No need to reformat the hard drive if they want to remove avast antivirus it is formatting the disk for a person who does not like research and want more resources to incoerentes way because there are some programs to uninstall one of them is the total unistall and Optronic is clear avast leave a link here I try it works 100%. 
Backgrounder: Patent J. Craig Venter Institute on the first species of the world completely synthesized in the laboratory. 
What Synthia going to use? 
[iii] 
Subject: 
These drugs and devices, nano-enabled, could lead to an era with two levels of humans-Homo sapiens and Homo sapiens 2.0. 
Proper application of microwaves in food reduces the deterioration of their components and improves the organoleptic characteristics
Although heat treatment microwave foods known since late 1940, it was not until the 60's when the household microwave became popular, especially in the U.S., where he began to use first. The advantages over conventional treatments are speed, cleanliness, selective heating of food, lack of contact hot surfaces, reducing costs, improving quality and saving energy.
The microwaves are generated in the magnetron, a device that converts electrical energy into an electromagnetic field. When microwaves are applied to food, the polarity of the electromagnetic field changes direction causes several million times per second. Thus, polar and ionizable components (water and mineral salts, mainly) trying to orient with the direction of the electromagnetic field, producing friction and collisions between molecules that lead to an increase in temperature inside the food, the fact that unlike microwave heating with traditional heat treatments. Once heat is generated in the food, it is transferred by conduction and convection heat. Limits
The lack of uniformity in the distribution of temperature is one of the biggest drawbacks of the microwave as it affects the final product quality in relation to the effects of microwaves on microorganisms Some studies raised the possibility a few years ago that there were non-thermal effects causing the fatality. However, after it has been shown that the microbial inactivation exclusively due to the heat generated inside the food, with microbial inactivation curves similar to those of conventional heat treatments. Despite the many advantages offered by microwave treatment, there are disadvantages such as limited application to foods high volume, high cost of facilities and, above all, lack of uniformity in the temperature distribution inside the food, one of the aspects that affects the final quality of the treated product.
When there is no adequate control of the uniformity of heating may appear "cold spots" in which the microbial inactivation is incomplete, and "Hot spots", where thermal degradation can occur with consequent excessive expense on the sensory properties and nutritional value of food. Therefore, we need to know and control the factors affecting the heating of both those related to equipment (furnace type, frequency, power) as the characteristics inherent to the food (composition, physical properties, size, shape). One option to improve the uniformity of heating liquid foods is making continuous flow treatments. In general, we have seen that these treatments provide effective heating for pasteurization, for example, milk and orange juice, retaining and even improving their nutritional and sensory properties compared to conventional treatments carried out in heat exchangers.
addition to the well-known uses in the home for heating, cooking and thawing, have developed various industrial equipment that has greatly expanded the range of application of microwaves in food. Thus, the microwaves have been used in recent years in applications such as drying process for the manufacture of pasta, blanching vegetables and pasteurization of packaged foods.
Perhaps the most successful industrial use is the use of microwaves to raise the temperature of frozen pieces of meat, fish, poultry, vegetables and fruits. Today, in the U.S. there are over 400 plants that work for this purpose. This application is particularly appropriate where large pieces of meat and fish. During this process, parts found at -20 ° C must pass or -2 to -5 ° C, with the aim of enhancing, well, your cutting or filleted for subsequent packaging and marketing. Traditionally, the process is carried out leaving in cold weather for several days, which caused loss of fluids such as blood and protein solutions, significantly impairing quality. However, when using the microwave for this purpose, the process is very fast. For example, in parts of 10-40 kg is achieved by reaching the required temperature in 5-10 minutes.
Similarly, in the dairy industry, the microwaves are also used in the treatment of frozen butter, which must remain frozen at very low temperature until further cutting and marketing to prevent the development of rancidity. An effective method to raise the temperature of the butter and, thus, facilitate cutting, the microwave treatment. Currently, there are at least four large-scale plants working in England. Another application of microwaves which is proving attractive to industries is the pre-cooked bacon. We have seen that when the bacon is heated in a traditional team like the grill, there are substantial losses of water and fat, and, therefore, food structure shrinks. In addition, the fat melts into the hot grill surface and deteriorates significantly, reducing its quality. However, the microwaved bacon better preserved in its original composition and, consequently, product dimensions vary little. In the U.S. alone there are over 30 teams for continuous process.
