THE MAIN TECHNOLOGICAL PARAMETERS IN THE PROCESS OF DRYING HERBS: HUMIDITY AND TEMPERATURE CONTROL

ABSTRACT

This article explores the critical role of humidity and temperature control in herb drying, delving into their individual impacts, their synergistic relationship, and the optimization strategies employed to achieve optimal drying results. The art of preserving nature's bounty in its purest form lies in the process of drying herbs. This age-old practice, fundamental to herbal medicine, culinary arts, and aromatherapy, necessitates careful control of two crucial parameters: humidity and temperature. These variables, acting in concert, determine the effectiveness and quality of the dried herb, influencing its color, aroma, flavor, and therapeutic potency.

АННОТАЦИЯ

В этой статье исследуется решающая роль контроля влажности и температуры при сушке трав, углубляясь в их индивидуальное воздействие, их синергетическое взаимодействие и стратегии оптимизации, используемые для достижения оптимальных результатов сушки. Искусство сохранения даров природы в чистом виде заключается в процессе сушки трав. Эта древняя практика, имеющая фундаментальное значение для фитотерапии, кулинарного искусства и ароматерапии, требует тщательного контроля двух важнейших параметров: влажности и температуры. Эти переменные, действующие совместно, определяют эффективность и качество сушеной травы, влияя на ее цвет, аромат, вкус и терапевтическую эффективность.

Keywords: herb drying, individual impacts, quality of the dried herb, influencing its color, aroma, flavor,  humidity, temperature.

Ключевые слова: сушка травы, индивидуальное воздействие, качество сушеной травы, влияющее на ее цвет, аромат, вкус, влажность, температуру.

Introduction.  The rate of drying is decided by the dampness substance and the temperature of the grain and the temperature, the (relative) mugginess and the speed of the discuss in contact with the grain. Drying strategies depend on the drug's constituents - clears out and above-ground parts are dried at 40-60°C, roots and rhizomes take weeks to sun dry, and blooms are low-heat discuss or machine dried. Drying, a dehydration process, removes excess moisture from herbs, preventing spoilage and preserving their valuable constituents.  These constituents, including volatile oils, flavonoids, tannins, and vitamins, are responsible for the therapeutic properties and characteristic flavors of herbs. However, if not carried out correctly, the drying process can degrade these constituents, diminishing the herb's quality and effectiveness [1]. 

Preserving Volatile Compounds:  Volatile oils, responsible for the aroma and many of the therapeutic properties of herbs, are sensitive to heat.  High temperatures can vaporize these compounds, leading to a diminished aroma and a reduction in the effectiveness of the herb.

Materials and methods.  Temperature, the degree of heat applied during drying, acts as the primary driving force in removing moisture from the herb. Optimal temperature control is essential for.

Maintaining Color: High humidity levels can lead to browning and discoloration of herbs due to enzymatic activity and oxidation.  This not only affects the visual appeal but can also indicate reducing of the quality of the product. potentially leading to prolonged drying times and increased risk of spoilage. Conversely, lower humidity levels promote faster drying, but too low a humidity can lead to excessive drying [2,3].

The low humidity promotes moisture evaporation, while the controlled temperature ensures the preservation of valuable compounds.

Figure 1. Technological process of drying spices and herbs

Humidity, the amount of moisture present in the air, plays a pivotal role in herb drying.  Optimizing humidity levels is crucial for several reasons. Humidity and temperature work in concert to determine the success of herb drying. Their interplay is crucial for achieving a balanced and effective drying process. Synergy for Optimal Drying:  A combination of low humidity and appropriate temperature creates the ideal environment for effective and efficient herb drying [4,5].

Minimizing Nutrient Degradation:  Excessive heat can damage or degrade other beneficial constituents, such as vitamins, flavonoids, and tannins, reducing the overall nutritional value and therapeutic potency of the herb.  Controlling Evaporation Rate: Humidity affects the rate of moisture evaporation from the herb. Higher humidity slows down the drying process.

Controlling Drying Rate: Higher temperatures accelerate the drying process, reducing drying times. However, too high a temperature can result in uneven drying, with some parts of the herb drying too quickly and others remaining damp, increasing the risk of spoilage.

Avoiding Extreme Conditions:  Both excessively high and low humidity and temperature levels can negatively impact the quality of the dried herb.  High humidity can lead to spoilage, while excessively low humidity can result in the loss of volatile compounds. High temperatures can degrade nutrients, while low temperatures can prolong the drying process and increase the risk of microbial growth [6].

Various technological methods can be employed to control humidity and temperature during herb drying:

1. Dehydrators: Electric dehydrators offer precise control over both humidity and temperature, providing a consistent and reliable environment for drying herbs.

Temperature Control: Dehydrators typically feature adjustable temperature settings, allowing for precise control over the drying process, optimizing it based on the specific herb being dried.

Humidity Control: Some dehydrators feature built-in humidity control mechanisms, allowing for the removal of excess moisture from the air circulating within the drying chamber. Others utilize open-air drying methods with circulating fans to promote airflow and control humidity.

