Entrapment of Probiotics in Water Extractable Arabinoxylan Gels: Rheological and Microstructural Characterization

Abstract

Due to their porous structure, aqueous environment and dietary fiber nature arabinoxylan (AX) gels could have potential applications for colon-specific therapeutic molecule delivery. In addition, prebiotic and health related effects of AX have been previously demonstrated. It has been also reported that cross-linked AX can be degraded by bacteria from the intestinal microbiota. However, AX gels have not been abundantly studied as carrier systems and there is no information available concerning their capability to entrap cells. In this regard, probiotic bacteria such as Bifidobacterium longum have been the focus of intense research activity lately. The objective of this research was to investigate the entrapment of probiotic B. longum in AX gels. AX solution at 2% (w/v) containing B. longum (1 × 10 7 CFU/cm) formed gels induced by laccase as cross-linking agent. The entrapment of B. longum decreased gel elasticity from 31 to 23 Pa, probably by affecting the physical interactions taking place between WEAX chains. Images of AX gels containing B. longum viewed under a scanning electron microscope show the gel network with the bacterial cells entrapped inside. The microstructure of these gels resembles that of an imperfect honeycomb. The results suggest that AX gels can be potential candidates for the entrapment of probiotics.

Gelation of Arabinoxylans from Maize Wastewater — Effect of Alkaline Hydrolysis Conditions on the Gel Rheology and Microstructure

“…Higher cell dimensions were reported in lyophilized AX gels (>200 μm) [17,19], and this difference could be related to the method used to freeze the gels before lyophilization. In the present study AX gels were frozen by immersion in liquid nitrogen (fast congelation), while previous studies [17,19] reported AX gel congelation at -20°C for several hours (slow congelation).…”

“…This behavior reflects an initial formation of covalent linkages between FA of adjacent AX molecules producing a three-dimensional network [19]. At the end of gelation, G' and G" were 78 and 13 Pa for AX1, respectively, while for AX2 they were 32 Pa and 8 Pa for G' and G", respectively (Table 1).…”

“…The entrapment of biomolecules or microorganisms in high cell dimension (>200μm) AX gels has been previously reported [14,19,31], but reducing cell dimensions of AX gels could increase the possibility of carried out smaller compounds or cells. Therefore, AX1 and AX2 gels microstructural characteristics could be of interest for the development of designed delivery systems, which could allow alternative uses for maize wastewater.…”

“…The microstructure of Wastewater Treatment Engineeringthe freeze-dried gels was studied by scanning electron microscopy (SEM) (JEOL 5410LV, JEOL, Peabody, MA, USA) at low voltage (20 kV) and Secondary Electron Imaging (SEI) mode [19].…”

Maize Processing Waste Water Upcycling in Mexico: Recovery of Arabinoxylans for Probiotic Encapsulation

“…The stability of the AX gels to changes in temperature, pH, and ionic strength offers an advantage for the industrial applications of this polysaccharide. A previous study has demonstrated that AX gels can be used for the entrapment of probiotics [10,11]. However, that investigation used water extractable AX from wheat flour as a model molecule due the less complex structure of this polysaccharide in comparison to water un-extractable AX from cereal brans.…”