Despite adequate caloric intake of food, developed nations are still struggling with the problem of “hidden hunger” due to overconsumption of nutrient-poor foods. Biofortification with vitamins and nutrients offers a solution to mitigate this issue by increasing nutrient and vitamin content in crops through different techniques such as agronomic practices, conventional plant breeding and modern biotechnology. This study investigates agronomic Vitamin C biofortification in lettuce through foliar sprays in two different hydroponics systems: Deep water (DW) and nutrient film technique (NFT). For this, replicated experiments were conducted. Seedlings were first grown to maturity in each system, then two days prior to harvest, foliar sprays of 200 and 400 ppm ascorbic acid (AsA) rate along with a control (DI water) were applied to each system. At harvest, plants were measured for fresh biomass, processed, and then flash frozen in liquid nitrogen prior to lyophilization. Certain samples remained fresh to determine persistence of Vitamin C at room and refrigerated temperatures (4C) at 24, 48, and 72 hrs. after harvest. Ascorbic acid (AsA) and total ascorbic acid (TAsA) content were measured for all samples. Overall, biomass was higher for DW grown lettuce compared to NFT. While biofortification rate did not affect DW grown lettuce, NFT biofortified lettuce treated with 200 ppm AsA had greater AsA and TAsA content. In the shelf-life study, AsA declined over time. Temperatures also affected AsA, where refrigerated lettuce treated with 400 ppm had greater TAsA content. These data show higher variability of AsA among the different hydroponics systems. In conclusion, this study demonstrates the potential of foliar spray of ascorbic acid to enhance the Vitamin C content of lettuce grown in hydroponics system. The observed variability between different systems suggests that system-specific optimization is necessary to achieve the benefits of biofortification.
