Hi All, 

Many times students ask for some new topic for their presentation. I have tried to list down few emerging technologies in food processing. Any one of these technologies can be a good topic of discussion and presentation. These technologies could be old but not yet industrially exploited to a large extend, so the name of this discussion is kept as - Emerging Technologies in Food Processing not as New technologies.

We can discuss one by one each technologies. This will depend on your response and enthusiam :)

Some of the emerging technologies are 

a. High pressure processing

b. Pulsed electric field processing

c. Osmotic dehydration

d. High intensity pulsed light technology

e. Athermal membrane processing

f. Ultrasound technology

g. Irradiation technology

h. New chemical and biochemical hurdle technology

i. Radio-frequency

j. Ohmic heating

k. Combined microwave and vacuum drying

l. Vacuum cooling of food

m. Ultrasonic freezing

n. High pressure freezing

o. Use of anti-freezing proteins

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Well if it is about Enthusiasm so i would like to take the honours and start with very first topic i.e HPP. 

Consumers these days demand for high quality, natural and fresh tasting food, free from preservatives and additives, with a clean label and an extended shelf life. High pressure processing (HPP), also known as high hydrostatic pressure, is a non-thermal food preservation technique that has the potential to meet these demands. It is an opportunity to preserve food, by applying intensive pressure in the range of 300-900 MPa, without adversely affecting organoleptic, textural and nutritional qualities as thermal processing like pasteurization and sterilization may do.

In a typical high pressure batch cycle, the food prepackaged in a high-barrier flexible pouch or a plastic container is loaded into a perforated basket that goes into the pressure vessel; the pressure is then increased to the processing target pressure (come-up time); the product is held at the desired pressure for 3 to 10 minutes (pressure holding time); after which the pressure is released in usually few seconds (decompression time) and the product can be unloaded at this point. The pressure is applied uniformly in all directions simultaneously and this is known as isostatic pressure. Pressurization is usually accompanied by a moderate and uniform temperature increase called adiabatic heating. However, the food product usually rapidly returns to its initial temperature at decompression.

High pressure processing History in brief
•First research in 1890s –milk pathogens.First commercialised in Japan in the early 1990s for pasteurisation of acid foods for chilled storage.High pressure treated foodstuffs have been marketed in Japan since 1990, in Europe and the United States since 1996 & Australia since 2001.Rapid commercialisation since 2000.

Why high pressure processing?
High Pressure Processing (HPP) is a method of food processing where food is subjected to elevated pressures (up to 87,000 pounds per square inch or approximately 6,000 atmospheres), with or without the addition of heat, to achieve microbial inactivation or to alter the food attributes in order to achieve consumer-desired qualities. Pressure inactivates most vegetative bacteria at pressures above 60,000 pounds per square inch. HPP retains food quality, maintains natural freshness, and extends microbiological shelf life. The process is also known as high hydrostatic pressure processing (HHP) and ultra high-pressure processing (UHP).

How does HPP work?
Most processed foods today are heat treated to kill bacteria,which often diminishes product quality. High pressure processing provides an alternative means of killing bacteria that can cause spoilage or food-borne disease without a loss of sensory quality or nutrients.

In a typical HPP process, the product is packaged in a flexible container (usually a pouch or plastic bottle) and is loaded
into a high pressure chamber filled with a pressure-transmitting (hydraulic) fluid. The hydraulic fluid (normally water) in the chamber is pressurized with a pump, and this pressure is transmitted through the package into the food itself. Pressure is applied for a specific time, usually 3 to 5 minutes. The processed product is then removed and stored/distributed in the conventional manner. Because the pressure is transmitted uniformly (in all directions simultaneously), food retains its shape, even at extreme pressures. And because no heat is needed, the sensory characteristics of the food are retained without compromising microbial safety.

Uses:
Like any other processing method, HPP cannot be universally applied to all types of foods. HPP can be used to process both liquid and solid foods. Foods with a high acid content are particularly good candidates for HPP technology. At the moment, HPP is being used in the United States, Europe, and Japan on a select variety of high-value foods either to extend shelf life or to improve food safety. Some products that are commercially produced using HPP are cooked ready-to-eat meats, avocado products (guacamole), tomato salsa, applesauce, orange juice, and oysters. HPP cannot yet be used to make shelf-stable versions of lowacid products such as vegetables, milk, or soups because of the inability of this process to destroy spores without added heat. However, it can be used to extend the refrigerated shelf life of these products and to eliminate the risk of various food-borne pathogens such as Escherichia coli, Salmonella and Listeria. Another limitation is that the food must contain water and not have internal air pockets. Food materials containing  entrapped air such as strawberries or marshmallows would be crushed under high pressure treatment, and dry solids do not have sufficient moisture to make HPP effective for microbial destruction.

