Watermelon BOTANY Citrullus vulgaris Schrader or Citrullus lanatus belongs to the Cucurbitaceae family, and it is commonly known as watermelon. Watermelons are native to the Kalahari Desert of Southern Africa. The first recorded watermelon harvest is found in Egypt, depicted in hieroglyphics on tomb walls dating back as far as 5000 years ago. Watermelons were left as food to nourish the dearly departed in the afterlife. From Egypt, watermelons spread throughout countries along the Mediterranean Sea by way of merchant ships. They were documented in China in the 10th century, and in the 13th century were found throughout the rest of Europe after being introduced by the Moors. Ultimately, the watermelon crossed the Atlantic Ocean and made its way to North America with African slaves. It wasn't until 1615 however that the word "watermelon" first appeared in the English dictionary. Watermelon is cultivated for its large and delicious fruit, which is usually ripened in August, the flowers appearing in June, and July. Watermelons are a warm season (frost intolerant) trailing annual, with stems as long as 5 meters with tendrils at the nodes. Watermelons have an extensive but usually shallow root system. Leaves are generally broad and lobed. Flowers are large, yellow, and occur at the nodes. Plants are usually monoecious. The fruit is edible and globular to oblong. Skin is smooth and weight varies depending on cultivars and growing conditions, ranging from 1 to 60 Kg but mostly 2-10 Kg. Fruit wall is firm and usually thick, 1-4 cm of white inner flesh between hard outer skin and softer interior edible pulp. The seeds imbedded in placental tissue. The greater bulk of the fruit is the solid flesh which is sweet and watery. This is in contrast with many other members of cucurbitaceae where the rind is the principal edible portion. The flesh seldom has a cavity. Fruit skin color ranges from pale green to blackish green, some yellow and may be solid, striped, or marbled. Flesh color ranges from white through creamy yellow pink to orange reds. Seeds vary in size, number, and color from white through tan, dark brown, and black. Watermelon extract is produced from the fruit of Citrullus vulgaris. CHEMISTRY The average chemical composition of watermelon is shown in table 1: V 03-06/09 40471,40611,41651,43380,43450,46040-1
Ingredients per 100 g Fruit Seeds Water (%) 91.51 5.05 Protein (g) 0.50-0.62 28.33 Total Lipid (g) 0.43 47.37 Carbohydrate (g) 6.40-7.18 15.31 Calcium (mg) 8 54 Iron (mg) 0.17-0.50 7.28 Magnesium (mg) 11 515 Phosphorus (mg) 9-10 755 Potassium (mg) 100-116 648 Sodium (mg) 1-2 99 Zinc (mg) 0.07 10.24 Copper (mg) 0.032 0.686 Manganese (mg) 0.037 1.614 Selenium (µg) 0.10 Vitamin C (mg) 9.60 0 Thiamin (mg) 0.03-0.08 0.19 Riboflavin (mg) 0.02-0.03 0.145 Niacin (mg) 0.20 3.55 Pantothenic acid (mg) 0.212 0.346 Vitamin B 6 (mg) 0.144 0.089 Folate, total (mg) 2 58 Vitamin A (IU) 366 0 Vitamin E (mg ATE) 0.15 -- Table 1. Chemical composition of watermelon (USDA, 2003). Watermelon also has considerable amounts of citrulline (amino acid), lycopene (carotenoid) and different phenol compounds. Its seeds have high amounts of unsaturated fatty acids with linoleic and oleic acids as the major acids. TRADITIONAL USES Most often eaten as a dessert, chilled and eaten in slices or chunks, watermelon also serves as an ingredient in mixed fruit salads. Fruits are sometimes juiced. The rind maybe preserved as sweet or brined pickles. Seeds are a popular snack food in parts of S.E. Asia and Israel. They are sold roasted and sometimes are flavored with licorice or other flavorings. Watermelons can be used for animal feed or as a water source in desert areas. Watermelon is good for overcoming summer heat. It relieves restlessness, thirst and clears heat, and is a good diuretic. The fruit, eaten when fully ripe, is used as a febrifuge and also as a diuretic, becoming effective in the treatment of dropsy and renal stones. The fruit also contains lycopene (also found in the skins of tomatoes), which has been shown to protect from heart attacks. COSMETIC PROPERTIES Watermelon is incorporated into cosmetics because of its emollient and moisturising action but also for its antioxidant and anti-aging properties. Softening and Trans-epidermal water loss regulatory activity Carbohydrates are active principles extensively used in cosmetics. Monosaccharides are hygroscopic, namely they absorb water thus contributing to keep a healthy moisture level in the horny layer. V 03-06/09 40471,40611,41651,43380,43450,46040-2
Oligosaccharides have the same property. These active compounds build hydrogen bonds, prevent massive water loss and reduce dehydration. Additionally, some of these compounds make a protective coat on the skin, thus preventing and slowing down transepidermal water loss. Laboratory and clinical tests provide strong evidence that vitamins, used in proper amounts, play an important role in skin protection, correction, and renewal. These studies indicate that topically applied vitamins are beneficial to treat several skin disorders and especially, to prevent delay or arrest certain age-associated degenerative changes, such as skin dryness and desquamation. Furthermore, the nature of vitamins has prompted their use in creams and lotions to maintain a soft and smooth skin by replenishing nature s moisture. They are functional, penetrate the skin and are safe (Idson, B., 1993). Thus, watermelon extract is recommended to formulate cosmetic products with moisturizing, refreshing and