Complex Formation between Groundnut Skin Pigments and Conarachin II

Abstract

WHEN defatted groundnut meal containing a portion of the red skins of the nut was extracted with 10 per cent (w/v) sodium chloride solution and the extract dialysed against phosphate–sodium chloride buffer, ionic strength I 0.5, pH 8, the sedimentation-velocity diagram (Fig. 1a) revealed the presence of three components: arachin, the major component (sedimentation constant, s°₂₀ = 13.3 S., conarachin II (s°₂₀ = 8.4 S.) and conarachin I (s°₂₀ ≈ 2 S.)¹. When the extraction was carried out at pH 8–9 with sodium hydroxide, the solution was considerably more red in colour, the conarachin II component was less apparent, and the presence of a fourth, very fast sedimenting component (s°₂₀ = 32 S.) was observed (Fig. 1b). This fast component was absent, however, in extracts of blanched nuts or white skinned nuts. It would therefore appear to be connected with the presence of the red skin pigments in the meal.