Preparation And Emulsifying Properties Of Nano Crystalline Cellulose (NCC)

Nano microcrystalline cellulose (NCC) is one unique biological nanoparticle for the Pickering emulsions. Due to its good characteristics, such as excellent physicochemical properties, biocompatibility, and low cost, NCC has potential applications in food processing, drug delivery and other industrial fields.In this study,5 kinds of NCC were prepared from cotton linter derived MCC by sulfuric acid hydrolysis in terms of various time (1.5 h,2.0 h,2.5 h,3.0 h,3.5 h). The properties of the NCCs were chracteristized by Scanning electron microscopy (SEM), atomic force microscope (AFM), the nano particle size analyzer, Zeta potential, X-ray (XRD), Fourier transform infrared (FTIR), viscosity, and thermal gravimetric analysis (TGA). The results showed that with the increase of acid hydrolysis time, the negative charge of NCC increased, particle size decreased, and the length of NCC shorted to about 200 nm. As expected, the degree of crystallinity of NCC increased about 10% with increase of hydrolysis time, but showed a decrease tendency at the late stage (3 h and longer). In the hydrolysis, no new functional groups appeared and hydroxyl increased significantly. In addition, thermal stability of NCC was decreased compared with MCC.The Pickering emulsifying properties of NCCs were studied with the NCC:palm oil (70:30, v:v) emulsion as modle. NCC interfacial film was formed on the outside of the oil droplets to form a stable oil-in-water Pickering emulsion, suggesting a successful emulsion. With the increase of acid hydrolysis time until 3.0 h, emulsion stability was enhanced, however, hydrolysis with over 3 h casued a decrease of emulsion stability. The results indicated that emulsifying properties of NCC are closely related with its characteristics (particle size, crystallinity, surface charge, etc.). Furthermore, the effects of various external factors, such as concentration, pH, sodium chloride, casein, on emsulion stability were studied. The results showed that the content of NCC and sodium chloride benifited the emulsifying effect, pH off neutral improved the emulsifying stability with a worst one at 6, and low casein concentration decreased the stability of the emulsion, but higher casein made the stability improved.The NCC (3.0 h) Pickering emulsion was selected to investigate fat digestion experiments in vitro. The results showed that a complicated cooperation occurred bwteen NCC lipase and ions benenfited the adsortipon of lipase to the interface film formed by NCC, and increase of the contact area with the fat, contributing acceleration of lipolysis. That is to say, the better the stability of the emulsion was, the faster fat digestion was.All in all, NCC prepared by CL-MCC, showed excellent emulsion stability and beneficts to digestion and absorption of fat, suggesting potential applications in the food industry.