Higher quality and longer shelf-life fruit products
High pressure can easily kill many of the microorganisms that typically spoil fruit products such as juices, sauces, jams and purees. However, the main advantage this technology as over other treatments, such as heat, is that flavour, colour and vitamin content are not adversely affected. Fruit juices, for example, retain their fresh, “just-squeezed” properties with a shelf-life extended for several weeks when held at refrigeration temperatures. The technology also has potential advantages for producing high quality fruit smoothies, wet salads and sauces and vegetable products such as carrot juice and garlic puree.
The guacamole story
One of the most successful HPP products available in the USA is guacamole. The fresh product normally spoils rapidly, mainly due to enzyme activity that discolours the avocado pulp. Traditional preservation treatments such as heating, flash freezing or modified atmosphere packaging all result in a product of inferior quality compared to fresh. However, HPP can be used to retain the natural fresh flavour and texture. HPP guacamole, which requires refrigeration, is now available in an ever-increasing number of US states. The technology is also used commercially to improve the quality of a wide range of products including wet salads and dips such as coleslaw, salsa and houmous
Valdramidis, V.P., Graham. W.D., Beattie, A., Linton, M., McKay, A., Fearon, A.M. & Patterson, M.F. (2009) Defining the stability interfaces of apple juice: implications on the optimisation and design of high hydrostatic pressure treatment. Innovative Food Science & Emerging Technologies 10 (4) 396-404.
Patterson, M.F. and Linton, M. (2008). Factors affecting inactivation of foodborne bacteria by high presure. In: High Pressure Microbiology, (Eds. C.W. Michiels, A Aersten, D.H. Bartlett and A. Yayanos), ASM press, USA. pp: 181-193.
Patterson, M.F., Linton, M.. and Doona, C.J. (2007). Introduction to high pressure processing of foods. In: High Pressure Processing of Foods, (Eds. C.J. Doona, C.P. Dunne and F.E. Feehery), Blackwells Publishing, Iowa, USA. pp: 1-14.
Patterson, M.F., Ledward, D.A. and Rogers, N. (2006) High pressure processing of foods. In: Food processing handbook. (ed. J.G. Brennan), Wiley-VCH, Germany, pp173-200.