Microencapsulation of red palm oil with soy protein concentrate–carrageenan conjugates for compound dark chocolate applications

Abstract

Red palm oil (RPO) is a rich source of carotenoids but is susceptible to degradation and possesses a distinct palm-like odor and taste that may affect the sensory quality of food products. Microencapsulation is considered a potential approach to address these challenges. This study aimed to minimize the aftertaste of RPO through the characterization and formulation of the microencapsulation process. Soy Protein Concentrate (SPC) and carrageenan (CG) were conjugated at various ratios, with the optimal ratio being 3 : 1, which demonstrated improved emulsifying properties, a higher degree of glycation (DG), and greater formation of Maillard reaction products. The resulting microcapsules exhibited a high encapsulation efficiency of up to 82.27% at an oil-to-wall material ratio of 1 : 3, along with good color retention and in situ absorption, as indicated by 82% carotenoid absorption in an in situ intestinal study. The addition of RPO microcapsules to dark chocolate bars did not affect the texture, melting point, morphology, and sensory attributes. However, it had a significant effect (p < 0.05) on color and rheology parameters. Overall, the encapsulation of RPO using the SPC–CG conjugate as the wall material effectively masked the inherent palm-like taste and odor of the oil when incorporated into the chocolate product, making them undetectable to panelists. These findings support the application of protein–polysaccharide conjugates as a wall material for encapsulating bioactive compounds in functional food products.