Chemical composition and sensory analysis of fresh pineapple juice and deacidified pineapple juice using electrodialysis

Electrodialysis with monopolar ion exchange membranes was used to reduce the acid content of pineapple juice. It is an electrochemical membrane separation process in which electrically charged membranes and an electrical potential difference are used to separate ionic species in the pineapple juice from other uncharged components. Several physico-chemical (pH, titratable acidity and soluble solids) and chemical (elemental contents) characteristics and sensory attributes (sweetness, tartness, colour, odour and acceptability) of fresh pineapple juice and deacidified pineapple juice were studied. Electrodialysis of pineapple juice resulted in the reduction of titratable acidity. However there was a pH reduction in the diluting stream. The transfer of the acids salts through the membrane along with the weak acids disturbed the buffer action and resulting in the reduction of pH along with reduction in acidity. The soluble solids content was unchanged. Result from elemental analysis showed that the major mineral components in pineapple juice (magnesium, phosphorus and potassium) were reduced in the diluting stream compared to fresh juice. The result of sensory analysis of the deacidified pineapple juice showed considerable increased in sweetness and reduction in the tartness. No significant changes were observed in odour and colour.