QUANTITATIVE STUDY OF FREE SUGARS AND MYO-INOSITOL IN CITRUS JUICES BY HPLC AND A LITERATURE COMPILATION

Three hundred and six (306) commercial samples from 19 processing plants in Florida, composed of frozen concentrated orange juice, orange juice from concentrate, and pasteurized orange juice, were analyzed for their sugars content by HPLC. In addition, the sugar profile of fresh-squeezed juice from 9 different cultivars of sweet oranges, 2 tangors, and 4 tangelos grown in Florida are included. Sucrose, fructose, glucose, total sugars, glucose/fructose ratio, and myo-inositol contents are presented. Mean ± standard deviation sugar levels for 100 mL of frozen concentrated orange juice were 4.1 ± 0.5 g of sucrose, 2.1 ± 0.2 g of fructose, 1.9 ± 0.2 g of glucose, and 0.1 ± 0.1 g of myo-inositol, from juices processed in Florida. A review of the methodology for the detection of sugars by HPLC in citrus products is presented; most results having been acquired by HPLC analysis utilizing NH2 column and acetonitrile/water. A compilation of literature furnishing information on free sugar contents in orange and grap...