Influence of oak wood and grape tannins on the lactic acid bacterium?nococcus ?ni (Leuconostoc oenos, 8413)

Abstract

Grape tannins, procyanidins, and oak wood tannins, ellagitannins, do not have the same effect on Œnococcus œni. Oligomer procyanidins which are extracted from grape seeds are powerful inhibitors, affecting bacterial viability in non-growing conditions, bacterial growth and malolactic activity. Pure ellagitannins on the contrary appear to be propitious to the viability of Œ œni, while the total oak extract is also a powerful inhibitor. We demonstrate that ellagitannins when oxidised have a strong inhibiting effect, as opposed to procyanidins which lose all effect when oxidised. One of the mechanisms involved may be compared to the one that occurs for medium-chain fatty acids, through adsorption on the bacterial walls.