Preparation of functional lupine protein fractions by dry separation

Samenvatting

Lupine protein concentrate is a promising ingredient that can be obtained by a combination of milling and air classification, generally called dry fractionation. This is a more sustainable route than conventional wet extraction and delivers a protein concentrate with native functional properties. Critical is the detachment of the protein bodies from other seed components during milling. Ideally, the protein bodies are released during milling, whereas the other components remain in larger particles (D0.5 > 40 µm) to facilitate effective air classification. Coarse milling (down to 100 µm) followed by air classification gave concentrates with protein contents between 54 and 59 g protein/100 g dry solids and yields up to 13%. The application of flowability aids (fused silica particles) during air classification doubled the yield of the protein-rich fraction. The air classified protein concentrate could provide a 2.3 times extended half-life of the foam compared to an intensively heated protein concentrate. In addition, the viscosity of the native concentrate was lower, while after (in vitro) digestion the amount of proteins smaller than 3 kDa was higher in native and mildly heated concentrates compared to intensively heated concentrate. These results suggest promising development of liquid-like formulations from air classified lupine protein concentrates.