The edible quality of watermelon fruit is dependent upon crisp texture, juiciness, deep-red flesh color and sweetness. Of these, high sugar content is perhaps the most important factor in ensuring consumer acceptability. However, it is also the factor that piles up calories – particularly since people tend to eat large servings of watermelon.
In experiments conducted at the Hebrew University's Faculty of Agricultural, Food and Environmental Quality Sciences in Rehovot, Prof. Shmuel Wolf has developed a strain of lowered-calorie, sweet watermelon with reduced sugar content.
Prof. Wolf explains that three types of sugar are found in watermelon -- fructose, glucose and sucrose. Perception of sweetness is stimulated differently by each of these sugars, with fructose producing the greatest sensation of sweetness. Thus, less fructose is required to provide the same sweet taste that is obtained from greater quantities of either glucose or sucrose.
In a breeding program carried out by Prof. Wolf involving wild varieties of watermelon with varying degrees and proportions of the different types of sugars, a watermelon was produced in which fructose is the major sugar. This enables overall sugar content to be reduced by up to 40 percent, with no loss of sweet taste.
The new watermelon, which does not involve genetic engineering, should be on the market by next summer, said Prof. Wolf.