Sorbate Detoxification by Spoilage Yeasts Isolated from Marzipan Products
Esperanza Casas*, María José Valderrama and José M. Peinado
Departamento de Microbiología, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain
Article history:
Received September 9, 1997
Accepted June 17, 1998
Key words:
spoilage yeasts, marzipan, sorbate, 1,3-pentadiene
Summary:
Two yeast species were isolated from spoiled marzipan-based products, using enrichment procedures in Yeast Morphology Broth (YMB) supplemented with 330 g L–1 glucose. The isolates were identified as Zygosaccharomyces rouxii and Debaryomyces hansenii. They were tested in an experimental medium containing 600 g L–1 table sugar (sucrose) and 0.5 g L–1 potassium sorbate for reproduction of the alteration observed in the marzipan samples. Both yeasts reproduced the 'petroleum-like' off-odor, while only Z. rouxii produced gas. Using the same growth conditions, the volatile compound responsible for the characteristic off-odor was identified by gas chromatography coupled to mass spectrometry (GC/MS) as 1,3-pentadiene. It was concluded that this volatile compound is due to decarboxylation of sorbate to 1,3-pentadiene, a compound previously reported in Penicillium moulds and lactic acid bacteria as being a detoxification product of sorbate. To our knowledge this is the first report of this detoxification activity in spoilage yeasts associated with high sugar foods.
*Corresponding author: 
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