Borrowing from the automobile industry, researchers from the University of Reading in the United Kingdom teamed up with engineers from Besmoke, a company that specializes in natural smoke flavors, to develop and test the effectiveness of a specially designed zeolite filter to reduce polycyclic aromatic hydrocarbons (PAHs) in smoke that is used to flavor foods. Zeolite is a porous material that has been used in filters to reduce the pollutants in car exhaust.
Jane Parker, PhD, director of The Flavour Centre at the University of Reading, said at a press conference during the American Chemical Society meeting in New Orleans in March that the aim of its study was to “remove carcinogens, but we absolutely did not want to change or reduce or have any adverse effects on the smoky flavor.” The research was published in March 2018 Journal of Agricultural and Food Chemistry.
The zeolite filter Dr. Parker and colleagues developed reduced PAHs by 80-90 percent and benzo[a]pyrene, a known carcinogen, by 93 percent. The taste of the food flavored with the filtered smoke was compared with the taste of food flavored with unfiltered smoke.
Benzo[a]pyrene and other PAHs are environmental contaminants, with high concentrations found in tobacco smoke. “We know from the tobacco industry that smoke contains carcinogens, and we also know that these carcinogens are in food but in very low concentrations. In most foods they are way below the regulated limit. At the moment there is no direct link between the increase in consumption of smoked foods and increased incidence in cancer; we believe, however, that we should be reducing these compounds in food to levels that are as low as reasonably achievable,” Dr. Parker said.
For the study, the research team smoked tomato flakes, coconut oil, and water using either smoke that was filtered through the zeolite filter or unfiltered smoke. The smoked tomato flakes were then added to cream cheese and the water was used as brine for cooking chicken. An expert panel of flavor testers then tried the cream cheese and chicken. The panel noted a reduction in the ‘acrid, ash-tray’ taste in the food that had been flavored with filtered smoke as well as an increase in ‘smoked food notes.’ They described the chicken made with filtered smoke as having a ‘Christmas ham aroma’ and a ‘more rounded and balanced flavor,’ she said.
The researchers used mass spectrometry to analyze the compounds in the two types of smoke to determine how the filtering affected the chemical content. “The profiles showed that it was largely the higher molecular weight components that were removed by the filter. These may be the ones giving the foods a harsher flavor and aroma profile,” Dr. Parker said.