In general, HPP can provide shelf lives similar to thermal pasteurization. Pressure pasteurization kills vegetative bacteria
and, unless the product is acidic, it requires refrigerated storage. For foods where thermal pasteurization is not an option (due to flavor, texture or color changes) HPP can extend the shelf life by two to three fold over a non-pasteurized counterpart, and improve food safety. As commercial products are developed, shelf life can be established based on microbiological and sensory testing. 

HPP -Advantages
•Attractive for consumers -meets demand for freshness and minimal processingas it require no chemical additivesor no high temperatures
•No consumer negativity e.g.irradiation and GM
•Extended shelf life -wider product distribution and results in fewer product returns
•Uses less energy(hence greenhouse gases) than other technologies and has the highest processing efficiency for pumpable foods
•Processing can be done in final packaging which avoids post-processing contamination and tempering
•Required processing times are also reduced and there are no by-products
•Permits the inactivation of microorganisms and enzymes at low temperatures, while valuable low molecular constituents, such as bioactives, vitamins, colours and flavourings, remain largely unaffected

nice information bindiya thank u

That is called a trigger - thanks Pankaj and Bindiya (Sharma common) ;)

Thank u pankaj also......:-)

OHMIC HEATING

  • What is ohmic heating?

Ohmic heating is an advanced thermal processing method wherein the food material, which serves as an electrical resistor, is heated by passing electricity through it. Electrical energy is dissipated into heat, which results in rapid and uniform heating. Ohmic heating is also called electrical resistance heating, Joule heating, or electro-heating, and may be used for a variety of applications in the food industry.

  • How is ohmic heating different from conventional thermal processing?

During conventional thermal processing, either in cans or aseptic processing systems for particulate foods, significant product quality damage may occur due to slow conduction and convection heat transfer. On the other hand, ohmic heating volumetrically heats the entire mass of the food material, thus the resulting product is of far greater quality than its canned counterpart. It is possible to process large particulate foods (up to 1 inch) that would be difficult to process using conventional heat exchangers. Additionally, ohmic heater cleaning requirements are comparatively less than those of traditional heat exchangers due to reduced product fouling on the food contact surface.

 

  • What type of products are suitable for ohmic heating?

Ohmic heating can be used for heating liquid foods containing large particulates, such as soups, stews, and fruit slices in syrups and sauces, and heat sensitive liquids. The technology is useful for the treatment of proteinaceous foods, which tend to denature and coagulate when thermally processed. For example, liquid egg can be ohmically heated in a fraction of a second without coagulating it. Juices can be treated to inactivate enzymes without affecting the flavor. Other potential applications of ohmic heating include blanching, thawing, on-line detection of starch gelatinization, fermentation, peeling, dehydration, and extraction.

  • How does ohmic heating inactivate microorganisms?

Like thermal processing, ohmic heating inactivates microorganisms by heat. Additional non-thermal electroporation type effects have been reported at low-frequency (50-60 Hz), when electrical charges can build up and form pores across microbial cells, however, it is not necessary to claim such effects since heating is the main mechanism.

  • What is the shelf life of an ohmically processed product?

The shelf life of ohmically processed foods is comparable to that of canned and sterile, aseptically processed products.

  • Are there any ohmically processed commercial products available on the market?

A number of processing plants currently produce sliced, diced, and whole fruit within sauces in various countries, including Italy, Greece, France, Mexico, and Japan. In the United States, ohmic heating has been used to produce a low-acid particulate product in a can, as well as pasteurized liquid egg.

  • Is ohmic heating environmentally friendly?

Yes. This process uses ordinary electricity. No emissions are produced at the point of use. One emerging application of ohmic heating is fruit peeling, which may greatly reduce the use of lye that is common to such operations, and results in environmental benefits.

  • What regulatory approval is required for commercializing an ohmically processed product?

For in-container processing, the requirements are similar to that of traditional thermal processing in the United States. For continuous flow processing with aseptic packaging, the approaches are currently in development in a project funded by the USDA National Integrated Food Safety Initiative. The Food and Drug Administration (FDA) is responsible for evaluating and monitoring the safety of ohmically processed foods, unless the product contains a specified minimum amount of meat and poultry. In such cases, it falls under USDA's purview.

