What are the basic steps of enzymatic browning starting with polyphenol oxidases?
a) Oxidation of polyphenols, formation of o-quinones, polymerization of melanin
b) Reduction of polyphenols, formation of o-quinones, polymerization of melanin
c) Hydrolysis of polyphenols, formation of o-quinones, polymerization of melanin
d) Hydroxylation of polyphenols, formation of o-quinones, polymerization of melanin