Changes in the TTC reducing ability and in the contents of a few chemical constituents were studied periodically on the fronds of Porphyra sp. during a six months storage in frozen state (-25℃). The results obtained can be summarized as follows:
1) The TTC reducing ability declined in the frozen fronds either stored in the air or in nitrogen gas; it dropped to one tenth and one fifth of the initial level, respectively, after six months storage. In both cases, rapid decrease occurred during the first two months of freezing storage.
2) Chlorophyll a contents were almost constant in the fronds during the storage.
3) Little changes were observed in the total nitrogen contents of the fronds regardless to the storage period.
4) Extractive amino acids such as aspartic acid, glycine, alanine, isoleucine and threonine and/or serine showed tendencies to decrease during the storage. Among these amino acids, aspartic acid and isoleucine had the most conspicuous rates of diminution.
5) Extractive nitrogen contents in the frozen thalli decreased gradually to about 60% in the air and to about 70% in nitrogen gas within the six months.