Effects of high-pressure treatment on the sensory quality of white grape juice

The effects of high-pressure treatment on the colour (objective measurement) and sensory characteristics of white grape juice were studied during storage at 4°C for 60 days. Grape juice was subjected to three different treatments: 400 or 500 MPa at 2°C, and 400 MPa at 40°C during 10 min. Untreated juice was used as control. Colour parameters (CIE L*a*b*), hue angle (tan-1 b*/a*), chroma {(a*2 + b*2)1/2}, luminosity Q*{(10 x log(L*) + 100} and saturation S*(C*/L*) were measured. Juices were evaluated for sweetness, acidity, off-flavour and aroma. High-pressure treatments did not affect the colour parameters of juice, and similar sensory characteristics were observed in both control and treated samples on the first day. The colour and sensory characteristics of pressure-treated samples remained more stable than those of the control juice during 60 days of storage. The control juice was slightly fermented developing some changes in flavour and colour.