Effect of production parameters and stress conditions on beta-carotene-loaded lipid particles produced with palm stearin and whey protein isolate

Abstract Microencapsulation is currently used by the food industry for different purposes, including the protection of ingredients against factors such as oxidation and volatilization, as well as to increase the bioavailability and bioaccessibility of nutrients. The current study aimed to encapsulate beta-carotene in solid lipid microparticles stabilized with whey protein isolate (WPI), and also investigate their integrity during storage and under stress conditions such as different ionic strengths, sucrose concentrations and thermal treatments. Solid lipid microparticles were produced using palm stearin, a food grade vegetable fat, using a single-step high shear process. Of the different formulations used for lipid microparticle production, characterization studies showed that the greatest stability was obtained with systems produced using 1.25% (w/v) whey protein isolate, 5% (w/v) palm stearin and 0.2% (w/v) xanthan gum. This formulation was applied for the production of beta-carotene-loaded solid lipid microparticles, with different concentrations of alpha-tocopherol, in order to verify its possible antioxidant activity. The results showed that the addition of alpha-tocopherol to the dispersions provided an increase in encapsulation efficiency after 40 days of storage that ranged from 29.4% to 30.8% when compared to the system without it. Furthermore, the solid lipid microparticles remained stable even when submitted to high ionic strength and to heating in the proposed temperature range (40 °C to 80 °C), highlighting their feasible application under typical food processing conditions. (AU)