Engineering Process Characterization of High-Pressure Homogenization-from Laboratory to Industrial Scale

Fluid foods are a rapidly growing segment serving the needs of consumers' healthy life style. Though high-pressure pasteurized beverages have been recently commercialized, the batch nature of the technology has been a hurdle for wider adaptation of the technology for high-throughput commodity-oriented beverage products. Further development of continuous flow through high-pressure processing methods is desired. High-pressure homogenization (HPH) consists of forcing a pressurized fluid to flow through a minute gap, which not only homogenizes the fluid but also increases the fluid's temperature. HPH offers the possibility of combining homogenization and preservation into a single unit operation. By manipulating initial temperature and applied pressure, HPH treatment can be used to pasteurize or sterilize the product. This work critically examines the efforts in understanding fundamental process engineering aspects of HPH, including pressure-thermal process characterization, valve design (gap size and pressure relation), flow pattern, temperature history, and residence time distribution. This review will also highlight the HPH impact on food quality and bioactive compound retention. Quality aspects examined include particle size distribution and microbial and enzyme inactivation. The insight gained by this review will assist readers to gain a better appreciation of the HPH process design and system scale-up.