EXTRACTOS DE RESIDUOS DE LA VITIVINICULTURA: CONCENTRACIÓN DE POLIFENOLES.

Our aim has been to determine the polyphenols concentration from summer and autumn leaves and from the stem of Vitis vinifera red wine varieties, obtained by different methods. We have worked with Syrah summer and autumn leaves, with Malbec autumn leaves, and with Malbec stem. Considering the colours of the leaves, we have divided them in red and yellow. The extracts were obtained by using these methods: Maceration into a container with water put into a boiling pot during 3 hours (1), maceration in water and agitation at moderate temperature during 48 hours (2). Rosemary oleoresin was used as reference. According to polyphenolics concentration expressed in g quercetin / g dried extract the result was: Rosemary Oleoresin: 56,3 ±03 Syrah autumn leaves' extract (2): 27,5 ± 0,3; Malbec stem extract (2): 24 ±0,3, Malbec red autumn leaves' extract (2): 22 ± 0,3; Malbec stem extract (1): 21,4 ± 0,3; Syrah autumn leaves extract (1): 21,1 ± 0,3; Malbec yellow autumn leaves extract (2): 17 ± 0,3; Syrah summer leaves extract (1): 16,5 ± 0,3; Malbec red autumn leaves extract (1): 13,8 ± 0,3; Malbec yellow autumn leaves extract (1): 12,4 ±0,3 ; Syrah summer leaves extract (2): 12,2 ± 0,3. Our conclusion was: the autumn leaves have a greater amount of phenolics than the summer ones; Syrah leaves have more phenolics than Malbec leaves; Malbec stem has more polyphenols than the leaves of the same variety; and the best extraction method to get these actives composts is maceration in water and agitation at a moderate temperature during 48 hours. [ABSTRACT FROM AUTHOR]