SOURCE-- http://ohioline.osu.edu/fse-fact/0004.html

 

Pulse Electric Field processing 

 

Pulsed electric field (PEF) is a nonthermal alternative to traditional food processing. PEF is effective in microbial inactivation without significant impair on food quality, including flavor, nutrition, and physical properties such as color, viscosity and electric conductivity. Dielectric breakdown of cellular membrane in microorganisms has been widely accepted as the mechanism corresponding to microbial inactivation by PEF. To execute its microbial inactivation effect, PEF needs to acquire electric field strength

higher than the critical value that can induce higher than 1 volt of transmembrane potential to most of the vegetative cells. Inactivation of food enzymes has been extensively studied since 1960s. Inactivation effect of PEF depends on both the dosage and the structures of the target enzymes.

        PEF is effective in inactivating natural flora and can significantly extend microbial stability of the bovine milk concentrate enriched soymilk. PEF treatment at higher electric field strength shows higher natural flora inactivation and results in higher microbial stability during a 30-day storage test at 4°C. PEF treatment at 41.1kV/cm for 54ms inactivates 5.3 logs of natural flora population (p<0.01). With continuous thermal processing, 78°C for 120s is needed to achieve same microbial inactivation. Temperature increase per pair of PEF treatment chambers (dT), with inlet temperature (T1) ranging

from 13°C to 27°C and electric field strength ranging from 0 to 38kV/cm, is primarily aiii function of electric field strength and energy input. Sample inlet temperature does not show significant influences on dT. However, T1 determines the maximum temperature induced in PEF treatment chambers. PEF significantly inactivates  E. coli 8739 cells (p<0.05). The inactivation effect increases with the increase of electric field strength and the number of pulses delivered to samples. When electric field strength is higher than 30kV/cm, increase in treatment time and sample inlet temperature cause an increase in PEF inactivation of E. coli 8739. Nevertheless, when electric field strength is lower than 25kV/cm, the microbial inactivation effect of treatment time and  T1 is negligible. Experimental data illustrate that the microbial inactivation effect of PEF is due to the high intensity of electric field strength. Thermal effect contributes minimal to the total inactivation of natural flora and E. coli 8739.

         PEF treatment at 41.1kV/cm for 54ms cause no significant changes in soy isoflavone profile comparing to the passing through controls. However, significant changes after thermal treatment at 78°C for 120s were observed in malonyl glycosides of isoflavone in soymilk. Thermal treatment at 78°C for 120s destroys malonyl glycosides of isoflavones due to the enhanced hydrolysis at high temperature. During the 30-day storage test at 4°C, color, viscosity and other physical properties of enriched soymilk were maintained unchanged.

 

 

1. What is pulsed electric field processing?

Pulsed electric field (PEF) processing is a non-thermal  method of food preservation that uses short bursts of electricity for microbial inactivation and causes minimal or no  detrimental effect on food quality attributes. PEF can be  used for processing liquid and semi-liquid food products

2. How does this technology benefit consumers?

PEF processing offers high quality fresh-like liquid foods  with excellent flavor, nutritional value, and shelf-life. Since  it preserves foods without using heat, foods treated this way  retain their fresh aroma, taste, and appearance.

3. How does PEF work?

PEF processing involves treating foods placed between  electrodes by high voltage pulses in the order of 20–80  kV (usually for a couple of microseconds). The applied  high voltage results in an electric field that causes microbial inactivation. The electric field may be applied in the  form of exponentially decaying, square wave, bipolar, or oscillatory pulses and at ambient, sub-ambient, or slightly  above-ambient temperature. After the treatment, the food  is packaged aseptically and stored under refrigeration

4. How does PEF inactivate microorganisms?

PEF treatment has lethal effects on various vegetative  bacteria, mold, and yeast. Efficacy of spore inactivation by  PEF in combination with heat or other hurdles is a subject  of current research. A series of short, high-voltage pulses  breaks the cell membranes of vegetative microorganisms  in liquid media by expanding existing pores (electroporation) or creating new ones. Pore formation is reversible  or irreversible depending on factors such as the electric  field intensity, the pulse duration, and number of pulses.  The membranes of PEF-treated cells become permeable to  small molecules; permeation causes swelling and eventual  rupture of the cell membrane

5. What types of foods benefit from PEF treatment?

Application of PEF technology has been successfully  demonstrated for the pasteurization of foods such as juices,  milk, yogurt, soups, and liquid eggs. Application of PEF  processing is restricted to food products with no air bubbles  and with low electrical conductivity. The maximum particle size in the liquid must be smaller than the gap of the  treatment region in the chamber in order to ensure proper  treatment. PEF is a continuous processing method, which  is not suitable for solid food products that are not pumpable. PEF is also applied to enhance extraction of sugars  and other cellular content from plant cells, such as sugar  beets. PEF also found application in reducing the solid volume (sludge) of wastewater

 

 

 

6. What is the shelf-life of a PEF processed product?

In general, the shelf-life of PEF-treated and thermally pasteurized foods is comparable. PEF pasteurization kills microorganisms and inactivates some enzymes and, unless the product is acidic, it requires refrigerated storage. For heat-sensitive liquid foods where thermal pasteurization is not an option (due to flavor, texture, or color changes), PEF treatment would be advantageous.