In recent years it has developed a team to carry out heating by microwave continuous flow of various types food more or less viscous, and even inhomogeneous. It has been found that could be particularly useful for treatment of high temperature pasteurization and short and UHT milk, cream, yogurt, sauces, purees and baby foods. Due to the absence of hot surfaces in contact with food and speed of the process (140 ° C are reached in less than 1 second), prevents overheating, while preserving product quality and reducing processing costs.
For the application of microwaves in packaged foods, have also devoted much effort in developing specific types of packaging for microwave treatment. Depending on the purpose of warming, there are passive containers (glass, ceramics, paper, cardboard and plastic), which do not interfere with microwave and active packaging, consisting of thin metal pieces between sheets of cardboard or metallic polyester, which affect food warming improving uniformity. The latter are particularly useful in the case of heterogeneous foods, for example, lasagna, pizza, croissant, potato chips and foods that have to reach high temperatures, as is the case of popcorn.
However, if there is proper control of heat distribution during the process, hopefully in quantity less deterioration of the components and even better organoleptic characteristics, when subjected to microwave food compared with those treated by conventional process conducted under identical conditions of heating, holding and cooling temperature.
Although sometimes studies have emerged that seemed to point to possible adverse health effects of processed food products with microwave, after more than half a century of use in the home, could not corroborate any of the adverse effects identified.
http://www.consumer.es/seguridad-alimentaria/ciencia-y-tecnologia/2006/04/05/23073.php
The microcapsules act as barriers against odors and flavors and resist processing conditions and packaging
Encapsulation is a process by which bioactive food substances are introduced into a matrix to prevent the loss, to protect them from reacting with other compounds or to slow oxidation due to light or oxygen. In general, encapsulation is a means to pack, sort and store materials for later release under controlled conditions. This technology brings in the food sector, products with better sensory and nutritional characteristics.
encapsulation processes were first developed between 1930 and 1940 by the National Cash Register (NCR ), Ohio, USA, for the commercial application of a dye from gelatin encapsulating agent. The food application is more recent, mainly due to cheaper technology, which has attracted interest from the food industry. This process allows, depending on the applied technology to encapsulate nutrients are not attacked, degraded or oxidized, as well as enzymes or whole cells, allowing substrates and products into and out of the capsule.
The latter idea was applied in the development of an artificial liver, liver enzymes placed in semipermeable membranes to improve their function. Nylon membranes have been used to encapsulate and entrap enzymes like pepsin, pectin esterase, Invertase for sucrose inversion and renin for coagulation of milk. Even as lactic acid bacteria Lactobacillus lactis can also be encapsulated, which could facilitate the production of fermented products continuously.
microcapsules for production have been proposed various methods are divided into physical processes (spray drying, extrusion and spray coating) physicochemical processes (simple or complex coacervation and entrapment in liposomes) and chemical processes. The choice of method depends on the average particle size required and the physicochemical properties of encapsulating agent and the substance to be encapsulated, applications for microencapsulated material, the release mechanism required and cost.
The encapsulation of flavors prevent undesirable reactions with other food components, even for a long storage process have been developed various methods for encapsulating flavors and aromas. Spray drying is the most used in the food industry because it is a cheap and effective in the protection of materials. Modified starches, maltodextrins and gums are used as wall materials. The encapsulated material is homogenized with the carrier. Subsequently, the mixture is spray dried and sprayed through a nozzle or disk. After this process, the capsules formed are collected ready to be employed.
are currently studying new materials wall, including colloids and natural gums, for obtaining mixtures which increase the retention of volatile compounds and the commercial life of the microcapsules. Thus, we have obtained the retention of essential oils of orange and decreased oxidation by using gum arabic, which undoubtedly allows the inclusion of active substances without being affected by the process of digestion begins in the mouth and stomach.
Another method is to spray chilling or freezing, which consists in mixing the material to be encapsulated with the product carrier and atomized by means of cold air. The microcapsules produced by spraying the emulsion or suspension containing the wall material and active ingredient of solid or liquid. The coverages are vegetable oils used in the case of spray chilling or hydrogenated vegetable oil spray to freeze, and can be encapsulated heat-sensitive liquids and materials that are insoluble in conventional solvents.
reduction produces a solidification temperature of the lipid that acts as a wall and the entrapment of the active substance in the center of the capsule. The spraying of cooling is usually used to encapsulate ferrous sulfate, vitamins, minerals or acidulants. The most common applications of spray freeze include dried soups and foods high in fat. The microcapsules produced by cooling or freezing are insoluble in water due to its coverage of lipids, which are encapsulated soluble materials such as enzymes, vitamins and water soluble acidulants.
