Contribution of Katsura-uri (Japan's Heirloom Pickling Melon, Cucumis melo var. conomon) at the Completely Ripe Stage to Diabetes Control.

Abstract

The fruit of Katsura-uri (Japan's heirloom pickling melon, Cucumis melo var. conomon) possesses a fruity aroma and moderate sweetness. The fruit juice has potential to minimize human postprandial blood glucose levels. This study provides information regarding the health benefits of Katsura-uri and its utility in treating diabetes. The study methodology involved measuring the color and firmness of Katsura-uri fruit at five ripening stages, and quantitation of the aroma substances, proximate composition, and sugars. Significant changes were detected in the color, firmness, and level of aroma substances with ripening of Katsura-uri fruit, albeit with no major changes in proximate composition, with the exception of dietary fiber, and sugars. To determine the effects of Katsura-uri juice, the blood glucose levels of ten diabetic volunteers aged 46-75 y were monitored after its consumption, and compared with after consumption of muskmelon juice equivalent to the total weight of Katsura-uri juice. The blood glucose area under the curve level was significantly lower after consumption of Katsura-uri juice (16±5 h • mg/dL) than after consumption of muskmelon juice (55±17 h • mg/dL; p<0.05). The level of the glucose spike was also significantly lower after consumption of Katsura-uri juice (22±5 mg/dL) than after consumption of muskmelon juice (64±6 mg/dL; p<0.05). The completely ripe Katsura-uri fruit provides the best results for diabetic subjects, which is the first case of fruits sweetened with the addition of zero-calorie sweeteners.