Bioactives Research New Zealand

Napier, New Zealand

Bioactives Research New Zealand

Napier, New Zealand
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Chen S.,University of Auckland | Chen S.,Bioactives Research New Zealand | Cao Y.,Asure Quality | Ferguson L.R.,University of Auckland | And 3 more authors.
Journal of Microencapsulation | Year: 2013

Probiotic bacteria were previously encapsulated in sub-100 μm Ca 2+ alginate microcapsules for enhanced survival in human gastrointestinal tract. The aim of this study is to evaluate the altered mucoadhesive property of the probiotic delivery system by coating it with mucoadhesive chitosan or thiolated chitosan, for prolonged retention in human colon. The results confirmed that cross-linking with calcium ions reduced the mucoadhesive property of alginate hydrogel, thus questioning the intrinsic mucoadhesiveness of uncoated systems. In contrast, chitosan and thiolated chitosan were found to be adsorbed on sub-100 μm Ca2+ alginate microcapsules, and substantially improved the mucoadhesion performance of the system. The adhesion performance was correlated to the amount of mucoadhesive coating polymer adsorbed on the surface of the system. The coated system was demonstrated on HT29-MTX colonic epithelial monolayer to deliver markedly higher amount of probiotic bacteria to the in vitro model of colonic mucosa. Additionally, the coatings were also found to exert significantly stronger mucoadhesion to colonic mucosa tissue at slight acid neutral pH with less ambient water, which conforms to the physiological environment of the colon, thus supporting prolonged retention in this region. © 2013 Informa UK Ltd All rights reserved.


Chen S.,University of Auckland | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand | Garg S.,University of Auckland
LWT - Food Science and Technology | Year: 2011

In this study, we applied flow cytometric (FCM) analyses to characterize the resistance of a probiotic strain Lactobacillus reuteri DPC16 (DPC16) against diverse stresses. Two fluorescent probes, propidium iodide (PI) and carboxylfluorescein diacetate (cFDA), were combined to the FCM method to reveal multiple cellular statuses of DPC16. The FCM results confirmed that the DPC16 strain had probiotic potential in respect of acid tolerance and bile acid resistance, whereby more than 60% of DPC16 bacteria remained intact after 1 h exposure to pH 2.0, and over half of DPC16 bacteria were unaffected by the presence of bile salts at a concentration of 0.2 g/100 mL for 1 h even without nutrient supply. In addition, the comparison among a number of lyo-preservatives for the DPC16 strain confirmed that lactose was able to maintain over 60% viable DPC16 bacteria after the lyophilization and subsequent storage period, outperforming all the other selected sugars. To conclude, the superior stress resistance of the novel DPC16 strain was confirmed by the FCM analyses in this study. The FCM technique also proved to be readily incorporated into probiotics research, and capable of providing insightful information. © 2011 Elsevier Ltd.


Chen S.,University of Auckland | Cao Y.,AsureQuality | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand | Garg S.,University of Auckland
Applied Microbiology and Biotechnology | Year: 2012

The aim of this study was to apply flow cytometric (FCM) analysis to assess the use of sucrose and lecithin vesicles for the protection of probiotic lactic acid bacteria in response to the challenge of gastric acidity and bile salts. FCM analysis in combination with fluorescent probes carboxyfluorescein (cF) and propidium iodide was used to reveal the physiological heterogeneity in the stressed bacteria population. Three subpopulations (intact, stressed, and damaged) were differentiated by FCM in all six examined strains. Significant changes were observed in the presence of the selected protectants. The addition of 20 mM sucrose in the simulated gastric fluid substantially increased the number of intact cells over 20 folds and reduced the damaged subpopulation by half. The presence of 2 % (w/v) lecithin vesicles was shown to protect 50 % more intact cells from the challenge of bile salts. The improved survival as evaluated by FCM analysis was further assessed for the proliferation capacity by sorting a number of cells from each subpopulation on nutrient agar plate. The result confirmed conformity between the proliferation-based cultivability and the probeindicated viability in the samples of the intact and the damaged subpopulations. However, it also revealed the complexities of the stressed (injured) subpopulation. In conclusion, FCM analysis confirmed that the selected protectants could improve the survival of the probiotic strains in the simulated GI environments. The FCM analysis also proved to be a useful analytical tool for the probiotics research. © Springer-Verlag 2012.


