Influence of Selected Compositions of Wall Materials and Drying Techniques Used for Encapsulation of Linseed Oil and Its Ethyl Esters

Featured Application An encapsulation strategy with the use of a spray-drying technique and whey protein concentrate with maltodextrin as wall material is recommended to obtain oxidatively stable powders with linseed oil and ethyl esters of this oil. These powders can be easily applied to various food matrices, increasing the share of valuable alpha-linolenic acid.Abstract The aim of the study was to compare the encapsulation of linseed oil and its ethyl esters using two coating materials (maltodextrin with whey protein concentrate (WPC) vs. maltodextrin with gum arabic) and two drying methods (spray-drying vs. freeze-drying) to obtain powders with the highest oxidative stability. A comparison was made based on the properties of emulsions (morphology, particle size distribution, and stability) and powders (morphology, physicochemical properties, fatty acid composition, and oxidative stability). The powder's oxidative stability was determined based on the Rancimat protocol. The most uniform distribution of oil droplets in prepared emulsions was stated for ethyl esters in a mixture of maltodextrin and gum arabic. Emulsions with WPC had a bimodal character, while those with gum arabic had a monomodal character. Gum arabic promoted emulsion stability, while in samples containing WPC, sedimentation and creaming processes were more visible. Powders obtained using spray-drying had a spherical shape, while those obtained by freeze-drying were similar to flakes. Although encapsulation efficiency was the highest for freeze-dried powders made of linseed ethyl esters with gum arabic, the highest oxidative stability was stated for powders made by spray-drying with WPC as wall material (independently of linseed sample form). These powders can be easily applied to various food matrices, increasing the share of valuable alpha-linolenic acid.