Carboxymethylpachymaran/alginate gel entrapping of natural pollen capsules for the encapsulation, protection and delivery of probiotics with enhanced viability

There are multiple obstacles for the storage and digestion of probiotic products because of their poor viability. This study developed a new core-shell structure (sporopollenin exine capsules (SECs) as the core and Ca-alginate (Alg)/carboxymethylpachymaran (CMP) gel as the shell) for the protection of probiotics, which could not only enhance the storage and lyophilization stability of probiotics, but also achieve sustained release in the gastrointestinal tract. By using (L. plantarum) as the model probiotic, the loading process (SECs-encapsulated L. plantarum, SL) was optimized with the maximum probiotic loading capacity reaching 1.17 × 1010 CFU/g. In the Ca-Alg/CMP shell, the introduction of CMP could improve the thermal stability of the shell. Also, the CMP content could affect the swelling behavior and microstructure of the shell by influencing the hydrogen bonds between CMP and Alg, and thus could regulate the release behavior of probiotics. Compared with Ca-Alg coated SL gel (ASG), the Ca-Alg/CMP coated SL gel (ACSG) showed superior properties in terms of sustainable release and lyophilization stability: the number of viable cells exceeded 107 CFU/mL and was about 1.68 × 107 CFU/mL and 1.44 × 107 CFU/mL before and after lyophilization, respectively. Besides, ACSG (1.44 × 107 CFU/mL for day 0 and 2.09 × 106 CFU/mL for day 90 at 4 °C) showed an obvious advantage over ASG (2.01 × 105 CFU/mL for day 0 and 5.66 × 102 CFU/mL for day 90 at 4 °C) in achieving high storage stability. Overall, this core-shell structure may be utilized in the food industry for better protection and delivery of probiotics.