Physicochemical Properties and Antimicrobial Activity of Acetylated Chicory Fructooligosaccharides

Abstract

Inulin acetates attract attention as the novel drug carrier. However, the acetylated derivаties of fructooligosaccharides (FOSs) (a low molecular fraction of inulin) were not evaluated. The study aimed to obtain FOSs acetyl esters and to evaluate their foaming properties, water- and oilholding capacities (WHC and OHC), as well as their antimicrobial activity. One-pot acetylation of chicory FOS with two different degrees of polymerization (DP = 7–9 and 9–12) was performed. The resulting FOSs esters presented white, bitter, water-insoluble substances. The spectroscopic techniques as ultraviolet (UV), Fourier-transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopy were used for characterization and structural elucidation. The antimicrobial activity of acetylated FOSs (1 mg/mL) was tested against 16 microorganisms (Gram-positive and negative bacteria, yeasts, and fungi). Foams prepared with 0.2% FOSs acetates demonstrated the formation of highly stable foams (50–70%). FOSs acetates showed antifungal activity against Fusarium oxysporum and Aspergillus niger and inhibited the growth of yeasts Candida albicans 8673. The inhibition against Gram-positive (Bacillus subtilis 46/H1 and Bacillus subtilis ATCC 6633) and negative (Salmonella abony and Escherichia coli ATCC 8739) bacteria were not observed. However, FOSs acetate with DP 7–9 were active against E. coli 3398, Salmonella typhy 745, and Staphylococus aureus 745 against – which other acetates with DP = 9–12 were inactive. These results demonstrate the potential applications of FOS acetates as a foaming agent and an antifungal substance in pharmaceutical and cosmetic preparations.