Abstract:

The contents, subunit compositions and molecular weight distribution of total protein and proteins with differentsolubility in lotus seed and its peel waste were analyzed using Kjeldahl method, sodium dodecyl sulfate-polyacrylamidegelelectrophoresis (SDS-PAGE) and size exclusion chromatography-high performance liquid chromatography (SEC-HPLC).The results showed that the protein contents of lotus seed and its peel waste were 188.10 and 186.54 mg/g, respectively.They were similar in terms of the composition of proteins with different solubility; water and salt soluble proteins as well asacid and alkali soluble proteins altogether represented more than 60% and less than 23% of the total proteins, respectively.The SDS-PAGE profiles of proteins from lotus seeds and its peel waste showed a high similarity, and the molecular weightsof main protein subunits were 15–20 and 30–50 kD. The HPLC elution patterns of total and water soluble proteins in lotusseed and its peel waste were highly similar, indicating similar molecular weight distribution, except that the elution peaksof acid soluble proteins and relative intensity of alkali soluble proteins separated from lotus seeds were more or larger thanthose from its peel waste. This study proved that the peel waste had similar protein composition characteristics with lotusseed, and could be used as an alternative material for producing lotus seed protein powder or other related foods.

Key words: lotus seed, peel waste, by-products, protein, composition, comparison