Identification by GeLC‐MS/MS of Trypsin Inhibitor in Sarcoplasmic Proteins of Three Tropical Fish and Characterization of Their Inhibitory Properties

• Published in: Journal of food science 2014-07, Vol.79 (7), p.C1305-C1314
• Main Authors: Siriangkanakun, Siriphon, Li‐Chan, Eunice C.Y, Yongsawadigul, Jirawat
• Format: Article
• Language: English
• Subjects: ammonium sulfate; Animals; Bream; Chromatography, Liquid; creatine kinase; Distillation; Fish; Fish Proteins - chemistry; Fishes - metabolism; Food science; freeze drying; gel electrophoresis; GeLC-MS/MS; gels; Gels - chemistry; glyceraldehyde-3-phosphate dehydrogenase; heat treatment; ingredients; Marine; mass spectrometry; molecular weight; Myosin Heavy Chains - metabolism; phosphorylase; Proteins; sarcoplasmic proteins; Sarcoplasmic Reticulum - chemistry; Seafood; snapper; sodium chloride; Species Specificity; Surface layer; Surimi; Tandem Mass Spectrometry; Texture; tropical fish; Trypsin; Trypsin - metabolism; trypsin inhibitor; trypsin inhibitors; Trypsin Inhibitors - chemistry; Trypsin Inhibitors - metabolism
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.12521

Sarcoplasmic proteins from 3 fish species were fractionated by 50% to 70% ammonium sulfate precipitation. Lyophilized fractionated sarcoplasmic proteins of threadfin bream (TB‐SP), bigeye snapper (BS‐SP), and yellow croaker (YC‐SP) showed 80% to 92% trypsin inhibitory activity. Trypsin inhibitory activity staining gel electrophoresis revealed bands at 32, 33, 37, 45, 48, and 50 kDa for the 3 species, and a band at 95 kDa was observed for TB‐SP and YC‐SP. Alpha‐1‐antitrypsin with molecular mass of 45 to 50 kDa was identified in YC‐SP by gel‐based liquid chromatography‐tandem mass spectrometry (GeLC‐MS/MS). Other major protein bands appeared on trypsin activity staining included phosphorylase, glyceraldehyde‐3‐phosphate dehydrogenase, and creatine kinase with molecular mass of 95 and 35 to 40 kDa, respectively. But, these 3 proteins did not show true trypsin inhibitory activity. Trypsin inhibitory activity of fractionated sarcoplasmic proteins showed good stability, with >80% activity retained at 60 °C and up to 0.6 M NaCl. TB‐SP showed the highest inhibitory activity against autolysis of washed threadfin bream mince at 65 °C. Addition of 0.5% or 1% TB‐SP improved textural properties of threadfin bream surimi gels preincubated at 37 or 65 °C followed by heating at 90 °C. Therefore, TB‐SP could be a promising protein ingredient for enhancing surimi gel texture.