An Index of Fresh Vegetable Nutritional Value That Incorporates Biomass Yield and Crop Composition

Consumer interest in foods, including vegetables, with properties that benefit human health (e.g., minerals, dietary fiber, and secondary metabolites) is rising. Many, including farmers, desire to increase the dietary health value of fresh vegetables but they face three challenges. First, there are few, if any, accepted on-farm processes and/or metrics to describe and manage fresh vegetable composition, especially as it relates to dietary health value. Second, data suggest that primary and secondary metabolism may compete for metabolite pools, thus creating the scenario in which growth or health-related secondary metabolite accumulation is favored, but not both. And, third, fresh vegetable producers are rarely directly compensated based on the composition of their crop. Therefore, we developed and are testing a ‘nutritional yield’ index that combines biomass and various composition factors specifically to address the first and second obstacles to increasing the nutritional value of the fresh vegetables named above. We use fresh biomass and antioxidant potential of a leaf lettuce (Lactuca sativa) crop produced in spring and fall seasons in Ohio and data from the literature to describe an ‘antioxidant yield’ index. Together, these data suggest that antioxidant yield: 1) is sensitive to genetic and environmental production factors and 2) may be useful in describing changes in crop production and valuation that would be needed to enhance the use of fresh vegetable production systems as more focused and purposeful instruments of human nutrition and health.