INVESTIGATION OF THE OPTIMAL GARLIC DRYING METHOD

ABSTRACT

The article provides a comparative analysis of the effectiveness of modern garlic (Allium sativum) drying methods: infrared (IR) and vacuum-impulse drying (VID). The influence of temperature regimes in the range of 40–80 °C on the kinetics of moisture removal and the safety of thermolabile components is investigated. It is established that the VID method provides a higher retention coefficient K_rec of aromatic substances (up to 85%) compared to the IR method with comparable energy consumption. The obtained quantitative indicators allow optimizing technological parameters to obtain high-quality dry raw materials with specified organoleptic properties.

АННОТАЦИЯ

В статье проводится сравнительный анализ эффективности современных методов сушки чеснока (Allium sativum): инфракрасного (ИК) и вакуумно-импульсного (ВИД). Исследовано влияние температурных режимов в диапазоне 40–80 °C на кинетику удаления влаги и сохранность термолабильных компонентов. Установлено, что метод ВИД обеспечивает более высокий коэффициент сохранения K_rec ароматических веществ (до 85%) по сравнению с ИК-методом при сопоставимых энергозатратах. Полученные количественные показатели позволяют оптимизировать технологические параметры для получения высококачественного сухого сырья с заданными органолептическими свойствами.

Keywords: drying, garlic, efficiency, agriculture.

Ключевые слова: сушка, чеснок, эффективность, сельское хозяйство.

INTRODUCTION

The purpose of this study is to analyze and compare different garlic drying methods, including natural drying, oven thermal processing, and advanced drying technologies. Special attention is given to the influence of temperature, humidity, and processing duration on drying efficiency. The advantages and disadvantages of each method are evaluated in terms of nutrient retention and overall product quality.

Thus, selecting the most effective method for drying garlic is a relevant task for the food industry, agricultural enterprises, and household users. The results of this research allow for recommendations on optimal drying conditions depending on specific requirements for the final product quality [3].

The scientific novelty of this study lies in establishing quantitative relationships between vacuum-impulse processing parameters and the degradation rate of garlic's thermolabile compounds. For the first time, it has been experimentally proven that employing cyclic pressure changes at a temperature of 60 °C increases the retention coefficient К_rec of active substances to 85%, which significantly exceeds the results of traditional infrared drying (25% at 80 °C) with comparable energy consumption.

METHODS OF RESEARCH

An experimental study was conducted to determine the optimal method for drying garlic. Two drying techniques were selected for comparative analysis: infrared drying at various temperatures and vacuum-impulse drying.

The primary objective of the drying process is to remove moisture from the product in order to prevent spoilage. At the same time, the drying method must ensure the preservation of key beneficial components, such as:

• Allicin — a powerful antioxidant and natural antimicrobial compound.

 • Essential oils, which determine the characteristic aroma and flavor of garlic.

 • Vitamins of groups B and C, as well as various microelements essential for nutritional value.

To mathematically describe the dehydration process and evaluate the efficiency of the drying methods studied, the following indicators were used:

Current moisture content W, % of garlic samples during the drying process was calculated using the formula:

where is the  mass of the sample at a given time (g), and  is the mass of the bone-dry matter (g).

The drying rate V, % / min was determined as the change in moisture content over a specific time interval:

where dW is the change in moisture content during the time interval

The retention coefficient (,%) was used to assess the preservation of thermolabile components (essential oils and allicin):

where  is the concentration of the substance in the dried product, and  is the initial concentration in the fresh raw material.

Table 1 presents the chemical composition of garlic, including its caloric value, proteins, fats, carbohydrates, vitamins, and minerals per 100 grams of edible portion [4].

Table 1.

Chemical Composition of Garlic per 100 g of Edible Portion

The energy content of garlic is 149 kcal.

Comparative Analysis of Research Results

Infrared drying is a thermal processing method in which energy is transferred from the source to the product surface in the form of infrared (IR) radiation. Infrared waves induce oscillation of water molecules within the garlic tissue, resulting in rapid evaporation of moisture both from the surface and from internal layers.

The use of infrared radiation significantly accelerates the dehydration process compared to traditional convective drying. The energy is absorbed by the surface of the garlic and penetrates into the product to a certain depth, ensuring uniform heating and moisture removal without overheating [5–8].

Advantages of infrared drying:

• High drying rate

• Reduced overall loss of nutrients

• Energy efficiency due to direct energy transfer

• Improved preservation of aroma and color

• Compactness of the equipment

Disadvantages:

• Requirement for precise temperature control and correct distance from the radiation source

• Risk of uneven drying when the product is improperly arranged

• Limited penetration depth of IR waves (not suitable for very thick layers)

Typical technical parameters:

• Temperature range: 50–70 °C

• Wavelength range: 0.75–10 µm (near and mid-IR zone)

 • Drying time: 2–5 hours (depending on slice thickness and initial moisture content)

The final moisture content of infrared-dried garlic typically ranges from 6–8%. For thin slices (1.5–2 mm), moisture should be checked at several points to avoid areas with elevated residual moisture and

Figure 1. Drying time of garlic at different temperatures

The graph 1 shows the relationship between infrared drying time and temperature. According to the drying rate calculations (Equation 2), the IR method at 80 °C reduces the process time to 30 minutes.

