Encapsulation of Capsaicin in Whey Protein and OSA-Modified Starch Using Spray-Drying: Physicochemical Properties and Its Stability

The poor water-solubility and stability of capsaicin limits its widespread application in the industry. Spray-dried capsaicin microcapsules were fabricated using whey protein (WP) and octenyl-succinic-anhydride-modified starch (OS) as wall materials in this study. The aim is to investigate the impact of protein/starch ratio on microcapsules’ physicochemical characteristics and stability. SEM images showed that microcapsule granules were uneven in size, and irregular, with some wrinkles and dents. FTIR illustrated a chemical interaction between capsaicin and composite wall materials. XRD showed that the spray-dried powders were mainly in amorphous form. As the whey protein content decreased, the yield (9.32–68.18%), encapsulation efficiency (49.91–94.57%), wettability (158.87–232.63 s), and solubility (74.99–96.57%) of samples decreased, but the mean particle size (3.22–26.03 μm), apparent viscosity, and shear stress tended to increase. Besides, DSC revealed that the glass transition temperatures (Tg) of samples were at around 85 °C. Capsaicin microcapsules with WP:OS at the ratio of 7:3 possessed the highest Tg, and the best storage stability. Based on our research, microencapsulation significantly improved the stability and the water-solubility of capsaicin. A small amount of OSA-starch mixed with whey protein as a promising carrier for capsaicin would greatly promote the application of capsaicin in the food industry.