Recent development in pulsed electric field (PEF) processing of food

Topic: Recent development in pulsed electric field (PEF) processing of food

Advantages and disadvantages of PEF(Pulsed electric field processing) comparing with the following treatment methods:

Drying

Refrigeration

Freezing

Vacuum packing

Salt and Sugar

Pickling

Canning and bottling

Jellying

Potting

Irradiation

Introduction

Food being undeniably vital for survival, its processing and preservation is important to make it free of microbes, improve its quality and extend storage life. Technologies used in food processing and preservation have evolved over the years making the food industry to move from a craft based industry to an enterprise that is science based. Pulsed electric field food processing technology is a non thermal method of processing food that is becoming popular in the modern food industry as compared to chemical and thermal food processing operations. In PEF technology of food processing, short pulses of a strong electric field are used where food products are placed between two electrodes with an electric field. Thermal food processing includes cooking, pasteurization and canning while cold preservation methods comprise of refrigeration and freezing. Other methods of food treatment such as irradiation, dehydration, fermentation, vacuum packing, pickling and bottling are also used in food processing and preservation industries. This paper is a dissertation chapter that reviews literature on the advantages and disadvantages of Pulsed Electric Field (PEF) processing of food as compared to other food treatment methods.

Advantages

The short bursts of electricity used in PEF processing inactivate microorganisms with minimal or no effect on the quality attributes of food. This is the major advantage of the PEF technology over other food preservation methods. Fryer & Versteeg (2008) emphasize that the use of the PEF technology ensures that food remains in its natural form hence quality is maintained during the preservation. On the other hand freezing and refrigeration reduces the natural quality of the food which is being preserved by these methods. As Min, Evrendilek & Zhang, (2007) explain, refrigeration usually leads to loss of the natural flavor of food especially after prolonged freezing which also alters the taste of the food to some extent. AIDing sugar or salt as a method of preservation alters the flavor of the food. Moreover not all consumers use sugar or salt and thus these methods of preserving food become inappropriate at some instances.

Rastogi (2003) explains that PEF technology plays a major role in benefiting food consumers by providing liquid foods of high quality, nutritional value, flavor and shelf life. The nutritious components of food are not lost during PEF processing. This makes this technology advantageous than food treatment such as freezing. Blanching of vegetable food prior to freezing for example leads to loss of vitamin C and some of the B-group vitamins. Therefore the nutritious quality of food is reduced by such methods of preserving food. Moreover, use of irradiation in food processing can lead to great nutrient losses. The preservation of food should limit the loss of nutrients as much as possible so that consumers are guaranteed of quality in the food products that they consume.

McGinnis, (2006) explains that the PEF technology preserves food products without the use of heat hence the flavor, fresh aroma, appearance and taste of the foods are retained. This is an advantage of the PEF food processing compared to the thermal methods such as pasteurization and canning which cause substantial loss of food flavor.  Therefore consumers are more likely to prefer food products processed by PEF technology as compared to the thermal and chemical methods of preservation that alters the natural flavor of food. The flavor of food is lost by the chemicals that are aIDed during canning processes. Preservation by aIDing sugar or salt to food also alters the flavor of food substantially. According to Fryer & Versteeg (2008), the growing popularity of the PEF food processing technique is attributed to the retention of the fresh aroma and flavor of the food. This is because loss of flavor alters the taste of the food making it less desirable by the consumers.

The use of Pulsed electric field food processing has an advantage over other food treatment methods because it can also be applied in other industrial food processes such as extraction of sugar from plants. Ranjeet & Kumar (2011), point out that the role of the PEF technology in extraction of sugars from plant cells has facilitated the processing of sugar. Sugar and other cellular contents of plants are extracted to prepare juices and wines. The technology has thus increased the efficiency of extracting sugar from plants in aIDition to ensuring that the extraction of sugar is economical and that it lacks any wastage. The wide application of the PEF technology thus makes it worthy investing in by the food processing industries as compared to other processing methods such as canning that are usually confined to extending the shelf life of food products.

