Fabrication of buckwheat-shellac complex by pH-driven enhances the viability of Lactiplantibacillus plantarum during simulated gastrointestinal and storage conditions

Abstract

The acid sensitivity and moisture absorption of dry probiotic products during digestion and storage are challenges. In this study, different mass ratios (1, 1.5, 2, 2.5, 5) of buckwheat protein (BWP) and hydrophobic polyester shellac were firstly combined by a pH-shifting method and then applied for the construction of Lactobacillus plantarum (L. plantarum) microcapsules. Circular dichroism (CD) and fluorescence spectroscopy results revealed that the complexes were stabilized primarily by hydrophobic interaction forces and the conformational changes after co-folding with shellac. With a decreasing ratio of shellac, the enthalpy (ΔH) and peak temperature increased, resulting in enhanced thermal stability. BS2 encapsulated probiotics successfully enhances the survival of L. plantarum during freeze-drying and gastrointestinal (GI) digestion. The probiotic was fully coated by the complex, determined through scanning electron microscopy (SEM) images. After encapsulated, the colon adhesion efficiency enhanced 30.92% than free cells. The encapsulated probiotics presented a maximum reduction of 0.89 log CFU/mL after 30 days of storage at 25 °C, and probiotics protected by the BS1 complex had superior storage stability under an Aw of 0.76, for which K value was 1.218. BWP-based shellac pH-shift complexes exhibit enormous potential for the encapsulation of probiotics.