Studies on N-methylene phosphonic chitosan

N-methylene phosphonic (NMPC) chitosan was studied by several techniques to determine their properties in aqueous solution and its capacity to emulsify edible oils. The phosphonic groups are all equivalent and their ionization constants were estimated (pKa1=6.45 and pKa2=11.75). The chitosan derivative in pure water starts to aggregate at 0.09% w/v, and the aggregates’ structure at 0.5% w/v. Unlike pure chitosan, NMPC chitosan is strongly surface active. Its hydrophile-lipophile balance (HLB) value was estimated in 37, very similar to that of chitosan. As a consequence, it favors the formation of oil in water (o/w) emulsions with scarce water/oil/water (w/o/w) droplets.