Electrospray whey protein-polysaccharide microcapsules co-encapsulating Lactiplantibacillus plantarum and EGCG: Enhanced probiotic viability and antioxidant activity

Probiotics are often subjected to adverse factors during processing, storage and digestion. To enhance the viability and function of probiotics, whey protein concentrate (WPC)-based microcapsules were systematically fabricated to co-encapsulate probiotic Lactiplantibacillus plantarum KLDS 1.0328 (LP KLDS 1.0328) and epigallocatechin gallate (EGCG) by electrospray. Scanning electron microscopy showed that spherical and smooth particles were developed. Attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray diffraction suggested that probiotics and EGCG were successfully encapsulated in WPC-based microcapsules. Thermogravimetric analysis revealed that the addition of EGCG and probiotics improved the thermal stability of WPC-based microcapsules. Furthermore, the incorporation of polysaccharides and polyphenol significantly enhanced the antioxidant activity of the microcapsules (P < 0.05). The viability of probiotics encapsulated in WPC/polysaccharides microcapsules was elevated compared with that of encapsulated in WPC microcapsules under simulated gastrointestinal digestion, thermal treatments and NaCl stresses. Notably, WPC/beta-CD/EGCG/LP KLDS 1.0328 exhibited better protection against these environmental stresses. Moreover, the incorporation of polysaccharides could maintain viability over 7.50 lg CFU/g after 28 d of storage. Furthermore, WPC/beta-CD/LP KLD 1.0328/EGCG microcapsules exhibited the highest scores by the results of principal component analysis. This study provides valuable insights for protecting probiotics with appropriate polysaccharide-protein composites and developing functional foods with probiotics.