Microencapsulation by extrusion, developed another method involves the passage of an emulsion of active material and the wall material through a die at high pressure. The extrusion process is the second most used, after spray drying for the encapsulation of flavors. A typical process involves mixing flavored with corn syrup and modified starch hot extruding the mixture into small sphere ( pellets) in a bathroom with a cold as isopropoanol solvent. The cold solvent syrup solidifies into an amorphous solid, bathing the flavors. The flavors have a longer life as well. Vitamin C and dyes may have a shelf life exceeding two years, and are protected from oxidation. In addition, the solid form of flavors is more convenient to use. The application of this method in food processing includes drinks, cakes, jellies and desserts.
coverage fluidized bed consists of particles suspended sound in air at high speeds inside a chamber with controlled temperature and humidity, which sprays the wall material. The amount of coated particles depends on the length of the camera and the residence time within it. The technique is applicable to coatings that melt easily (such as hydrogenated vegetable oil, stearin, fatty acids, emulsifiers and waxes) or soluble coverage (such as starches, gums and maltodextrin). For hedges that melt cold air is used to harden the carrier, while for the coating soluble hot air is used to evaporate the solvent. The ingredients are easy to blend released by increasing temperature or by physical disruption, coverage while soluble release their contents by adding water. Some fortified foods and nutritional ingredients encapsulated mixtures fluidized bed, for example: citric, lactic and sorbic acid or sodium bicarbonate used in bakery products.
A type of housing properties with more versatile and less fragile than those made of fat is of the liposomes used for the release of vaccines, enzymes and vitamins in the body after passing through the initial stages of the digestive tract. The method of encapsulation in liposomes consists of one or more layers of lipids and acceptable non-toxic food whose permeability, stability, surface activity and affinity may vary with the size and composition of the lipid. Liposomes are vesicles that form when phospholipids are dispersed films in an aqueous medium. They act the same way as natural membranes, being selectively permeable to ions.
A major advantage of encapsulation is the ability to retain certain food substances or microorganisms and protect them from the action of the stomach, allowing the passage into the intestine of microorganisms and nutrients are not altered with proven nutritional and digestive protection. At the same time, it is possible to encapsulate drugs, which opens the door to the use of substances that could not stand the passage through the stomach and the first sections of the alimentary tract and, according to this principle, may be administered via oral.
development miniaturized tools for detection of microorganisms help to obtain universal instruments and microbiological quality control
From a consumer perspective is increasingly important to have a total guarantee of safety and quality food. At the industry level, the supply of safe food is to identify, as soon as possible pollution problems. It is therefore necessary to develop techniques increasingly faster and more accurate, something that has helped the progress of biotechnology, which has facilitated the development of previous technologies such as optical traps, lasers, electronic scanning microscopes tunneling.
All these tools allow biotechnologist greater knowledge and a better characterization and control of living cells. Currently, the nanomachines and bio-inspired materials are formed by self-assembly, molecular imprinting and other assembly techniques. The R & D in nanobiotechnology has a vast future ahead, particularly in areas such as medicine, of which 50% are hydrophobic and useful for the reduction of drug particle size to nanoscale could improve its administration.
On the other hand, nanomaterials with high porosity are suitable to achieve a more controlled application of drugs. In gene therapy, the success depends on developing safe and effective gene vectors. Non-viral vectors, nanoparticles, lipid complexes with DNA polymers have been proposed as alternatives to viruses, used to introduce specific genes in certain cells.
Advances in nanotechnology will soon be realized in improving the preparation of such nanoparticles to DNA. Finally, nanobiosensors have several immediate applications in generic research, among which we should emphasize monitoring nanoscale components inherent in living cells and biological threat detection.
coexist, however, several problems associated with the commercialization of nanotechnology. Often cited the superior performance of transistors made from carbon nanotubes. Unfortunately, it is almost impossible to mass produce such transistors for computer chip manufacturing. Similarly, there are still many challenges to overcome in relation to the synthesis and processing of nanoparticles carrying drugs on a commercial level. Another critical issue is the integration of nanostructures and nanodevices into systems or broader platforms on a human scale, that surround them, so they can be used as components in electronic devices or sensors, among others.
