Lipase and protease activities in Koji cheeses surface-ripened with <i>Aspergillus</i> strains

Abstract

Koji molds are safe microorganisms belonging to the genus Aspergillus and are used in the production of traditional Japanese fermented foods, such as miso, soy sauce, and sake. Koji molds produce many types of enzymes, including amylase, lipase, and protease, that are used in food processing treatments. To examine the potential of Koji molds for cheese ripening, we measured the lipase and protease activities on cheese curds ripened using five strains of Koji molds (Aspergillus oryzae or A. sojae) and compared them with curds ripened using Penicillium candidum or P. roqueforti. Compared with Penicillium, Koji molds showed similar or higher protease activity on the cheese surface. Lipase activity varied markedly among Koji mold strains; some showed comparable activity to Penicillium, and others showed lower activity. Considering the lipase and protease activities, some Koji molds can be applied to the production of surface mold-ripened cheeses.