Browsing by Author "Alaya, Ikbel Ben"
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- Development of a natural preservative from chestnut flowers: ultrasound-assisted extraction optimization and functionality assessmentPublication . Alaya, Ikbel Ben; Pereira, Eliana; Dias, Maria Inês; Pinela, José; Calhelha, Ricardo C.; Soković, Marina; Kostić, Marina; Prieto Lage, Miguel A.; Essid, Faten; Caleja, Cristina; Ferreira, Isabel C.F.R.; Barros, LillianThis study was carried out with the aim of optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from male chestnut flowers (C. sativa Mill) to develop a bioactive extract with potential to be used as a natural antioxidant preservative ingredient in the food in-dustry. Time (t, 1–39 min), solvent concentration (S, 0–100%), and ultrasonic power (P, 5–500 W) were used as the independent variables for a 5-level experimental circumscribed central composite design (CCCD) coupled with response surface methodology (RSM) to optimize the extraction of phenolic compounds by UAE. Regarding the variables, the three showed a significant effect on the extraction of phenolic compounds. The content of phenolic compounds (including flavonoids and tannins) and the extraction yield (extract weight gravimetrically assessed) were the response criteria for the optimization. Based on the statistically validated predictive polynomial models, it was possible to reach a maximum content of phenolic compounds at the global optimal conditions of 24 ± 3 min, 259 ± 16 W, and 51 ± 7% ethanol. Additionally, pentagalloyl-glucoside and trigalloyl-hexahydroxydiphenoyl-glucoside were the major phenolic compounds identified. The optimized extract was then analyzed for their biological properties. The bioactive potential of the chestnut flower extract obtained under these optimized conditions was evaluated using in vitro assays for antioxidant, anti-inflammatory, and antimicrobial activity, as well as cytotoxicity and hepatotoxicity tests. The results revealed that the enriched extract has antioxidant, antitumoral, and anti-inflammatory activities without toxicity issues. Overall, this study allowed to define the optimal conditions for the extraction of phenolic compounds from chestnuts male flowers by UAE, to obtain an enriched extract with biological properties that could be further used as a natural antioxidant ingredient with applications on functional foods.
- Development of a natural preservative obtained from chestnut flowers through the optimization of an ultrasonic assisted extraction techniquePublication . Alaya, Ikbel Ben; Caleja, Cristina; Barros, Lillian; Essid, FatenThe chestnuts are a group of nine species of deciduous trees and shrubs in the genus Castanea, in the beech family Fagaceae. Due to the nutritional properties, chestnuts have historically been used for human and animal consumption. Several by-products are produced during chestnut industrial processing, such as chestnut wood, flowers, leaves, shells, barks, and burs. Such by-products are a significant source of antioxidant compounds and can be used as food additives to be incorporated in food products to optimize nutritional and quality characteristics and to prevent oxidation processes. The aim of this research work was to optimize the conditions for the extraction of phenolic compounds from male chestnut flowers using ultrasonic-assisted extraction in order to develop an extract rich in phenolic compounds and, study it potential as a natural ingredient with potential industrial application. Time (t), ultrasound potencial (P) and solvent (S) were the conditions optimized by response surface methodology using a 5-level experimental design. The responses used as criteria were the quantification of the individual phenolic compounds identified by HPLC-DAD-ESI/MS and the extraction yield of the obtained residue. Based on their chromatographic, UV-vis and mass spectra characteristics, fourteen compounds were identified of which seven were hydrolysable tannins and seven were flavonoids being trigalloyl-HHDP-glucoside the major compound found. The conditions that maximized the total phenolic content was found at t= 23.47±2.90 min, P= 258.78±16.09 W and S= 50.51±7.11% ethanol producing an extract with 21.86±8.84 mg of phenolic compounds per g of extract. In this way, this study allowed to define the best conditions for the extraction of bioactive compounds and confirm the potential of the extract of male chestnut flowers as a natural ingredient for functional foods, providing health benefits.