title: Birch pulp xylan works as a food hydrocolloid in acid milk gels and is fermented slowly in vitro.
abstract: The objective was to evaluate the potential of birch xylan as a food hydrocolloid and dietary fibre. High-molecular weight xylan was isolated from birch kraft pulp by alkaline extraction, and enzymatically hydrolysed. Fermentability of xylans was evaluated using an in vitro colon model and performance as a hydrocolloid was studied in low-fat acid milk gels (1.5% and 3% w/w). Texture of the gels and water holding capacity of xylans were compared with inulin, fructooligosaccharide and xylooligosaccharide. Xylans showed slower fermentation rate by faecal microbiota than the references. Xylan-enriched acid milk gels (3% w/w) had improved water holding capacity (over 2-fold) and showed lower spontaneous syneresis, firmness and elasticity when compared to control (no hydrocolloids) or to references. In conclusion, birch xylan improved texture of low-fat acid milk gel applications, and the slow in vitro fermentation rate predicts lower incidence of intestinal discomfort in comparison to the commercial references.
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
authors: Natalia
authors: N
authors: Rosa-Sibakov
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
authors: Terhi K
authors: TK
authors: Hakala
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
authors: Nesli
authors: N
authors: Sözer
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
authors: Emilia
authors: E
authors: Nordlund
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland.
authors: Kaisa
authors: K
authors: Poutanen
authors: VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland. Electronic address: anna-marja.aura@vtt.fi.
authors: Anna-Marja
authors: AM
authors: Aura
mesh_terms: D000818:Animals; D029662:Betula / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D004043:Dietary Fiber; D005285:Fermentation; D005782:Gels / Q000737:chemistry*; D006801:Humans; D006868:Hydrolysis; D008892:Milk / Q000737:chemistry*; D014934:Wood / Q000737:chemistry; D014990:Xylans / Q000737:chemistry*
chemical_list: D003102:Colloids; D004043:Dietary Fiber; D005782:Gels; D014990:Xylans
keywords: Acid milk gel; Birch pulp xylan; Gas pressure evolution; In vitro colonic fermentation; Short-chain fatty acid