Highly Stable Pickering Emulsions with Xylan Hydrate Nanocrystals

Abstract

Xylan is a highly abundant plant-based biopolymer. Original xylans in plants are in an amorphous state, but deacetylated and low-branched xylan can form a crystalline structure with water molecules. The utilizations of xylan have been limited to bulk applications either with inconsistency and uncertainty or with extensive chemical derivatization due to the insufficient studies on its crystallization. The applications of xylan could be greatly broadened in advanced green materials if xylan crystals are effectively utilized. In this paper, we show a completely green production of nano-sized xylan crystals and propose their application in forming Pickering emulsions. The branches of xylan were regulated during the separation step to controllably induce the formation of xylan hydrate crystals. Xylan hydrate nanocrystals (XNCs) with a uniform size were successfully produced solely by a mild ultrasonic treatment. XNCs can be adsorbed onto oil–water interfaces at a high density to form highly stable Pickering emulsions. The emulsifying properties of XNCs were comparable to some synthetic emulsifiers and better than some other common biopolymer nanocrystals, demonstrating that XNCs have great potential in industrial emulsification.

Potential of Wood Hemicelluloses and Their Derivates as Food Ingredients

“…138,139 It is possible to prepare nanocrystals with xylan extracted from birchwood kraft pulp 140 as well as nanoparticles from xylan and xylan derivates. 141−143 Xylan nanocrystals from sugar cane bagasse have been successfully utilized as Pickering emulsifiers, 144 which might indicate that wood-derived xylan nanocrystals have the potential to be used similarly. Additionally, insoluble clusters of alkaliextracted xylans from birch and beech also demonstrated efficient stabilization properties.…”

“…The particles are considered to be adsorbed irreversibly at the oil–water interface due to the high free energy barrier associated with their desorption . There have been many explorations into the use of polysaccharide-based solid particles as Pickering emulsifiers. , It is possible to prepare nanocrystals with xylan extracted from birchwood kraft pulp as well as nanoparticles from xylan and xylan derivates. − Xylan nanocrystals from sugar cane bagasse have been successfully utilized as Pickering emulsifiers, which might indicate that wood-derived xylan nanocrystals have the potential to be used similarly. Additionally, insoluble clusters of alkali-extracted xylans from birch and beech also demonstrated efficient stabilization properties .…”

Pickering emulsion: From controllable fabrication to biomedical application

“…51 The homogenization process was easy and rapid. 52 However, during the preparation process of Pickering emulsions, there are the risks of particle deformation or disruption similar to rotor-stator homogenization and high-pressure homogenization. Also, the obtained Pickering emulsion exhibited a broad size distribution.…”

Enzymatic Synthesis of Xylan Microparticles with Tunable Morphologies

“…Enzymatic removal of xylan side chains has been shown to influence the crystallinity of xylan aggregates, suggesting a negative correlation between the degree of substitution and crystallinity. , In addition, recent work using glycosynthases, glycoside hydrolases modified to function as transferases, demonstrated that long xylan chains can be generated by stitching together chemically synthesized xylan oligosaccharide fluorides of defined structures by repetitive condensation. , Glycosynthase-formed xylans can assemble into crystalline aggregates where the degree of crystallinity was found to be dependent not just on side-chain abundance but also on the linkage and structural features of side-chain groups decorating the polymers . Further, studies have investigated the formation of xylan hydrate nanocrystals from the mild ultrasonic treatment of aqueous xylan suspensions . However, the mechanisms that might govern the processes of xylan aggregation have remained largely unexplored.…”

“…14 Further, studies have investigated the formation of xylan hydrate nanocrystals from the mild ultrasonic treatment of aqueous xylan suspensions. 22 However, the mechanisms that might govern the processes of xylan aggregation have remained largely unexplored.…”