The composition of a gel formed when wheat flour is suspended in phenol‐acetic acid‐water (1:1:1, w/v/v)

Abstract

AbstractA gel which formed when wheat flour was suspended in phenol‐acetic acid‐water (1:1:1, w/v/v/) was fractionated into a protein‐rich soluble fraction and a carbohydrate‐rich insoluble fraction. Gel electrophoresis showed that the soluble fraction contained several proteins and had an amino acid composition with a high content of proline and glutamyl residues and a low content of lysine. The soluble fraction also contained lipids which were mainly phospholipids, phospholipid derivatives and glycolipids and other compounds, which yielded galactose and glucose after acid hydrolysis. The insoluble fraction contained a polysaccharide with similar properties to starch, and lipids which were mainly neutral fats, sterols and sterol esters. Both fractions contained arabinoxylans and mannans. The gel did not contain any nucleic acids. The protein‐rich soluble fractions of gels prepared from other wheat flours and air‐classified flour fractions, from wheat gluten and from rye and barley flours, showed marked differences in amino acid composition. It is concluded that a heterogeneous class of proteins, rather than specific proteins in fixed proportions, is involved in gel formation.