Radka Arabadzhieva

Sucrose octaacetate (octa-O-acetylsucrose) has been synthesized by esterification of sucrose with acetic anhydride using ultrasound-assisted irradiation. This sucrose ester is a white, water-insoluble substance with a bitter taste. The FT-IR and NMR spectra confirmed acetylation and revealed the hydrophobic incorporation in sucrose molecule. Furthermore , the foamability, foam stability, emulsification and antimicrobial properties of octa-O-acetylsucrose were evaluated. Foams and 50 % (oil/water) model emulsions were prepared with 2 % (w/w) octa-O-acetylsucrose. The obtained results demonstrate the formation of emulsions and foams with high stability (50–70 %). The antimicrobial activity of octa-O-acetylsucrose was evaluated against seventeen microorganisms (Gram-positive and Gram-negative bacteria, yeasts, and fungi). Octa-O-acetylsucrose inhibited the growth of fungi Penicillium sp., Rhizopus sp. and Fusarium moniliforme at 5 mg cm –3 , and yeasts Candida albicans at 1 mg cm –3. Inhibition against Gram-positive and Gram-negative bacteria was not observed. The obtained results demonstrate the potential applications of octa-O-acetylsucrose as a foaming agent, oil-in-water emulsion stabilizer, and antifungal substance in pharmaceutical and cosmetic preparations.

Pharmacologically interesting sucrose undecylenic acid esters were synthesized by transesterification reaction with methyl ester of 10-undecylenic acid under conventional conditions and ultrasonic irradiation. The effect of catalyst (NaOCH3 and K2CO3), molar ratio of reactant and temperature of esterification on the esters yield was studied. The highest yield was obtained in DMSO with 13 mol % K2CO3 as a catalyst, temperature 45°С for 2 h under 45 kHz ultrasonic frequency. The structure of sucrose esters and the stability of terminal double bond in alkyl chain of undecylenoyl sucrose esters was confirmed by IR-FT and 1H NMR spectra.

Сукроестерите представляват нейоногенни повърхностно-активни вещества с важно значение в растителната защитата, медицината, козметиката и хранителната промишленост. Освен регламентираното им приложение като добавки в храните (емулгатори), те се утвърдиха и като вещества с потенциална антимикробната активност. Настоящият преглед има за цел да разгледа новите подходи прилагани при синтеза на естери на захарозата, характеризиращи се с повишена биологична активност. Химичният синтез на сукроестери (каприлати, лаурати, миристати и палмитати) обикновено се осъществява в DMSO чрез преестерификация с винилови или етилови естери на съответните мастни киселини в присъствие на алкални катализатори. В настоящия обзор е направена сравнителна характеристика на новите химични и ензимни методи за естерификация на захароза. Подробно са разгледани ускореният ултразвуков химичен синтез на сукроестери, както и ензимна модификация, осъществена в присъствие на липаза, проведена под микровълново, ултразву...

Pharmacologically interesting sucrose undecylenic acid esters were synthesized by transesterification reaction with methyl ester of 10-undecylenic acid under conventional conditions and ultrasonic irradiation. The effect of catalyst (NaOCH3 and K2CO3), molar ratio of reactant and temperature of esterification on the esters yield was studied. The highest yield was obtained in DMSO with 13 mol % K2CO3 as a catalyst, temperature 45°С for 2 h under 45 kHz ultrasonic frequency. The structure of sucrose esters and the stability of terminal double bond in alkyl chain of undecylenoyl sucrose esters was confirmed by IR-FT and 1H NMR spectra.