High-pressure processing ensures that broccoli sprouts keep cancer-fighting compounds, researchers find

22 Sep 2017 --- High-pressure processing could wipe out harmful bacteria in raw broccoli sprouts while maintaining high concentrations of its health-promoting ingredients, researchers have reported in the American Chemical Society’s Journal of Agricultural and Food Chemistry.

Raw broccoli sprouts, a rich source of potential cancer-fighting compounds, have become a popular health food in recent years. But conventional heat treatment used to kill bacteria on produce can reduce levels of the broccoli sprouts’ helpful phytochemicals. The discovery related to high-pressure processing could therefore be an important development.

Important compounds protected
Research has found that broccoli sprouts contain anywhere from ten to 100 times more glucosinolates than their mature counterparts, according to the Americal Chemical Society press release. Glucosinolates are the main compounds in broccoli and its sprouts that are transformed into isothiocyanates when chopped or chewed.

Studies suggest that isothiocyanates have anti-cancer and anti-inflammatory activity. To help prevent bacterial contamination, the sprouts can be heated, but high temperatures can affect the conversion of glucosinolates to isothiocyanates. Professor Volker Böhm and colleagues therefore wanted to explore an alternative method for getting rid of broccoli sprouts’ microbial contamination.

The researchers treated sprouts with high pressure, a method that is sometimes used to ensure the safety of seeds, fruits and vegetables while preserving heat-sensitive nutrients. Results showed that processing broccoli sprouts at 400 to 600 megapascals increased the amount of glucosinolates that turned into isothiocyanates.

Up to 85 percent of glucosinolates were converted under high-pressure processing, boosting the plants’ potential health-promoting compounds. The rate of conversion for mild heat treatment at 60 degrees Celsius was 69 percent. Isothiocyanate levels in boiled samples were undetectable or not quantifiable.

Considering the results of the study, the researchers say high pressure could be a preferred method over heating for processing broccoli sprouts.

The study’s results are especially welcome as broccoli’s various health benefits continue to make the news. Recently, research from the University of Gothenburg identified an antioxidant – richly occurring in broccoli – as a new antidiabetic substance. The patient study showed significantly lower blood sugar levels in participants who ate broccoli extract with high levels of sulforaphane.

Broccoli has also been linked to vision, heart, anti-asthma, anti-cancer and anti-atherosclerosis benefits in the past.