title: Bilberry and bilberry press cake as sources of dietary fibre.
abstract: BACKGROUND
  Dietary recommendations for Nordic countries urge the use of plant foods as a basis for healthy nutrition. Currently, the level of dietary fibre (DF) intake is not adequate. Berries are an elementary part of the recommended Nordic healthy diet and could be consumed in higher amounts.
  
  
  METHODS
  Finnish bilberries and a bilberry press cake from juice processing were studied for DF content, carbohydrate composition, and non-carbohydrate fibre content, which was analysed as sulphuric acid insoluble and soluble material. The microstructure of all samples was also studied using light microscopy and toluidine blue O, calcofluor, and acid fuchsin staining.
  
  
  RESULTS
  The total DF contents of fresh and freeze-dried bilberries and the press cake were 3.0, 24.1, and 58.9%, respectively. Most of the DF was insoluble. Only about half of it was carbohydrate, the rest being mostly sulphuric acid-insoluble material, waxy cutin from skins, and resilient seeds. Bilberry seeds represented over half of the press cake fraction, and in addition to skin, they were the major DF sources. Microscopy revealed that skins in the press cake were intact and the surface of the seeds had thick-walled cells.
  
  
  CONCLUSIONS
  Bilberry press cake is thus a good source of insoluble non-carbohydrate DF, and could be used to provide DF-rich foods to contribute to versatile intake of DF.
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland; anna-marja.aura@vtt.fi.
authors.forename: Anna-Marja
authors.initials: AM
authors.lastname: Aura
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
authors.forename: Ulla
authors.initials: U
authors.lastname: Holopainen-Mantila
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
authors.forename: Juhani
authors.initials: J
authors.lastname: Sibakov
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
authors.forename: Tuija
authors.initials: T
authors.lastname: Kössö
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
authors.forename: Mirja
authors.initials: M
authors.lastname: Mokkila
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
authors.forename: Poutanen
authors.initials: P
authors.lastname: Kaisa
keywords: bilberry; microstructure; non-digestible carbohydrate; press cake; sulphuric acid–insoluble material