Extraction, purification, antioxidant properties and stability conditions of phytomelanin pigment on the sunflower seeds

Abstract

Phytomelanin pigment, a rare secondary matabolite in plants, has potential for use in the cosmetic and food sectors. This pigment has antioxidant, antimicrobial and ultraviolet (UV) light absorbing properties, so it can be used as natural food coloring and in the field of cosmetics. In this study, extraction, purification, antioxidant properties and stability conditions of phytomelanin pigment found in sunflower (Helianthus annuus L.) seed coat were investigated. NaOH, KOH and NH4OH solutions were tested at different concentrations for extraction. It has been determined that the most suitable solvent for extraction is 0.3 M NaOH. The purification process involves precipitation with HCl followed by washing with ethyl alcohol, ethyl acetate and acetone. The findings show that the proportion of phytomelanin in sunflower seeds is 1.95% and that the antioxidant capacity is 9.8% ascorbic acid equivalent. The purity degree of the purified phytomelanin pigment and that of the synthetic phytomelanin pigment were compared by thin layer chromatography (TLC). Chromatography findings have shown that the purification performance is quite high. It was determined that the pigment was slowly deteriorated in temperature and light, and was not affected by air. Consequently, sunflower seed coat can be a convenient and economical source of producing pure phytomelanin for industrial use.

Melanin found in wheat spike husks

“…Thus, our extraction experiments showed that the dark pigment in the Persian wheat spike is not of anthocyanin origin. Sodium hydroxide extraction, on the contrary, produced colored solutions both in sunflower achenes, which are the proven source of melanin [24], and in Persian wheat dark-colored spike husks. Spectral measurements showed similarity of sunflower and wheat extracts light absorbance.…”

“…The mature spikes (Figure 1a) were threshed manually, and the husks were gathered. Sunflower (Helianthus annuus L.) black-colored achenes husks were taken as a positive melanin-containing control [24], while dark-colored blueberry (Vaccinium corymbosum L.) fruit exocarp , red-colored and black-colored tissues of tulip (Tulipa L., Darwin hybrid 'Apeldoorn') perianth [25] were taken as anthocyanin-positive controls (Figure 1). The tulip was grown at the same place as wheat, while sunflower and blueberry fruits were purchased in local supermarket.…”

“…To extract melanin, 1 ml of 0.3 M NaOH aqueous solution [24] was added to grinded tissues per tube, while for extraction of anthocyanins, 95% ethanol with addition of 0.1 M citric acid [26] was used in the same quantity. The contents of the tubes were shaken on a TissueLyser II 30 seconds at 25 Hz and then incubated on a tube rotator for 30 minutes at room temperature.…”

Agro-Industrial Waste Revalorization: The Growing Biorefinery

“…For example, fruit, wheat bran extracts, and cabbage wastes were used as inoculum in Bacillus safensis [41], fungus Auricularia auricula [42], and Pseudomonas sp. [43] for the melanin production. Melanin is specially found in the seed coat of different plants; however, it is also found in other plant structures such as black spots of leaves, flowers, and seeds [44].…”

Разработка Технологий Получения Фитомеланинов На Отходах Масличного Производства

“…Эти отходы скапливаются в колоссальных количествах, загрязняют почву и требуют дополнительных площадей для складирования. Микробная биоконверсия подсолнечной лузги затруднительна в связи с наличием большого количества лигнина в ее составе, который является ингибитором большинства гидролитических ферментов микроорганизмов (Adams et al, 1994;Keles and Özdemir, 2018;Schweitzer et al, 2010). Вышеуказанные факты говорят о том, что данный отход представляет экологическую проблему для окружающей среды и в связи с этим, научное сообщество во всем мире разрабатывает новые способы использования этого целлюлозосодержащего сырья.…”