Technology options varying from simple and inexpensive to complex and sophisticated, are available to produce cold conditions for food handling, processing, storage, and transport. Globally, R&D efforts are on to develop new technologies that can be deployed by frozen food industry across the cold value chain including processing/freezing, storage and distribution of frozen foods. The drivers for new technologies in cold chain include: (i) improving the quality, nutrition, and safety of frozen food products (ii) increased demand for freezing & cooling requirements (iii) increased focus on energy efficiencies and (iv) reduction in GHG emissions.  

In this article, some of the emerging technologies in the processing of frozen food as well as storage, logistics and monitoring of frozen food that play a key role in frozen food industry are covered. The cold chain sector in India has not progressed at par with the global developments in the monitoring and control technologies, so monitoring systems are being considered as new technologies with specific reference to Indian frozen food industry.  

Isochoric freezing – Emerging Processing/ Freezing technology 

Isochoric freezing (ICF) is a new freezing technology that allows preserving biological matter at subfreezing temperatures without any ice formation in the products. The isochoric (constant volume) freezing approach represents a radical departure from conventional food freezing technologies that use isobaric (constant pressure) freezing. ICF is regarded as a high-pressure freezing technique, wherein the pressure is increased by reducing the temperature under a constant volume. In ICF, the food product is immersed in a solution and processed inside a pressure chamber. When freezing occurs, ice forms and expands in the chamber. However, due to the constant volume of the chamber, the amount of ice that can form is restricted. In this way, the food product can be safely preserved at subfreezing temperatures without being frozen if it remains in the non-frozen volume1. 

ICF, developed by UC, Berkeley in 2005 as a cryopreservation method for medical transplantations, was examined as a preservation/ freezing method in the food industry, by collaborating with the U.S. Department of Agriculture in 2017. To date, they have successfully demonstrated the technique with studies on cherries, tomatoes, potatoes, and tuna fish. Other foods that could benefit from the process include berries and leafy greens, which normally deteriorate on traditional freezing and thawing. Recently, studies demonstrating the potential of ICF in reducing energy consumption2 and inactivating pathogenic microorganisms3,4 were also conducted. The potential of this novel technology to substantially improve the quality, nutrition, and safety of frozen food products, and to reduce energy costs of refrigeration holds great promise for the frozen food industry. Development of industrial-scale prototype, along with further R&D on applications and optimizing cost-benefit ratio, will be key to further progress of this technology and adoption by the frozen food industry.   

Emerging Technologies for cold chain  

Liquid air is another technology with the potential to cater to the full range of cold chain services – supplying the cold for blast freezing and other forms of food processing, cold storage and transport refrigeration.  

Liquid Air Cooling: Natural gas is liquefied by cooling it (at -1620C) to reduce the volume in shipping. At receiving terminal, the Liquefied Natural Gas (LNG) undergoes a regasification (reheating) process before supplying to customers and in the process, vast amount of cold energy is lost to the environment. This energy recycling at LNG terminals can develop dedicated gateways for perishable foods in the region and the waste cold from India’s projected LNG imports in 2022 could fuel over half a million liquid air refrigeration units5. National Center for Cold-chain Development (NCCD) is pursuing the potential of clean energy from liquid air-based cold chains by recovering stranded cold from LNG re-gasification. The economics of liquid air refrigerated transport in India look promising, even without the help of waste LNG cold. According to a report6, there is a strong case for urban delivery using liquid air equipped reefer vans in India. It was found that for a 1-tonne reefer van, liquid air refrigeration could be 20 – 35% cheaper per kg of cargo, than a diesel truck. Currently, Petronet LNG is investigating the feasibility of building import/export hubs for perishable produce close to its terminals at Dahej and Kochi.  

Liquid Air Power & Cooling: Dearman, a UK-based technology company, has developed a family of engines that uses liquid air/ liquid nitrogen to deliver zero-emission power and cooling. The Dearman engine is a novel piston engine powered by the phase-change expansion of liquid air or liquid nitrogen, with cold air as the only exhaust. This technology can reduce fuel costs (refrigeration alone consumes as much as 20% of a truck’s fuel) and eliminate all emissions associated with refrigeration. Sainsbury in the UK has become the first company in the world to introduce a refrigerated delivery truck cooled by a liquid nitrogen powered engine.  

Alternatives for energy storage: Cold Thermal Energy Storage (CTES) systems allow the storage of cold for later use. Latent heat storage using phase change materials is one of the efficient methods to store thermal energy. Phase change materials (PCMs) are substances that undergo a phase transition (e.g. liquid to solid) at a specific temperature and, as a result of which they can absorb and release latent heat with a very small temperature variation. PCMs can be used during transport, storage and distribution stages to maintain the cold chain. PLUSS is a leading Indian player in the field of PCMs designed to cater to a wide range of temperatures including freezing range. PCM based cold chain logistics solutions are being offered in India by TESSOL. The PCM solution is being further extended to cold storage combined with renewable technologies like solar.  

Monitoring Systems for Cold Chain: 

Monitoring and control of basic parameters like temperature and humidity are some of the critical elements in the cold chain as the disruption in the set parameters leads to food safety issues, food loss, loss of resources like energy, packaging material, and environmental impact. The progress of cold chain monitoring systems in India has not been at par with other developed markets. Most of the earlier generation cold storages are still dependent on the manual modes of monitoring assisted with conventional measuring systems. The emerging trends that need to be fully embraced by Indian companies are RFID based systems for unit-level measurement, WSN based systems for a local unit, and IoT based monitoring systems for covering the entire supply chain. 

Radio Frequency Identification (RFID): RFID is the generic name for technologies that use radio waves to identify items and gather data on items without human intervention or data entry. RFID sensors/ labels can be equipped with additional sensors like temperature, humidity and gas sensors to map the history of these parameters across the supply chain. 

Wireless Sensor Network (WSN) and Internet of Things (IoT): WSN is a combination of sensors, micro-controllers, and RF handsets, which communicate with each other at a local location. An array of WSNs is connected through the Internet to act as sensory organs for IoT. IoT is an ideal platform for remotely monitoring and controlling the real-time status of perishable goods across the cold chain with very little human intervention. IoT also enables the integration of food safety systems and regulatory requirements and support specific report generation (as programmed in the algorithm). 

Time Temperature Indicators (TTI): TTI’s are simple and inexpensive devices, which indicate the time-temperature history of the product when applied to them. The TTI labels can ensure specific food product safety and quality status by indicating accumulated time-temperature history across the value chain and temperature abuse by means of irreversible color change. 

The early adoption of the latest monitoring, control mechanisms and automation in data capturing will be very useful as the cold-chain sector in India has a long way to go.  

Way Forward:  

Cold chain infrastructure creation is an important factor for the growth of the agri-food sector and is receiving attention from the government too. Investments in India’s cold chains are expected to increase in the coming years. This provides India with a great opportunity to leapfrog the early generation technologies by adopting the latest technologies that are energy-efficient, environment friendly and also ensure the quality and safety of frozen foods.  

References: 

1. McHugh and Bilbao-Sainz (2019). Food Tech., 73 (11). 

1. Powell-Palm & Rubinsky (2019). J. Food Eng., 251:1-10.  

1. Bridges et al., (2020). J. Food Saf. 40, 12840.  

1. Powell-Palm et al., (2018). Cryobiology, 85:17-24. 

1. Birmingham Energy Institute (2014). The prospects for liquid air cold chains in India. 

1. Kitinoja, L (2014). Exploring the Potential for Cold Chain Development in Emerging and Rapidly Industrializing Economies through Liquid Air Refrigeration Technologies. Postharvest Education Foundation. 

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