Nanostructures are often unstable because of the small size of their constituents and their high chemical activity. Therefore, a major challenge is to increase the thermal stability and structural chemistry of these materials, and devices made therefrom. The biggest problem that could face nanotechnology in its quest to market, is the cost of production.
List binding analysis of microorganisms is growing currently accepted standards for detection of microorganisms based on their crop from food to reach their isolation and identification on selective media. Is simple but time consuming. Traditional microbiological analysis are complemented by several rapid molecular biology technologies that are able to identify contaminating organisms, including detection by ELISA (Enzyme Linked Immunosorbent Assay), which determines the presence of surface proteins or secreted by microorganisms, quantitative PCR reaction (Polymerase Chain), which allows amplification of DNA fragments or in combination with a reverse transcription reaction, the RNA of microorganisms.
Because many foods are processed from raw materials to a certain level of contamination at source, and even with pathogenic microorganisms, it is necessary to apply various technologies for reducing microorganisms, thereby reducing or even eliminating the danger . In these cases, the technologies could provide positive detections because if there antigen or genetic material may produce results that eliminate the presence of living microorganisms. For this reason, we have a premise true: always have to be able to detect living microorganisms because the dead will not affect us negatively.
The market offers various protocols and ready to use and reliably for the detection of living organisms. Including kits quantitative PCR detection, such as Salmonella foodproof Lightcycler, Listeria monocytogenes, E. coli O157 and Listeria-genus kits of Roche Company. The disadvantage of detection kits is that they require the introduction of a molecular biology laboratory and the analysis effort is directly proportional the number of organisms tested.
Indeed, the list of mandatory and desirable microorganisms to be analyzed is increasingly high, and it is foreseeable that in the future will be good to distinguish between different related strains, which may present a risk to the consumer completely different. Therefore, it is desirable to develop inexpensive systems capable of analyzing multiple (tens or even hundreds) of organisms or variants simultaneously, and can carry out in situ a simple and easy for production technicians.
development and production of miniaturized tools detection of microorganisms focused on specific foods and contaminating microorganisms characteristic can open the possibility of developing tools for safety and quality control of microbiological universal, thus encouraging standardization.
For this reason, the application of innovative technology and fast come from the hand of the largest producers, who manage to invest significant amounts of resources to innovation. And in most cases the food control is associated with a high cost, which includes a representative sampling and analysis protocols. Given this situation, it is often cheaper and analysis are selected without an appropriate management of test results. However, when we have a rejection of non-conformity product, the cost is much more important.
A refund means you have to bear the cost of production, transport costs and, depending on the contamination, the costs of destruction or disposal of the goods. In many cases, it is the self that leads to the existence of lots rejected, because if the food is perishable can not stay a week to obtain analytical results. The existence of adequate controls in time and cost mean lower costs and increased profits because, in many cases, the fact of not having a benefit denials that may pay checks.
Citizens of developed countries have good reason to worry about the quality and safety of the food they eat. The number of food-borne diseases has increased over the past 20 years. It is estimated that today and every year, 1 in 3 European and 1 in 4 Americans have a consumption-borne by spoiled food.
These diseases cause 20 deaths per million inhabitants and cost to their governments "billions of euros." The World Health Organization (WHO) estimates that 2 million children die each year from diseases transmitted by food and water. Moreover, the "travelers' diarrhea, the disease is most commonly contracted by visitors to developing countries has been estimated affecting between 20 and 50% of the 35 million travelers who annually cross the borders of these countries.
What are the causes of the problem?
The new foods that are processed with old technology or new methods not yet sufficiently tested is one of the most important. This is the cause of the "appearance" of microorganisms called "emerging pathogens, including species of bacteria that were not traditionally a major health problem. The development of new power foods, sometimes, its growth relative to other pathogens "traditional."
change conventional methods of plant and animal production favors the emergence of new diseases (syndrome of mad cow disease, dioxin poisoning etc..) And the spread of large groups of animals and plants with well-known pathogenic species.
concentration in large agribusiness companies causes a breakdown in quality control systems affects a large number of consumers, even from different countries. For the same reasons, the change in lifestyle, with the creation of great eating places, is also a major cause of the problem.
Finally, changes demographic developed countries have experienced have led to a substantial increase in population particularly sensitive (yopis = young, elderly, pregnant and immunosuppressed).
"What are the limitations of traditional technologies?.
Currently, the only preservation method that simultaneously guarantees the health safety of food is heat. However, recently it has been shown that various microbial species pathogenic to man (that cause disease) are able to survive the current heat treatment. In addition, seemingly well-unpasteurized foods have been responsible of severe food poisoning.
