Modification of glass transition temperature through carbohydrates addition and anthocyanin and soluble phenol stability of frozen blueberry juices Original Research Article

To evaluate the influence of carbohydrate addition on anthocyanin and soluble phenol stability, blueberry juices were added with 20% (wt/wt) of maltose, sorbitol and a mixture (1:1) of glucose and fructose. A juice without addition of carbohydrates was used as a control. The juices were frozen and stored up to six months at −10, −20 and −30 °C. The transition temperatures Tm′ correlated with those of the added sugars. The glass transition was shifted to higher temperatures by addition of maltose and no significant changes in the transition temperatures were noticed with storage time. Anthocyanin and soluble phenol changes were mainly influenced by storage temperature and storage time: the lower the temperature, the shorter the storage time, the lower the changes. Sugar addition had no influence on anthocyanin content.