Spray-Dried Whey Protein Microcapsules for the Stabilization of Mexican Firecracker (Hamelia patens)-Derived Phytochemicals: Antioxidant and Antimicrobial Efficacy

This study evaluated spray-dried microcapsules as a strategy for preserving the antioxidant and antimicrobial activities of purified phytochemicals from Hamelia patens. Maltodextrin, whey protein, and pectin were screened as wall materials, and whey protein produced the highest encapsulation efficiency (96.33%). A 32 full factorial design was then used to evaluate the effects of the amounts of phytochemicals (1.0–3.0 mg) and whey protein (0.5–1.5 g). The formulation containing 1.0 mg of phytochemicals and 0.5 g of whey protein achieved the highest efficiency (92.30 ± 0.53%). Scanning electron microscopy showed aggregated, irregular-to-quasi-spherical particles with apparent micrometric dimensions. During four weeks of storage, the microcapsules retained activity against lipid peroxidation and maintained reducing capacity, although DPPH radical inhibition and total polyphenol content decreased. Antimicrobial activity was detected from weeks 7 to 10 against Escherichia coli β (−), Enterococcus faecalis, and Klebsiella pneumoniae at microcapsule concentrations of 12,500–25,000 µg/mL. Overall, whey protein was an effective wall material for retaining H. patens phytochemicals, although the assay-dependent changes observed during storage indicate that further studies of release behavior and application-specific stability are required.