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Inactivation of rice bran lipase with metal ions
Author(s) -
Munshi S. K.,
Bhatia Neena,
Sekhon B. S.,
Sukhija P. S.
Publication year - 1993
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280570212
Subject(s) - lipase , bran , chemistry , metal ions in aqueous solution , metal , food science , biochemistry , enzyme , organic chemistry , raw material
The inactivation of rice bran lipase was studied in vitro and in vivo using metal ions in methanol or HCl. Lipase was extracted from rice bran in 0.1 M potassium phosphate buffer, pH 7.0 and purified by ammonium sulphate fractionation. The 25–55% ammonium sulphate fraction was subjected to DEAE‐cellulose ion exchange chromatography and the fraction (F6) eluted at V e / V o of 14.37 was purified about 333‐fold. In‐vitro studies on F6 lipase showed that Fe 3+ and Ni 2+ completely inhibited the lipase activity at 5 × 10 −5 M concentration, while Zn 2+ and Cu 2+ did so at 2.5 × 10 −4 M. The results on in‐vivo inactivation of rice bran lipase showed that Fe 3+ and Ni 2+ at 200 μg g −1 significantly checked the release of free fatty acids (FFA) from rice bran for 6 days of storage when compared with using concentrated HCl (2%, v/w) only. The triglyceride content of oil was also maximum with Fe 3+ and Ni 2+ treatment at 200 μg g −1 . The present results suggest that Fe 3+ and Ni 2+ could be effectively used to arrest the release of FFA in rice bran and thus contribute to improving the edible quality of rice bran oil.