Electrophoretic Behavior in Relation to the Structural Integrity of Codfish Parvalbumin upon Heat Treatment

Exploring the impact of processing temperatures on cod protein modifications by α, β-unsaturated aldehydes using a clickable probe

To investigate the effects of processing temperatures on α, β-unsaturated aldehyde-mediated modifications of cod protein, a clickable probe, 4-(2-Propyn-1-yloxy)-2-butenal (yne-ACR), was developed to simulate α, β-unsaturated aldehyde modifications on cod protein in simulated processing systems (25 °C, 90 °C, and 180 °C). Processing at 180 °C resulted in a 3-fold increase in the hydrophobicity, while modifications under thermal processing had limited effects on the content of free nucleophilic amino acids. However, modification at 180 °C significantly increased the content of carbonylated proteins to 14.7 nmol/mg protein. Cod protein modified during thermal processing (90 °C and 180 °C) exhibited superior emulsifying and foaming properties than those subjected to heating alone. Cod protein processed at 90 °C exhibited 757 identified modified components, representing the highest number among the three processing temperatures, and thermally induced structural changes in cod protein facilitated multiple modifications on a single peptide. These findings provide new tools and insights for the study of food protein modification.

A Comparison of the Structural Changes and IgG Immunobinding Activity of Parvalbumin in Salangid Icefish (Neosalanx taihuensis) After Glycation and Ultra-High Pressure Treatment

The aim of this study was to compare the effects of glycation and ultra-high pressure (UHP) treatment on the structure and IgG immunobinding activity of Salangidae icefish PV. The Circular Dichroism (CD) and Fluorescence Spectroscopy (FS) findings indicated that the glycation significantly affected both the secondary and tertiary structures of PV. However, the impact of UHP processing on the structure of PV was found to be less significant compared to the glycation. Western Blot analysis also revealed that the glycation markedly reduced the antigen specificity of PV. Conversely, UHP treatments at 300 MPa and 400 MPa slightly decreased the antigen specificity, whereas lower or excessively high pressures did not have a substantial impact. This research contributes valuable insights into strategies for reducing the allergenic potential of Salangid icefish.

Purification, Characterization, and Crystal Structure of Parvalbumins, the Major Allergens in Mustelus griseus

Fish play important roles in human nutrition and health, but also trigger allergic reactions in some population. Parvalbumin (PV) represents the major allergen of fish. While IgE cross-reactivity to PV in various bony fish species has been well characterized, little information is available about allergens in cartilaginous fish. In this study, two shark PV isoforms (named as SPV-I and SPV-II) from Mustelus griseus were purified. Their identities were further confirmed by mass spectroscopic analysis. IgE immunoblot analysis showed that sera from fish-allergic patients reacted to both SPV-I and SPV-II, but the majority of sera reacted more intensely to SPV-I than SPV-II. Thermal denaturation monitored by CD spectrum showed that both of the SPV allergens are highly thermostable. SPV-I maintained its IgE-binding capability after heat denaturation, while the IgE-binding capability of SPV-II was reduced. The results of crystal structure showed that SPV-I and SPV-II were similar in their overall tertiary structure, but their amino acid sequences shared lower similarities, indicating that the differences in the IgE-binding capabilities of SPV-I and SPV-II might be due to differential antigen epitopes in these two isoforms.