Antioxidant activity of orange fruit pectic substance [electronic resource].

Includes references.

The oxidation of ascorbic acid and the consequent browning reactions is considered as a serious quality defect in orange juice. Therefore, the control of these reactions is of prime importance to preserve the nutritional value and the quality of orange juice. The aim of this study was to evaluate the effect of pectin fractions isolated from orange fruit as retardation of ascorbic acid oxidation and browning reaction of orange juice. The results indicated that the orange fruits were rich in total soluble solids (12.9%) total titratable acidity as citric acid 1.59% and ascorbic acid (58.93mg/100 g). Alcohol insoluble solids (AlS) of orange fruits contained anhydrogalacturonic acid; 35.34%, degree of esterification (DE); 75%, protein; 6.52% and ash; 3.75% as well as pectic substances such as water soluble pectin; 19.87%, hot water soluble pectin; 25.18% and HCl-soluble pectin, 15.26%. Water soluble pectin and hot water soluble pectin inhibited ascorbic acid oxidakion and colour deterioration as browning index at 420 nm of orange juice, while HCI-soluble pectin showed lowest effect.

Summary in Arabic.

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