Abstract: Traditionally, alkali dissolution and acid precipitation is used for protein extraction. The structure and function of proteins are damaged due to the use of a strong acid or alkali to adjust the pH during the extraction process and, at the same time, the aqueous environment is deterioratedapplication. In order to develop a new extraction method, in the present study, electrolyzed water was used as a solvent to extract seed kernel protein from Citrullus lanatus var. megalaspermus and the extraction efficiency was compared with that of the alkali dissolution and acid precipitation method (using ultrapure water as extraction solvent). The results revealed that at pH 9.5, the yield, solubility, and emulsifying and foaming properties of electrolyzed water extracted seed kernel protein (EWP) were significantly superior to those of ultrapure water extracted seed kernel protein (UWP) (P < 0.05). In the case of essential amino acid composition, cysteine, proline, isoleucine and leucine in EWP were significantly more abundant than in UWP (P < 0.05). Moreover, andwith the secondary structure of EWP was more ordered; the relative contents α-helix and β-sheet (ordered) were 60.2% and 2.3%, and the relative contents of β-turn and random coil (disordered) were 35.8% and 1.7%. In conclusion, compared with ultrapure water extraction, electrolyzed water extraction could not only increase the extraction yield of protein from seed kernels of Citrullus lanatus var. megalaspermus, but also cause less damage to protein structure and function and was an efficient and environmentally friendly extraction method.

Key words: Citrullus lanatus var. megalaspermus seed kernel, protein, electrolyzed water, extraction efficiency