Vacuum cooling for the food industry - a review of recent research advances

Vacuum cooling is a rapid evaporative cooling technique for moist and porous products. Traditionally, it is used in the food processing industry for pre-cooling of leafy vegetables and mushroom. In the past decade, its application has been extended to other sectors of the food industry, e.g. bakery, fishery, sauces and particulate foods processing. The advantages of vacuum cooling include short processing time, extension of product shelf life and improvement of product quality and safety, which have encouraged food research engineers and scientists to explore its wider applications. This paper reviews the latest research progresses made in the past few years, especially the research results from the Food Refrigeration and Computerised Food Technology (FRCFT) Research Group in National University of Ireland, which have carried out extensive research work since 1997 funded by the EU Non-Commissioned Food Research Programme and the Food institutional Research Measures administered by the Department of Agriculture and Food of Ireland. These results indicate that significant advances have been made for vacuum cooling of cooked meats. Extensive amount of the research work was conducted with regards to cooling rate, yield, product quality and factors that improve process efficiency and product quality. Research results show that vacuum cooling significantly reduced cooling time required for cooked meat while only caused slight cost to product quality. The results also demonstrate that vacuum cooling is the only cooling method that meets the cook-chill guidelines issued by many European governments. Another major new application explored for vacuum cooling is its use in ready meals manufacturing. Research work on ready meals is still ongoing, however, current results show that this technique is a potential cooling treatment to be integrated into the processing procedures. In addition to these new applications, good progresses were also made in mathematical modelling of vacuum cooling of both liquid and solid foods. These research advances together as anticipated will eventually make this new cooling technique more competitive for the food processing industry.