The main problem of the heat treatment lies in its specificity, since, while microorganisms and inactivate enzymes produce a series of chemical changes in food components whose consequences are the loss of its nutritional value, sensory and functional . This prevents, in many cases, increase the intensity of the treatments currently used, and therefore their health security.
Moreover, changes in consumer habits and the main concern of the average for the quality of the food they eat, have prompted the food industry to develop new minimally processed. One of the major constraints to industrial expansion in this area is the lack of conservation methods and adequate sanitation, ensuring the preservation and safety of these foods, minimally affecting their quality.
Are there solutions to this problem?
Food Technology is currently undertaking a major effort to develop new methods of preservation and cleanliness of food. On the one hand, trying to improve on current treatments possible to search for more efficient thermal heating such as microwave, ohmic heating, etc. Second, they attempt to combine various technologies to reduce the intensity of treatment and, thus, its effect on the loss of quality (eg acid addition reduces the temperature and time of sterilization of some canned vegetables) . Finally, try to find new treatment methods, more specific, allowing effectively destroy microorganisms and minimally affect the quality of food. Within this latter group, ultrasound, and pulsed electric fields are two of the most promising technologies under investigation.
"What is Ultrasound? How can be used?
Ultrasound is sound waves that are inaudible to humans because of its high frequency. Passing through the liquid media, ultrasounds generate alternating cycles of compression and expansion and, therefore, the appearance of gas bubbles in the liquid mass. In successive cycles, the bubbles grow, they reach a critical size and, to overcome this, implode (similar to suddenly remove the air inside a balloon). When molecules collide fluid as a result of the collapse, there are pressure waves that are transmitted through the middle inactivating bacteria and disruption suspended matter. Although the effect This phenomenon, called cavitation, is known from ancient, its usefulness is very limited given the low efficiency in the normal process of treatment.
Our group has investigated the possibility of increasing the intensity of cavitation through the application of ultrasound under pressure (Manosonicación), and enhance the lethal efficiency of the process through the simultaneous application of heat (Manotermosonicación). Our laboratory has designed a facility that allows you to apply ultrasound and heat in perfectly controlled conditions of temperature, pressure and amplitude of ultrasonic waves. This facility has enabled us to demonstrate that inactivation Ultrasonic microbial increases with system pressure, so it is possible to design treatments manosonicación increase up to 100 times the health security afforded by ultrasound treatment of pressure and temperature. On the other hand, it is possible to design processes manotermosonicación (ultrasound under pressure + heat) at moderate temperatures that can act synergistically to increase "thousands" of times health security that confer heat treatment at the same temperature. The Manosonicación and / or Manotermosonicación can be particularly useful for food pasteurization and sterilization of contaminated liquids very heat resistant microorganisms, and for those whose composition significantly increases the microbial heat resistance (jams, pickles, etc.) or hinders the transmission of heat (ie liquid egg). You may also be useful for the decontamination of raw vegetables and commonly used tools in the food industry.
What are pulsed electric fields? What can you use?
One of the new technologies that could replace conventional heat treatments are pulsed electric fields (CEP), produced by applying electric shocks high voltage in controlled conditions. Electric fields produce the accumulation of charges of different signs on both sides of cell membranes. When the field strength (E) reaches a critical value (Ec), the attraction between charges overcomes the mechanical resistance of the membranes and pores occur. If the field strength exceeds the critical value (Ec), the pores produced are numerous, large and irreversible leading to cell death.
Our group has worked with the group of Prof. D. Knorr, Technical University of Berlin, to develop a new set of electrical pulses that is currently and globally, the better to control treatment parameters. It has been shown that the effectiveness of pulsed electric fields increases with the applied electric field strength. Although to achieve microbial inactivation is necessary to apply electric fields that generally exceed 10000-15000 volts / cm, the mean treatment temperature increases just as the electrical pulses that generate only last a few millionths of a second. This is the reason why this technology only affects the quality of food.
Its main uses food sanitation would be particularly sensitive to heat liquids (eg fruit juice) and, since that breaks the cell envelopes, the application on plant and animal tissues as a prelude to the process of extracting its components (eg to extract starch from potatoes, sugar beets, fruit juice etc).
