Comparative Evaluation of Whey Protein Concentrate-based Microencapsulation of Flaxseed Oil as a Source of Omega-3 Fatty Acids: Characterization and Morphological Analysis

Abstract

The microencapsulation of flaxseed oil, a rich plant-based source of omega-3 polyunsaturated fatty acids, particularly α-linolenic acid, was comparatively evaluated using spray-drying technology. Three fixed food-grade wall-material systems were formulated and analysed: whey protein concentrate with lactose (FO/WPC/L), maltodextrin with lactose (FO/MD/L), and gelatin with lactose (FO/Gelatin/L). Oil-in-water emulsions were homogenised at a high pressure of 241.31 bar and subsequently spray-dried using an inlet temperature of 182 °C and an outlet temperature of 75 °C. The morphological characteristics of the resulting microcapsules were assessed using scanning electron microscopy (SEM). The FO/WPC/L microcapsules showed superior structural integrity, with smooth, intact and spherical external surfaces without visible cracks or fissures. Internally, the FO/WPC/L formulation presented a dense and homogeneous structure, indicating effective oil entrapment and favourable barrier properties against oxidative degradation. Conversely, the FO/MD/L and FO/Gelatin/L formulations displayed irregular external surfaces, highly porous internal matrices and evidence of structural collapse, reflecting lower encapsulation performance. The structural features of the FO/WPC/L microcapsules may be attributed to the amphiphilic nature of whey proteins and Maillard-mediated protein–carbohydrate interactions between WPC and lactose, which collectively enhance interfacial film strength and restrict oxygen permeability. Based on these morphological findings, the FO/WPC/L formulation was identified as the most suitable matrix for the microencapsulation of flaxseed oil. This study provides visual and structural evidence supporting WPC-based microcapsules as a delivery system for incorporating omega-3 fatty acids into functional foods, including value-added poultry and meat products.