Effects of mechanical harvesting and grape processing on the composition of Sauvignon Blanc juice and wine

Abstract

The concentration of protein and phenolic compounds in juice and wine from hand harvested and mechanically harvested ‘Sauvignon blanc’ grapes was determined under different juice processing conditions. Destemming and crushing resulted in higher concentrations of protein and phenolics in the resultant juice. Most of the proteins and phenolics were extracted in the 0-0.4 MPa pressing. Juice and wine from mechanically harvested grapes consistently showed lower protein level than that from hand harvested grapes under the same juice processing conditions, but no significant difference was detected in phenolic content. The results suggest wines from mechanically harvested grapes with lower protein content might require less bentonite for protein stabilization.