The term "enzymes" usually means alpha-amylase enzyme. Most frequently, it is in the form of a diastatic barley malt. There is also a fungal alpha-amylase, but if I had to guess I would say that the Mondello flour you mentioned most likely includes barley malt (diastatic) as the source of the alpha-amylase enzyme. Either way, the purpose of the enzyme is to extract more sugar from the damaged starch in the flour. I recently saw a Mexican all-purpose flour that also uses the term enzymes in the list of ingredients.