Effect of temperature and removal of amino acids on non-enzymatic browning of lemon juice concentrates during storage

Abstract

Browning of lemon juice concentrates during storage especially at higher temperatures, not only causes loss of sensory appeal but also reduces the nutritional value of the product. The effect of removal of amino acids from lemon juice by cation exchange resin treatment is evaluated for reduction of browning of prepared concentrates (45, 60 and 71°B) during nine months storage at two temperatures, i.e., ambient and low temperatures. The storage of concentrates prepared both from untreated and treated lemon juices brings about some increase in furfural, HMF and browning with consistent loss of sugars, ascorbic acid, amino acids, and phenols. However, during storage, the removal of amino acids by cation exchange resin treatment of lemon juice is highly effective to reduce furfural, HMF, and browning of concentrates by about 7.54, 42.99, and 3.81 - folds as compared to their untreated counterparts. Also the retention of ascorbic acid, amino acids, and phenols is higher in concentrates of treated juice as compared to those from untreated juice. The changes in various quality characteristics of concentrates stored at refrigerated temperatures is lesser as compared to those stored at ambient temperatures. Further the retention of quality attributes is better in concentrates of 45 and 60°B than in the concentrate of 71°B.