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

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… 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

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, foam stability and emulsifying properties… More >