Influence of the Fermentation Temperature and the Strain of Acetic Acid Bacteria on the Volatile and Polyphenolic Composition of a Red Wine Vinegar Produced by Surface Culture

This work aims to determine the effect on the aromatic profile and phenolic content of red wine vinegars produced by surface culture at two different temperatures (30 and 37ºC) and using different inocula of acetic acid bacteria (Acetobacter malorum, Gluconobacter oxydans and a mixture of bacteria isolated from a Sherry vinegar). Fifty-seven volatile compounds and 23 polyphenolic and furfural compounds were identified. Vinegars obtained at 37ºC had poorer volatile profiles, with no significant influence of the strain of acetic bacteria. For polyphenolic content, temperature was also the most significant variable, so that the vinegars produced at higher temperatures had lower total anthocyanin contents, while no clear trend was observed regarding the influence of temperature on the low-molecular-weight phenolic constituents. The total tannin content in the vinegars obtained experienced slight increases after acetification, although this was not affected by temperature, and it was observed that when using the mixture of acetic acid bacteria from the Sherry vinegar, the total tannin content was significantly higher than when individual bacteria cultures of Acetobacter malorum or Gluconobacter oxydans were used. Temperature appears as a key parameter for the volatile and phenolic composition of red wine vinegar versus the use of different acetic acid bacteria.