If you getting ready to fire up the grill this summer, be sure to grab some beer! Beer and barbecue often go hand in hand, and a Portuguese group recently showed that marinating pork in beer prior to grilling could potentially have some health benefits (in addition to being really tasty!).
Polycyclic aromatic hydrocarbons (PAHs) are hydrocarbons with multiple aromatic rings, and are found on many cooked foods, particularly smoked and charcoal-grilled food items. PAHs are ubiquitous in our environment, and some have been found to be carcinogenic. While one could give up barbecue meats entirely, a more ideal solution for some people would be to find a way to minimize exposure to and consumption of PAHs. Isabel Ferreira and her colleagues at the Universidade do Porto in Portugal had previously shown that beer, wine (red or white), and tea marinades for meat could reduce levels of heterocyclic aromatic amines, another class of molecules which can have carcinogenic properties. In a recent paper published in the Journal of Agricultural and Food Chemistry her group decided to look at whether beer marinades could also effectively inhibit PAH formation. In particular, they focused on Pilsner beer, nonalcoholic Pilsner beer and Black beer, and marinated loin pork steaks in each of the beers for 4 hours prior to charcoal grilling.
First they tested the antioxidant activity of the three beers using the DPPH assay (DPPH is made of stable free radicals, and changes color from deep violet to colorless when it is neutralized). They found that the Black Beer had the highest DPPH-scavenging ability, followed by the nonalcoholic Pilsner. After the 4 hour marinade however, the black beer’s scavenging ability was significantly reduced, suggesting that the antioxidant compounds may have interacted with oxidative species on the meat. After grilling the pork for 15 minutes, they took samples of the meat and ran it through an HPLC to analyze the PAH content (I hope they saved some of the meat for taste testing!) They focused on 8 PAHs (PAH8) which have been found by the EU Scientific Committee on Food to be “possible indicators of the carcinogenic potency of PAHs in food.” While all three beer marinades decreased PAH8 levels relative to control, the black beer marinade reduced PAH8 by more than 50% (Pilsner beer reduced PAH8 levels by 13%, and non-alcoholic Pilsner beer by 25%)
What does this all mean? Well, it’s unclear how exactly PAH exposure, especially in food, is related to cancer risk. Based on a 2008 report from the European Food Safety Authority, the average European consumes about 1700-3000ng of PAH8 per day. A single piece of grilled, unmarinated pork loin contains approximately 2000ng of PAH8, while a pork loin marinated in black beer contains approximately 1300ng, so the marinade certainly puts PAH8 levels below the average dietary intake and is something to consider when barbecuing this summer.
Now, if you'll excuse me, I’m going to the store to buy some Schwarzbier and steaks - all in the name of health and science of course!