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DOI: 10.32743/UniChem.2025.127.1.19062 IR SPECTROSCOPY STUDY OF CATTLE SKIN TANNED WITH CHESTNUT EXTRACT
Gullola Umarova
Master of Fergana State University, Uzbekistan, Fergana
Toyiraxon Amirova
PhD, Associate Professor, Department ofchemistry, Fergana State University, Uzbekistan, Fergana
Otabek Nazarov
PhD, Associate Professor, Department ofchemistry Fergana State University Uzbekistan, Fergana
ИЗУЧЕНИЕ МЕТОДОМ ИК-СПЕКТРОСКОПИИ ШКУРЫ КРУПНОГО РОГАТОГО СКОТА
ДУБЛЕННОЙ ЭКСТРАКТОМ КАШТАНА
Умарова Гуллола Абдурашид кизи
Магистр
Ферганского государственного университета, Узбекистан, г. Фергана
Амирова Тойирахон Шералиевна
PhD, доц. кафедры химии Ферганского государственного университета, Узбекистан, г. Фергана E-mail: amirova1988@internet. ru
Назаров Отабек Мамадалиевич
PhD, доц. кафедры химии Ферганского государственного университета Республика Узбекистан, г. Фергана
ABSTRACT
Extraction methods were used to obtain alcohol and water extracts of chestnut. Cattle skins were treated with the extract, washed and dried. IR spectra of the inner and outer sides of dried cattle skins were recorded and the corresponding absorption curves were studied. Valence and deformation vibrations of amide and carbonyl groups in IR spectra were analyzed.
АННОТАЦИЯ
Методами экстракции получены спиртовые и водные вытяжки из каштана. Шкуру крупного рогатого скота обработали экстрактом, промывали и сушили. Снимали ИК-спектры внутренней и внешней сторон высушенных шкур крупного рогатого скота и исследовали соответствующие кривые поглощения. Анализированы валентные и деформационные колебания амидных и карбонильных групп в ИК-спектрах.
Keywords: chestnut, extract, cattle hide, tanning, IR spectrum, vibrations.
Ключевые слова: каштан, экстракт, шкура крупного рогатого скота, дубление, ИК-спектр, колебания.
Introduction. Globally, countries like China, Brazil, Russia, India, Italy, Argentina, South Korea, Turkey, Vietnam, and Pakistan lead in the production of leather goods [1]. Today, the application of modern high-tech processes and the use of various chemical substances in the complex processes of leather
processing have enabled diverse innovations [2]. Leather made from animal hides and skins has become a luxurious material of choice in furniture making, clothing, accessories, sports, automotive, aviation, and marine industries [3]. The tanning of animal hides and skins using natural, eco-friendly agents with minimal
Библиографическое описание: Umarova G., Amirova T., Nazarov O. IR SPECTROSCOPY STUDY OF CATTLE SKIN TANNED WITH CHESTNUT EXTRACT // Universum: химия и биология : электрон. научн. журн. 2025. 1(127). URL: https://7universum.com/ru/nature/archive/item/19062
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adverse effects, along with a complete chemical composition analysis and classification and certification based on these findings, holds significant practical importance [4]. For this reason, to increase the durability, strength, and hardness of leather products made from cattle hides, one of the most alternative natural tanning agents is horse chestnut (Aesculus hippocastanum), which was used for tanning. Its effects were analyzed through IR spectroscopy and compared with other types of tanned leather [5].
Horse chestnut is rich in tannins, making it an effective natural agent in the tanning process. The use of horse chestnut in the preparation of leather products from cattle hides is recognized as an environmentally friendly technology. Leather tanned using this method possesses the following characteristics [6].
1. High Quality: Leather products tanned with horse chestnut stand out for their strength and durability. They are highly water-resistant and elastic.
2. Natural Color: The leather has a natural brown hue, giving the product an aesthetic appearance.
3. Environmental Friendliness: Unlike chemical tannins, chestnut tannin is non-toxic and does not harm the human body.
Leather tanned with chestnut is widely used in the production of:
high-quality footwear; bags and accessories; upholstery for home furnishings; leather seats in automobile interiors. The horse chestnut tanning method is currently suitable for sustainable development requirements and plays a significant role in modern leather production [7].The aim of the study is to investigate the characteristic groups of proteins in cattle hide tanned with chestnut extract.
