Potential of dry fractionation of wheat bran for the development of food ingredients, part II: Electrostatic separation of particles

Youna Hemery, Ulla Holopainen, Anna-Maija Lampi, Pekka Lehtinen, Tanja Nurmi, Vieno Piironen, Minnamari Edelmann, Xavier Rouau

Research output: Contribution to journalArticleScientificpeer-review

119 Citations (Scopus)


Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.
Original languageEnglish
Pages (from-to)9-18
JournalJournal of Cereal Science
Issue number1
Publication statusPublished - Jan 2011
MoE publication typeA1 Journal article-refereed


  • Aleurone
  • Bran
  • Electrostatic separation
  • Ferulic acid
  • Fibre
  • Folates
  • Fractionation
  • Ingredient
  • Micronization
  • Particles
  • Phenolics
  • Sterols
  • Wheat


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