Effect of transglutaminase cross-linking on debittering of Alaska pollock frame hydrolysate

Abstract

The present study aimed to investigate the impact of TGase cross-linking on the flavour characteristics, particularly focusing on its ability to reduce bitterness in enzymatically digested Alaska Pollock framework (APF) hydrolysates using Protease A ‘Amano’ 2SD (A2SD) and Protease A ‘Amano’ 6SD (A6SD). Electronic tongue results showed that the umami was enhanced, accompanied by a reduction in both bitterness and bitter aftertaste. The contents of glutamic acid (Glu) and nucleotides (AMP, IMP and GMP) exhibited significant differences among all treatment groups (P < 0.05). There was a notable increase in the types and relative concentrations of alcohols, ketones, alkanes and aldehydes in the cross-linked APF enzymatic hydrolysate. The Fourier transform infrared spectroscopy, ultraviolet spectrum and fluorescence spectrum analyses indicate that TGase cross-linking leads to a reduction in the exposure of hydrophobic amino acid residues. The surface hydrophobicity of H_A2SD-C and H_A6SD-C exhibited a significantly lower level compared with that of H_A2SD and H_A6SD. The present study presents an effective approach for mitigating the bitter taste of aquatic hydrolysate, thereby positively contributing to the advancement and utilisation of this valuable resource.