Heteropolysaccharides

Abstract

The present invention relates a heteropolysaccharide characterized in that it is substantially composed of the monosaccharides glucose and galactose and rhamnose and N-acetylgalactosamine and a process for the production thereof. The invention further relates to a bacterium capable of producing said heteropolysaccharide and to the use of the heteropolysaccharide and the bacterium for improving the texture of fermented milk products.

1 . A fermented milk product comprising a heteropolysaccharide composed of at least about 90%, based on dry matter, of monosaccharides glucose and galactose and rhamnose and N-acetylgalactosamine, and wherein the heteropolysaccharide has a molecular weight of 400 kDa to 4000 kDa, wherein the heteropolysaccharide comprises a repeating unit whereby the repeating unit is a pentasaccharide composed of the monosaccharides glucose and galactose and rhamnose and N-acetylgalactosamine, and wherein the pentasaccharide has the following composition:glucose:galactose:rhamnose:N-acetylgalactosamine=2:1:1:1, wherein the heteropolysaccharide is from  Streptococcus thermophilus.    
     
     
         2 . The fermented milk product according to  claim 1 , wherein the heteropolysaccharide comprises 30-50 mole % glucose, 10-30 mole % galactose, 10-30 mole % rhamnose and 10-30 mole % N-acetylgalactosamine and whereby the total mole % is 100%. 
     
     
         3 . The fermented milk product according to  claim 2 , wherein the ratio of the mole % of glucose and the mole % of galactose is between ≥1.0 and ≤2.0. 
     
     
         4 . The fermented milk product according to  claim 2 , wherein the heteropolysaccharide comprises 40 mole % glucose, 20 mole % galactose, 20 mole % rhamnose and 20 mole % N-acetylgalactosamine. 
     
     
         5 . The fermented milk product according to  claim 1 , wherein the pentasaccharide is composed of 40 mole % glucose, 20 mole % galactose, 20 mole % rhamnose and 20 mole % N-acetylgalactosamine. 
     
     
         6 . The fermented milk product comprising the heteropolysacchride according to  claim 1 , wherein the texture and/or viscosity is improved, as evaluated by allowing a spoonful of yoghurt to flow from the spoon, wherein the yoghurt flowing from the spoon while forming a formation of a thread indicates improved texture and/or viscosity. 
     
     
         7 . The fermented milk product of  claim 1 , wherein the heteropolysacchcaride is from  Streptococcus salivarius thermophilus.    
     
     
         8 . The fermented milk product of  claim 7 , wherein the heteropolysacchcaride is from a bacterium selected from the group consisting of
   Streptococcus salivarius thermophilus  NGB-22D, deposited on 28-02-2012 as CBS132067 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht and     Streptococcus salivarius thermophilus  DS65008, deposited on 18-06-2013 as CBS135685 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht.   
     
     
         9 . The fermented milk product of  claim 2 , wherein the heteropolysacchcaride is from a bacterium selected from the group consisting of
   Streptococcus salivarius thermophilus  NGB-22D, deposited on 28-02-2012 as CBS132067 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht and     Streptococcus salivarius thermophilus  DS65008, deposited on 18-06-2013 as CBS135685 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht.   
     
     
         10 . The fermented milk product of  claim 1 , wherein the heteropolysaccharide has a molecular weight of 500 kDa to 1500 kDa. 
     
     
         11 . A process for production of a fermented milk product comprising adding a heteropolysaccharide composed of at least about 90%, based on dry matter, of monosaccharides glucose and galactose and rhamnose and N-acetylgalactosamine, and wherein the heteropolysaccharide has a molecular weight of 400 kDa to 4000 kDa, wherein the heteropolysaccharide comprises a repeating unit whereby the repeating unit is a pentasaccharide composed of the monosaccharides glucose and galactose and rhamnose and N-acetylgalactosamine, or adding a bacterium capable of producing said heteropolysaccharide, to a milk product, and then fermenting the milk product, wherein the pentasaccharide has the following composition: glucose:galactose:rhamnose:N-acetylgalactosamine=2:1:1:1; wherein the heteropolysaccharide is from  Streptococcus thermophilus.    
     
     
         12 . The process of  claim 11 , wherein the heteropolysaccharide has a molecular weight of 500 kDa to 1500 kDa. 
     
     
         13 . The process of  claim 11 , wherein the heteropolysacchcaride is from a bacterium selected from the group consisting of
 a.  Streptococcus salivarius thermophilus  NGB-22D, deposited on 28-02-2012 as CBS132067 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht and   b.  Streptococcus salivarius thermophilus  DS65008, deposited on 18-06-2013 as CBS135685 at the Centraalbureau voor Schimmelcultures (Fungal Biodiversity Centre), Utrecht.   
     
     
         14 . The fermented milk product of  claim 1 , which is yoghurt. 
     
     
         15 . The process of  claim 11 , wherein the fermented milk product is yoghurt.