Quality evaluation of slightly concentrated tomato juice produced under high pressure conditions

AbstractConsumer acceptance of tomato products is highly correlated to their organoleptic characteristics and quality parameters such as color and texture. Textural properties of tomato juice can be attributed to the activity of pectinolytic enzymes such as pectinmethylesterase and polygalacturonase. High pressure processing has been proposed as an alternative physical method for intrinsic tomato enzymes inactivation. The objective of this work was to evaluate the quality characteristics of slightly concentrated tomato juice produced under high pressure conditions. Whole tomatoes (var. Red Sea) were pressure-treated at 250, 400, 500 or 600MPa and 50°C for 10min. The processed tomatoes were then crushed, the peels and seeds were removed, and the resulted tomato juice was concentrated to 8.5°Brix. The viscosity, consistency and color of the concentrated juice were measured and compared to the corresponding properties of tomato juice, at the same concentration, produced under the traditional methods of both cold and hot break. High pressure processing did not affect the color of tomato juice at all pressure levels tested, while during hot break color deterioration was always observed. Pressure treatment at 400, 500 and 600MPa led to products of higher viscosity. Increase in applied pressure resulted in an increase in product viscosity and improved consistency. High pressure processing can be used to produce minimally heat processed products with nutritional and sensorial characteristics comparable to that of fresh fruit. It provides a successful alternative to traditional thermal processing leading to products with desirable, or even predesigned, characteristics