Could you offer some support for this claim? There is a recent book called "Illiberal Reformers" that seems to suggest exactly the opposite: that minimum wage policies were put in place with the intent of putting minorities out of work (rather than raising their standard of living).
See some of the quotations here:
http://www.econtalk.org/archives/2016/12/thomas_leonard.html
""" The low-standard or undercutting-of-wages part of the theory, got its start with the violent activism of white Americans against Chinese immigrant workers. The title of a pamphlet published by the American Federation of Labor trenchantly captured the heart of the claim: Meat versus Rice: American Manhood against Asiatic Coolieism, Which Shall Survive? If wages were determined by living standards rather than by productivity, then the meat-eating Anglo-Saxon could not compete with the Chinese worker accustomed to eating rice.
Professor Woodrow Wilson, in his popular History of the American People, preferred the same theory of low-standard races undercutting American wages, adding a fillip of racism to cement the notion that race explained the low standards. White laborers, unable to "live upon a handful of rice for a pittance," could not compete with the Chinese, "who with their yellow skin and strange debasing habits of life seemed to them hardly fellow men at all but evil spirits, rather." """