The effect of degree of substitution (DS), concentration, and freeze-thaw on the emulsifying properties of inulin and octenyl succnic anhydride modified inulin (OSA-In) were studied. Furthermore, the inhibitory effects of OSA on the growth of hyphae, spore germination, and germ tube elongation of Penicillium expansum, Aspergillus niger, and Rhizopus nigricans were investigated. The results showed that OSA-In improved emulsifying properties compared to inulin, and its emulsifying ability increased with the increasing concentrations of DS. OSA-In (DS = 3.17 × 10-2) at a concentration of 2.5% exhibited good emulsification and freeze-thaw stability. The minimum inhibitory concentrations (MIC) of OSA-In were one, four, and two percent (m/V) for Penicillium expansum, Aspergillus niger, and Rhizopus nigricans, respectively. OSA-In inhibited the hyphal growth, spore germination, and germ-tube elongation of Penicillium expansum, Aspergillus niger, and Rhizopus nigricans in a dose-dependent manner. At sub-MIC levels of OSA-In, the inhibitory effect was highest on Penicillium expansum followed by Aspergillus niger and Rhizopus nigricans.
