Floridean Starch

A survey was made of about 30 species of red algae from thePacific Coast to find the best starting-material for the isolation,in pure and native form, of the controversial substance, florideanstarch. Constantinea subulifera Setchell turned out to be theideal alga for this purpose. The isolated starches were subjectedto a number of physical, chemical, and enzymatic tests in orderto bring out possible differences from other starch-family substances,such as amylopectin and glycogen, isolated from higher plants.According to all criteria applied there is no real differencebetween the various compounds, except for the fact that florideanstarch gelatinizes only after very long boiling in water. End-groupdeterminations with the aid of periodate show that the florideanstarch molecule is a strongly branched structure somewhat comparableto glycogen.