7. How are PEF processed foods stored?

PEF pasteurized products currently are stored refrigerated. In some cases (for example, milk), this is necessary for safety (to prevent the growth of spores in low-acid foods). For acid foods, refrigeration is not necessary for microbial stability, but is used to preserve flavor quality for extended periods of time.

8. Is commercial scale equipment available?

Yes. In the United States, the first commercial scale continuous PEF system is installed at The Ohio State University’s Department of Food Science and Technology. This PEF system is part of a new food treatment system assembled by a DoD sponsored, University directed industry consortium. Diversified Technologies Inc., Bedford, MA, builds commercial PEF systems of processing volumes ranging from 500 to 2,000 liters per hour, with The Ohio State University supplying the PEF treatment chambers.

9. Is PEF equipment safe for the environment?

Yes. This process uses ordinary electricity. The facility meets electrical safety standards and no harmful environmental by-products are produced.

10. What is an integrated continuous PEF Processing System?

An integrated PEF system consists of a fluid handling unit, high voltage pulse generator, PEF treatment chambers, and packaging machine. The fluid handling unit delivers stable, uniform flow with sterilize-in-place (SIP) and cleanin-place (CIP) functions. The pulse generator supplies high voltage pulses into foods flowing through PEF treatment chambers. Treated foods are packaged continuously.

11. What is a PEF treatment chamber?

A PEF treatment chamber consists of at least two electrodes and insulation that forms a volume, i.e., PEF treatment zone, where the foods receive pulses. The electrodes are made of inert materials, such as titanium. 12. How economical is PEF processing? PEF is an energy efficient process compared to thermal pasteurization. The PEF processing would add only $0.03–$0.07/L to final food costs. A commercial-scale PEF system can process between 1,000 and 5,000 liters of liquid foods per hour and this equipment is scalable. Generation of high voltage pulses having sufficient peak power (typically megawatts) is the limitation in processinglarge quantities of fluid economically. The emergence of solid-state pulsed power systems, which can be arbitrarily sized by combining switch modules in series and parallel, removes this limitation.

 

13. What regulatory approval is required forcommercializing a PEF processed product?

Currently, regulatory requirements are evolving, but will likely involve the development of Hazard Analysis Critical Control Point (HACCP) plan for most juices and beverages. A current USDA project will address these

14. Are facilities available for product development before venturing into PEF processing?

An industrial scale-up PEF pilot plant facility is available at The Ohio State University in the Department of Food Science and Technology. Food processors are invited to take advantage of the expertise of OSU faculty and staff, and facilities to conduct confidential product evaluations for food safety, quality, and shelf-life, and to obtain guidance on product development. A portable pilot scale PEF processing system is also available for customer-site evaluation. The resources at OSU can be accessed for a nominal fee.

 

 

Thats the spirit. Thanks again to Sanjeev, Nirav, Bindiya & Poorva. Somehow you guys missed out reading Nitin's post on Ultrasonication,  its a very nice ppt which he has uploaded on web. Have a look at it.

but pankaj it cant open in my lappy

A Brief On Ozone Technology 

 

1. What is ozone and where can it be found?

Ozone is a highly reactive form of oxygen, consisting of three oxygen atoms (O3). It is a potent oxidant/disinfectant that quickly decomposes to diatomic oxygen (O2), while reacting with targeted organic matter or microorganisms. Ozone is naturally generated in the stratosphere, the upper atmospheric layer that protects us from harmful radiation. Gaseous ozone is formed also in the atmosphere during lightning discharges, and on the earth’s surface by photochemical reactions, UV sterilization lamps, and high voltage electric arcs.

 

2. Significance of ozone in food processing.

Ozone is a potent antimicrobial agent. It can effectively kill viruses, bacteria, fungi, and parasites, including those causing food spoilage or human diseases. Efficacy of ozone, however, depends on the target microorganism and the treatment condition. Commercial applications of ozone include purification of drinking water, sterilization of containers for aseptic packaging, decontamination of fresh produce, and food preservation in cold storage. Ozone also is useful in deodorizing air and water.

