Watermelons, yellow and red, are essentially different versions of the same fruit. The biggest difference between yellow watermelon and red watermelon is the flesh color. Yellow watermelon is yellow inside because it contains more yellow-pigmented antioxidants called xanthophylls, vs red watermelon which is red inside because it contains more orange and red-pigmented antioxidants such as lycopene.
Yellow watermelon and red watermelon are the exact same fruit, just different varieties of it, hence their different flesh color. The reason why yellow watermelon is yellow inside is because it is high in yellow-pigmented chemicals known as xanthophylls and, at the same time, lower in orange and red-pigmented chemicals. Versus yellow, red watermelon is red inside because it is high in orange and red-pigmented chemicals, notably the carotenoid lycopene, but also beta-carotene, alpha-carotene and gamma-carotene, among others, and lower in yellow pigments. Depending on the exact ratio of each pigment, various shades of yellow and red are possible, from pale yellow to canary yellow in yellow watermelon to several shades of medium to dark pink, pink-red, red and orange-red in red watermelon.
How do you tell if a watermelon is yellow or red? Unless you know beforehand, you can’t really tell from the outside if a watermelon is yellow or red inside. The difference in flesh color is owed to varying levels of pigmented chemicals, primarily antioxidants. Yellow watermelon is high in xanthophylls, yellow-colored carotene antioxidants. Existing research shows yellow watermelon is highest in neoxanthin followed by violaxanthin, neochrome, luteoxanthin, lutein, all yellow pigments (source).
Some research also identifies beta-carotene as one of the main pigments in some yellow watermelon varieties (source). By comparison, red watermelon is highest in lycopene. Lycopene is a bright red carotenoid antioxidant and the major pigment in red watermelon. Also responsible for red watermelon color are beta-carotene and, to a lesser extent, alpha-carotene, gamma-carotene, zeta-carotene and other red and orange pigments.
Taste and flavor profile
Yellow watermelon definitely does not taste the same as red watermelon and the differences in taste and flavor profile between yellow and red-fleshed watermelons can be traced back to factors such as variety, growing conditions, fruit maturity and ripeness. But what color watermelon is the sweetest between yellow and red? On average, yellow watermelon tends to be sweeter and more flavorful than red. Yellow watermelon has a deeper sweet taste with honey and fruity flavors vs red watermelon which is also quite sweet, but in a different way, lighter and fresher. If your taste buds are more sensitive, you will likely notice the differences in taste from the first bite.
There are over a 1000 different watermelon varieties, including yellow and red, so, chances are, the sugar content will vary between them. Factors such as variety, growing conditions, degree of fruit ripeness and more impact end sugar content in the fruit. This being said, perfectly ripe yellow watermelon generally tends to be sweeter than red because of its slightly higher sugar content. At the same time, according to Purdue University, sugar content in most orange and yellow-fleshed watermelon varieties studied by them was in the similar range as the sugar content in red-fleshed varieties (source). So, depending on your experience with yellow and red watermelons, you may find either is true.
Both yellow and red watermelon are extremely juicy, with soft, crisp flesh. But yellow watermelon is denser and somewhat softer, although still crisp, while red watermelon is less dense, crunchier and also a bit stringy, with short strands of flesh sometimes getting stuck in between the teeth.
Red and yellow watermelon are essentially the same fruit, just different varieties of it. Assuming they are grown in the exact same conditions, their nutrition should be fairly similar. However, the difference in flesh color, taste and other organoleptic differences between the two watermelon colors further entail differences in nutritional value. For example, red watermelon is higher in the antioxidant beta-carotene and beta-carotene has vitamin A activity. Eating red watermelon instead of yellow will likely provide more vitamin A and associated benefits for skin, eyesight and the immune system. Red watermelon is also a better source of other carotenoid antioxidants with vitamin A activity.
If indeed higher in sugar (and that will depend on variety, growing conditions, degree of ripeness etc.), yellow watermelon will also be slightly higher in calories, but not to the extent that it would significantly impact a reasonable intake of the fruit. Except for a higher vitamin A equivalent from pro-vitamin A antioxidants in red watermelon and a slightly higher sugar content in some yellow watermelon varieties, there are no other significant nutritional differences between yellow and red watermelon that could produce a quantifiable impact on daily nutritional demands and health.
The difference in flesh color between the two watermelon colors further entails differences in nutrition and health benefits. Red watermelon is higher in beta-carotene and other carotenes with vitamin A activity which provide it with benefits for eyesight, skin and the immune system function. Red watermelon is also significantly higher in lycopene, a red antioxidant carotenoid with benefits for hypertension, known to actively lower both systolic and diastolic blood pressure in hypertensive individuals. While yellow watermelon also has minor benefits for blood pressure thanks to its magnesium and potassium content, red watermelon is superior in its anti-hypertensive benefits due to its lycopene content.
At the same time, yellow watermelon is higher in yellow antioxidants such as lutein which actively benefit eye health. Lutein is physically part of the eye and gets absorbed at the retina level in the macula lutea area where it protects against radiation from light and provides benefits for improving vision.
This post was updated on Sunday / August 23rd, 2020 at 1:15 AM