Volatile compounds and bacterial community dynamics of chestnut-flour-based sourdoughs

The aims of this study were the monitoring of the microbial dynamics by means of a polyphasic approach based on conventional isolation techniques and PCR-DGGE-based methods in different chestnut-based sourdoughs and the evaluation of the impact of fermentation on volatile organic compounds formation during sourdoughs ripening. Members of the Lactobacillus plantarum group and Pediococcus pentosaceous dominated the sourdough ecosystems. Nevertheless, RAPD-PCR allowed recording a relevant genotypic biodiversity among strains coming from gluten-free flour combinations. Volatile compounds were characterised by GC/MS. A total of 59 volatile compounds were identified, mainly alcohols, esters, acids, aldehydes and ketones. Principal component analysis of samples at the beginning and at the end of ripening offered a good separation of the samples and highlighted the effect of fermentation on the sensorial profile.