Production and properties of rapeseed albumin

Rapeseed is one of the main sources of vegetable proteins worldwide. After oil extraction the protein enriched rapeseed meal is used as it is exclusively for animal feeding, having a low added value. This Special Feature describes a novel technology to produce pure rapeseed proteins. The purification scheme consists of gentle oilseed processing, aqueous protein extraction, precipitation of cruciferin and expanded bed adsorption ion exchange chromatography for isolation of pure napin. The purity of the resulting napin is >98%, and the purity of cruciferin is >95%. With the same methodology but appropriately modified process conditions a defined protein mix consisting of about 56–57% napin and 43–44% cruciferin is obtained. In comparison with egg albumin, the functional properties of napin showed better (for thermal stability) or comparable properties (for solubility, film formation, emulsion stability) and thus napin could replace animal albumins in various applications. Cruciferin and the blend with napin possess excellent foaming properties.