Abstract:

In the present study, lotus seed peelpowder protein (LSPP) and lotus seed protein (LSP) were extracted by alkali
solubilization and isoelectric precipitation. Sodium dodecyl sulfonate-polyacrylamide gel electrophoresis (SDS-PAGE)
and size-exclusion high performance liquid chromatography (SEC-HPLC) were used to examine the differences in the
composition of the extracted proteins. Differential scanning calorimetry (DSC) and Fourier transform infrared spectrometer
(FT-IR) were used to characterize some properties and structures of LSPP and LSP. The results showed that the extraction
rates of proteins from lotus seed peel powder and lotus seed were 72.24% and 78.93%, respectively. SDS-PAGE analysis
revealed that the molecular weights of LSPP subunits were distributed in the range from 15 to 70 kD, while those of LSP in
the range from 10 to 45 kD. SEC-HPLC also revealed that LSPP was composed of a larger number of molecular fractions
than LSP. DSC analysis showed that denaturation peak temperatures of LSPP and LSP were 118.28 ℃ and 108.05 ℃,
respectively, and the former had a higher enthalpy of denaturation. These results combined with FT-IR analysis results
showed that the conformation of LSPP was more regular.

Key words: lotus seed, peel powder protein, molecular property