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 patt ern. 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 intern al lipids, included triglycerides (45%), free fatty acids (FFA, 39%), lysophospholipids (10%) and diglycerides (6%). The major fatty acids f ound in polar and FFA fraction were palmitic, oleic and linoleic acids . Cow cockle starch exhibited similar viscoamylograph viscosity, solub ility and swelling profiles to those of rice starch. Concentrated star ch gels also showed the typical viscoelastic behavior of non-waxy cere al starches. In vitro digestibility studies of cow cockle granular sta rch with B. subtilis indicated that this starch, compared to rice, is very susceptible to alpha-amylolysis presumably because of its small g ranule size.