Extraction of Agar from Gelidium Seaweeds by Use of the Commercial Polyphosphates

The selected commercial polyphosphates which are approved as the food additives were used in the cooking process of four kinds of seaweeds of Gelidium species in order to find out ohe appropriate conditions for extraction of agar.When the polyphosphates were used alone without sulfuric acid, the extraction of agar from Gelidium subcostatum was effectively promoted, but they were not so effective to Gelidium pacificum and Gelicium amansii as sulfuric acid. On the other hand, when the polyphosphates were used together whth sulfuric acid, the extractability of agar from Ge. amansii as well as from Ge. subcostatum was practically much improved.With respect to gel strength (jelly strength in old term) of the extracted agar, polyphosphate containing 67-68% of P2O5 was better than the one containing 75% of P2O5.(Note: The term 'jelly strength of agar' used elsewhere by the first author shall be amended as 'gel strength of agar', hereafter.)