Reduction of non-enzymatic browning of lemon juice concentrates by removal of reaction substrates.

摘要

The removal of the non-enzymic browning reaction substances, sugars and amino acids, from lemon juice to reduce the colour deterioration of prepared concentrates was investigated. Lemon juice was treated with glucose oxidase, activated charcoal and cation exchange resin. Treatment of lemon juice with glucose oxidase was not feasible as it removed only 10.36% of the total sugars, even after raising the pH to approx. 6 and enzyme concn. to 500 ppm. Similarly, activated charcoal removed approx. 13.05% of amino acids simultaneously causing approx. 17.04 and 12.16% loss of acidity and ascorbic acid, respectively, which was not desirable. The use of cation exchange resin, however, was highly effective as it removed approx. 96.79% of the amino acids. Treated lemon juice exhibited approx. 3.18 and 3.28 times less browning when concentrated to 45 and 60degBrix, respectively. Results indicated that the use of cation exchange resin is promising for the manufacture of concentrates with improved acceptability.