Comparative study between conventional and microwave‐assisted pasteurization of packaged milk by finite element modeling

Abstract

In this study, a comprehensive computer simulation model was developed to evaluate and compare temperature distribution, flow pattern, slowest heating zone (SHZ) location, and processing time in prepackaged milk during microwave‐assisted pasteurization (MWP) and conventional pasteurization (CNP). Temperatures predicted by simulations were successfully validated against experimental data. C value, color, and thiamine kinetics coupled to temperatures predicted by simulation model were used to assess the impact of the process on product quality. Considering an equivalent microbial safety between both processes, MWP achieves a more uniform heating and, consequently, reductions of 28.6% in processing time and 14.8% in overall quality losses. Color changes were 35.5% and 37.0% for MWP and CNP, respectively; while thiamine losses were lower than 1% in both cases. Additionally, container orientation was evaluated for MWP, showing that horizontal orientation provided better temperature distribution and reduced quality losses. Practical applications Pasteurization has to ensure the prolongation of food lifetime, while the quality of product should be preserved. Minimizing the quality losses and at the same time for providing an adequate process with a desired sterility is one of the challenges to canning industry. In this sense, MWP provides an alternative to reduce damages to food quality in comparison with traditional treatment. Volumetric heating of microwave, can be extremely beneficial for liquids, such as milk, solving the fouling problem of heat transfer surfaces existing in conventional process. This study found that MWP and the horizontal position could be considered alternatives of processing to reduce the severity of the thermal treatment of milk and hence obtain a product of higher quality. This batch pasteurization using microwaves can represent a technological advance to apply by small dairy producers in rural areas, with possibility to be scaled up it to a higher production level.

Analysis of the Effects of Microwave Combined Induction Heating on Steamed Pork with Rice Powder

“…Therefore, microwave heating overcomes the slow heat transfer resistance and rapidly reaches the required sterilizing temperature [3]. Additionally, shorter sterilization times prevent the loss of heat-sensitive nutrients, particularly vitamins B and C, which are susceptible to thermal degradation, retaining the commercial value of the product [9]. A microwave-assisted pasteurization system (MAPS) utilizes microwave as a heat source, employing a four-stage process of preheating, microwave heating, holding, and cooling to achieve commercial sterilization of RTE foods.…”

Effects of Container Design on the Temperature and Moisture Content Distribution in Pork Patties during Microwave Heating: Experiment and Numerical Simulation

“…In particular, the textural quality, which is highly influenced by the temperature and moisture of food after heating, is the most important concern in domestic applications of the microwave. The factors affecting microwave heating are the oven (design, microwave field distribution, size, turntables, oven power, power cycling, mode stirrers, and feed location) [8][9][10][11], food (dielectric and thermophysical properties, penetration depth, thickness, shape, and size) [12,13], and container (materials, shapes, dimensions, Processes 2022, 10, 2382 2 of 17 and places and directions in the oven) [14]. In most cases, microwave heating patterns are determined by a combination of those factors.…”

Numerical modeling of heating tomato pulp in continuous flow microwave‐assisted thermal processing: Estimation of quality parameters

“…The electromagnetic energy turns to thermal energy due to the oscillatory polarization of the electric field inside the food, which promotes dipole rotation and ionic conduction (Teleken et al, 2020). However, the major concern of microwave heating is the non‐uniform temperature distribution, which can have implications for food safety and quality (Lespinard et al, 2019; Topcam & Erdogdu, 2021). In microwave heating, many factors can affect the amount and distribution of the absorbed energy by the food, namely, dielectric properties, volume, and shape of the material, design, and geometric parameters of the microwave cavity.…”

“…However, those models have not considered the effect of non‐uniform temperature distribution on the microorganism's thermal inactivation and the impact of food qualitative properties. An exception case was the numerical study of Lespinard et al (2019), which evaluated the batch pasteurization of milk using a domestic microwave oven. They evaluated the effect of glass bottle orientation in the oven on the temperature uniformity, microbial destruction, and food quality.…”