Energy Requirements for Alternative Food Processing Technologies-Principles, Assumptions, and Evaluation of Efficiency

Alternative food preservation technologies include substitutes to heating methods that may have benefits that include reduction of energy consumption. High-pressure processing (HPP), membrane filtration (MF), pulsed electric fields (PEF), and ultraviolet radiation (UV) are examples of alternative preservation technologies of growing commercial interest. As unit operations these technologies operate in 4 modes of energy transfer: momentum, heat, electromagnetic, or photon transfer. The objectives of this review were: (1) to examine the fundamentals of energy requirements of 4 alternative food processing technologies such as HPP, MF, PEF, UV, and conventional high-temperature short-time (HTST) processing, (2) to establish a basis for comparison of energy consumption between or within technologies, and (3) to evaluate specific energy requirements for the 5 technologies to achieve required safety performance in apple juice. Three levels of energy evaluation for each technology including internal energy, applied energy, and consumed energy were reviewed. The comparison of the specific energy for the 5 technologies was based on information published in scientific papers where the inactivation of Escherichia coli in apple juice was explored. Based on the analysis of energy consumption of these technologies it was concluded that MF and UV have the potential to consume less specific energy than HTST, PEF, and HPP. Differences in energy consumption within each group of technologies were also observed and these could be attributed to differences in the systems. The differences in energy consumption within each group of technologies illustrate that there is potential of improvement in most technologies.