Design and manufacturing of Satureja Khouzestanica essential oil emulsions stabilized by modified starch-bacterial cellulose nanofiber gel and investigating its physico-chemical and antimicrobial properties.

Abstract

Results: The chemical, physical and morpholojy characteristics of SNCs showed an increase in crystallinity in SNCs with increasing acidity of the hydrolysis solution. The results of measuring the size of emulsion particles showed reducing the size of starch nanocrystals (SNCs) and increasing the amount of bacterial cellulose nanofiber (B-CNF) gel, led to decretion in the emulsion droplet size and the absolute value of zeta potential increased. Measuring the stability of emulsions during storage and heat treatment confirmed the high stability of the emulsions against environmental changes. The viscosity of the emulsions stabilized with the combination of SNC and B-CNF was higher than the emulsions without B-CNF, and in addition, SNCs with a higher degree of acid hydrolysis led to the production of Pickering emulsions with lower viscosity. The presence and absence of B-CNF did not show any significant change in the antimicrobial activity of emulsions against Staphylococcus aureus and Salmonella enterica in the disc diffusion test; which shows that there is no detrimental effect of adding B-CNF on the antimicrobial activity. However, the highest anti-biofilm activity against the mentioned bacteria was observed in the emulsions stabilized by SNC-0.8 and without the presence of B-CNF. Conclusion: The degree of acid hydrolysis of starch nanocrystals and the presence or absence of bacterial cellulose nanofiber gel was clearly evident in terms of physical stability, viscosity, and antimicrobial and antioxidant activity, which indicates the high potential of these compounds for use in the formulation of various emulsions in food and pharmaceutical systems.

Keywords: Octinyl succinic anhydride starch, Nanocrystal, Emulsion, Stability, Bacterial cellulose nanofiber