The role of HHP in terms of enhancing food safety through its ability to kill microorganisms is well established but there is also a significant body of research into how the technology can affect and improve meat quality, said authors Xiang Dong and Richard Holley. The paper – High Hydrostatic Pressure Effects on the Texture of Meat and Meat Products - has been published in the Journal of Food Science and Technology.
Speaking about the potential of HHP, Holley told FoodProductionDaily.com: “It should be possible to manufacture processed meat products with acceptable texture at salt levels lower than is currently possible. This can lead to a new generation of processed meat products.”
Research findings
The study concluded found that HHP treatment causes protein denaturation, aggregation or gelation which can result in meat becoming either tenderised or toughened. These outcomes depend on the meat protein system, the temperature, the pressure used and its duration.
“HHP treatment of foods can be used to create new texturised products without thermal degradation, or to obtain analogue products with minimal effects on flavour, colour or nutritional value," said the research paper.
The review evaluated such issues as differences of muscle texture induced by HPP – finding that the process can changes the structure and function of many proteins. It concluded that HHP-treated fresh meat becomes tenderer after cooking as opposed to similar meat that has not been treated becomes tougher.
“Frozen hot-boned meat will be tenderer after HHP treatment than untreated meat,” said Holley. “This offers accelerated processing alternatives for processed meats manufacture.”
HHP also improves gelation of fresh meats by increasing the solubility of myofibrillar protein as well as causing depolymerisation. But the authors added that pressure should be applied at “relatively low levels” to avoid toughening the meat.
The toughness and tenderness of meat is also dependent on the rigour stage of the meat as well as the combination of temperature and pressure.
“Usually low pressure (below 200 MPa) treatment can tenderise prerigor meat, whereas tenderisation postrigor with HHP can only be achieved at higher temperatures (40-80°C),” said Dong and Holley.
Meat processors might consider HHP as a way of extending microbial shelf, and improve tenderness in meat where toughness is not caused by connective tissue - so-called actomyosin toughness. In processed meats, safety from bacterial pathogens – such as Listeria - is improved by HHP treatment of vacuum packed, flexible film pouches, Holley summarised.
Potential limitations
A substantial capital outlay and the need for its use on hot-boned - prerigour - meat were the “greatest limitations’" for the application of HHP technology, said the research. The establishments of conditions where antimicrobial effects and beneficial texture effects could be achieved simultaneously would be valuable. Browning of meat when HHP is used together with thermal treatment is also a potential drawback, said the study.