Squash

Abstract: Carotenoids play an important role in human health by acting as sources of provitamin A or as protective antioxidants. Pumpkins and squash (Cucurbita spp.) are excellent dietary sources of carotenoids. The diversity and range of carotenoid types and concentrations within pumpkins and squash provide a means to increase the nutritional value of this crop through plant breeding. Breeding requires reliable estimates of carotenoid types and concentrations to distinguish differences among breeding material. One method used for carotenoid identification and quantification is high-performance liquid chromatography (HPLC). It is a highly sensitive and reproducible method but expensive and time-consuming. In contrast, colorimeters objectively describing visible color are relatively inexpensive and easy to use. The objective of this research was to determine if the carotenoid content within pumpkin and squash measured by HPLC was correlated with colorimeter L * a * b * color space values. Cultigens (cultivars, heirlooms, and PIs) representing white, yellow, and orange flesh color were grown at multiple locations using a randomized complete block design with two replicates at each location. Fruit flesh of each cultigen was evaluated using HPLC and colorimetric analysis. Strong correlations were found between color value a * and total carotenoids (r = 0.91) and color value b * and chroma with lutein (r = 0.87). Regression equations based on these correlations will be useful for estimating carotenoid type and concentrations. These close associations will also assure that breeding for enhanced carotenoid content within pumpkins and squash can be achieved using an easy-to-use and inexpensive method.