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Emerging trends in refrigeration and cold storage sector
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Thursday, 27 May, 2021, 12 : 00 PM [IST]
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Deepthi Devatha
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Refrigeration is the most common means of preserving food. It is the science that involves removal of unwanted heat from an object or surrounding and transferring it to other objects or surroundings. It is a process of removing heat from a low-temperature reservoir and transferring it to a high-temperature reservoir.
Refrigeration has found its importance in various industrial sectors. One of them is processing, preservation and distribution of food by storing them in an ambient temperature.
Refrigeration processes in food processing industries:
The principle behind preservation of foods by refrigeration is continued extraction of heat from a body whose temperature is already below the temperature of its surroundings to mitigate any detrimental or undesirable changes in food. These changes can be microbiological, biochemical, physiological or physical. There are several refrigeration processes involved in the processing and preservation of food. The refrigeration techniques that are implemented one after the other.
• Pre-cooling: Rapid cooling is practiced to retard the chemical reactions occurring in food products and to increase their life span. The lesser the temperature is, the better the quality and longevity of the product. Different refrigeration techniques are adopted based on the type of the food product.
• Chilling: After pre-cooling, the food product has to be chilled and maintained at a most suitable temperature. Chilling is usually done in cold rooms equipped with enough ventilation.
• Freezing: It is the process which involves lowering the temperature of a product below its solidification point. Freezing hinders the metabolism fruit and vegetables allowing to food product to be stored for a much longer time.
• Super-cooling and Super-chilling: Super cooling is lowering down the temperature of a food product just below its freezing point without solidification. Super-chilling is a technique where the food is partially frozen at a temperature just below its freezing point.
A cold chain is a temperature controlled supply chain that involves storage, transportation and distribution of perishable goods/ products. These goods should always be kept within the range of temperatures to preserve and extend their shelf life.
Refrigeration is a part of cold chain or supply chain and crucial to food industry. It involves the ‘Farm to Fork' phenomena and is very much necessary for storage, preservation, transportation and distribution of frozen materials with ambient temperature, which is also essential in order to control and avoid spoilage, decay and contamination right from the time of produce, storage, transportation, distribution and consumption and is related to one of the most important aspects of food safety and food hygiene, health of the consumers.
Growth drivers of cold chain
According to a market research report, the cold chain industry in India is forecast to grow at a CAGR of 19 per cent during the period of 2017-2022.
• Cold chains are globalised. Changing lifestyle patterns and increased interest in healthful foods, in urban areas is leading to increasing demand for processed and preserved frozen food and beverages.
• Market pressure raises demand for cold chain efficiency. Growth in e-commerce sector and technological advancement has raised supply chain demand.
• Increasing demand for packaged or frozen or ready-to-eat products.
• Globalisation and an increase in the number of food safety incidents are aiding the government to tighten regulations on supply chains.
• Increasing interest and focus on quality, health, and integrity.
Emerging Trends in the sector:
• Automation in Warehouses
The use of robotics in warehouses will bridge the gap between robots and humans and bring out greater efficiency. Robotics enhance the hard-freeze process by upgrading speed and consistency, while automated storage and retrieval systems (AS/RS) enable higher storage density within cold storage warehouses to reduce the surge in demand.
• Use of Natural Refrigerants
The market for the use of chlorofluorocarbon (CFC), hydrofluorocarbon (HCF) and hydro-chloro-fluoro-carbon (HCFC) as refrigerants is still maintained only because of the lack of awareness on safety. Use of natural refrigerants like ammonia (NH3), carbon dioxide (CO2) and hydrocarbons like propane or isobutane will not only aid in maintaining a better environment but also are cost effective.
• Use of solar energy instead of conventional energy
The food industry depends mainly on the vapor compression refrigeration system for food processing and preservation. To reduce environmental impact, many technologies were developed and tested based on air cycle refrigeration, sorptionadsorption refrigeration, ejector refrigeration system, thermoacoustic refrigeration, stirling refrigeration cycle, thermoelectric refrigeration or trigeneration, technologies that can decrease the quantity of used energy and can promote the use of solar energy instead of conventional energy and can be environmental friendly.
In the food industry, refrigeration technologies are applied in all stages from raw materials transport, storage and food processing to distribution and also at the final stage of consumption at consumer’s home.
• Innovative Freezing techniques:
Impingement freezing: Impingement technology increases the surface heat transfer in air freezing systems and has been one of the recent innovations that is used commercially. Impingementation is the process of applying jets of air at a solid surface to bring a change. The process is applied for products that require very rapid surface freezing.
Hydro-fluidisation freezing: Hydro-fluidisation freezing is a form of immersion freezing. It uses a circulating system that pumps the refrigerating liquid upwards, through nozzles within a vessel, thereby creating jets. It provide extremely high surface heat transfer coefficients that enable rapid freezing with the formation of a fluidised bed of turbulent liquid and moving products.
High pressure assisted freezing: High pressure freezing or pressure shift freezing is done by using pressures of 200 to 400 MPa. With an increased pressure the freezing points drops down to -20°C, enabling freezing of objects with a thickness of up to 0.6 millimetres. The food does not undergo a phase change enabling rapid nucleation which results in small and even ice crystals.
Ultrasonic assisted freezing: Researchers has determined that use of a form of ultrasound wave with low frequency (18-20 kHz to 100 kHz) and high intensity which is generally higher than 1 W/cm2 can assist in freezing. The ultrasound creates bubbles throughout the product, which promotes even ice nucleation and also aids in fragmentation of already present ice crystals into smaller crystals, speeding up the freezing process.
Electrostatic assisted freezing:. The principle of this technique is that applying an electric field to a food might orientate the polar molecules like water in turn controlling ice crystallisation and super cooling.
Microwave assisted freezing: The principle behind microwave assisted freezing is to disrupt ice nucleation by exploiting water dipole rotation induced by microwaves during freezing.
• Use of multi-segmented refrigerated trucks
In the recent years, multi segmented refrigerated trucks have been developed which contain multiple segments holding a variety of products at different but ambient temperature as per the requirement.
Refrigeration techniques are implemented in food processing industries for storage and preservation. A cold chain or a supply chain is established for the storage, maintenance and transportation. The refrigeration sector faces many challenges with respect to energy consumption, environmental impact regulations, reliability, efficiency and other economic concerns. With the emerging trends in refrigeration, cold storage and supply chain will enable increase shelf life of frozen food and reach the surge in demand for them.
(The author is business executive at Nutrify Today)
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