties. The characteristics of partially hydrolyzed proteins obtained from sunflower meal are presented in this work. Materials and methods. Proteins of sunflower meal were extracted in the presence of two proteases viz. neutral protease and Alkalase during 40 min. Partially hydrolyzed protein samples were prepared by isoelectric
... ed by isoelectric precipitation and next drying. The polypeptide composition of protein isolates were studied by polyacrylamide gel electrophoresis, degree of protein hydrolysis, amino acid composition, surface activity and functional properties were estimated. Results and discussion. The polypeptides of higher molecular weight (45-54 and about 32-35 kDa) were absent in polypeptide profile of partially hydrolyzed proteins either of proteases. At the same time they were abounded with 14-16 kDa polypeptides and polypeptides with molecular weight lower 14 kDa. Partially hydrolyzed protein samples had higher protein content, lower content of ash and carbohydrates as compared with the control sample. The biological value of sunflower protein isolates were limited by three amino acids -sulfur containing amino acids (methionine and cysteine) and lysine. The content of methionine, cysteine and lysine has been increased in protein samples obtained with neutral protease, relative to protein isolate. Differential scanning calorimetric analyze of protein samples have demonstrated that partially hydrolyzed samples contained undenaturated proteins, but their denaturation degree was higher compared with control samples. Partial hydrolysis of sunflower seed proteins have improved their solubility in pH range from 2 to 8, water holding, oil binding, foaming, emulsifying capacities and surface activity. Conclusions. Partially hydrolyzed protein samples had higher protein content, lighter color, lower degree of denaturation and better functional properties compared to the traditional protein isolates.