COMPOSITION AND PHYSICOCHEMICAL PROPERTIES OF STARCH FROM COW COCKLE (SAPONARIA-VACCARIA L) SEEDS

Starch isolated from two accessions of cow cockle (Saponaria vaccaria L.) seeds consisted of uniform size polygonal granules 0.3-1.5 mum in diameter, having 18% amylose content and a melting peak temperature 68-degrees-C. The intact granules gave the A-type X-ray diffraction pattern. The debranched starch exhibited the typical bimodal distribution of amylopectin chains (CL 45 and 12) on Biogel P-10. Lipids associated with the cow cockle starch preparations, involving surface and internal lipids, included triglycerides (45%), free fatty acids (FFA, 39%), lysophospholipids (10%) and diglycerides (6%). The major fatty acids found in polar and FFA fraction were palmitic, oleic and linoleic acids. Cow cockle starch exhibited similar viscoamylograph viscosity, solubility and swelling profiles to those of rice starch. Concentrated starch gels also showed the typical viscoelastic behavior of non-waxy cereal starches. In vitro digestibility studies of cow cockle granular starch with B. subtilis indicated that this starch, compared to rice, is very susceptible to alpha-amylolysis presumably because of its small granule size.