Tian H.,Massey University | Tian H.,Bioactives Research New Zealand | Maddox I.S.,Massey University | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand
BioMetals | Year: 2010

This study investigated the effects of bovine lactoferrin (BLf) on the growth of different groups of bacteria in vitro. BLf showed a significant inhibitory effect on the growth of selected pathogens but not probiotics. BLf, in combination with probiotics, has the potential to influence the composition of the gut microflora via inhibition of intestinal pathogens with no significant effect on probiotic bacteria. © 2010 Springer Science+Business Media, LLC.


Tian H.,Massey University | Tian H.,Bioactives Research New Zealand | Maddox I.S.,Massey University | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand
BioMetals | Year: 2010

Lactoferrin is an iron-binding glycoprotein that exhibits a range of health benefits including immune regulation and disease prevention derived from its structural properties. The present study employed immune cell models and a colon epithelial cell model to investigate the protective effects of bovine lactoferrin (BLf) on both immune cells and colon epithelium cells. BLf caused significant reduction of faecal genotoxin-induced DNA damage in HT29 cells, and down-regulation of lipopolysaccharide (LPS)-induced macrophage cell stress and endotoxic response, in an infection status. © 2010 Springer Science+Business Media, LLC.


Zhao Q.,Massey University | Maddox I.S.,Massey University | Mutukumira A.,Massey University | Lee S.J.,Massey University | Shu Q.,Bioactives Research New Zealand
World Journal of Microbiology and Biotechnology | Year: 2012

Cell immobilization has the ability to influence the survival and functional characteristics of probiotic bacterial strains in harsh environments. This study investigated the effect of cell immobilization and passage through a simulated gastrointestinal tract (GI) on the antibacterial activity of Lactobacillus reuteri DPC16. Antibacterial activity, reuterin production and diol dehydratase activity were assayed in recovered isolates of L. reuteri that had been immobilized in Ca alginate-skim milk, and incubated in simulated GI fluids. Among all the recovered isolates tested, any that had undergone immobilization followed by immediate recovery of the cells without subsequent incubation in any fluids demonstrated the highest reuterin production, antimicrobial activity and diol dehydratase enzyme activity. L. reuteri DPC16 cells that had been immobilized, incubated in simulated GI fluids, and subsequently recovered from the beads often showed some loss of antimicrobial activity compared to the immobilized cells. The data confirm that the process of immobilization of L. reuteri in Ca alginate-skim milk, rather than the passage through simulated GI fluids, resulted in enhanced antibacterial activity. This is attributed to increased diol dehydratase activity, resulting in increased reuterin production. © 2012 Springer Science+Business Media B.V.


Chen S.,University of Auckland | Zhao Q.,Massey University | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2012

The establishment of the health-promoting benefits of probiotics is challenged by the antimicrobial bio-barriers throughout the host's gastrointestinal (GI) tract after oral administration. Although microencapsulation has been frequently utilised to enhance the delivery of probiotics, microcapsules of sub-100 μm were found to be ineffective and therefore questioned as an effective delivery vehicle for viable probiotics despite the sensory advantage. In this study, four probiotics strains were encapsulated in chitosan-coated alginate microcapsules of sub-100 μm. Only a minor protective effect was observed from this original type of microcapsule. In order to enhance the survival of these probiotics, sucrose, a metabolisable sugar, and lecithin vesicles were added to the wall material. Both of the ingredients could be readily encapsulated with the probiotics, and protected them from stresses in the simulated GI fluids. The metabolisable sugar effectively increased the survival of the probiotics in gastric acid, mainly through energizing the membrane-bound F 1F 0-ATPases. The lecithin vesicles proved to alleviate the bile salt stress, and hence notably reduced the viability loss at the elevated bile salt concentrations. Overall, three out of the total four probiotics in the reinforced sub-100 μm microencapsules could significantly survive through an 8-h sequential treatment of the simulated GI fluids, giving less than 1-log drop in viable count. The most vulnerable strain of bifidobacteria also yielded a viability increase of 3-logs from this protection. In conclusion, the sub-100 μm microcapsules can be a useful vehicle for the delivery of probiotics, as long as suitable protectants are incorporated in the wall matrix. © 2011 Springer-Verlag.


