УДК 664.5

ИССЛЕДОВАНИЕ СУШКИ ЧАБРЕЦА РАЗНЫМИ МЕТОДАМИ И ИХ ВЛИЯНИЕ НА ЕГО ХИМИЧЕСКИЙ СОСТАВ

Чалаташвили Александр, Гагнидзе Торнике

INVESTIGATION OF DIFFERENT DRYING METHODS AND THEIR INFLUENCE ON THYMES CHEMICAL COMPOSITION

Chalatashvili Aleksandre1, Gagnidze Tornike2
11, Doctor of Food Technology
21, Doctor of Sciences

Abstract
In this paper we present drying process instigation of thyme. It is broadly distributed plant widely used in different types of applications, such as pharmaceutical industry, perfumery and food industry. Raw thyme contains many different types of biologically active substances, including protocrocin. Its significant amount is presented in the raw plants. The aim of our study was to define presences of protocrocin in the raw thyme and to analyse produced substances due to its disintegration. We have performed experiments by the spectrophotometric method of analysis on thyme dried with two different way and their influence on thyme chemical composition.

Keywords: carotenoid nature of glycosides, crocin, protocrocin, safranal, spectrophotometry, thyme


Рубрика: 06.00.00 СЕЛЬСКОХОЗЯЙСТВЕННЫЕ НАУКИ

Библиографическая ссылка на статью:
Чалаташвили А., Гагнидзе Т. Investigation of different drying methods and their influence on thymes chemical composition // Современные научные исследования и инновации. 2020. № 9 [Электронный ресурс]. URL: https://web.snauka.ru/issues/2020/09/93442 (дата обращения: 07.12.2021).

Introduction

Thyme is a broadly distributed annual plant, which is widely used in different types of applications, such as pharmaceutical industry, perfumery, food industry, etc. These versatile applications are due to its chemical composition, aroma and taste properties. Additionally, its high adaptation capacity to different environmental conditions enables to cultivate this specie all over the Europe and also in the regions of temperate climate. Thyme contains many different types of biologically active substances broadly used in food industry, including non-alcoholic beverage industry[1,2].

Beverage manufacturing is not seasonal process and take place for entire year, while required raw materials can be picked in summer. This requires to properly preserve materials for whole year to keep drink production running. Unfortunately, preserving raw plants is complex process and requires detailed investigation in order to find out which method is optimal for each material. Drying as a method of preservation of plants is an important process of maintenance. During growth and vegetation of plants many different chemical and biochemical transformation take place. These transformations are not stopped after picking of plants. Compounds present in plant, including biologically active substances, undergoes disintegration and instead new compounds are reproduced. The disintegration of one material and reproduction of another one strongly depends on drying methods and conditions. The chemical composition of the picked plants depends on its vegetative period, the time of the picking, the storage conditions and the processing. Additionally, it also depends on physical parameters such as temperature, humidity, sun radiation, etc[3,4].

During the solar drying plants are exposed to the sun to the whole spectra (see figure 1) in open air. This figure shows the solar radiation spectrum for direct light at both the top of the Earth’s atmosphere (represented by yellow area) and at sea level (red area). These curves are based on the American Society for Testing and Materials (ASTM) Terrestrial Reference Spectra. Regions for ultraviolet (UV), visible and infrared (IR) light are indicated. The part of the spectrum, which is absorbed by water, and therefore is relevant for drying is marked on the figure. Inset of the figure shows relative distribution of the three regions of the sun radiation: visible light, UV and IR. Here we can see that majority of sun radiation contains IR and visible light, but where is also small fraction of UV (about 2%) which can be destructive for biologically active substances in thyme[5].

Part of the sun’s spectra is absorbed by material and transferred into thermal energy, as a result water molecule are evaporated. Temperature of the air near surface of the material is increased and conventional wind is produced, which blows away evaporated molecules into open air. Draying in the open air requires spreading the selected material for several days or weeks.


Figure 1. shows the solar radiation spectrum for direct light at the top of the Earth’s atmosphere (represented by yellow area) and at sea level (red area). (source: American Society for Testing and Materials (ASTM) Terrestrial Reference Spectra). Inset: relative distribution of the three regions of the sun radiation: visible light, UV and IR.

Another commonly used method for drying is shade drying. This method requires months for proper drying; however, it also has some advantages. Firstly, during drying in shade, heat fresh air is separated from the plant chamber, so the sample is not exposed to direct sunlight. This is particularly important for plants which loose nutritional value when exposed to direct sunlight. Secondly, compared to direct sun drying it less depends on weather. Thirdly, temperature day-night variation amplitude is lower than in case of sun drying. Additionally, during shade drying material is protected from UV light which can damage material[5].

Materials and methods:

In this paper we have studied thyme. Materials investigated were picked in Georgia, Kakheti region, in 2017 season.

As known in literature, amount of protocrocin is higher in the raw thyme, and disintegrates during drying process[6]. Therefore, one has to pay attention to the drying methods and conditions.

The aim of our research was to study optimal conditions for thyme drying and to define quality parameters of the dried materials. In order to determine in which condition is protocrocin disintegrated and what other substances are created during drying, we performed two different experiments on the freshly picked thyme: I -thyme leaves were dried in the shadow, at room temperature (later we call “shade drying”) and II – thyme leaves were dried in the sun, by direct sun radiation (later we call “sun drying”)

In order to properly dry by shade drying, we spread thyme for 5 months. For comparison, during sun drying, we spread thyme with relative high thickness – 5-8 cm for 2-3 weeks. This thickness helps to avoid evaporation ether-oils during drying.

