EFFECT OF FRUCTANS WITH DIFFERENT DEGREE OF POLYMERIZATION AND STRUCTURE ON GROWTH OF SELECTED PROBIOTIC STRAINS AND FORMATION OF SHORT CHAIN FATTY ACIDS

Mueller M., Viernstein H., Loeppert R., Praznik W.
University of Vienna, Department of Pharmaceutical Technology and Biopharmaceutics, Vienna, Austria

Introduction:
Fructans are well known prebiotics which are accumulated by a great variety of plants including composites (e.g. chichory, Jerusalem artichoke) or agavacaee (div. agave species) (1). The influence of structure and polymerization degree (dp) of fructans on the prebiotic potential is not fully elucidated yet. Thus, we compared the growth of selected probiotic strains with fructans from different sources including chicory and agave related to diverse structures such as unbranched inulin-type (only ß2-1 linkages), mixed-type (combined ß2-1 and ß2-6 linkages with branching) and levans (ß2-6 linkages) with branching characteristics (1). Furthermore we tested the influence of branching and dp on the formation of short chain fatty acids (SCFAs).

Methods:
Fructans from chicory or agaves were separated into 3 to 5 fractions using size exclusion chromatography and the polymerization degree of the fructan fractions was determined using ions exchange chromatography. The influence of the fructan samples on the growth curve of selected probiotic strains was determined including Lactobacilli spp. and Bifidobacteria spp. based on a turbidity measurement. The degradation of fructo-oligosaccharides by probiotics and the formation of short chain fatty acids (SCFAs) were studied.

Results:
Fructan samples with lower polymerization degree and branching induced the growth of the probiotics faster than those with higher polymerization degree. The correlation between growth induction and polymerization degree was strain dependent. The degradation process of the fructo-oligosaccharides by probiotics correlated well with the growth curves. Some strains grew only with fructans of low dp, some with fructans from all dp, but faster with fructans from low dp and a few strains grew fast even with higher molecular fructans (2,3). The formation of SCFAs by selected prebiotic strains or by a mixture of gut bacteria was dependent on the polymerization degree and branching (4).

Discussion:
Fructans from agave and chicory significantly induce the growth of probiotic bacteria. In contrast to a previous study, all our tested probiotics could use fructans as sole carbon source (5) with strain dependency on the usage of higher molecular fructans. The study also elucidates the correlation of the growth of the bacteria with the degradation process of the oligosaccharides and the formation of SCFAs. Unbranched and branched fructans led to the formation of butyrate which plays a major role in the prevention of colon cancer and other colonic diseases.
In conclusion, this study contributes to elucidate the fermentation behavior of selected prebiotic strains dependent on the molecular structure and polymerization degree of the fructans and on their formation of SCFAs which play a major role in health for usage in Functional Food industry and pharmaceutical applications.

Keywords: 
Fructans, Short chain fatty acids, Polymerization degree, Probiotic

References:
1. Peshev D, Van den Ende W. (2014) Fructans: Prebiotics and immunomodulators. J Funct Food 8: 348-357

2. Mueller M, Reiner J, Fleischhacker L, Viernstein H, Loeppert R, Praznik W. (2016) Growth of selected probiotic strains with fructans from different sources relating to degree of polymerization and structure. J Funct Foods 24: 264-275

3. Mueller M, Schwarz S, Viernstein H, Löppert R, Praznik W. (2016) Growth of selected probiotic strains with fructans from chicory and agaves. AGRO FOOD Chem. Industry high-tech 27(2): 40-42

4. Koenen ME, Cruz Rubio JM, Mueller M and Venema K (2015) The effect of agave fructan products on the activity and composition of the microbiota determined in a dynamic in vitro model of the human proximal large intestine. J Funct Foods 22: 201-10.

5.Velázquez-Martínez JR, González-Cervantes RM, Hernández-Gallegos MA, Mendiola RC, Aparicio AR, Ocampo ML. (2014) Prebiotic potential of Agave angustifolia Haw fructans with different degrees of polymerization. Molecules 9: 12660-75

Citation:
Mueller M., Viernstein H., Loeppert R., Praznik W. (2016). Effect of fructans with different degree of polymerization and structure on growth of selected probiotic strains and formation of short chain fatty acids. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 51.). IPC2016

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