Chapter 2 - Fluid Dynamics in Novel Thermal and Non-Thermal Processes

Abstract

This chapter deals with the novel treatment technologies applicable for food capable of flowing, which can be considered as fluid in a general sense. It discusses the major fluid-dynamical phenomena connected with novel food treatment concepts. It focuses on the nonthermal technologies such as high-pressure processing, pulsed electric fields, power ultrasound, and pulsed light and also thermal treatment making use of ohmic heating. Highly competitive markets in industrial nations and well-developed countries are generating an urgent need for developing novel food-processing technologies. Consumers demand food with high levels of organoleptic and nutritional quality but free of any health risks. The development of such kinds of products is usually connected with a reduction in the processing temperature, since thermal treatment often leads to loss of the desired organoleptic properties of fresh products and damage to temperature labile nutrients and vitamins. Therefore, the general tendency in development of novel food technologies consists in nonthermal processing or mild thermal processing, where the impact of temperature is aimed to be reduced by replacing pure thermal treatment by methods such as elevated pressure, electrical or acoustic fields, and light pulses or by combining methods. The state of the art concerning fluid dynamics in novel thermal and nonthermal technologies has achieved unequal levels. Fluid-mechanical effects regarding food treatment by means of pulsed light and ultrasound are far from being sufficiently understood. Overcoming the difficulties corresponding to the gaps in the available knowledge represents one of the most challenging tasks in literature.