In the first case of our experiments, we were measuring several substances present in the thyme after every month by spectrophotometric method of analysis. By this analysis we could measure dynamics of changes in amount of protocrocin, crocin, picrocrocin and safranal during thyme drying. In the second case, we performed the same analyses before drying (on the fresh thyme) and after 2 weeks.

Results and discussion

In the following table we present obtained results of spectrophotometric analysis of shade drying of thyme.

Table 1 – Dynamics of changes in amount of protocrocin, crocin, picrocrocin and Safranal during thyme drying (1-5 months).

Chemical component

quantity, mg/100g

Months

row

1

2

3

4

5

Protocrocin

159,6

125,4

83,3

47,8

31,4

23,1

Crocin

2,1

12,3

15,5

18,6

19,8

21,5

Picrocrocin

5,3

31,6

58,4

80,9

93,1

114,0

Safranal

3,5

7,2

9,9

12,1

13,2

13,9

Dynamics of changes in amount of protocrocin, crocin, picrocrocin and safranal during thyme drying (1-5 months) is visualized on figure 2. As one can see on this figure, amount of protocrocin decrease by 136.5 mg/100g in 5 months of drying, which is about 86% reduction. The protocrocin disintegration rate is reported on figure 3. Here we report disintegrated protocrocin in percent of total amount of protocrocin by previous month. This figure shows that the most active period of disintegration was 3rd month of drying, when about 43%
of protocrocin were disintegrated
.

Figure 2. Dynamics of changes in amount of protocrocin, crocin, picrocrocin and safranal during thyme drying (1-5 months).

Total amount of crocin was increased by 19.4 mg/100g after these 5 months, Picrocrocin was increased by 108.7 mg/100g, and safranal by 10.4 mg/100g. Picrocrocin is obtained by disintegration of protocrocin. On parallel of this process, picrocrocin can be transformed into safranal. It is known in literature, that safranal is produced as a result of picrocrocin hydrolyse.

In the second part of our investigation, we dried thyme on the direct beam of the sun rays. Drying process was continuing until we could not observe moisture by smashing of thyme, thus it lasts for 2 weeks. We performed measurements before start drying and after 2 weeks.

Figure 3. Protocrocin disintegration rate

We found that up to 90% of protocrocin was disintegrated after two-week sun drying (137,4 mg/100g from 154.1 mg/100g). It is higher value than in case of shade drying. In contrast, amount of produced safranal was only 2.6 mg/100g, much lower value compared to shade drying.

Conclusions

Based on our experiments we can conclude that drying in the sun is much faster than in shade. Obtained dry thyme can be used in food industry as a flavor. However, thyme dried in shade shows higher amount of safranal therefore can be used not only as a flavor but also as a food additive with positive effects on human’s health. Therefore, we suggest to use shade drying method to obtain material with biologically active substances.


References
  1. E. Abbasloo et al., “The anti-inflammatory properties of Satureja khuzistanica Jamzad essential oil attenuate the effects of traumatic brain injuries in rats,” Sci. Rep., vol. 6, no. 1, pp. 1–12, Aug. 2016.
  2. G. L. ALONSO, M. R. SALINAS, J. GARIJO, and M. A. SÁNCHEZ-FERNÁNDEZ, “COMPOSITION OF CROCINS AND PICROCROCIN FROM SPANISH SAFFRON (CROCUS SATIVUS L.),” J. Food Qual., vol. 24, no. 3, pp. 219–233, Jul. 2001.
  3. A. J. Buglass, “Handbook of Alcoholic Beverages: Technical, Analytical and Nutritional Aspects, 2 Volume Set | Wiley.” [Online]. Available: https://www.wiley.com/en-us/Handbook+of+Alcoholic+Beverages%3A+Technical%2C+Analytical+and+Nutritional+Aspects%2C+2+Volume+Set-p-9780470512029. [Accessed: 21-Jul-2020].
  4. H. Hazrati, M. J. Saharkhiz, M. Niakousari, and M. Moein, “Natural herbicide activity of Satureja hortensis L. essential oil nanoemulsion on the seed germination and morphophysiological features of two important weed species,” Ecotoxicol. Environ. Saf., vol. 142, pp. 423–430, Aug. 2017.
  5. M. G. Green, “Solar Drying Technology for Food Preservation,” no. November, 2014.
  6. A. Chalatashvili, M. Khositashvili, M. Ardzenadze, “The production of dessert liquors using some medical plants extended in Georgia”, editor: M. Jghenti, Tbilisi, 2020 (in Georgian)


Количество просмотров публикации: Please wait

Все статьи автора «Chalatashvili Aleksandre»


© Если вы обнаружили нарушение авторских или смежных прав, пожалуйста, незамедлительно сообщите нам об этом по электронной почте или через форму обратной связи.

Связь с автором (комментарии/рецензии к статье)

Оставить комментарий

Вы должны авторизоваться, чтобы оставить комментарий.

Если Вы еще не зарегистрированы на сайте, то Вам необходимо зарегистрироваться:
  • Регистрация