Integration of Three Processes for Production of Two Nutraceuticals and Ethanol Biofuel from Cull Watermelons

About 20% of the annual U.S. watermelon crop is rejected for the fresh fruit market because of surface blemishes or atypical shape. This unrealized income after production cost investment amounted to ~$88 million dollars for the 2010 growing season. Watermelon is a rich source of two health-promoting nutraceuticals, lycopene and L-citrulline, as well as containing up to 10% fermentable free sugars. Scalable processes for production of each of the nutraceuticals were integrated together with a fermentation process to convert watermelon sugars to ethanol. Four hundred kg of watermelons carried through the three integrated processes yielded an equivalent of 31g lycopene/tonne (~95% recovery), 1.85 kg citrulline/tonne (~80% recovery), and 30L ethanol/tonne (~85% recovery). Use of these integrated processes or selected processes used individually or in combination may afford watermelon growers and packers the opportunity to recuperate part of their crop losses.