How to boost nutritional value of pumpkins, squash

Carotenoids, which give white, yellow, and orange hues to pumpkins and squash, could help breeders improve the vegetables' nutritional value, say researchers.

Carotenoids play an important role in human health by acting as sources of provitamin A or as protective antioxidants.

Pumpkins and squash, available in a wide range of white, yellow, and orange colours, are excellent sources of dietary carotenoids, particularly lutein, alpha-carotene, and beta-carotene.

The colours of these nutritional vegetables are determined by their genetic makeup-the concentration and type of carotenoids they contain-which are influenced by both genetic and environmental factors.

And now researchers have found that this wide range of carotenoids in pumpkins and squash could help breeders to improve the vegetables' nutritional value and create new varieties of antioxidant-packed offerings for consumers.

Traditionally, scientists have been using a method called "high-performance liquid chromatography", or HPLC, to identify and quantify carotenoids.

HPLC is highly sensitive and reproducible, but can be expensive and time-consuming.

Thus, Rachel A. Itle and Eileen A. Kabelka from the University of Florida's Horticultural Sciences Department, embarked upon developing a less-expensive and simpler method to accurately measure the carotenoid content of pumpkin and squash.

For this, she designed a research study using colorimetric analysis to correlate colour space values with carotenoid content in pumpkins and squash.

Pumpkins and squash with white, yellow, and orange flesh color were grown at multiple locations for the study.

The flesh of each specimen was evaluated using both HPLC and colorimetric analysis.

According to the research, "strong correlations between colorimetric values and carotenoid content were identified."

Interestingly, the researchers found a "nine-fold increase in total carotenoids provided within orange-red and yellow-orange colored cultigens versus yellow colored cultigens."

The research determined that colormetric analysis could aid breeders interested in increasing carotenoid content in pumpkins and squash.

The method, "will be successful, easy to implement, and inexpensive", concluded Kabelka.

The study appeared in a recent issue of HortScience.