Enhancing nutritional quality of spray‐dried concentrated watermelon juice using watermelon by‐product carrier blends

Abstract

Blends of watermelon (Citrullus lanatus) by-products (freeze-dried and ground into powders) and maltodextrin were used as carriers for the pilot-scale spray drying of preconcentrated watermelon juice. Watermelon juice was first concentrated to 65 °Brix via forward osmosis and then diluted to 16 °Brix. The concentrate was mixed with 25% w/w carrier using one of five carrier blends: 100% maltodextrin, 11% rind (89% maltodextrin), 11% pomace (89% maltodextrin), 25% rind (75% maltodextrin), and 25% pomace (75% maltodextrin). The powders were analyzed for moisture content, water activity, color, true density, bulk density, lycopene and citrulline contents, and total soluble phenolics and antioxidant activity Results indicated that carrier composition had a significant (p < 0.05) effect on all the quality metrics. Powders with any amount of byproduct carrier had higher a* color value than the 100% maltodextrin control. All of the by-product carrier blends conferred an increase of at least fivefold in lycopene, 1.5-fold in citrulline, and 1.3-fold in total soluble phenolics, compared to the all-maltodextrin carrier. The results of this work will inform the development of new environmentally-sustainable processing strategies for watermelon juice powder.