CHIRALITY OF THE GAMMA-LACTONES PRODUCED BY SPORIDIOBOLUS SALMONICOLOR GROWN IN 2 DIFFERENT MEDIA

Sporidiobolus salmonicolor is an aroma-producing yeast which gives a p each-like smell to the culture media. The enantiomeric ratios of the f ive gamma-lactones produced by this yeast cultivated in two different media were determined by multidimensional gas chromatography (MDGC) on a fused silica capillary column coupled to a modified beta-cyclodextr in column. These ratios remain constant during growth and are not affe cted by the composition of the medium. The (R)-enantiomer is highly pr edominant (99%) for gamma-decalactone and predominant (68-88%) for gam ma-octalactone, gamma-nonalactone, and (Z6)-gamma-dodecenolactone. A r atio close to racemic was found for gamma-dodecalactone. A discussion on the metabolic origin of these lactones is based on the analysis of the enantiomeric ratios obtained. With respect to consumers' preferenc e for products considered as ''natural,'' microbial lactone production may represent a valuable alternative to fruit flavors. The enantiomer ic lactone ratios produced by Sporidiobolus salmonicolor are compared with those reported from some fruits. (C) 1997 Wiley-Liss, Inc.