Food Science for Microwave Heating of Food - myassignmenthelp

Question: Discuss about theFood Science for Microwave Heating of Food. Answer: Introduction Microwave oven is one of the biggest revolutions in the food technology. The modern cooking as well as lifestyle is heavily dependent on the microwave oven. The oven can not only heat up the food, but it can cook also using the microwave energy, which is electromagnetic radiation. The instrument acts very fast and efficiently as it transfers the energy to all the molecules inside the food, and with the help of the water content present in the food, it gets heated evenly (Gould 2012). History of microwave oven goes back to the time of World War II. Dr. Percy Spencer, an American electrical engineer, first found that electric waves of the radar technology can heat the food. He founded the first commercially available microwave oven and named it Radarange (Chen et al. 2014). In 1967, Amana Corporation invented the first countertop microwave oven (Regier, Knoerzer and Schubert 2016). The microwave oven has gone through many technological changes in the past fifty years. The purpose of th is report is to highlight the impact of the radiation on human health. Problem statement It is a matter of debate for long that, since, the oven applies highly powerful radiation on the food; it activates many different types of bacterias and may change the nature of the nutritional elements in the food, which may not be good for health. Hence, whether the food, heated in microwave oven, is nutritional and good for health is to be addressed in this report. Objectives of the report The objectives of the report are to find out the pros and cons of the microwave heating of the food and whether the powerful electric radiation is harmful for the human health. The possible solution of the problem is to use ultrasound for food processing and preservation. Body and discussion Overview of current developments/advances in the microwave heating technology Microwaves are a part of the electromagnetic waves with a frequency ranging between 300 MHz and 300 GHz, corresponding to the range of wavelength between 1mm to 1m (Datta and Rakesh 2013). In the food processing activities, microwaves are applied for tempering, drying, cooking, defrosting frozen food, baking and sterilization. Since its invention, the technology of microwave heating has become very much advanced. Initially the machine only had the capacity to heat the food. Later on, the advancement of technology enabled the options for cooking, grilling and baking too. In the initial stage, the high frequency radio waves were generated through vacuum tube radio transmitters, which were used in microwave ovens (Gould 2012). Overtime, short waves were used through shortwave transmitters. Lower frequency dielectric heating is similar to induction heating, having the effect of electromagnetic heating, with near-field effects existing in an electromagnetic cavity. This cavity is quite sm all compared to the wavelength of the electromagnetic field. In the modern microwaves, the dielectric heating technology with radio frequency (RF) heating is used. In these technology, lower frequency radiation is used which has a wavelength small relative to the cavity and it affects the polarized molecules in the food by a quickly alternating electric field (Meda, Orsat and Raghavan 2017). Developments in process design Process design refers to the activity for determination of the workflow, equipment requirement and implementation needs for a specific method or process. The process design of a microwave oven is illustrated in the figure below. Figure 1: Process design of a microwave oven (Source: Sce.uhcl.edu 2013) Equipment developments A microwave oven consists of the following equipments. A high voltage source of power, in form of simple transformer or electric power converter, passing the energy to magnetron; high voltage capacitor, which is connected to the magnetron and the transformer and to the chassis via a diode; a cavity magnetron, converting the high voltage energy into the micro radiation; microcontroller, which is a magnetron control circuit; short wave guide, metallic cooking chamber, a turntable and a digital or manual control panel (Puligundla et al. 2013). The design of the machine has transformed quite rapidly in the past few years, when people started to use it in their households. The size has become compact and the new machines also offer autocook options with preloaded combination of time and temperature for specific recipes and convection heating technology (Sun 2012) New applications in food processing / preservation The food industry is now starting to adopt new technologies for food processing and preservation. New research studies have found that application of ultrasound technology has been beneficial for the processing and preservation of food. Ultrasonication is referred to as the application of the high intensity waves of sound at the frequencies between 16 kHz and 100 MHz (Majid, Nayik and Nanda 2015). In the food industry, the ultrasound is applied for microbial inactivation along with foaming, defoaming, degassing, deaeration, cooking, freezing and crystallization, drying, meat