MW heating is a method of food preservation which is known to preserve food by applying heat. This process is also referred to as Ohmic heating, and it is a process of radiative heating. This method is also used for pasteurization and sterilization.
MW heating is a radiative process
MW heating is a radiative process that transfers heat from the external atmosphere to the interior of a food product. The main goal of this technique is to increase the shelf life of the food while improving its quality. It is also an effective means of stimulating microbial activity. Several studies have been conducted to determine the effects of MW heating on the microbiology of food.
While MW heating has a few nifty tricks up its sleeve, it has some crucial flaws. Among the ills, the main one is MW heating’s inability to replicate the effectiveness of conventional methods of food preservation. MW drying has a number of advantages over the conventional method, but it is also susceptible to its own set of problems.
The main problem is the inability to fully control the complex interactions between MWs and the material they are used on. This is especially true when the product being dried is large in size compared to its penetration depth.
Nonthermal effect of microwaves on microorganisms
Using microwave technology on microorganisms in food preservation has been a subject of debate. Several studies have indicated that microwave radiation can damage nerves, produce oxidative stress and cause inflammation in humans. In addition, microwaves can damage the structure of natural products, produce toxic substances and alter the flavor, color and texture of the products.
In order to understand the nonthermal effect of microwaves on microorganisms in food preservation, researchers had to compare the effects of conventional inactivation with MW inactivation. Most studies of this type measured temperature at a single point rather than the whole sample. In many of the studies, the MW inactivation had no effect on the microorganisms.
Microwaves can also produce beneficial effects. They can increase the bioactivity of proteins, change the structure of polysaccharides and reduce the viscosity of polysaccharide solutions. They also have a selective effect on polar bonds. This selective effect is useful for the processing of medicinal materials.
Microwave technology is also used to sterilize natural products. It has great significance in the processing of Chinese medicinal materials.
Ohmic heating preserves foods by the application of heat
ohmic heating is a thermal food processing technique that preserves foods by the application of heat. The process involves the use of alternating current to produce heat. The electrical conductivity of the product and the strength of the electrical field affect the rate at which the heat is generated. ohmic heating is used in food reheating, thawing, and blanching.
ohmic heating has several advantages over conventional thermal methods. The process offers better energy efficiency and requires less capital investment. It can also be used to produce a higher quality product. In addition, ohmic heating is an environmentally friendly process.
Ohmic heating is especially advantageous for particulate foods. For instance, vegetable tissue has a high electrical conductivity. Therefore, ohmic heating can be used to speed up the hot air drying of vegetable tissue. However, the process requires close match of the electrical conductivities of the liquid and solid phases.
During ohmic heating, the food product is heated uniformly. This improves extraction yields. It also eliminates the degradation of thermosensitive compounds. It has also been shown that the ohmic heating process can reduce the cooking time of foods.
Computational fluid dynamics for understanding and optimizing a reliable MW pasteurization and sterilization process
During the past few years, the use of computational fluid dynamics (CFD) in the food processing industry has increased. It is a powerful simulation tool that predicts the quantitative flow of fluids and the chemical reaction. It is based on partial differential equations of momentum and energy. The computer solves these equations and generates numerical results.
The process of MW pasteurization is a complex process that requires a computational model and kinetic models. This model must mimic the microbial inactivation in every point in the sample. It is also necessary to incorporate thermal resistance values. Using this type of modeling, researchers have been able to characterize the microbial inactivation of MW heating.
For this reason, it is very important to minimize the heating heterogeneity of MW. In this process, smaller products heat more rapidly than large products. As a result, the heating heterogeneity can lead to incomplete inactivation of microorganisms.
The shape of a product has a major effect on the penetration depth of MWs. For instance, an oval or circular shape can reduce the overheating of the edges of the product. However, sharp edges or right angles can lead to local overheating.
In food preservation, the oven drying method has become an important method of preserving food. Link