soothing actions, including hair care. Antioxidant activity Vitamin C is a powerful antioxidant with radical scavenging activity very useful in the treatment of photoaging. Vitamin C has photoprotective properties similar to those of vitamin E. Vitamin C can neutralize free radicals generated by UVB radiation. In a study carried out with pigs, a vitamin C 10% pretreatment was found to reduce UVB-induced erythema and skin burns. Ascorbate may also have similar protective effects on UVA radiation, since in a further study it reduced UVA-induced skin burns in psoralen-sensitized pigs. Other experimental models using human skin demonstrated similar effects for ascorbate as well as for the combination of ascorbate and vitamin E (Chiu, A. & Kimball, AB., 2003). Citrulline has also been confirmed as a potent free radicals scavenger, mainly for active oxygen species, and as a global antioxidant (Hayashi, T., et al., 2005, and http://www.articlesnatch.com). Lycopene also enhances the antioxidant properties of watermelon. As a carotenoid, it prevents the formation of free radicals and reduces their reactions thus minimizing oxidative damage. Exposure of living organisms to UV light leads to photo-oxidative reactions. Peroxyl radicals are involved in the propagation of lipid peroxidation. Carotenoids are dietary antioxidants with photo-protective effects in human skin, which efficiently scavenge peroxyl radicals and inhibit lipid peroxidation. Eichler, O. et al. (2002) carried out a study using cultured human skin fibroblasts to examine the protective effects of the carotenoids, lycopene, β-carotene and lutein on UVB-induced lipid peroxidation. The carotenoids were delivered to the cells using liposomes as the vehicle and cells were exposed to UVB light for 20 min. Lycopene, β-carotene and lutein decreased UV-induced formation of thiobarbituric acid-reactive substances at 1h to levels 40-50% of controls free of carotenoids. The amounts of carotenoids needed for optimal protection were 0.05, 0.40 and 0.30 nmol/mg protein for lycopene, β-carotene and lutein, respectively. Considering these two compounds it can be said that watermelon helps also to maintain hair color, avoiding its fading as a result of a fast oxidative process. Therefore, watermelon extract is recommended to formulate cosmetic products aimed at the protection of skin and hair integrity against oxidative processes. V 03-06/09 40471,40611,41651,43380,43450,46040-3
Vitamin and mineral replenishing activity Incorporation of cucumber to the world of cosmetics helps restore the natural skin balance, due to its vitamins and minerals. In terms of beauty and functionality, current studies indicate that certain vitamins and their derivatives enhance the performance of cosmetics and toiletries. Furthermore, laboratory and clinical tests provide strong evidence that these vitamins, used in proper amounts, play an important role in the protection, correction, and renewal processes of skin. Laboratory and clinical studies indicate that topically applied vitamins are beneficial to treat several skin disorders and especially to prevent, delay or arrest certain ageassociated degenerative changes, such as skin dryness as well as the formation of wrinkles (Idson, B., 1993). Moreover, vitamins are used in cosmetics to maintain a soft and smooth skin and hair. Of particular interest are vitamins E, A, and C, which are useful to get to the inner cells and when used in proper amounts, they are safe and free of side effects (Idson, B., 1993). Thus watermelon extract is recommendable to formulate cosmetic products with stimulating and revitalizing activity, also for hair care products. COSMETIC APPLICATIONS Action Active Cosmetic Applications Softening and TEWL regulation Carbohydrates - Moisturizing - Refreshing - Smoothing Antioxidant Vitamin and mineral replenishing Citrulline Lycopene Minerals - Hair color protection - Anti-aging - Photo-protection - Stimulant - Revitalizing RECOMMENDED DOSE Recommended doses are between 2.0 5.0% BIBLIOGRAPHY Belitz, HD. & Grosch, W. Química de los Alimentos. Zaragoza: Ed.Acribia S.A, 1997,p: 825-860 (613 BEL). Chiu, A. & Kimball AB. Topical vitamins, minerals and botanical ingredients as modulators of environmental and chronological skin damage. Br J Dermatol., 2003; 149: 681-691. Eichler, O., Sies, H. & Stahl, W. Divergent Optimum Levels of Lycopene, β-carotene and Lutein Protecting Against UVB Irradiation in Human Fibroblasts. Photochem Photobiol, 2002; 75 (5): 503-506 (ref. 6220). V 03-06/09 40471,40611,41651,43380,43450,46040-4
Hayashi, T., Juliet, P. A. R., Matsui-Hirai, H., Miyazaki, A., Fukatsu, A., Funami, J., Iguchi, A. and Ignarro, L.J. l-citrulline and l-arginine supplementation retards the progression of high-cholesterol-dietinduced atherosclerosis in rabbits. PNAS, 2005; September 20, vol. 102 (38): 13681-13686. Idson, B. and the Skin. Cosmetics & Toiletries, 1993; 108:(12): 79-94 (ref. 1202). Tarek, A., El-Adawy and Taha, KM. Characteristics and Composition of Watermelon, Pumpkin, and Paprika Seed Oils and Flours. J. Agric. Food Chem., 2001; 49 (3): 1253 1259. Webs: http://pubs.acs.org/doi/abs/10.1021/jf001117%2b http://watermelons.ifas.ufl.edu/uses_and_nutritional_composition.htm http://www.freepatentsonline.com/y2007/0191485.html http://www.articlesnatch.com/article/l-arginine-and-l-citrulline-tests-and-medical-studies/542454 http://www.pnas.org/content/102/38/13681.full http://health.learninginfo.org/lycopene-benefits.htm V 03-06/09 40471,40611,41651,43380,43450,46040-5