Comparative study of sodium nitrite loaded gelatin microspheres and gelatin gels: Physicochemical and antibacterial properties

In this study, under the action of microbial transglutaminase (mTGase), sodium nitrite (NaNO2) loaded type-A gelatin microspheres (NaNO2-GAMs) were prepared by water-in-oil (W/O) emulsification cross-linking method, and NaNO2 loaded type-A gelatin gels (NaNO2-GAGs) were prepared by cross-linking freeze-drying method. The physicochemical properties and antibacterial effect of NaNO2-GAMs and NaNO2-GAGs were compared. Both scanning electron microscope and fourier transform infrared spectroscopy revealed that NaNO2 was successfully encapsulated in the microspheres and gels. The NO release and encapsulation efficiency of NaNO2 increased with mTGase ranging from 0 to 30 U/g. Rheological analysis confirmed that mTGase increased the viscosity of NaNO2-GAMs and NaNO2-GAGs. In addition, NaNO2-GAMs and NaNO2-GAGs were applied to actual environment (as in low-temperature sausages), and the antibacterial effect was judged according to the number of microbial colonies. In summary, the NaNO2-GAMs showed better antibacterial effect than NaNO2- GAGs, achieving the effect of extending the shelf life of meat products.