Analysis of volatile compounds produced by different species of lactobacilli in rye sourdough using multiple headspace extraction

Abstract

Profiles of volatile organic compound (VOC) produced by nine individual lactic acid bacteria (LAB) during rye sourdough fermentation were compared by automated SPME and GC/MS-Tof. The dough samples were inoculated with individual strains, placed inside the headspace vials and incubated during next 24h. The production or loss of VOC-s was followed by adsorbing volatiles onto 85-m Car/PDMS fibre in every 4h. Volatile profiles differed among LAB species and divided LAB into two main groups - hetero- and homofermentative. Hetrofermentative LAB (Lactobacillus brevis; Leuconostoc citreum; Lactobacillus vaginalis, Lactobacillus panis) showed high production of acetic acid, CO2, ethanol, ethylacetate, producing also hexyl acetate, ethyl hexanoate and isopentyl acetate. Whereas homofermentative LAB species (Lactobacillus helveticus; Lactobacillus casei; Lactobacillus sakei; Lactobacillus curvatus) produced a considerable amount of 2,3-butanedione. Production of l-leucine methyl ester was unique for Lb. sakei, Lb. casei and Lb. curvatus strains. Lb. helveticus was the only LAB that produced benzaldehyde. © 2011 The Authors. International Journal of Food Science and Technology © 2011 Institute of Food Science and Technology.