According to Altuntas & Zhang, (2010), food processed by the PEF technology has a long shelf life as compared to the use of salt and sugar in which some microorganisms become inactivated by the salt or sugar leading to fast decomposition of food. The pulsed electric field food processing uses electric pulses that kills all microorganisms in food products and therefore lead to profound increase in the shelf life of food. Rodrigo, & Palop, (2010) emphasize that electric fields used in PEF food processing are able to destroy resistant microbes hence it is more advantageous over the thermal methods of preservation such as pasteurization in which some microbes would resist heating. According to Ranjeet & Kumar (2011), the role of PEF technology in increasing shelf life of food products is made possible through inactivation of microbes and deactivation of enzymes that facilitates food decomposition.

The advantage of PEF food processing over canning preservation method is that some consumers are sensitive to the chemicals used to deactivate microorganisms in canning. PEF food processing does not use any chemicals and instead microbes are killed though an electric field. According to Rastogi, (2003), pickled foods also contain chemicals such as brine, alcohol and vinegar to which some consumers would be sensitive hence justifies the use of PEF food processing technology. In aIDition, chemicals may result to change of taste of the food products.

Rodrigo, & Palop, (2010) demonstrate that the PEF technology has reduced the cost of food processing in commercial scales because it is an energy saving food preservation method unlike the thermal processes such as canning and bottling that consume a lot of energy. In aIDition pickling and canning methods are expensive in terms of the cost of the chemicals used to preserve the food products. Min, Evrendilek & Zhang (2007), say that in terms of efficiency PEF food processing technology is better than the traditional thermal methods that take long periods of time when heating food to kill microorganisms. PEF food processing processes food at a high speed through exposure to busts of strong electrical fields. In large scale food processing cost and efficiency are important factors for success of any food industry. Since the PEF technology guarantees quality for the food consumer, the aIDed advantages of speed and relatively low cost of processing makes this technology desirable in large scale food processing and preservation. In aIDition speed in processing ensures that food supply is adequate and efficient to meet market demand.

Disadvantages

According to Senorans, Ibanez & Cifuentes (2003), Pulsed Electric Field food processing is a non thermal method used in food industries to process and preserve liquid and semi solid foods. The confinement of this technology to non solid food products makes it less advantageous as compared to drying which preserves food by reducing water activity enough to delay or prevent microbial growth. Furthermore canning are refrigeration are not limited to non solid foods hence are more advantageous than the PEF technology of food processing.  Drying is not limited to solid food products because milk processing industries dry milk as a method of preserving it and thus increasing their shelf life. The food industries thus would prefer to apply drying techniques in preserving food as compared to the use of the PEF technology.

Altuntas & Zhang, (2010), assert that the development of PEF technology has played a role in preservation of a variety of foods such as soups, juices and milk. This technology is applied on food products with low electrical conductivity. This shows that thermal and chemical food treatment techniques are preferable in this sense because they are not limited by the electrical conductivity of food products in processing. The PEF technology is involved in processing foods of liquid and semi liquid nature that do not have air bubbles. This is so because bubbles usually cause technical problems during the processing. Rodrigo & Palop (2010) explain that since PEF food treatment technology is a continuous process, solid food products that would not be pumped are not preserved using this technology.

Fryer & Versteeg, (2008) point out that the major disadvantage of applying pulsed electric field technology in processing and preservation of food is the fact that spores of microorganisms are able to survive PEF food processing. Thermal methods such as canning involve heating food at a very high temperature which usually destroys spores. Spores have a tough dehydrated cells and protective coats which are able to survive the electric field in the PEF food processing. Therefore refrigeration becomes necessary after PEF processing to make sure that growth of pathogens is prevented. The issue of resistant spores hence makes the choice of thermal food treatment methods preferable than the use of the PEF technology. Spores that persist in the food during the processing in industries would lead to spoilage of food sooner than expected. Furthermore, spores that contaminate food would be consumed by people leading to health issues.

As McGinnis (2006) demonstrates, during PEF food processing there is a possibility of increase of electrical arcs and temperatures up to thirty degrees Celsius. This is usually caused by gas bubbles which cause electric arcing between the two electrodes of the PEF machines. Electrical arcing in return burns the food products being processed and this generates unwanted substances such as carcinogens. These substances thus find their way into the food products making them unsafe for human consumption. Carcinogens would contribute to cancers and other conditions especially with prolonged consumption of for contaminated with such hazardous substances. This advantage of the PEF food processing technology makes refrigeration method of food preservation more suitable. Other methods such as aIDition of sugar and salt can be used because they do not introduce unwanted substances to the food products being processed.

