**1. Introduction**

Drying remains an essential part of food processing to enhance the shelf life of agricultural produce. To facilitate storage, preserve nutritional value, and add value in farm products, drying has been an essential solution [1]. Vegetables and fruits are one of the primary sources of vitamins and minerals. They have a high amount of nutritional components due to which they are considered a basic need for a balanced diet. Food products contained a high amount of moisture, such as vegetables and fruits, which have more than 80% and cereals more and less 30% [2]. Therefore, vast amounts of foodstuff deteriorate annually because of the inappropriate handling (pre- and postharvesting) and lack of processing facilities. Approximately 30–50% of losses occur in vegetables and fruits from field to consumer. The easy availability of fresh food to consumers for an extended period, process, and storage facilities are compulsory [3]. However, the increasing infrastructure and processing cost of post-storage techniques are essential limitations. Due to increasing demand of high-quality food products, various conventional and mechanical food drying methods have been employed to process and protect from deterioration such as solar drying, oven drying, hot air drying, vacuum drying, freeze drying, microwave drying, infrared drying, and air source heat pump (ASHP) drying [4].

The ASHP drying system has two main components: an HP and a drying assembly—a functional HP system is composed of a compressor, condenser, evaporator, refrigerant, and throttle valve [5, 6]. Similarly, the drying system consists of the dryer and other necessary accessories. In the drying cycle, the materials to be dried are fed into the drying chamber and dehydrated until attained desired moisture content. In the HP cycle, the condenser provides the heat for the drying process by condensation of the refrigerant; similarly, the refrigerant absorbs heat and evaporates in the evaporator. The compressor of the HP compressed it again and delivered to the condenser to complete the cycle [7]. The hot heat generated by the condenser and cold heat by the evaporator can be used at the same time during the HP operation. The hot and cold heat from condenser and evaporator will be used to heat the product and dehumanization, respectively. Due to the excellent capability of the HP to convert the latent heat of vapor condensation into sensible heat of air makes it attractive in the drying industry. Many investigators recognized the utilization of HP in drying, which has attracted applied and theoretical research on drying using the HP [8–10].

The energy-saving capability and the ability to control air humidity and temperature are the main advantages of HP technology. These factors create options for variable drying conditions. Drying is one of the most energy-intensive practices, as it consumes up to 15% of industrial energy and 9–25% of national energy in developed countries [11]. About 40% of energy could be saved by using HP dryers as compared to electric resistance dryers. The drying process utilizes up to 70, 50, and 60% of total energy in the manufacturing of wood products, textile fabrics, and farm corn production, respectively [12]. Therefore, it is necessary to find out appropriate HP technology to reduce energy consumption. It has been reported that HP drying helps to improve product quality.

The performance of the HP system can be improved by the implementation of a sophisticated control strategy [13]. The three-layer ANN model has been used in the prediction of HP system performance. The study depicted that the application of ANN in the prediction of the HP system was consistent and robust [14]. Yang et al. [15] have used a simultaneous control strategy to improve the precision of drying temperature and superheat. A stable drying temperature was attained using two fuzzy controllers with different membership functions and control rules. The study revealed that the newly developed controller is reliable to reduce the nonlinearities of drying temperature and superheat. The yum slices of different thicknesses and longan were dried using the step-down and continues dehumidification strategies of controlling relative humidity [16]. It concluded that a step-down approach was found more energy efficient for 12 or 18 mm thickness, whereas a continuous decrease of relative humidity strategy was found energy efficient for longan, respectively.

Besides these drying systems, smart drying mechanisms (biomimetic systems) can be cost-effective in controlling various foodstuffs quality parameters with variable drying process time. The quality of food products can be assessed through many senses such as appearance, smell, and taste. The human sense inspired systems including electronic noses (odor sensing technology) and electronic tongues (taste sensing technology) are extensively under considerations

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**Figure 1.**

*The primary classification of heat pump dryers [17].*

*An Introduction of Biomimetic System and Heat Pump Technology in Food Drying Industry*

by researchers and scientists for different food processing steps, e.g., drying, packaging, and storage. These biomimetic systems provide reasonable information on odor and taste to analyze the quality of food products. The combination of these biomimetic systems, computer software, and data analysis methods exhibits environment-friendly, cost-effective, and multifunctional results for food quality control. Many studies highlighted the significance of HP technology in terms of energy efficiency, cost-effectiveness, and product quality. However, there is a need to summarize the technological advancement of the HP drying system in the food industry. The HP drying system can be more sophisticated and attractive if coupled with biomimetic odor and taste sensing systems for food safety and quality. This chapter presents the recent developments in HP drying technologies of food products, studies these advancements to maintain the food

quality, and further discusses the research potential in this field.

contribution of significant HP technologies in the food drying sector.

Heat pumps raise the energy gained from the low-temperature level to high-temperature level and transfer it to the energy carrier medium. In an HP, both the heating and cooling processes of the refrigerator are utilized. Nowadays, HP technology is used in the domestic and commercial sectors for space heating and cooling such as in offices, water heating, swimming pools, commercial drying in agriculture, and the wood industry as well as the cotton industry. The main objective of the utilization of HP technology in the food drying sector is to dehydrate the food products for quality enhancement at minimum cost. HP drying technology is one of the most efficient and controllable methods of water extraction from the material. The research and development in HP technology have improved its performance. HP drying technology has been modified to air source HP drying, ground source heat pump drying (GSHPD), chemical source heat pump drying (CSHPD), and hybrid heat pump drying (HHPD), as shown in **Figure 1**. The following chapter reflects the

**2. HP drying and its application in the food industry**

**2.1 HP drying**

*DOI: http://dx.doi.org/10.5772/intechopen.93386*

*An Introduction of Biomimetic System and Heat Pump Technology in Food Drying Industry DOI: http://dx.doi.org/10.5772/intechopen.93386*

by researchers and scientists for different food processing steps, e.g., drying, packaging, and storage. These biomimetic systems provide reasonable information on odor and taste to analyze the quality of food products. The combination of these biomimetic systems, computer software, and data analysis methods exhibits environment-friendly, cost-effective, and multifunctional results for food quality control. Many studies highlighted the significance of HP technology in terms of energy efficiency, cost-effectiveness, and product quality. However, there is a need to summarize the technological advancement of the HP drying system in the food industry. The HP drying system can be more sophisticated and attractive if coupled with biomimetic odor and taste sensing systems for food safety and quality. This chapter presents the recent developments in HP drying technologies of food products, studies these advancements to maintain the food quality, and further discusses the research potential in this field.
