Review on mechanisms leading to fouling and stability issues related to heat treatment of casein-based RTD beverages

The milk-based high protein (HP) ready-to-drink (RTD) beverages have increasingly gained popularity over the past years as they are currently used by consumers looking to improve their nutritional status such as athletes and sick people at risk for nutrient deficiencies. Heat treatments are commonly applied during processing to ensure the safety and the longer shelf life of HP beverages. However, the heat treatment can compromise the final nutritional, organoleptic and technological product properties (aggregation, apparent viscosity and sedimentation). In situations where heat exchangers are used, considerable fouling accumulates on surface and often reaches a point where the efficiency of heat exchange systems becomes critical. This instability to heat treatment and the fouling formation are highly dependent on the nature of the used-protein, mineral content, pH and the presence of sensory attributes. In this context, this review will explore the impact of formulation conditions on the fouling of heat exchangers at high temperatures (UHT) and on the stability of dairy-based products, during and after heat treatments, with more focus on caseins at neutral pH. The aim of this review is to have one document which characterizes and understand the impact of heat treatment and formulation conditions on modifications at molecular and structural levels of casein, in order to improve the stability of casein-based RTD beverages and to reduce the fouling of heat exchangers and associated losses.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.