Impact of extraction methods on the quality, physicochemical, and functional properties of white melon (Cucumeropsis mannii) seed protein concentrates

Abstract

Protein concentrate extracted from Cucumeropsis mannii using acid precipitation, salt solubilization, and alcohol wash methods were analyzed for the amino acid profile, fluorescence intensity, functional properties such as solubility, water, and oil absorption capacities, and swelling index. Salt solubilized protein concentrate (SSPC) had higher protein content and better yield compared to alcohol-washed and acid precipitated protein concentrates. Fluorescence spectra showed the least intensity for acid precipitated protein concentrate (APPC), indicating that the structure was unfolded compared to others. Glutamic and aspartic acid were the major amino acids in the protein concentrates. The SSPC had the highest amount of hydrophobic and aromatic amino acids. The solubility profile of the concentrates indicated that SSPC had significantly (p ≤ 0.05) highest solubility over a wide pH range (pH 3.0-9.0) in comparison to the APPC and alcohol washed concentrates (AWPC). In contrast, AWPC had significantly (p ≤ 0.05) highest water and oil absorption capacities compared to those extracted using other solvents. The foaming capacity of AWPC was significantly lowered, whilst its solubility index increased with temperature compared to others. Higher percent whiteness and swelling power were recorded in SSPC The Melon protein concentrate could be applied to the food system.

Keywords

• Cucumeropsis mannii, Amino acid, Protein concentrate, Fluorescence
• Functional properties