Effect of Enzymatic Protein Deamidation on Protein Solubility and Flavor Binding Properties of Soymilk
Article first published online: 21 DEC 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 78, Issue 1, pages C1–C7, January 2013
How to Cite
Suppavorasatit, I., Lee, S.-Y. and Cadwallader, K. R. (2013), Effect of Enzymatic Protein Deamidation on Protein Solubility and Flavor Binding Properties of Soymilk. Journal of Food Science, 78: C1–C7. doi: 10.1111/j.1750-3841.2012.03012.x
- Issue published online: 9 JAN 2013
- Article first published online: 21 DEC 2012
- MS 20120601 Submitted 4/28/2012, Accepted 10/21/2012.
- odor detection threshold;
- protein deamidation;
- protein glutaminase;
- protein solubility;
Abstract: The effect of enzymatic deamidation by protein-glutaminase (PG) on protein solubility and flavor binding potential of soymilk was studied. Treatment of soymilk with PG for 2 h (temperature of 44 °C and enzyme:substrate ratio (E/S) of 40 U/g protein) resulted in high degree of protein deamidation (66.4% DD) and relatively low degree of protein hydrolysis (4.25% DH). Deamidated (DSM) and control soymilks (CSM) did not differ with respect to aroma, but differed in taste characteristics by sensory evaluation. Protein solubility in DSM was enhanced at weakly acidic conditions (pH 5.0), but did not differ from non-deamidated soymilk at pH values of 3.0 and 7.0. Odor detection thresholds for the flavor compounds vanillin and maltol were approximately 5 and 3 fold lower, respectively, in DSM than in CSM. Dose-response curves (Fechner's law plots and n exponents from Stevens's power law) further demonstrated that DSM had a lower flavor binding potential than CSM. PG deamidation has the potential to reduce flavor binding problems encountered in high protein-containing foods and beverages.
Practical Application: The findings of this study can help lead to the development of technology to produce protein-containing foods with improved functional properties, especially protein solubility, and potentially decreased flavor fade problems associated with flavor-protein interactions, especially with carbonyl containing flavor compounds.