Optimal condition to remove mercury in yellowfin tuna protein isolates and ACE-inhibitory property of peptide prepared using commercial proteases

Hathaigan Kokkaew, Supawan Thawornchinsombut, Jae W. Park

Research output: Contribution to journalArticle

2 Citations (Scopus)


Response surface methodology (RSM) was performed to maximize the mercury (Hg) reduction from yellowfin tuna (Thunnus albacare) by products protein isolates (YBPI). The optimal condition of Hg reduction (89.3%) was 10.5 mM CaCl2 and a Water:YB of 12.9:1, while other variables were fixed at 5 mM citric acid, 60 min incubation, pH 11 and 8,000 x g for 15 min of centrifugation. At these conditions, the significant protein recovery (80.1%) was obtained. Hydrolysates sequentially hydrolyzed with G6 followed by GN exhibited the highest angiotensin I-converting enzyme (ACE) inhibitory activity than other enzyme preparations. Fractionated yellowfin tuna by products protein hydrolysate (YBPH) increased in ACE-inhibitory activity when peptide size decreased. In-vitro gastrointestinal (GI) digestion significantly increased bioactive property. ACEinhibitory activity of YBPH with and without simulated GI digestion significantly increased after incubating against ACE, demonstrating pro-drug type peptides.

Original languageEnglish
Pages (from-to)439-447
Number of pages9
JournalSongklanakarin Journal of Science and Technology
Issue number4
Publication statusPublished - 2016
Externally publishedYes



  • Commercial enzymes
  • Gastrointestinal digestion
  • Pro-drug type peptides
  • Response surface methodology

ASJC Scopus subject areas

  • General

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