title: Characterisation of the Poly-(Vinylpyrrolidone)-Poly-(Vinylacetate-Co-Crotonic Acid) (PVP:PVAc-CA) Interpolymer Complex Matrix Microparticles Encapsulating a Bifidobacterium lactis Bb12 Probiotic Strain.
abstract: The method of producing poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid) (PVP:PVAc-CA) interpolymer complex matrix microparticles in supercritical carbon dioxide (scCO2), encapsulating bacteria, has recently been developed. This study was aimed at probing the external and internal structure of these microparticles, which can be used in food. The encapsulation efficiency and distribution of encapsulated Bifidobacterium lactis Bb12 within these microparticles were also investigated. Scanning electron microscopy (SEM) revealed irregular, mostly small, smooth microparticles with no visible bacterial cells on the surface. However, some of the microparticles appeared to have porous surfaces. The results of a Microtrac S3500 particle size analyzer showed that the PVP:PVAc-CA interpolymer complex matrix microparticles encapsulating B. lactis Bb12 had an average particle size of 166.1 μm (<350 μm designated standard size for microparticles). The D 10, D 50 and D 90 values for these microparticles were 48.16, 166.06 and 382.55 μm, respectively. Both SEM and confocal laser scanning microscopy showed a high density of bacterial cells within the microparticles. An average encapsulation efficiency of 96% was achieved. Consequently, the microparticles have the potential to be evenly distributed in foods, deliver adequate amounts of probiotics and produce minimal adverse effects on the texture and mouth feel of the foods into which they are incorporated.
authors.affiliation: Faculty of Natural and Agricultural Sciences, Department of Microbiology and Plant Pathology, University of Pretoria, New Agricultural Sciences Building, Lunnon road, Pretoria, 0002, South Africa.
authors.forename: C I
authors.initials: CI
authors.lastname: Mamvura
authors.affiliation: Materials Science and Manufacturing, Centre of Polymers and Composites, Council for Scientific and Industrial Research (CSIR), P.O. Box 395, Meiring Naude road, Brummeria, Pretoria, 0001, South Africa.
authors.forename: F S
authors.initials: FS
authors.lastname: Moolman
authors.affiliation: Materials Science and Manufacturing, Centre of Polymers and Composites, Council for Scientific and Industrial Research (CSIR), P.O. Box 395, Meiring Naude road, Brummeria, Pretoria, 0001, South Africa.
authors.forename: L
authors.initials: L
authors.lastname: Kalombo
authors.affiliation: Laboratory for Microscopy and Microanalysis, University of Pretoria, Pretoria, South Africa.
authors.forename: A N
authors.initials: AN
authors.lastname: Hall
authors.affiliation: Faculty of Natural and Agricultural Sciences, Department of Microbiology and Plant Pathology, University of Pretoria, New Agricultural Sciences Building, Lunnon road, Pretoria, 0002, South Africa. mapitsi.thantsha@up.ac.za.
authors.forename: M S
authors.initials: MS
authors.lastname: Thantsha
keywords: Bifidobacterium lactis Bb12; Interpolymer complex; Microencapsulation; Poly-(vinylpyrrolidone)-poly-(vinylacetate-co-crotonic acid); Probiotic; Supercritical CO2