ABSTRACT
In this study, the effect of chitosan-vanillin Schiff base emulsions (CSVAEs) on dough and bread characteristics was investigated. The results revealed that CSVAEs were embedded in the gluten and that the viscoelasticity and mechanical strength of the dough gradually increased with increasing CSVAEs concentration, α-helical and ß-fold content, and elastic structure in the dough increased with the same patterns. The basic properties of bread were measured, and it was found that low concentrations of CSVAEs were effective in improving the quality of bread and slowing the staling rate. As the storage time increased, CSVAEs had less effect on the rate of moisture loss, hardness and springiness of the bread and more effect on the inhibition of the acidity of the bread. The addition of CSVAEs slowed the increase in bacteria and molds and extended the shelf life of the bread.
ABSTRACT
In the current work, vanillin-conjugated chitosan stabilized emulsions (CSVAEs) were successfully prepared and its characterization and antibacterial properties were investigated. Under stirring condition, CSVAEs were produced by a Schiff base reaction between the vanillin aldehyde group and the chitosan active amino group. The CSVAEs were described through Fourier transform infrared spectroscopy, X-ray diffraction, ultraviolet spectrophotometry and thermogravimetric analysis, which demonstrated the generation of Schiff bases between vanillin and chitosan. Furthermore, the CSVAEs displayed differences at different pH values, indicating their potential as pH-responsive materials. By studying their release behavior, pH 4 was a critical point at which the properties of the CSVAEs changed. The antibacterial tests showed that the CSVAEs had good pH-responsive antibacterial abilities against Staphylococcus aureus and Escherichia coli.
ABSTRACT
In this paper, chitosan/ethyl-vanillin (CS-EV) Schiff-base edible films with CS and EV at different concentrations and ratios were successfully prepared. The optical barrier properties, water contact angle, mechanical performance, water vapor transmission, antioxidant properties, thermal properties, and morphological structure of the films were compared. The results suggested that the tensile strength (TS) attained a maximum value of 64.63 MPa at a concentration of 4% EV. Moreover, water diffusion was prevented through the compact structure of the CS-EV edible film. Additionally, the two sides of the CS-EV film show different textures due to their different hydrophilicity/hydrophobicity. In particular, the films of CS possessed superior thermal stability, while those of CS-EV exhibited higher antioxidant activity.
