15B-11 |
Influence of physicochemical characteristics of hydrolyzed whey proteins on their antioxidant activity |
E. A. PEŅA-RAMOS, Animal Derived Food Department /Meat Science Lab, CIAD, A.C., P.O. Box 1735, Hermosillo, 83000, Mexico, Y. L. Xiong, Animal Sciences, Food Science Section, University of Kentucky, 206 W.P. Garrigus Bldg., Lexington, KY 40546, and G. E. Arteaga-MacKinney, Quality Assurance, Grupo Industrial MASECA, Ave. La Clinica 2510, Monterrey, 64710, Mexico. Size-exclusion chromatography (SEC) can separate antioxidative peptide fractions from whey protein hydrolysates (WPH). The antioxidant activity of these peptides appears to be related to their nature and characteristic amino acid content. Several antioxidative peptide fractions with different amino acid compositions have been separated from various protein sources. Multivariate analysis offers a useful tool for evaluating whether an alteration in the concentration of some particular amino acids could affect the ability of WPH fractions to act as lipid oxidation inhibitors. The objective was to establish the relationship between physicochemical characteristics of whey and soy peptides and their antioxidative activity using multivariate analysis. SEC was used to isolate antioxidative peptide fractions from WPHs, established based on thiobarbituric acid-reactive substances analysis in a liposome system. Amino acid composition was determined by HPLC. The influence of amino acid composition and peptide molecular weight (pMW) on antioxidant activity was evaluated using correlation analysis, principal component analysis (PCA), discriminant analysis (DA), and multiple linear regression (MLR). Lysine, isoleucine, valine, histidine, and pMW presented the highest correlation coefficients with liposamal oxidation inhibition. PCA resulted in four main principal components (PC). Peptide fractions exerting the strongest inhibitory effect had high PC1 scores, which were attributed to low pMW and preponderance of hydrophobic amino acids, Lys, and His. DA led to two discriminant functions; His, Pro, Val, Leu and pMW were the variables that allowed a 100% discrimination between low, medium, and high antioxidative peptide groups. Antioxidative ability exhibited by WPH peptides was related to high concentrations of histidine and some hydrophobic amino acids and to their low molecular weights. Models obtained by multivariate analysis methods can be used to predict and classify the antioxidative potential of various peptide fractions on the basis of their pMW and amino acid composition.
Session 15B, Dairy Foods: Chemistry, microbiology and sensory analysis of various cheeses
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