Moisture-Absorption and Water Dynamics in the Powder of Egg Albumen Peptide, Met-Pro-Asp-Ala-His-Leu.

Moisture absorbed into the powder of Met-Pro-Asp-Ala-His-Leu (MPDAHL)-a novel egg albumen antioxidant peptide-profoundly affects its properties. In this study, we elucidated water dynamics in MPDAHL using DVS, DSC, and low-field H NMR. Based on the DVS data, we found that MPDAHL sorption kinetics obey a parallel exponential model. DSC results indicated that both water and heating could change the microstructure of MPDAHL. The T parameters of NMR reflected the different phases of moisture absorption revealed that there were 4 categories of water with different states or mobility in the MPDAHL during the moisture absorption process. The fastest fraction T mainly dominated the hygroscopicity of MPDAHL and the absorbed water significantly changed the proton distribution and structure of MPDAHL. Thus, this study shows that DVS, DSC, and low-field H NMR are effective methods for monitoring water mobility and distribution in synthetic peptides. It can be used to improve the quality assurance of functional peptides.