Watermelon (Citrullus lanatus) is commonly consumed by humans and widely available around the world. It has impressive nutritional properties, a rich phytochemical profile, and various claimed medicinal and health benefits. The major carotenoids in watermelon include lycopene, β-carotene, phytofluene, phytoene, lutein, and neurosporene. Lycopene (approximately 6,888 μg/152 g) is the major bioactive component in the fruit and it reportedly promotes several therapeutic effects, such as anti-cancer and anti-inflammatory activities etc. in humans and animals. Watermelon is also a good source of the amino acid citrulline, which is involved in production of arginine. Pre- and postharvest factors, including fruit sampling area, application of fertilizer, climatic factors, and genetic variability, are known to affect its bioactive compounds and nutrient concentrations. This review summarizes our current understanding of the watermelon phytochemical profile and the factors affecting its bioactivities and therapeutic effects.

In recent years, consumers have increasingly demanded nutritious, healthy, and fresh-like food products with high organoleptic quality. Watermelon is rich in water, which is 92% mandatory for body functioning, and contains several vitamins, amino acids, antioxidants, carotenoids, and lycopenes with various health benefits. The present studyexamines the combined effect of ultrasound (US) and microwave (MW) on the physico-chemical and phytochemicals of watermelon juice during storage (up to 120 days). Sonication was employed for different time intervals, particularly from 2 to 8 min at 20kHz frequency and 525W power, while microwave was applied at two different time intervals (1min 50 s and 2min) at 1000W power and a frequency of 2450MHz.The product was stored at 4°C up to 120 days for further examination. Our results revealed that treatment T5 (10min ultrasound & 1min 50s microwave) manifested the maximum cloud value (3.00), acidity (0.15%), vitamin C content (202.67mg/100mL), phenolics (852.57mgGAE/100mL), flavonoids (1970.9µg CE/100mL), and total antioxidant activity (8650.3µg equivalent of ascorbic acid/mL of juice). Sonication in combination with microwave proved to be an efficient technique for increasing the antioxidant potential of watermelon juice. Thus, US and MW treatments may be incorporated for enhancing the phytochemical release and shelf life of watermelon juice.

The first primitive watermelon domestication has been reported more than 5,000 years ago in Northeast Africa. Watermelon is recognized all over the world as a delicious fruit that quenches the thirst that many people consume in the summer heat. There are about 1,200 varieties of watermelon. Watermelons are loaded with plentiful nutrients, such as vitamin C, pantothenic acid, copper, biotin, vitamin A, and vitamins B6 & B1. Watermelon is processed to manufacture various value-added foods, such as cookies, cakes, juice, jam, cadies, and biscuits. In this review, we discuss pre- and postharvest factors affecting watermelon nutritional concentration and antioxidant profile. Prominent factors comprise genetic and environmental constraints, processing and postharvest storage conditions, chemical treatments, temperature and humidity, packaging, and food processing conditions. This review summarizes the available literature on watermelon processing into different valuable products, pre- and postharvest factors affecting nutritional concentration, and antioxidant activity.