Influence of conventional clarification and ultrafiltration on the phenolic composition of golden delicious apple juice

The effects of conventional clarification and ultrafiltration techniques on the phenolic composition of apple juice was studied. Since the health benefit of fruits and fruit juices have been ascribed, in part, to the phenolic antioxidants, it is very important to know what the effects of processing steps are on the level of phenolic compounds in fruit juices. The total losses of phenolic compounds were determined to be 28% and 7% during conventional clarification using gelatin and bentonite, and ultrafiltration, respectively. A total of 14 phenolic compounds were identified in apple juice prepared from Golden Delicious apples. The phenolic compounds were found to be based mainly on hydroxycinnamic acids (similar to 50% of total phenolics) and chlorogenic acid was found to be the major phenolic compound with its concentration as high as 465.45 mg 1(-1) in raw apple juice.