Figure 2. Aroma retention of garlic at different temperatures

Vacuum-impulse drying (VID) showed higher efficiency  using the formula for K_res  for preserving valuable components of garlic — including essential oils, allicin, and other sulfur-containing compounds — while reducing the loss of aroma and color compared to traditional drying methods (such as convective, infrared, and others). However, analysis using Equation 3 showed that the aroma retention coefficient K_rec drops to 25% under these conditions

Figure 3. Aroma retention of garlic under different drying methods (infrared vs. vacuum-impulse)

Here is the comparative graph: vacuum-impulse drying (VID) demonstrates significantly better aroma retention of garlic across the entire temperature range compared to infrared drying. When using the VID method, the value of K_rec remains consistently high—82–85%. This difference becomes especially pronounced at higher temperatures, where VID helps prevent the degradation of volatile aromatic compounds [9–12].

Table 2.

Comparative Analysis of Garlic Drying Methods

For a clearer comparison, a diagram can be constructed that reflects time consumption, efficiency, nutrient preservation, and ease of application. Infrared drying is characterized by a relatively short processing time and does not require complex equipment; however, it is associated with moderate energy consumption and may lead to partial loss of volatile aromatic compounds at elevated temperatures. This reduces both the nutritional value and the aroma of the final product.

In contrast, vacuum-impulse drying (VID) offers much gentler processing conditions due to reduced pressure and controlled temperature. This allows for maximum preservation of vitamins, essential oils, and bioactive compounds. At the same time, the drying duration remains relatively short. Despite the higher cost and technical complexity of the equipment, VID demonstrates high efficiency and superior product quality, making it particularly relevant for industrial-scale production and functional food applications.

Conclusion

Process Kinetics: It was found that increasing the infrared drying temperature from 40°C to 80°C enhances the drying rate V by 3.5 times, reducing the total processing time to 30–40 minutes. However, temperatures exceeding 70°C lead to significant thermal degradation of the product.

Quality Assessment: The vacuum-impulse drying (VID) method at 60°C demonstrated the optimal balance between speed and quality. The retention coefficient K_res for aromatic substances reached 82–85%, which is 3 times higher than the values obtained during intensive IR drying at 80°C (22–25%).

Practical Application: For the industrial production of functional garlic powder, the VID method is recommended as the most efficient technology. It ensures a final moisture content of 6–8% while maximizing the preservation of allicin and B-group vitamins, fulfilling the requirements for high-quality natural products.

References:

1. Golubkina, N. A., Seredin, T. M., Koshevarov, A. A., Shilo, L. M., Baranova, E. V., & Pavlov, L. V. (2010). Selenium-enriched garlic powder.
2. Block, E. (2010). Garlic and other alliums: The lore and the science. Royal Society of Chemistry.
3. Health-Diet.ru. (n.d.). Chemical composition of garlic. https://health-diet.ru/base_of_food/sostav/436.php
4. Membrana. (2009). Scientists explain the healing properties of garlic.
5. Chen, S., Shen, X., Cheng, S., Li, P., Du, J., Chang, Y., & Meng, H. (2020). Evaluation of allicin stability in different garlic drying methods. Food Chemistry, 331, 127201. https://doi.org/10.1016/j.foodchem.2020.127201
6. Toğrul, H., & Pehlivan, D. (2018). Infrared drying kinetics and quality assessment of garlic slices. Journal of Food Processing and Preservation, 42(1), e13373. https://doi.org/10.1111/jfpp.13373
7. Kaveh, M., Amiri Chayjan, R., & Taghinezhad, E. (2019). Comparative analysis of infrared, convective, and microwave drying of garlic: Effects on drying rate, energy consumption, and quality. Journal of Food Engineering, 263, 1–10.
8. Li, X., Li, M., Yu, J., & Wang, L. (2021). Impact of vacuum drying conditions on bioactive components and aroma profile of garlic. LWT - Food Science and Technology, 147, 111599.
9. Wang, Y., Yu, X., & Zhao, Y. (2022). Effect of different dehydration techniques on antioxidant activity and volatile compounds in garlic. Food Research International, 158, 111562.
10. Choi, Y., Lee, H., & Kim, J. (2017). Quality characteristics of garlic powder obtained by various drying methods. Drying Technology, 35(6), 723–732.
11. Mujumdar, A. S. (2019). Handbook of drying technologies (4th ed.). CRC Press.