Evaluation of using chitosan on the clarity and color of apple juice

Today some fruit juices such as apple juice are processed clear in most of the countries. Production of clear and stable apple juice in beverage and fruit juice industries is an important object and clarification is an important step in the processing of fruit juices. The aim of this work was to investigate the clarification of apple juice with commercial acid soluble chitosan and to find out the best chitosan concentration as a clarifying aid and also to improve the apple juice color، titrable acidity، pH and soluble solids، and also the best reaction temperature. Apples of Golden Delicious variety were used. Clarification was performed by addition of soluble chitosan to apple juice at temperatures 35، 40 and 45˚C for 2 hrs. Chitosan solutions with medium molecular weight at concentrations 0/1، 0/5، 0/7، 1، 1/5، 2، 2/5 and 3g/l were used. The results showed that the clarity of apple juice was increased with increasing chitosan concentration. So that the sample with chitosan treatment at 0. 7g/l and 40˚C reached maximum clarity. Also use of chitosan improved the color of apple juice. The a-values (redness) and b-values (yellowness) were decreased with increasing L-values (brightness) and chitosan treatment with 0/5g/l and 0/7g/l resulted in higher clarity. Addition of chitosan at higher concentrations to apple juice reduced titrable acidity and increased pH values. Also increasing chitosan concentration had relative effect on apple juice brix