PROBLEM TO BE SOLVED: To provide soluble reduction type keratin (kerateine) which does not require means such as modification and is not needed to be reduced prior to use while having physical properties such as excellent solubility, a manufacturing method thereof, and composition containing the keratin.SOLUTION: There are provided soluble kerateine obtained by processes (1) to (4) below and a composition containing the kerateine. (1) after α- keratin is reduced at pH9 to 13.5 while adding thioglycolic acid or salt thereof under the presence of water, insoluble residue is removed by filtration to obtain filtrate (2) the obtained filtrate is adjusted to pH2.5 to 7, and generated sediments are recovered and rinsed (3) the recovered sediments are dissolved in alkali solution of pH9 to 12, and thioglycolic acid or salt thereof is added under an inert condition and (4) reaction liquid is adjusted to pH4 to 7, generated sediments are taken by filtration and rinsed to obtain solubilized kerateine.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2016,JPO&INPIT【課題】修飾等の手段を必要とせず、優れた可溶性等の物性を有しながら使用に先立ち還元する必要のない可溶性還元型ケラチン(ケラテイン)およびその製造法並びにこれを含有する組成物の提供。【解決手段】以下の工程(1)~(4)により得られる可溶性ケラテインおよびこれを含有する組成物。(1)水の存在下、α-ケラチンをチオグリコール酸またはその塩を加えてpH9~13.5で還元した後、不溶性残渣をろ去し、ろ液を得る;(2)得られたろ液を、pH2.5~7に調整し、生じた沈殿物を回収し、水洗する;(3)回収した沈殿物を、pH9~12のアルカリ溶液で溶解させた後、不活性条件下でチオグリコール酸またはその塩を加える;(4)反応液をpH4~7に調整し、生じた沈殿物をろ取、水洗し、可溶化ケラテインを得る;【選択図】図3