Activities of the group "New Technologies in Food Preservation at the University of Zaragoza
Our group pioneered the study of these new methods of microbial inactivation in Europe, has designed and patented a new process of preserving / sanitation based on the application of ultrasound, working with research groups in Europe and the United States and has trained its members in aspects are considered more important in some of the most prestigious in the field (University of Washington, Technical University of Berlin, University of Reading, etc). Now, our efforts are focused on the study of food preservation by ultrasound and pulsed electric fields, but in the medium term, we intend to expand our research to other technologies such as pulses of light, high magnetic fields, etc. .
Our working method is to study the biological basis governing the effects of these technologies, the design of new processes and as a last step, conducting research specific food applications for transfer to industry. Logically, the state of development of our research differs with the different technologies, whereas in the study of ultrasound we are almost at the last stage, in terms of pulsed electric fields we are in the first.
http://www.consumer.es/seguridad-alimentaria/ciencia-y-tecnologia/2006/07/05/24173.php
The use of pulses electrical treatment of milk enables effective microbial inactivation with a small increase in temperature
The use of high voltage electrical pulses (Pulsed Electric Fields, PEF) is a good alternative to conventional heat treatment of liquid foods and semi-liquids. Pasteurization of milk is one of its potential applications. Despite some of the limitations of this process, as the high cost of facilities, offers great potential in the treatment of milk because it allows a food sensory and nutritional characteristics similar to the starting product and in the future could be an alternative to traditional pasteurization.
According to the results of studies carried out so far, the main advantage of using PEF for treatment of milk resides in the effective microbial inactivation obtained at the level of pasteurization, with a small increase in the temperature. This also provides a product suitable for consumption with good nutritional and sensory quality, similar to fresh food. An additional advantage of this technique is the low formation of deposits, compared with a traditional pasteurization.
BasicsA treatment followed by PEF pasteurization can potentially increase the shelf life of milk up to 60 days PEF treatment involves the application for short times (2-300 microseconds) of high intensity electrical pulses. This technology is based on the ability of fluid foods conduct electricity because of their high water content and nutrients that may be carriers of electric charges. During treatment with PEF energy, stored in a capacitor, is discharged into high intensity pulses very fast to a treatment chamber, where the food is confined. Although initially the process was carried out in static cameras, computers today are suitable for continuous flow treatments.
fundamental aspects to ensure the effectiveness of the process are the generation of high field strengths and chamber design that allows uniform treatment with minimal temperature rise, avoiding electrolysis. Therefore, the main process parameters to be considered include, besides the electric field intensity, treatment time (pulse duration by the number of pulses) and pulse rate. There are different types of pulses but the exponential decay and square wave are the most used. Effect
inactivation achieved by PEF refers to vegetative cells because, in general, inactivation of the spores is negligible. Studies have been conducted in major milk bacteria such as Escherichia coli , Pseudomonas spp. Bacillus spp. Staphylococcus aureus, Lactobacillus spp. Listeria spp. Salmonella Dublin and bacteria in raw milk themselves. Recently, it has proven the effectiveness of PEF in the inactivation of Enterobacteriaceae in infant formulas.
The main effect an electric field on microorganisms is an increase in membrane permeability due to compression and electroporation phenomena. When the values \u200b\u200bof field strength exceeds 25 kV / cm rupture of the membrane becomes irreversible, leading to cell lysis. In general we have seen that short pulses, high intensity and high frequency field are perhaps the most effective conditions for microbial inactivation. Has also been shown that square pulses are more effective than those of exponential decay. Other factors that affect microbial inactivation is the initial temperature of the food, the initial concentration of bacteria and their size, species and growth stage, with those in the logarithmic phase more susceptible than stationary phase and latency.
As regards the effect of PEF on enzymes, generally require more intensive treatment than are required for vegetative cells. The parameters affecting the effectiveness of inactivation are similar to those mentioned above for microorganisms. We have studied the influence of PEF on enzymes important in milk such as alkaline phosphatase, plasmin, lipase and peroxidase, as well as lipases and proteases of microbial origin, obtaining variable results.
Of the studies conducted so time on the inactivation of microorganisms and enzymes by PEF in buffer solutions, model systems and milk with different fat content, has been the medium (composition and pH) also exerts an important effect when considering the effectiveness of the process. Some authors have suggested that high fat content and / or proteins may have a protective effect against inactivation during treatment of milk.
