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United States Department of Agriculture

Agricultural Research Service

Research Project: REDUCING THE ALLERGENIC PROPERTIES OF PEANUTS Title: The effects of boiling on the allergenic properties of tropomyosin of shrimp (litopenaeus vannamei).

Authors
item Liu, Guang-Ming -
item Cheng, Hsiaopo
item Nesbit, Jacqueline
item Su, Wen-Jin -
item Cao, Min-Jie -
item Maleki, Soheila

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 20, 2009
Publication Date: January 14, 2010
Citation: Liu, G., Cheng, H., Nesbit, J.B., Su, W., Cao, M., Maleki, S.J. 2010. The effects of boiling on the allergenic properties of tropomyosin of shrimp (litopenaeus vannamei). Journal of Food Science. 75:T1-T5.

Interpretive Summary: Shrimp play an important role in human nutrition, and is responsible for severe allergic reactions. The thermal stability of raw and boiled shrimp tropomyosins (TM) has never been reported. The aims of the study were to compare the stability of raw and boiled shrimp TM, and evaluate how the cooking process may alter the allergenicity. Boiled extracts were prepared after the raw material was boiled for 10 minutes in water. Raw and boiled extracts were homogenized, freeze-dried, and extracted with a buffer. Afterward, TM was purified from the extracts by standard protein purification techniques, and the structures were compared. The raw and boiled extracts were analyzed for protein profiles. The allergenicity was compared by measuring the binding of specific immunoglobulin E (IgE) from the blood of shrimp allergic patients to the raw and boiled extracts. The protein content in the boiled extracts decreased, and important differences were detected. IgE binding showed that both types of extracts retained similar allergenic characteristics. The thermal stability of boiled TM was shown to be less than that of raw TM. Raw extracts produce significantly higher IgE binding than boiled extracts; however, the purified TM from boiled shrimp shows enhanced IgE binding over that of purified TM from raw shrimp, therefore, the use of boiled TM seems to be more effective in diagnosing seafood allergy.

Technical Abstract: Shrimp play an important role in human nutrition, and is responsible for severe hypersensitivity reactions. The thermal stability of raw and boiled shrimp tropomyosins (TM) has never been reported. The aims of the study were to compare the stability of raw and boiled shrimp TM of Litopenaeus vannamei, and evaluate how the cooking process may alter the allergenicity of Lit. vannamei. Boiled extracts were prepared after the raw material was boiled for 10 minutes in water. Raw and boiled extracts were homogenized, freeze-dried, and extracted with Tris-buffer. Afterward, TM was purified from the extracts by centrifugation, ammonium sulfate fractionation, and anion-exchange chromatography. The raw and boiled extracts were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and two-dimensional (2-D) electrophoresis. Specific IgE against the extracts were measured by western-blot and inhibition enzyme-linked immunosorbent assay (iELISA). The secondary structure of the purified TM was analyzed by circular dichroism (CD). Dot-blot experiments were performed to measure IgE binding to purified TM. The protein content in the boiled extracts decreased, and important differences were detected by SDS-PAGE and 2-D electrophoresis. Western-blot showed that both types of extracts retained similar allergenic characteristics. iELISA results showed that raw extracts produced significantly higher IgE binding than boiled extracts, while dot-blot assay demonstrates increased IgE binding to TM purified from boiled shrimp than to that of raw shrimp. The secondary structure of the purified TM was confirmed by CD analysis showing minimums at 222 and 208 nm, typical of alpha-helical secondary structure. The thermal stability of boiled TM was shown to be less than that of raw TM. Raw extracts produced significantly higher IgE binding than boiled extracts, however, the purified TM from boiled shrimp shows enhanced IgE binding over that of purified TM from raw shrimp; therefore, the use of boiled TM seems to be more effective in diagnosing seafood allergy. The cooking process may provide the effect to shrimp extracts.

Last Modified: 10/24/2014