Influence of oak wood and grape tannins on the lactic acid bacterium OEnococcus oeni (Leuconostoc oenos, 8413)

Grape tannins, procyanidins, and oak wood tannins, ellagitannins, do not ha ve the same effect on OE nococcus oe ni. Oligomer procyanidins which are ex tracted from grape seeds are powerful inhibitors, affecting bacterial viabi lity in non-growing conditions, bacterial growth and malolactic activity. P ure ellagitannins on the contrary appear to be propitious to the viability of OE oe ni, while the total oak extract is also a powerful inhibitor. We d emonstrate that ellagitannins when oxidised have a strong inhibiting effect , as opposed to procyanidins which lose all effect when oxidised. One of th e mechanisms involved may be compared to the one that occurs for medium-cha in fatty acids, through adsorption on the bacterial walls. (C) 2000 Society of Chemical Industry.