2. Drying Racks and Screens:  Using drying racks or screens in well-ventilated spaces is a traditional method for herb drying.

Natural Airflow: Open-air drying relies on natural airflow to remove moisture, minimizing the use of artificial heat. This method is particularly suited for herbs with high moisture content, as the slow drying process allows for greater preservation of volatile compounds [7].

At slightest 2000 species of restorative and fragrant plants are showcased in Europe. Italy encompasses a contributes to 3% of by and large European generation. Italian imports are around 161 thousand tons with an cost of around USD 1.14 billion. The Italian generation of restorative plants fulfills as it were 30% of the national needs, the remaining 70% of the herbs devoured in our nation come from overseas; in specific, from nations of Eastern Europe and North Africa, but their development is certainly extending [8].

3. Solar Drying: Harnessing the power of the sun for drying herbs is a sustainable and energy-efficient method.

Natural Heat Source:  Solar drying utilizes natural sunlight to provide heat for drying. This method is particularly suitable for warm climates with abundant sunshine, but requires careful control to prevent excessive heat exposure.

Humidity Control: Solar drying often involves using drying racks or screens with a protective cover to minimize moisture absorption from the air.

While the principles of humidity and temperature control are fundamental, specific herb varieties require customized drying conditions to preserve their unique qualities:

Figure 2. Controlling the main technological parametres

Fragile Herbs: Delicate herbs with high volatile oil content, like lavender, chamomile, and mint, require lower temperatures and lower humidity to prevent the loss of their aromatic compounds. Hardy Herbs: Robust herbs with a higher moisture content, such as rosemary, thyme, and oregano, can tolerate higher temperatures and lower humidity, allowing for faster drying times [10].

The improvement of fragrant plants has numerous likenesses with the development of green species inside the open field and, in this way, a conventionally genuinely advancement system, which gives for planting, visit advancement care and one or more harvests in the midst of the advancement cycle of the alter inside the era season. The plants are accumulated inside the green field, in grow. When the parts create, but for a few and unprecedented cases, they are a thing that contain variable rates of vegetation water and, hence, cannot be protected and transported, but in a brief run. Gathering can be done by hand or by machine. Temperature Control: Drying racks and screens can be placed in warm, dry environments, such as attics or greenhouses, to promote faster drying. However, careful monitoring is essential to avoid excessive heat exposure [8,9].

Regular monitoring of the drying process is crucial to ensure optimal results:

Visual Inspection:  Observe the color, texture, and aroma of the herbs during drying.  Herbs should retain their natural color and develop a crisp texture as they dry.

Moisture Content Testing:  Using a moisture meter to measure the moisture content of the herb can provide accurate information on drying progress.  The desired moisture content for dried herbs generally ranges from 8% to 12%, depending on the herb and its intended use.

 Conclusion. The successful drying of herbs is a delicate balance between science and art.  By understanding the fundamental roles of humidity and temperature and employing the appropriate technological strategies and monitoring techniques, we can preserve the beauty and benefits of herbs, ensuring their continued use in medicine, food, and well-being.

References.

1. The Herbalist's Bible: By James Green, a comprehensive guide to herbalism, covering herb drying techniques.
2. The Complete Book of Herbs: By Lesley Bremness, an in-depth exploration of herbs, including information on drying and preservation.
3. The Science of Herbal Medicine:  By David Winston, a detailed look at the scientific principles underlying herbal medicine, including drying practices.
4. Herb Drying:  By The National Center for Home Food Preservation, a guide to drying herbs at home, outlining safety guidelines and best practices.
5. Syamaladevi, R.M.; Tang, J.; Villa-Rojas, R.; Sablani, S.; Carter, B.; Campbell, G. Influence of water activity on thermal resistance of microorganisms in low-moisture foods: A review. Compr. Rev. Food Sci. Food Saf. 2016, 15, 353–370
6. Motevali, A.; Minaei, S.; Banakar, A.; Ghobadian, B.; Khoshtaghaza, M.H. Comparison of energy parameters in various dryers. Energ. Convers. Manag. 2014, 87, 711–725.
7. ISMEA. Piante Officinali in Italia: Un’istantanea Della Filiera e dei Rapporti tra i Diversi Attori. 2013. Available online: https://www.ismea.it (accessed on 17 June 2020).
8. Sarsavadia, P.N. Development of a solar-assisted dryer and evaluation of energy requirement for the drying of onion. Renew. Energy 2007, 32, 2529–2547.
9. Tunde-Akintunde, T.Y.; Ogunlakin, G.O. Influence of drying conditions on the effective moisture diffusivity and energy requirements during the drying of pretreated and untreated pumpkin. Energ. Convers. Manag. 2011, 52, 1107–1113. 
10.  Diaz-Maroto, M.C.; Perez-Coello, M.S.; Cabezudo, M.D. Effect of drying method on the volatiles in bay leaf (Laurus nobilis L.). J. Agric. Food Chem. 2002, 50, 4520–4524.