Ambient storage of microencapsulated Lactobacillus plantarum ST-III by complex coacervation of type-A gelatin and gum arabic

Abstract

Ambient storage of dry powdered probiotics is necessary for manufacturer's cost reduction and customer's convenience. Complex coacervation is a promising microencapsulation technique. In this work, a probiotic matrix of type-A gelatin/gum arabic/sucrose (GE/GA/S) with high coacervation pH was designed, based on the alkaline isoelectric point of type-A gelatin. Bacterial survival during ambient storage at room temperature and certain relative humidity were detected. To clarify the protection factors of the coacervation matrix of GE/GA/S, dry microcapsules of GA, GE, GE/sucrose and GE/GA were prepared as controls and compared in terms of their morphology, moisture content, dynamic vapor absorption and cell viability. Probiotics in GE/GA/S microcapsules behaved the best during spray drying, ambient storage and heat treatment. The results proved that sucrose addition was necessary for cell viability against environmental stresses, and that encapsulation by complex coacervation was a positive factor in cell protection, especially at neutral coacervation pH.

Progress in microencapsulation of probiotics: A review

“…Microgels can be fabricated from a combination of biopolymers using complex coacervation, which involves mixing a negatively charged biopolymer with a positively charged one (Saravanan, and Panduranga, ). Complex coacervation has been reported to be advantageous in terms of high cell‐entrapment efficiency, enhanced functional performance, and good suitability for scaling up (De Prisco & Mauriello, ; Zhao et al., ). Moreover, complex coacervates can be designed to promote the complete release of encapsulated probiotics from biopolymer microgels (Bosnea et al., ).…”

“…Moreover, complex coacervates can be designed to promote the complete release of encapsulated probiotics from biopolymer microgels (Bosnea et al., ). Recent studies have reported that different biopolymer combinations can be used to successfully assemble complex coacervates suitable for probiotic delivery: whey protein isolate/gum arabic (WPI/GA) (Eratte et al., ), WPI/κ‐carrageenan (Hernandez‐Rodriguez, Lobato‐Calleros, Pimentel‐Gonzalez, & Vernon‐Carter, ), WPI/GA/alginate (Bosnea, Moschakis, Nigam, & Biliaderis, ), gelatin/GA (da Silva et al., ; Zhao et al., ), gelatin/alginate (Yao et al., ), and starch/alginate (Pankasemsuk et al., ). For instance, encapsulation of probiotics in alginate‐gelatin microgels formed through electrostatic complexation has been shown to improve the viability of L. salivarus Li01 after high temperature treatments, long‐term storage, and gastrointestinal passage (Yao et al., ).…”

“…Cellular accumulation of toxic oxygen metabolites eventually leads to cell death, which is referred to as oxygen toxicity (Talwalkar & Kailasapathy, ). Humidity and moisture are a huge problem for probiotic products, as moisture activates the bacteria and essentially starts the process of degradation, since the activation is intended to occur after ingestion (Kailasapathy & Chin, ; Zhao et al., ). The microorganisms in the human gut have evolved to survive primarily at human body temperature, and so they may be killed when exposed to the elevated temperatures associated with many food processing operations such as pasteurization, sterilization, dehydration, or cooking (Anal & Singh, ).…”

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release

“…5,6 Second, ambient storage of probiotics becomes more and more important due to the consumer needs for ambient probiotic foods, but the probiotic survival during ambient storage is poor. 7,8 One of the challenges of dry probiotic preparations is the moisture sorption during ambient storage, which decreases the glass transition temperature and leads to a significant acceleration of the inactivation of probiotic bacteria. [9][10][11] Therefore, in order to solve the above two challenges of the dry probiotic cells, it is necessary to design probiotic microcapsules to simultaneously improve probiotic survivals in simulated digestive juices and during ambient storage.…”

“…WPI and sucrose could provide good probiotic protection during drying and ambient storage. 7,[23][24][25] Alginate was the main gelling matrix with calcium ion during microcapsule preparation. The method of external emulsification was employed to prepare microcapsules, which is beneficial to obtain small microcapsules.…”