Novel rapid cooling system design and modeling for continuous flow food processing systems

Abstract

The commercial sterility in thermal processing is achieved by implementation of high temperatures that often has a negative impact on the heat sensitive health promoting nutrients like vitamins, antioxidants, flavors, and phytochemicals. Although tremendous progress has been made in rapid heating with the advancements in volumetric heating technologies like ohmic and microwave heating, the advancement in rapid cooling remains unexplored to further minimize the product quality degradation. A novel rapid cooling heat exchanger design modification was made to the traditional cooling system to improve the rate of cooling by direct injection of cooling gas media. Pilot-scale tests were conducted on a model food with an Ultra High Temperature (UHT) processing unit and an add-on novel cooling design. The cooling rate achieved by the rapid cooling design was found to be 7.5 ± 0.01 °C/s, which was 15 times the cooling rate provided by the traditional UHT cooling system. Mathematical models were developed to predict the time-temperature profile and the nutrient retention based on the new design. The model simulations for the new cooling design showed additional retention of 14.81% antioxidant content, 4.13% anthocyanins, 14.43% total flavonoid content as compared to the traditional cooling system.