New method to unlock secrets of beta-carotene

Beta-carotene is still the most-studied carotenoid. But the importance of other carotenoids, such as cryptoxanthin, lutein and lycopene - and the amounts in which they occur - isn't well known.

This knowledge gap however could soon be filled. The new process developed by Agricultural Research Service (ARS) scientists promises to accurately identify extracted compounds, and ultimately help food ingredients firms exploit the humble pumpkin's largely untapped nutritional potential.

There is certainly financial incentive to do so. A new report from BCC predicts that the carotenoid market will break the billion-dollar barrier by 2009, carried by the rise in demand for natural colorings and their purported health properties.

Called supercritical fluid extraction (SFE), the method works by efficiently drawing out significant amounts of carotenoids from pumpkin samples.

By pairing SFE with another technology - reversed-phase liquid chromatography -researchers are able to identify and measure the extracted compounds. It is also claimed to be less-labor intensive than other options, doesn't require harsh chemicals and provides rapid, reliable, reproducible results.

This new method will interest food scientists wanting to learn more about beta-carotene and other carotenoids, the natural plant compounds responsible for the orange hues of pumpkins and carrots and the deep reds of tomatoes. A powerful antioxidant, beta-carotene delivers provitamin A nutrients to the body, and is used widely in the food industry as a colorant.

Some carotenoids are thought to help reduce incidence of cataracts, cardiovascular disease and particular kinds of cancer. Vitamin A is essential for good eyesight and proper growth.

However, the exact sequence of steps that our bodies use to take up beta-carotene and convert it to vitamin A remains largely unknown. This latest breakthrough from ARS can therefore be seen as an important step in better understanding this important nutritional process.

ARS scientists also claim that the technique could be applicable to other members of the squash family, known to scientists as Cucurbitaceae, or cucurbits. Plant growers trying to develop superior crops could also put the assay to work when evaluating their most promising vegetables.

Neither SFE nor reversed-phase chromatography is new. But the ARS team claims to be the first to provide detailed guidelines for using these techniques to more precisely measure carotenoids in pumpkin, and other squashes.

Their work is highlighted in the October issue of Agricultural Research magazine, available online.​