I don't know about the fifth taste...but I do remember Terry Pratchett's five particles of magic:

"It was here that the thaum, hitherto believed to be the smallest possible particle of magic, was succesfully demonstrated to be made up of resons (Lit.: 'Thing-ies') or reality fragments. Currently research indicates that each reson is itself made up of a combination of at least five 'flavours', known as 'up', 'down', 'sideways', 'sex appeal' and 'peppermint'."

-- (Terry Pratchett, Lords and Ladies)