Location: Dairy and Functional Foods ResearchTitle: Encapsulation of Lactobacillus Rhamnosus GG in Edible Electrospun mats from Calcium and Sodium Caseinates with Pullulan Blends
Submitted to: Journal of Dairy Science Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2022
Publication Date: 10/21/2022
Citation: Akkurt, S., Renye Jr, J.A., Tomasula, M.M. 2022. Encapsulation of Lactobacillus Rhamnosus GG in Edible Electrospun mats from Calcium and Sodium Caseinates with Pullulan Blends. Journal of Dairy Science Communications. https://doi.org/10.3168/jdsc.2021-0173.
Interpretive Summary: Casein, the major protein found in milk, has been shown to make nanofibrous mats that may be used to develop new food products and edible packaging that augment the nutrition of food. However, the ability to encapsulate and maintain the bioactivity of sensitive components in the mats such as probiotic bacteria during processing has not been established. In this study, the electrospinning process, which was used to draw nanofibers from a casein-based solution and form them into a fibrous mat, was used to determine the fate of over a billion cells per milliliter of Lactobacillus rhamnosus GG (LGG), when added to the solution before processing. The LGG in the electrospun mats maintained activity after processing showing the potential of this encapsulation process for protecting sensitive components.
Technical Abstract: Electrospinning has been proposed as a method to encapsulate and preserve bioactive compounds in nanofibrous mats to ensure their delivery and associated health benefits when consumed directly or added to a food formulation. In previous work, we demonstrated the production of edible fibers to form mats of both calcium (CaCAS) and sodium (NaCAS) caseinate-pullulan (PUL), with the polysaccharide, PUL, added as a carrier to facilitate molecular entanglement for fiber formation. In this study, we determined the viability of the probiotic bacteria, Lactobacillus rhamnosus GG (LGG), used as a model bacterium, in mats of CaCAS-PUL and NaCAS-PUL. Electrospinning of aqueous solutions at 20C of 15% (wt/wt) CaCAS and NaCAS mixed with 15% (wt/wt) PUL, with a 1:1 ratio of CAS:PUL, resulted in fibrous mats with average fiber diameter sizes of 233±20 and 244±21 nm, respectively, as determined by SEM. Addition of LGG in the amounts of 9.3 log10 and 9.0 log10 cfu/g to the CaCAS-PUL and NaCAS-PUL solutions prior to electrospinning, resulted in average fiber diameter sizes of 202±10 and 292±16 nm, respectively. LGG was found distributed within the CaCAS- and NaCAS-PUL fibers. The addition of LGG increased the shear viscosity and the conductivity of the CaCAS-PUL solution enhancing molecular entanglement, and resulting in thinner fibers. For NaCAS, LGG increased the conductivity but reduced shear viscosity. Adjustment of the NaCAS-PUL composition would be needed to optimize conditions for thinner fibers. The numbers of viable LGG recovered from the CaCAS- and NaCAS-PUL nanofibrous mats after electrospinning were 9.5 log10 and 9.6 log10 CFU/g , respectively, proving that the electrospinning conditions used were capable of supporting probiotic encapsulation. These results demonstrate that food-grade electrospun fibrous mats can be utilized to develop functional foods with delivery of probiotics to improve human or animal health.