Chen S.,University of Auckland | Cao Y.,AsureQuality | Ferguson L.R.,University of Auckland | Shu Q.,Bioactives Research New Zealand | Garg S.,University of Auckland
World Journal of Microbiology and Biotechnology | Year: 2012

The aim of this study was to evaluate whether immobilizing a probiotic strain Lactobacillus reuteri DPC16 in chitosan-coated alginate microcapsules affected their inhibitory performance against food-borne pathogens. The probiotic strain was encapsulated in sub-100 μm alginate microspheres which were further coated with chitosan. This type of probiotic microcapsules was investigated in a co-culture model for its effect against two food-borne pathogenic bacteria. The results confirmed the comparable inhibitory performances between the planktonic and the microencapsulated DPC16 in terms of the medium acidification and the reuterin production in the presence of sufficient nutrients. However, if an infertile condition was present, in which energy source was limited, the planktonic DPC16 tended to instantly accumulate a higher concentration of reuterin but at the cost of substantial viability loss, whereas immobilization in the chitosan-coated alginate microcapsules extended the survival of DPC16, albeit with a significantly lower reuterin production. In conclusion, no attenuated antimicrobial effect was observed for the immobilized DPC16 in the co-culture model. Microencapsulation rendered an enhanced protection on the embedded probiotics, but it may also induce an altered availability of substrates to those microorganisms. © 2012 Springer Science+Business Media B.V.


Zhao Q.,Massey University | Lee S.J.,Massey University | Mutukumira A.N.,Massey University | Maddox I.,Massey University | Shu Q.,Bioactives Research New Zealand
Beneficial Microbes | Year: 2011

The objective of the study was to design and produce calcium alginate beads that can deliver immobilised Lactobacillus reuteri DPC16 to a target site of the colon in the gastrointestinal (GI) tract. In this study, several factors that might affect the effectiveness of calcium alginate gel beads entrapping L. reuteri DPC16 cells were investigated. An in vitro GI tract model was used to simulate the pH variation and the existence of enzymes. Firstly, by varying the concentration of alginate at a constant concentration of CaCl2 the survival of immobilised DPC16 cells in simulated gastric fluid (SGF) was observed; secondly, the physical stability of calcium alginate beads containing skim milk during sequential incubation in the GI fluids was observed using optimal concentrations of alginate; finally, the survival of DPC16 cells immobilised within alginate beads containing skim milk were compared when the beads were incubated for different times during sequential exposure to the simulated fluids. The results demonstrated that non-encapsulated DPC16 cells were sensitive to an acidic environment, and no viable cells were detected after 90 min exposure in SGF (pH 1.2). With the protection of calcium alginate gel, the survival rate of immobilised DPC16 cells was slightly improved. An alginate concentration of 4% (w/v) was the most effective of those tested, but due to the irregular shape it formed, an alginate concentration of 3% (w/v) was used in further investigations. When skim milk (8% (w/v)) was added to the alginate solution, the cell survival was improved markedly. The optimal concentration of calcium chloride was 0.3 M, because the beads maintained their integrity in SGF and simulated intestinal fluid while disintegrating in simulated colonic fluid. The beads made from 3% alginate, 8% skim milk and 0.3 M CaCl2 proved to be an effective delivery and release system for DPC16 cells. © 2011 Wageningen Academic Publishers.


PubMed | University of Auckland, Bioactives Research New Zealand and Massey University
Type: Journal Article | Journal: Applied microbiology and biotechnology | Year: 2016

The establishment of the health-promoting benefits of probiotics is challenged by the antimicrobial bio-barriers throughout the hosts gastrointestinal (GI) tract after oral administration. Although microencapsulation has been frequently utilised to enhance the delivery of probiotics, microcapsules of sub-100 m were found to be ineffective and therefore questioned as an effective delivery vehicle for viable probiotics despite the sensory advantage. In this study, four probiotics strains were encapsulated in chitosan-coated alginate microcapsules of sub-100 m. Only a minor protective effect was observed from this original type of microcapsule. In order to enhance the survival of these probiotics, sucrose, a metabolisable sugar, and lecithin vesicles were added to the wall material. Both of the ingredients could be readily encapsulated with the probiotics, and protected them from stresses in the simulated GI fluids. The metabolisable sugar effectively increased the survival of the probiotics in gastric acid, mainly through energizing the membrane-bound F1F0-ATPases. The lecithin vesicles proved to alleviate the bile salt stress, and hence notably reduced the viability loss at the elevated bile salt concentrations. Overall, three out of the total four probiotics in the reinforced sub-100 m microencapsules could significantly survive through an 8-h sequential treatment of the simulated GI fluids, giving less than 1-log drop in viable count. The most vulnerable strain of bifidobacteria also yielded a viability increase of 3-logs from this protection. In conclusion, the sub-100 m microcapsules can be a useful vehicle for the delivery of probiotics, as long as suitable protectants are incorporated in the wall matrix.

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