Microwave heating for solubilization of polysaccharide and polyphenol from soybean residue (Okara)

Shuntaro Tsubaki, Michiyo Nakauchi, Yoshihiko Ozaki, Jun Ichi Azuma

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Okara, a soybean by-product of tofu production, was treated with microwave irradiation in water for solubilization of its components. The solubilization rate increased with increasing temperature and reached higher than 70% around 200°C with a heating time of 7 min. The main solubilized components were neutral carbohydrates consisting of arabinose and galactose, while the residues were mainly composed of cellulose. LV-SEM images confirmed solubilization of cell wall components. Production of new polyphenolic compounds that have antioxidant activity was observed above 180°C. The heating temperature and heating time were optimized for neutral carbohydrate solubilization using the response surface methodology. The optimized condition was heating at 196°C for 2 min, indicating that a short heating time is effective for solubilization of carbohydrates to prevent secondary decomposition.

Original languageEnglish
Pages (from-to)307-314
Number of pages8
JournalFood Science and Technology Research
Issue number3
Publication statusPublished - May 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Food Science
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering
  • Marketing


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