Osmotic Concentration of Gooseberry Fruits - The Infl uence of Temperature, Time and Pretreatment Methods on Mass Transfer and Total Polyphenol and Organic Acid Content

The objective of this study is to assess the influence of temperature, time and enzymatic pretreatment on the osmotic concentration of gooseberry fruits (cultivar Bialy Triumf). The fruits were osmotically concentrated in a sucrose solution at 65 degree Brix and 40 to 70 degrees Celsius for 5 to 240 min. Two experimental procedures were employed. In the first procedure, prior to concentration the fruits were immersed in the solution containing lipolytic enzymes, and then in the solution containing pectinolytic enzymes. In the second procedure, pectinolytic enzymes were added to the sucrose solution. The kinetics of the osmotic concentration was studied based on the changes in dry matter content, water loss, and solid gain. Higher temperature and longer process time led to higher values of the mentioned parameters. After 1 h of concentration at 40 degrees Celsius, dry matter content was 13.9%, while at 70 degrees Celsius it was 20.4%.