Thermal induced the structural alterations, increased IgG/IgE binding capacity and reduced immunodetection recovery of tropomyosin from shrimp (Litopenaeus vannamei)

Understanding the Mechanism of Increased IgG/IgE Reactivity but Decreased Immunodetection Recovery in Thermally Induced Shrimp (Litopenaeus vannamei) Tropomyosin via Multispectroscopic and Molecular Dynamics Simulation Techniques

“…Similarly, our recent findings also confirmed that the major allergen TM could retain its extractability and IgG/IgE immunoreactivity after various cooking treatments. , Additionally, both heat-treated nTM and rTM showed higher IgG/IgE binding capacity than the control (25 °C), and autoclaved TM displayed the highest IgG/IgE binding value according to IgG/IgE immunoblotting and indirect ELISA analysis. Similarly, our recent findings demonstrated that the TM from different cooked shrimp (Litopenaeus vannamei) extracts showed significantly increased IgG/IgE binding capacity. , The increased IgE reactivity from TM also was found in the investigation of cooked extracts of blue swimmer crab (Portunus pelagicus) and other crustacean extracts, including shrimps (Penaeus sp), American lobster (Homarus sp), and spiny lobster (Palinurus sp), which might be attributed to the alteration of epitopes, thus promoting the antigen–antibody interaction. , Significantly, the rTM showed higher IgG binding capacity and lower IgE binding capacity, which might be due to their structural difference. Furthermore, the in vitro digestibility of both heat-treated nTM and rTM was significantly improved compared to the control, and the digested fraction from autoclaved TM could be detected within 1 min of SGF and SIF digestion.…”

“…Specifically, the percentage of α-helix was reduced by 22.4% (nTM) and 15.1% (rTM) in the autoclaved samples (Figure B). A similar reduction in α-helix percentage was in good agreement with the investigations of thermal-treated shrimp (Litopenaeus vannamei) TM at 95 °C, purified TMs from various cooked shrimp (Litopenaeus vannamei), and high pressure-treated Scylla paramamosain . According to previous reports, as a dimeric-helical coiled-coil protein along TM’s entire length, the interchain hydrophobic interactions in terms of the repeating pattern of nonpolar and polar residues in TM’s amino acid sequence play a vital role in stabilizing its structure. , The secondary structure alteration and rearrangement due to thermal processing would lead to more unordered structure elements (β-turn and random coil structure), which could cause the flexibility enhancement and the breakdown of hydrophobic interactions of heated TM.…”

“…To comply with labeling guidelines and safeguard the health of food-allergic consumers, sELISA is most commonly used as a simple, high-throughput, low-cost, highly sensitive, and specific technique for analyzing allergens in foods. , Heat treatments resulted in a considerably lower recovery of TM according to sELISA analysis, and the maximal underestimation recovery was observed in autoclaved TM with 39.2 and 74.8% reduction in PcAb sELISA tests and 50.1 and 91.6% reduction in mAb sELISA tests when compared to raw TM (Figure ). Similarly, a significant reduction in TM recovery (48.48–90.44%) also was observed in the investigation of various cooked shrimps (Litopenaeus vannamei) . The obvious underestimation in TM immunodetection recovery due to heating treatments was primarily attributed to the structural alterations and epitope masking. , It is noteworthy that the rTM recovery displayed a significantly lower recovery of TM than nTM under various heating conditions, which further confirmed that structural alterations could induce obvious underestimation in immunodetection recovery of TM.…”

“…Similarly, a significant reduction in TM recovery (48.48−90.44%) also was observed in the investigation of various cooked shrimps (Litopenaeus vannamei). 34 The obvious underestimation in TM immunodetection recovery due to heating treatments was primarily attributed to the structural alterations and epitope masking. 6,34 It is noteworthy that the rTM recovery displayed a significantly lower recovery of TM than nTM under various heating conditions, which further confirmed that structural alterations could induce obvious underestimation in immunodetection recovery of TM.…”

“…A certain number of capture antibodies are first coated in the microtiter plates for capturing the target analyte, and then another HRP-labeled detection antibody was put in to develop the antibody–antigen–antibody complex. The chance of antibody–antigen–antibody complex production will considerably be suppressed as a result of fewer IgG-binding sites of allergens and ultimately cause a significant underestimation of TM recovery. , It is worth noting that the immunodetection recovery of rTM displayed a significantly lower level compared to the nTM, which is primarily responsible for the less percentage of α-helix structures with more curled or folded conformation in rTM. A significant role for antigen-binding sites in sandwich immunodetection could be proved from the above results.…”