3. How is ozone generated industrially?

Ozone is commonly generated by electrical discharge. In this method, dry air or oxygen is passed between two parallel or concentric electrodes that are coated with a dielectric material. Oxygen molecules are broken down to charged oxygen atoms, which recombine to form ozone molecules. Depending on the feed gas, ozone production rate varies from 1�3% (w/w) to 6�16% (w/w) for air and pure oxygen, respectively.

4. How does ozone kill microbes?

Ozone destroys microorganisms by reacting with oxidizeable cellular components, particularly those containing double bonds, sulfhydryl groups, and phenolic rings. Therefore, membrane phospholipids, intracellular enzymes, and genomic material are targeted by ozone; these reactions result in cell damage and death of microorganisms.

5. How is ozone different from other chemical treatments?

The strong antimicrobial character of ozone is partially related to its oxidation-reduction potential (2.07 V), which is higher than that of chlorine (1.36 V). Ozone has many advantages over chlorine and other antimicrobials. Ozone destroys microorganisms instantly and effectively, without leaving harmful residues in treated food or processing water. Therefore, ozone is safer and environmentally friendlier than most other antimicrobials. Ozone gas should be produced on-site and it cannot be stored or transported. Although this may sometimes be considered a disadvantage, a desirable feature is that only air or oxygen is needed to produce the sanitizer.

6. Is ozone safe to use in food processing?

Ozone is a colorless gas at ambient conditions, and is readily detectable by the human nose at 0.01 0.05 ppm. At low concentrations, ozone has a characteristic pleasant odor, similar to that of fresh air after a thunderstorm. High concentration of ozone gas in air is objectionable and could pose health risks. According to OSHA regulations, the permissible level of exposure to ozone in the workplace environment is 0.1 ppm during a normal 8-hour day (40-hour workweek). The short-term exposure limit is 0.3 ppm for exposure of less than 15 minutes (4 times per day). Therefore, the production and use of ozone in food processing should be controlled and monitored, and excess ozone should be removed by a commercial  ozone destruct unit.

7. Current and potential applications of ozone in the food industry.

Ozone can be applied in an aqueous solution or gaseous phase to decontaminate food-contact surfaces, sanitize equipment, recycle wastewater, and decrease pesticide levels on fresh produce. The microbiological quality and shelf-life of vegetables, fruits, cheeses, eggs, nuts, and meats can be improved when these products are directly treated with ozone or stored in an ozone-containing environment. For fresh-produce processing, ozone can be used to sanitize processing water or to decontaminate the product itself. The use of ozone in the gaseous phase helps in controlling mold and bacteria, both in the air and on the surface of the product.

8. Commercial ozone-generation systems.

Gaseous or aqueous ozone generators are commercially available and relatively inexpensive instruments. Generators vary in production capacity from a few pounds to hundreds of pounds of ozone per day. It should be cautioned, however, that suitable treatment chambers, monitoring devices, and excess gas destruction units, should be designed and integrated with the ozone generators to produce functional food treatment systems.

9. Is the application of ozone approved by regulatory agencies?

In 1982, ozone was declared as Generally Recognized As Safe (GRAS) for treatment of bottled water. Since 2001, FDA approved its use as an antimicrobial agent in foods. Depending on the application, ozone use may fall under the guidelines of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), thus entering the jurisdiction of the Environmental Protection Agency (EPA). Food processors should confirm with ozone-equipment suppliers or directly with the EPA to determine if a particular ozone application will require a special pesticide registration under FIFRA. Ozone is also listed in the National Organic Program (NOP) final rule, which permits its use in processed products labeled as organic or  made with organic. There are no special labeling requirements for ozone-treated products.

10. Facility available for feasibility studies.

Many ozone equipment manufacturing and ozone treatment facilities are available worldwide. A simple search of the Internet can guide the reader to relevant and useful sites. The Ohio State University (OSU) food safety laboratory hosts ozone generators and product treatment chambers that vary in size, from bench-top to pilot-scale. At the OSU facility, ozone generators range in productivity from 1 to 16 lb/day and treatment chambers vary from 1 to 300 l-capacity. Some chambers were engineered to decontaminate fresh fruits and vegetables, or to produce Salmonella-free shell eggs. Pathogen-contaminated products can be treated at the OSU pathogenic pilot plant, a biosafety level-II facility.

 

 

is ozone treatment commercially applied to any food material ?  can a milk milk processed by pef replace that processed by uht method ?


 

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