Adding essential oils to uncooked meat could counter the negative effects of HPP on texture, color
HPP kills many pathogenic and spoilage bacteria by squashing their cells under high pressure rather than through a more traditional high-heat process. But the process still results in a slight uptick in the temperature of the product as the pressure is increased – meaning it causes the core temperature of uncooked meat to exceed the level at which USDA says it can still be considered ‘raw.’
In addition, the deadly pressure placed on the pathogens has a similar effect on protein cells – causing HPP meat to take on a darker color and in some cases have off-flavors due to lipid oxidation – two tradeoffs that most consumers are unwilling to make.
However, new research presented at IFT’s annual summit in Chicago by Kumar Mallikarjunan, a professor in the Department of Food Science and Nutrition at the University of Minnesota, suggests essential oils could minimize these negative effects – giving meat a chance to join the HPP party.
He explained to FoodNavigator-USA that because some essential oils, such as cumin, thyme and oregano, have antimicrobial and antioxidant properties his PhD students hypothesized if they were applied to meat they might reduce the pathogen load so that the HPP could be performed at a lower pressure or for less time so that the discoloration and lipid oxidation were lessened.
To test this, the team created a nano-emulsion of the oils at low concentrations that could be applied to beef prior to HPP and then after pasteurization they tested for E.coli as well as the color and texture of the beef.
The team found that when the essential oils were added to beef prior to pressurization they did not markedly reduce the pathogen count, however when the treated meat underwent HPP the oils created a synergestic effect – so that that the damage done to the cell walls by the pressure allowed the oils to have a greater impact on the pathogens.
The addition of oils did not, however, protect against a change of color in the beef when it was pressurized for longer amounts or at higher levels. However, because they did help reduce the pathogen load, it is possible the pressure and time of HPP could be reduced – lessening the discoloration – and the beef would still be safe.
Mallikarjunan noted the real breakthrough from the tests was that the meat treated even with low concentrations of essential oils saw improvement in the oxidative stability and less discoloration, and in addition, the texture was not as negatively affected as when it underwent HPP.
Flavor changes could be a value add to consumers
While the results are promising, Mallikarjunan noted that the oils did change the flavor of the meat, creating “a dilemma about how much to add and whether the consumer will accept a modified product which has ‘flavor enhancements,’ if you want to put it that way, but everyone has their own preferences for what spices to add.”
As Mallikarjunan hinted, by marketing the flavor change as an enhancement, the technique could be used to create value added meats that are pre-marinated and sold at the deli counter as a time-saver for shoppers in a hurry.
The technique also could be successfully applied for food service products, he said, explaining: “Food service institutions may prefer our products because they have already do the added step of preparing the final product.”
Outside of foodservice, the meat would need to include the essential oils on the label, but Mallikarjunan reassured that the labels would still qualify as clean because the oils are natural and they are familiar terms to most consumers.
Looking forward, Mallikarjunan says there is still research to be done on the technique – including what other essential oils might also synergistically enhance HPP. Other types of meat, including fish and poultry, also should be tested as well as the effect of different concentrations on consumer perceptions.
