Supercritical CO2 interpolymer complex encapsulation improves heat stability of probiotic bifidobacteria

Abstract

The probiotic industry faces the challenge of retention of probiotic culture viability as numbers of these cells within their products inevitably decrease over time. In order to retain probiotic viability levels above the therapeutic minimum over the duration of the product's shelf life, various methods have been employed, among which encapsulation has received much interest. In line with exploitation of encapsulation for protection of probiotics against adverse conditions, we have previously encapsulated bifidobacteria in poly-(vinylpyrrolidone)-poly-(vinylacetate-cocrotonic acid) (PVP:PVAc-CA) interpolymer complex microparticles under supercritical conditions. The microparticles produced had suitable characteristics for food applications and also protected the bacteria in simulated gastrointestinal fluids. The current study reports on accelerated shelf life studies of PVP:PVAc-CA encapsulated Bifidobacterium lactis Bb12 and Bifidobacterium longum Bb46. Samples were stored as free powders in glass vials at 30 °C for 12 weeks and then analysed for viable counts and water activity levels weekly or fortnightly. lactis Bb12, respectively, thereby extending their shelf lives under high storage temperature by between 4-7 weeks. These results reveal the possibility for manufacture of encapsulated probiotic powders with increased stability at ambient temperatures. This would potentially allow the supply of a stable probiotic formulation to impoverished communities without proper storage facilities recommended for most of the currently available commercial probiotic products.

Probiotics in Food Systems: Significance and Emerging Strategies Towards Improved Viability and Delivery of Enhanced Beneficial Value

“…Encapsulation of bifidobacteria in poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid) (PVP:PVAc-CA) interpolymer complex microparticles under supercritical conditions was applied by Thantsha, et al [165]. They reported that the produced microparticles had suitable characteristics for food applications and protected the bacteria in simulated gastrointestinal fluids as well as improved the shelf life for 12 weeks at 30 °C [165]. The strain B. adolescentis (ATCC 15703) was entrapped within microcapsules prepared using 10.00% ( w / w ) chickpea protein isolates cross-linked with 0.20% ( w / v ) of genipin, or in the presence of 0.20% ( w / v ) alginate or k-carrageenan.…”

Drying of probiotics to enhance the viability during preparation, storage, food application, and digestion: A review

“…For example, Thantsha et al. (2014) used polyvinylpyrrolidone and vinylacetate‐ co ‐crotonic acid, both of which can be plasticized in supercritical CO 2 to form an interpolymer complex though hydrogen bonding, to encapsulate B. lactis Bb12 and B. longum Bb46. The prepared probiotic powders with a w of 0.25–0.43 showed more than 6 log CFU/g viability after 12‐week storage at 30°C.…”

“…Supercritical technology is another novel method to prepare probiotic powders by immobilizing probiotics in interpolymer complexes formed in supercritical CO 2 as the solvent, and the subsequent depressurization removes CO 2 to form dry microcapsules (Liu et al, 2019). For example, Thantsha et al (2014) used polyvinylpyrrolidone and vinylacetateco-crotonic acid, both of which can be plasticized in supercritical CO 2 to form an interpolymer complex though hydrogen bonding, to encapsulate B. lactis Bb12 and B. longum Bb46. The prepared probiotic powders with a w of 0.25-0.43 showed more than 6 log CFU/g viability after 12-week storage at 30 • C. However, electrospinning, electrospray-assisted drying, and supercritical technology may not meet the production scale required for food manufacturing.…”

Commensal Obligate Anaerobic Bacteria and Health: Production, Storage, and Delivery Strategies

“…They showed that co-encapsulation of prebiotic resistant starch corns had a negative influence on the physical barrier of the protein matrix, leading to a decrease of the protective effect of the probiotic (Heidebach et al, 2010). Thantsha et al (2014) used poly-(vinylpyrrolidone)-poly-(vinyl acetate-co-crotonic acid) for encapsulation of B. lactis Bb12 and B. longum Bb46 under supercritical conditions. They described that microparticles were able to protect the bacteria in simulated gastrointestinal fluids as well as to improve the lifetime of storage for 12 weeks at 30 • C. Wang et al (2014) reported on the entrapment of B. adolescentis ATCC 15703 preparing microcapsules using 10% of chickpea protein isolates crosslinked with 0.20% of genipin, or in the presence of 0.10% of alginate.…”