var claims = new List<Claim>();
claims.Add(new Claim(ClaimTypes.Name, "some Name"));
claims.Add(new Claim(ClaimTypes.Email, "abc@xyz.com"));
var identity = new ClaimsIdentity(claims, DefaultAuthenticationTypes.ApplicationCookie);

var ctx = Request.GetOwinContext();
var authenticationManager = ctx.Authentication;
authenticationManager.SignIn(identity);

var identity = (ClaimsPrincipal)Thread.CurrentPrincipal;
string email = identity.Claims.Where(c => c.Type == ClaimTypes.Email).Select(c => c.Value).SingleOrDefault();