Angiotensin I Converting Enzyme Inhibitory Peptides from In Vitro Pepsin−Pancreatin Digestion of Soy Protein

Wendy M. Y. Lo and Eunice C. Y. Li-Chan*
The University of British Columbia, Faculty of Agricultural Sciences, Food Science Building, 6650 N.W. Marine Drive, Vancouver, British Columbia V6T 1Z4, Canada
J. Agric. Food Chem., 2005, 53 (9), pp 3369–3376
DOI: 10.1021/jf048174d
Publication Date (Web): March 30, 2005
Copyright © 2005 American Chemical Society
*

 To whom correspondence should be addressed. Tel:  604 822 6182. Fax:  604 822 3959. E-mail:  ecyl@interchange.ubc.ca.

Abstract

Angiotensin I converting enzyme (ACE) inhibitory activity was determined in the soy protein isolate (SPI) digest produced by in vitro pepsin−pancreatin sequential digestion. The inhibitory activity was highest within the first 20 min of pepsin digestion and decreased upon subsequent digestion with pancreatin. An IC50 value of 0.28 ± 0.04 mg/mL was determined after 180 min of digestion, while no ACE inhibitory activity was measured for the undigested SPI at 0.73 mg/mL. Chromatographic fractionation of the SPI digest resulted in IC50 values of active fractions ranging from 0.13 ± 0.03 to 0.93 ± 0.08 mg/mL. Although many of the fractions showed ACE inhibition, peptides with lower molecular masses and higher hydrophobicities were most active. The findings show that many different peptides with ACE inhibitory activities were produced after in vitro pepsin−pancreatin digestion of SPI and lead to the speculation that physiological gastrointestinal digestion could also yield ACE inhibitory peptides from SPI.

Keywords: Soy protein isolate; soy peptide; angiotensin I-converting enzyme inhibitory activity; in vitro digestion; pepsin; pancreatin

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History

  • Published In Issue May 04, 2005
  • Received for review November 2, 2004. Revised manuscript received February 12, 2005. Accepted February 24, 2005. This research was supported by the Natural Sciences and Engineering Research Council of Canada and by a University Graduate Fellowship to W.M.Y.L.

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