Tufts Medical Center, its physician group, and the publicly-traded parent company of MetroWest and St. Vincent hospitals have been awarded an $88.5-million loan by the federal government to create what would be the state's only member-owned health insurance plan. The nonprofit Minuteman Health Initiative expects to offer coverage starting in January 2014 to individuals and small businesses through the state's virtual health insurance market, the Massachusetts Health Connecter, and through insurance brokers. The organizers say the plan's ownership structure would help it to hold down costs.