A Review of the State of the Art of Hot Air Frying Technology

1. Introduction

The worldwide trend towards healthy food consumption has led to the development of novel technologies that can maintain and/or improve the quality characteristics of fried foods. Because of this, air fryers were developed, which are appliances that work in a similar way to a microwave oven that allows you to bake and roast, it is also necessary to mention that the difference is its heating elements that are placed at the top with a large fan that makes the food is fried with the characteristic crispy and crunchy texture, but most importantly with less oil because it is not necessary but advisable to use in low concentrations to obtain a similar texture to conventionally fried foods (Abd Rahman et al., 2016; Stratview Research, 2023). According to the literature reviewed, most of the research has been conducted using potatoes, highlighting mainly the study of their physicochemical characterization and sensory evaluation (Giovanelli et al., 2017; Haddarah et al., 2021; Gouyo et al., 2021; Ciccone et al., 2020; Santos et al., 2017; Verma et al., 2023; Bachir et al., 2023). The authors, Devi et al. (2021); Zaghi et al. (2019), and Dehghannya & Ngadi (2021) in their review articles explained that research on hot air frying in foods is generally limited and should receive greater focus on the precise study of the components and properties of foods, in addition to the effects it could have on human health when consumed. Thus, the objective of this review was to know the state of the art of hot air frying technology, focusing on trends, and thus to obtain new ideas for future work in this area of food.

2. How Hot Air Frying Technology Works

Hot air frying is a new method of frying food, where a small amount of oil is directly spread on the surface of the food to be fried and then uses circulating hot air to heat and cook as shown in Figure 1a. Compared to the conventional frying process, hot air fried foods give the appearance and physicochemical characteristics of conventionally fried foods to some extent (Jin et al., 2021). The objective of this type of frying (Figure 1a) is to cause uniform contact between the food to be fried and the oil droplets within the hot air stream, which significantly reduces the amount of cooking oil needed to achieve cooking, and this process takes place inside the fryer chamber, which simulates the hot oil flow of a conventional fryer. During this process, the food is heated, the water evaporates, and the crust progressively appears on the surface, giving it the characteristic appearance of fried food (Wang et al., 2021). It is important to mention that the availability of some advanced devices, with a touch screen panel, a temperature control knob and fast preheating, will increase the demand for hot air fryers, and this technology not only brings health benefits, but also has environmental advantages, such as reduced oil consumption and emissions.

3. Trends in Hot Air Frying Technology

At present, research on hot air frying technology is limited compared to other technologies that have been researched for decades, because air frying is relatively new, as it has been used for 10 years, as shown in Figure 1b, and it is only in 2020 that there was a significant increase in scientific articles, so an increase in the trend is expected in the coming years. It is important to note that the data for the year 2023 was reported as of the beginning of february and has already surpassed the number of documents published in its first years. According to Table 1, most of the articles are focused on the use of potato, followed by sweet potato and doughnut, although a variety of foods used are also shown, and some are characteristic of the authors' country. It is recommended that future work focus on foods such as tortilla chips, plantain chips, eggs, and meats such as beef, because there are not enough studies on the subject, in addition to being foods consumed worldwide and it is not known how the physicochemical and sensory modification of the food would be, compared to conventional frying. On the other hand, the introduction of different innovative products on the market, including some revamped designs, is the most significant factor driving the growth of hot air fryers. According to Stratview Research (2023), the global air fryer market is expected to grow from USD 753.02 million in 2020 to USD 1150.9 million by 2026. This trend can be observed in Figure 1c, as a linear increase can be seen in recent years, so it can be summarized that this frying technology is becoming of interest to the world population and in turn replacing conventional frying. Also, increasing health awareness about following a particularly healthy diet is expected to improve the demand for the product, which will support market growth, as well as offer savings in oil usage and thus lower calorie intake. Currently, research is being conducted on home fryers, so the use of fryers at the industrial level is a developing area that will require further research. However, key players in the global air fryer market are Breville, Inc., TTK Prestige Ltd., Ltd., KRUPS, NuWave Havells India Ltd., and SharkNinja Operating LLC.

4. Conclusions and Suggestions for Further Research

In summary, the availability of advanced devices will increase the demand for hot air fryers as demonstrated by the trend generating a great social and economic impact, in addition this technology not only brings health benefits, but also has environmental advantages. Most of the articles are focused on the use of potato, sweet potato and doughnut, so we recommend papers that focus on other foods (i.e. tortilla chips, plantain chips, eggs and meats), since there are not enough studies on this subject. Currently, research is being conducted on home fryers, so the use of fryers and their impact at the industrial level is a developing area that will require further research.

Declaration of Competing Interest: The author declares no conflict of interest.