The food industry from farm to fork must adapt and update to meet the demands of the growing population both in terms of nutrition and consumer expectations, but it should be achieved with the available resources. Innovation with this regard is must and one such innovation is cold plasma technique for processing of foods without much effect on colour, texture, flavour. It is also inexpensive as compared to other preservation and processing techniques like sterilization, pasteurisation which also has negative effect on food as it is exposed to heat and hence the heat labile nutrients get destructed.
Plasma which is 4th state of matter refers to quasi neutral ionised gas composed of photons, free electrons and ions. Cold plasma is an emerging green technology tool used in numerous food processing industries. Cold plasma leaves no residues, it is free of water or any types of solvent, and it also provides particular time for further reaction and hence makes it a complete environment friendly processing technique.
Cold plasma is developed in an atmospheric or vacuum pressure with a temperature of 30° to 60° Celsius using electrical or electromagnetic waves. Cold plasma is a powerful tool for surface contamination of food materials which is non thermal processing of food and also energy efficient. Plasma sources include dielectric barrier discharge, plasma discharge and microwave induced plasma. Choice of gas, Quantity, flow rate, pressure, and power are the other factors affecting plasma treatment on food.
Fig : Dielectric barrier discharge
APPLICATIONS IN FOOD PRODUCTS
Cold plasma in food industry is mainly focused on food decontamination, toxin degradation, Inactivation of fungi, sterilization of fruits and vegetables (apple, lettuce, mango, melon) and in improving overall food quality. Cold plasma offers microbial inactivation at low temperature (<50 degree Celsius) which extends shelf life of food and also reduces preservative use. Effective on bacteria, moulds, virus, yeast and spores. Cold plasma mainly improves microbiological safety along with maintenance of sensory attributes of the treated food.
In non-thermal cold plasma technique, the plasma is coated on the surface of the food to overcome all the barrier properties that have risk of lowering food quality. Cold plasma has been extensively used for packaging material sterilization, surface functionalisation, surface activation and surface deposition of both plant and animal origin foods. Cold plasma also improves seed germination and reduces enzymatic browning of crops after post-harvest. Cold plasma is a simple, safe and environment friendly alternative for the food packaging industry as it also reduces chemical usage. Considering several internal and external factors, cold plasma is a promising sector for plant and animal origin foods.
For a food manufacturer, the main challenges that revolve around the cold plasma technology are
- Regulatory approval
- Designing the plasma sources
- Process control
In broad spectrum, the food industry is not fully aware about the role of cold plasma technology. So far, the most practical application and the principal driving force behind the development of gas plasma technologies for food applications is focused on food safety. Now many researches are being conducted to understand its potential and it’s applications at large scale.
Nowadays Consumer preference have shifted towards healthy, tasty and convenient food like ready-to-eat food products which becomes a challenge for the food industries for such distribution and mass production of food without affecting flavour, colour, texture and nutritional properties. Cold plasma is one of the key factors in novel processing technologies within the food and agricultural industries as a solution to meet such requirements. However, clear understanding of mechanism and control over quality attributes is required to obtain full potential of cold plasma technology in food industry at commercial scale.