As for the effect on the organoleptic and nutritional quality of processed milk with PEF, the bulk of the work have not shown a significant influence on chemical and sensory properties of milk, with similar characteristics organoleptic a PEF-treated milk to pasteurized milk in a traditional way. In the case of the nutritional value has been only a slight change in the vitamin C in milk treated with a high number of pulses. Very recently it has been observed that treatment of milk with PEF may affect casein, reducing viscosity and improving milk coagulation properties. Comparing the life of conventionally pasteurized milk and milk subjected to PEF was found to have similar life span (two weeks). Pasteurization treatment followed by PEF can potentially increase the shelf life of milk up to 60 days.
The main problem that arises for the industrial application of PEF is the high cost of facilities. However, it has been shown that the application of this technology leads to more efficient use of energy than a conventional heat treatment, so in a timely manner, could be amortized capital originally invested in the plant. However, industrial applications of PEF require more studies to ensure the effectiveness and safety of the process, especially in foods such as milk, for its high concentration of microorganisms and enzymes that can impair their quality.
Another limitation of PEF is related to the formation of electrolytes in the food and release from the electrode material for the dielectric breakdown phenomenon. These aspects must be considered when designing a process by PEF. Despite these limitations, this type of process offers great potential in the treatment of milk, and you get a food sensory and nutritional characteristics very similar to the starting product and in the future, could provide an alternative to Traditional pasteurization.
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The application of ohmic heating in a wide range of foods provides products suitable organoleptic and nutritional
Ohmic heating occurs when a current electricity passes through a meal, causing the temperature rise inside as a result of the resistance offered to the passage of electrical current. The advantages of this process stem from the fact that the warming takes place inside the food. Thus, unlike what happens in conventional heating, no hot surface contact.
A large number of applications of ohmic heating include blanching, pasteurization, sterilization, thawing, evaporation, drying, fermentation and extraction, among others. One difference from the microwave is the lack of equipment in the home. Yes there is a pilot plant scale and industrial. In 2003 there were 19 plants for ohmic heating, with Japan, Italy, Greece, Great Britain, the USA and Mexico leading countries in the development of these plants. Among the various plants applying this treatment, are particularly notable that have been developed for continuous flow sterilization of fruits, fruit juices, soups, sauces or liquid egg.
The liquid egg is very appropriate for this type of process as ohmic heating can be very short time and without bleeding problems. Although equipment prices are falling, it's a technology whose initial costs can be high. However, profitability has assessed the long term because these are processes in which products are obtained with appropriate microbiological, organoleptic and nutritional conditions of low fouling and takes up little space and can be applied to a wide range of foods. Another advantage of this warming is related to operating costs. They are warm in that 95% of the energy is transformed into heat, while in a microwave heating is usually a 70% maximum. Effectiveness
density, size and shape of food are key factors in the effectiveness of ohmic heating of the heating effect depends on factors specific to the system as the food. There is evidence that the heating rate is directly proportional to the intensity of the electric field and electrical conductivity of the food. Food must be drivers but not much. The optimal values \u200b\u200bof conductivity at 20 ° C are in the range from 0.01 to 10 siemens / m. For example, a suitable food to be subjected to ohmic heating would milk the conductivity value is 0.5 siemens / m. Other factors that influence the effectiveness of warming are the density and specific heat of food as well as the size, shape and concentration of particles in the case of food particulates.
The main mechanism of microbial inactivation is thermal. Kinetic studies have been performed to compare the thermal treatments with conventional ohmic have shown no significant differences between the two processes. Some authors also consider that may occur in the cell membrane electroporation, although there are few studies and do not reach definitive conclusions.
An important aspect to be considered is the possible reactivation of microorganisms after the ohmic heating. Studies have been done in liquid egg show that after 12 weeks of storage there is a lower microbial counts in samples treated with ohmic heating, compared with a conventional heat treatment. In a study of pasteurized orange juice by both types of heating showed that, although the microbiological quality in the juice stored at 4 ° C after both heating was identical, the organoleptic quality was higher in the juice ohmic heating. Despite these promising results, further studies are needed. In general, it is true that the life of processed foods by ohmic heating to be comparable with that of conventionally processed foods.
Although few, there are works that demonstrate the suitability of this type of process in improving the functional properties of foods such as surimi from various fish. This effect could be related to ohmic heating uniformity.
Following the various studies conducted so far, the ohmic heating can be considered, among all emerging technologies, as one of the most promising in the food industry. As future prospects have to consider further studies on a microbiological level and constituents, not to mention the possible scaling optimizing domestic and industrial facilities to reduce initial costs.