Research object and methods.Horse chestnuts were collected from Fergana city for the extraction process. In the extractor, 200 grams of horse chestnuts were added and subjected to extraction for 5 hours at 65°C
using a mixture consisting of 1.0% sodium hydroxide, 10% ethyl alcohol, and 89% water. The liquid-to-solid ratio for the alcohol-based extraction stage was set at 6. The extract was collected, and the remaining residue was extracted with water at 90°C. The liquid-to-solid ratio for the water extraction stage was set at 120. The obtained extracts were mixed, and acetic acid was added dropwise until the mixture was neutralized to a pH of 7. To the neutralized extract, 1.8% formaldehyde was added. The extract was held at 65°C for 25 minutes, and then a 0.15% sodium sulfite solution (relative to the amount of tanning agents) was added. The mixture was held at 95°C for 55 minutes, after which 10-15% of the water was evaporated. The tanning extract was applied to the leather being processed in the tanning drum at a rate of 18-20% tannins relative to the weight of the leather. The liquid ratio was maintained at 0.8-0.85. The tanning duration was 20-22 hours, with the drum's rotation direction being changed every 30 minutes. The initial tanning temperature was 20°C, and the temperature during the tanning process was not allowed to exceed 40°C. The tanned leather was removed from the drum and hardened for one day. It was then dried for six days. Afterward, the cattle hide was immersed in a magnesium sulfate solution for six hours. After soaking for six hours in the solution, the sample was taken out and air-dried for one to two days. Once dried, the sample was scraped and analyzed using the IR spectroscopy method. The IR spectra of the tanned leather samples were recorded on a Shimadzu IR Spirit spectrometer within the range of 400-4000 cm-1.
Research results.Study of horse chestnut-tanned cattle leather samples.
The leather's composition, primarily consisting of proteins, was analyzed through its IR spectra to identify functional groups characteristic of proteins.
Figure 1. External Surface of Cattle Leather Tanned with Horse Chestnut Extract
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The external surface of cattle leather tanned with horse chestnut extract displayed the following absorption regions in the IR spectrum (Figure 1). The broad absorption region at 3219.93 cm-1 is due to the valence vibrations of the NH group of Amide A. This absorption also indicates the active involvement of water in the collagen molecule due to the OH group. The absorption region for Amide B appears at 2919.93 cm-1. The absorption at 1743.63 cm-1 corresponds to the carbonyl group.
The absorption line for Amide I appears at 1647.36 cm-1, formed due to the valence vibrations of the C=O bond in the peptide bond. The absorption line for Amide II is observed at 1526.75 cm-1, which is due to CNH bond vibrations. The absorption line at 1456.38 cm-1 corresponds to methyl and methylene groups. The absorption observed at 1091.56 cm-1 further characterizes the sample.
Figure 2. Internal Surface of Cattle Leather Tanned with Horse Chestnut Extract
The internal surface of cattle leather tanned with horse chestnut extract showed the following absorption regions in the IR spectrum (Figure 2): The absorption region of Amide B amino (NH2) groups appeared weakly at 3301.98 cm-1 and strongly at 2921.37 cm-1. The absorption line for Amide I appeared at 1637.35 cm-1, formed due to the valence vibrations of the C=O bond in the peptide bond. The absorption line for Amide II was observed at 1541.12 cm-1, which is caused by CNH bond vibrations. The vibrations at 1403.23 cm-1 are attributed to the symmetric valence vibrations of carboxylate groups. The absorption line for Amide III
appeared at 1239.50 cm-1. The vibration of a simple ether bond (-C-O-C-) was observed at 1081.51 cm-1.
Conclusion. The cattle hide was tanned using the extract obtained through alcohol and water-based extraction of horse chestnut. Various groups characteristic of keratin in the tanned cattle leather were studied using the IR spectroscopy method. The spectra revealed the valence and deformation vibrations specific to amide and carbonyl groups. The absorption lines characteristic of keratin in tanned cattle leather were identified.
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