In accordance to Ranjeet & Kumar (2011), PEF food processing technology is rather new and therefore its implementation in food processing industries has been slow compared to the thermal preservation methods such as canning and bottling. The use of PEF systems in the food industry has not been optimized because adequate research has not been done to justify the use of the systems in the food processing industries. Moreover, there has been inadequate assessment of kinetics and delivery of the PEF systems. On the other hand, preservation methods such as canning and refrigeration have been applied for a long time by the food processing industries. Traditional thermal methods have been studied extensively and the mechanisms of these methods in food preservation are well understood which has contributed to innovations that has improved the preservation of food.

There is limited commercial availability of Pulsed Electric Field food processing systems because of the high initial costs that are associated with these systems. According to Min, Evrendilek & Zhang (2007), initial investment costs of the PEF systems are higher than the other food processing systems such as refrigeration. The technical and economic limitations of acquisition of the PEF systems has therefore contributed to their reduced application in food processing industries as compared to the thermal processing methods. The PEF technology is only cost effective after it has already been installed. The high cost of the PEF systems has contributed to the resistance of the food processing industries in purchase of these systems. Therefore most food industries have opted to use food processing methods such as canning and refrigeration as opposed to application of the PEF technology.

There are inconsistencies in the issues regarding the enzymatic inactivation during PEF food processing. Rodrigo & Palop (2010) explain that the mechanism and the degree of inactivation of enzymes have not been clarified due to inadequate research in this area. Therefore there are potential food safety issues that need to be clarified before implementation of the PEF food processing technology by industries for the purposes of food preservation. The traditional thermal methods of food preservation are well understood and the shelf life of the food processed by these methods is accurately determined so that consumers are enabled to know the expiry date attached to the food products. This has helped to prevent consumption of already expired food.

 

Conclusion

The Pulsed Electric Field food processing technology is gaining popularity in the food industry due to the advantages associated with the use of this technology in processing food as compared to the traditional thermal methods. Food processed by PEF technology retains its natural flavor compared to refrigeration and salting techniques. The PEF technology does not lead to loss of nutritional value of food products during processing as compared to blanching and freezing that usually cause loss of nutrients such as vitamins in vegetables. The speed of processing food using the PEF technology is higher compared to other methods such as canning and thus making this technology preferable in large scale food processing. Chemicals to which some food consumers would be sensitive to are not aIDed during the PEF food processing like in Pickling in which chemicals such are vinegar and alcohol are used in food preservation. The disadvantages of the PEF technology include high initial cost of purchase and installation of PEF systems, potential introduction of carcinogens to food due to increased electrical arcs and inconsistencies in the mechanisms of enzymatic inactivation.

References

 

Altuntas, J., & Zhang, H (2010), €˜Effects of pulsed electric field  processing on the quality and

microbial inactivation of sour cherry juice€™, International Journal of Food Science & Technology, 45, 5, pp. 899-905

Fryer, P. J., & Versteeg, C. (2008). Processing technology innovation in the food industry.

Innovation : Management, Policy & Practice, 10(1), 74-74-90.

Min, S, Evrendilek, G, & Zhang, H (2007), €˜Pulsed Electric Fields: Processing System, Microbial

and Enzyme Inhibition, and Shelf Life Extension of Foods€™, IEEE Transactions on Plasma Science, 35, 12, pp. 59-73,

McGinnis, L. (2006), €œNonthermal Food Processing Is Heating Up€, Agricultural Research, vol.

54, no. 10, pp. 4-4-5.

Rodrigo, D., & Palop, A. (2010). New food processing technologies as a  paradigm of safety and

quality. British Food Journal, 112(5), 467-467-475.

Rastogi, NN (2003), €˜Application of High-Intensity Pulsed Electrical Fields in Food Processing€™,

Food Reviews International, 19, 3, p. 229

Ranjeet Singh & Ashok Kumar (2011), Pulsed Electric Fields, Processing and Application in

Food Industry, European Journal of Food Research & Review 1(2): 71-93, 2011

Senorans, F, Ibanez, E, & Cifuentes, A 2003, €˜New Trends in Food Processing€™, Critical Reviews

in Food Science & Nutrition, 43, 5, pp. 507-526

 

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