title: Effect of pH and pepsin limited hydrolysis on the structure and functional properties of soybean protein hydrolysates.
abstract: Effects of limited enzymatic hydrolysis with pepsin on the functional properties and structure characteristics of soybean proteins were investigated. Hydrolysates with different incubation time (10 to 900 min) were prepared. Results showed that SPI hydrolyzed for 60 min exhibited the best emulsibility and the ability of resisting freezing/thawing. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis proved that pepsin can degrade glycinin but had little effect on the α' subunit of β-conglycinin. The structure unfolding reached the largest extent after incubation for 60 min and the soluble and flexible aggregates were formed. After 120 min, glycinin was degraded totally and β-conglycinin formed insoluble aggregates. Moreover, 2 methods were applied for the deactivation of pepsin to obtain final hydrolysates at pH 2.0 and 7.0, respectively. The structure analysis revealed that the unfolding extent and structure characteristic were different in these 2 conditions. When adjusting the pH value from 2.0 to 7.0, the unfolding protein molecular would reaggregate again at pH 7.0 due to the charge neutralization, and the hydrodynamic diameter and λmax absorbance decreased compared to pH 2.0. Moreover, some of the insoluble aggregates formed at pH 2.0 became soluble at pH 7.0, because of the salt-in phenomenon.
authors.affiliation: College of Light Industry and Food Sciences, South China Univ. of Technology, Guangzhou 510640, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Cui
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
authors.forename: Boen
authors.initials: B
authors.lastname: Yuan
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Ren
mesh_terms: D052179:Antigens, Plant / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005511:Food Handling; D005916:Globulins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D010316:Particle Size; D010434:Pepsin A / Q000737:chemistry*; D011492:Protein Hydrolysates / Q000737:chemistry*; D055314:Seed Storage Proteins / Q000737:chemistry*; D030262:Soybean Proteins / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry
chemical_list: D052179:Antigens, Plant; D005916:Globulins; D011492:Protein Hydrolysates; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; C011474:glycinin; D010434:Pepsin A
keywords: functional properties; limited proteolysis; pepsin; soybean protein; structure change