Formation of Methyl Ketones from Milk Fat by Fungi Isolated from Camembert Cheese

Studies on the Production of Flavors by Biochemical Methods Part V

Abstract

It was observed that Penicillium sp. TK-2087 (tentatively identified as P. caseicolum) isolated from Camembert cheese could remarkably produce methyl ketones when cultivated on whole milk (or whole milk powder solution). C₃, C₅, C₇, C₉, C₁₁, C₁₃ methyl ketones were detected in the distillate from the cultured broth. Methyl ketones were also produced when whole milk powder was added after enough growth was achieved on the growth medium. Methyl ketone formation on the whole milk powder solution began to increase after about 50 hours of lag phase, reached to the maximum at about 190 hours and then decreased gradually. During cultivation, titratable acidity continuously increased after about 50 hours of lag phase. Whole milk powder concentration for the most effective methyl ketone production was in the range of about 20-25%. This strain could also produce methyl ketones from the lipolyzed whole milk powder when cultivated on it from the beginning. But methyl ketones were not produced in any significant amount when the lipolyzed whole milk powder was added after enough growth was achieved on the growth medium. These properties of methyl ketone formation by this strain were considerably different from those by fungi from blue cheese.