Encapsulation of N -acetylcysteine (NAC) using protein-polysaccharide combinations through spray drying and air drying

Although N -acetylcysteine (NAC) has shown significant medical and antioxidant activities, its strong sour taste and sulfur odor limits its use in food. Here we spray dried and air dried a mixture of proteins and polysaccharides that served as matrix materials to entangle NAC and delay its release in water. Proteins including egg white, gelatin, whey protein isolate, and casein, were combined with polysaccharides such as hydroxypropyl methylcellulose, and carboxymethyl cellulose and electrostatic interactions with NAC were formed. The resulting solutions were then air or spray dried. The powders were analyzed by SEM, FTIR, LC-MS, NMR, and conductometry. The resulting powders exhibited slower release in water, particularly when polysaccharides were incorporated with proteins as matrix materials. SEM results showed the spray-dried samples displayed spherical and concaved structures with particle sizes ranging from 2 to 10 μm. While in the air-dried samples, NAC crystals were observed on the surface. Conductometry revealed that gelatin, with different bloom strengths exhibited different patterns in their NAC release profiles upon spray drying. In comparison to the spray-dried samples, samples obtained from air drying showed a faster NAC release in water.