I am a Canadian living in Brazil...and i too had a difficult time finding black strap molasses...from research you are correct...spanish and portuguese is a very similiar language and in portuguese it's called "Molado de Cana"
it is not as dark as the molasses i get in canada nor as thick but you do have the right stuff...
try to find some that does not have any preservatives ...
best of luck...i am on my 9th day of fasting..it is worth it...