LIMONOIDS AND FLAVONOIDS IN JUICES OF OROBLANCO AND MELOGOLD GRAPEFRUIT HYBRIDS

Oroblanco and Melogold are hybrids obtained from pummelo and grapefrui t. Limonoids and flavonoids in both juices were analyzed, Oroblanco an d Melogold juices contained low concentrations of limonoid glucosides, an average of 99 and 59 ppm, respectively. However, they contained re latively high concentrations of bitter limonoid aglycones, limonin and nomilin, at levels above the limonin bitterness threshold. For compar ison, limonoid glucosides in juices of grapefruit, another pummelo hyb rid, were also analyzed, Limonin glucoside was the major limonoid gluc oside in all juices analyzed. Nomilin glucoside and nomilinic acid glu cosides were also present, Oroblanco and Melogold juices contained bit ter flavonoids normally found in grapefruit and pummelo including nari ngin; neohesperidin and poncerin in total amount of 440 ppm in Oroblan co juice and 495 ppm in Melogold juice, They also contained several ot her nonbitter flavonoids found in grapefruit.