tenderizaton, filtration, brining, pickling and marinating, extraction, homogenization or emulsifying, fermenting, cutting with ultrasonic knife, cleaning, and enzyme inactivation (nver 2016). It has been seen that ultrasound has been effective in many traditional food processing and preserving operations and innovative appliances and equipment have been developed to implement the new technology. This technology helps in reducing the time of food processing as it delivers high reproducibility of food, reduces the food processing cost, simplifies the particle manipulation resulting in higher purity of the food product using very less time than the traditional food processing systems (Jambrak and Herceg 2014). This technology has some advantages, such as, effective micro-mixing, mass transfer of faster energy, reduction of thermal and concentration gradients, selective extraction, faster start up, reduced temperature, reduced size of equipment, increased production and elimination of the steps of the processes. The processing and preserving steps performed under this technology are thought to be affected partly by the cavitation phenomena and the mass transfer enhancement (Chemat, Huma and Khan 2011). However, application of the ultrasound technology also has some disadvantages. According to Tang (2015), production of free radicals can occur, which can damage the food and its nutritional value. Application of this technology requires high level of expertise and highly efficient appliances as selection of appropriate amplitude, temperature, power, intensity, time and pressure is extremely critical to get the desired result. Effect on food quality and safety It has been a matter of debate for long that if the food heated or cooked in the microwave is good for health. The biggest concern is if the heating process kills the nutrients of the food items. The technology uses shorter radio waves to cook or heat the food, which are quite selective as they affect only the water and few other molecules which are electrically asymmetrical, with one end positively and the other end negatively charged. The microwaves make these molecules vibrate and build up the thermal energy faster. Regarding the question of killing the nutrients in the food, it is found that, some nutrients, especially, vitamin C breaks down very easily when heated; and since, microwaves are shorter, they help in preserving those nutrients (Ranadheera et al. 2017). Similarly, in case of vegetables, when they are boiled in water or fried, some of the nutritional value is washed out, but when steamed in microwave oven, the easily breakable good nutrients of the food do not wash awa y (Tang 2015). The best way to retain the food nutrients is to cook them quickly and heat them in a very short span of time by using very little amount of liquid. Microwave provides this scope, which is beneficial for health. However, the food can lose its nutritional value from the microwaves also if it is not cooked using the right amount of temperature. Different types of food require different time and temperature and hat needs to be maintained. For example, raw fish, meat and eggs require minimum 60 degree centigrade to be safe for health while the vegetables require less temperature (Regier, Knoerzer and Schubert 2016). Microwave heating of food has a major challenge of unevenness in the heating of food, as the temperature is distributed unevenly depending on the shape of the food item. This causes a potential safety issue. The disease causing bugs can only be killed through microwave when the correct combination of temperature and time is applied throughout the whole portion of the food. Temperature above 60 degree centigrade can kill all bugs known to produce food-borne illness, while some toxins produced by those bugs can be heat tolerant and stay in the cooked food even after applying the correc t combination of time and temperature (Chandrasekaran, Ramanathan and Basak 2013). Hence, appropriate process of storing the food is important to retain the nutritional value. Conclusion Microwave oven has become a household name in the past few years. It has been a revolutionary invention for the food industry for cooking food using shorter radio waves. It has been found that microwaves are good for preserving the nutritional values of the food as it involves very short span of heating and shorter radio waves. However, for high risk food items, such as, meat, fish and eggs, the combination of the time and temperature is critical, which might not produce the desired result of high nutritious food. New technologies, such as, ultrasound, are being developed, which may be a substitute for the microwave heating in future. However, with the advancement of technology, microwave ovens are improving and are expected to be more widely used in the food industry and in households. References Chandrasekaran, S., Ramanathan, S. and Basak, T., 2013. Microwave food processingA review.Food Research International,52(1), pp.243-261. Chemat, F., Huma, Z. and Khan, M., 2011. Applications of ultrasound in food technology: Processing, preservation and extraction.Ultrasonics Sonochemistry, [online] 18(4), pp.813-835. 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