Preparation of cellulose nanocrystals from asparagus (Asparagus officinalis L.) and their applications to palm oil/water Pickering emulsion

• Cellulose nanocrystals (CNC) were prepared from stem of Asparagus officinalis L. using the sulfuric acid hydrolysis method.
• The prepared CNC were used to form food grade oil/water Pickering emulsions.
• The Asparagus derived CNC can provide a potential material as a new green emulsifier in food applications.

Nano cellulosic materials as promising emulsion stabilizers have attracted great interest in food industry. In this paper, five different sized cellulose nanocrystals (CNC) samples were prepared from stem of Asparagus officinalis L. using the same sulfuric acid hydrolysis conditions but different times (1.5, 2, 2.5, 3.0, and 3.5 h). The sizes of these CNC ranged from 178.2 to 261.8 nm, with their crystallinity of 72.4–77.2%. The CNC aqueous dispersions showed a typical shear thinning behavior. In a palm oil/water (30/70, v/v) model solution, stable Pickering emulsions were formed with the addition of CNC, and their sizes are in the range of 1–10 μm based on the optical and confocal laser scanning microscopy (CLSM) observation. The CNC sample prepared at 3 h hydrolysis time, showed a relative efficient emulsion capacity for palm oil droplets, among these CNCs. Other parameters including the CNC, salt, and casein concentrations on the emulsion stability were studied.