Abstract
(1) The change of fat in Gyomiso during the ripening was studied.
(2) The matter extracted by ether increased at the beginning of ripening. This is due to the fact that the ether extracted protein, lecithin, in addition to the fat. Then the amount of the ether extracted matter decreased gradually. This is due to the creation of ether non extracting matter and the action of lipase.
(3) The acid value increased slowly until the 10th day and there-after increased rapidly, and then decreased.
The increasing of the acid value is due to the autolytic creation of the decomposed fat, the existence of fish meat protein along with the decomposed protein, and the catalytic action of salt and lipase. The decreasing of the acid value thereafter is due to the creation of organic bases owing to the decomposition of the protein and therefore the formation of soap.
(4) The saponification value was not necessarily a constant value.
(5) The iodine value decreased in the process of ripening.
(6) The color of the ether extracted matter varied from ligth yellow to dark brown owing to the existence of the protein, the creation of its decomposed matter and the catalytic action of ammonium soap.
