Dragomir Vassilev^1,*, Nadezhda Petkova², Yulian Tumbarski³, Milena Koleva¹, Panteley Denev²

Journal of Renewable Materials, Vol.8, No.6, pp. 675-686, 2020, DOI:10.32604/jrm.2020.09279 - 12 May 2020

Abstract Undenicylic acid (10:1) is known as an antifungal agent and an active ingredient of many topical medicines [1–6]. The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucidation of the resulting compounds, by FTIR and NMR spectroscopy. The antimicrobial properties of the obtained 10-undecylenic esters were tested against Gram-positive bacteria (Staphylococcus aureus; Enterococcus faecalis; Listeria monocytogenes), Gram-negative bacteria (Escherichia coli; Salmonella sp.) and filamentous fungi (Penicillium sp.; Aspergillus niger; Fusarium moniliforme) using the conventional agar-well diffusion assay. The results demonstrated that all More >

Nadezhda Petkova^1,*, Radka Arabadzhieva¹, Dragomir Vassilev², Gergana Gencheva¹, Yulian Tumbarski³, Tsveteslava Ignatova-Ivanova⁴, Sevginar Ibryamova⁴, Mina Todorova¹, Milena Koleva², Panteley Denev¹

Journal of Renewable Materials, Vol.8, No.4, pp. 365-381, 2020, DOI:10.32604/jrm.2020.09292 - 24 April 2020

Abstract Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst. The resulting esters were characterized by melting point, hydrophilic-lipophilic balance, thin-layer chromatography, ultraviolet spectroscopy, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Inulin acetate demonstrated a high degree of acetylation (2.5–3.0) and presented a white, water-insoluble substance with bitter taste. The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone. Swelling capacity, water holding, oil-holding capacities, the foamability,… More >

Ibtissem Moussa^1,2, Ramzi Khiari^1,3,4,*, Ali Moussa², Gérard Mortha⁴, Mohamed Farouk Mhenni¹

Journal of Renewable Materials, Vol.7, No.4, pp. 345-354, 2019, DOI:10.32604/jrm.2019.04011

Abstract The most abundant phenolic biopolymer in the biosphere is the lignin. This phenolic biopolymer commonly exists in combination with polysaccharides and other cell wall components. In this study, the solvent system dioxane-water is used to extract lignin, which is considered as unaltered native lignin. The dioxane lignin extracted from fig stems was characterized regarding to its structural feature, quantification of its functional groups, molecular weight, and evaluation of its thermal properties. Purity and molecular weight distribution of the studied lignin indicated that isolated lignin contained a low amount of sugar (c.a. 19%) and had a More >