Effect of Selected Nonthermal Processing Methods on the Allergen Reactivity of Atlantic White Shrimp (Litopenaeus setiferus)

Abstract

Food allergies are adverse reactions to food components and can cause moderate to severe symptoms and even death. To date, there is no cure for food allergy and often the only relief comes from complete avoidance of the problem foods. Thus, a demand for methods aimed to reduce allergens from food products is becoming a popular topic of study. Food processing techniques have the ability to alter food components such as allergens. In this study, the efficacy of using emerging nonthermal methods to reduce the detectable levels of the major shrimp allergen, tropomyosin (36-kDa), and attenuate immunoglobulin E (IgE) binding to shrimp extract was examined. Pulsed ultraviolet light (PUV) technology, which has been shown to reduce allergen levels in peanut and soybean samples, was the focus of this research. High hydrostatic pressure (HHP) and nonthermal plasma (NTP) processing were also examined. Atlantic white shrimp (Litopenaeus setiferus) extract was treated with PUV (3 pulses/s, 10 cm from light source) for 4 min. For NTP treatment, plasma was generated using a voltage of 30 kV and a frequency of 60 Hz and treatment was carried out for 1, 3, and 5 min at ambient temperature. To determine the effects of HHP, shrimp extracts were treated for 15 min at temperatures of 4, 21, and 70?C and a pressure of 600 MPa. Tropomyosin was compared in the untreated and treated shrimp samples by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblot, and enzyme-linked immunosorbent assay (ELISA). Results showed that levels of detectable tropomyosin and IgE binding to tropomyosin were reduced following PUV or NTP treatment. Dot blot and ELISA confirmed a decrease in tropomyosin reactivity following PUV or NTP treatment. Furthermore, PUV-treated samples were subjected to simulated human digestion to examine allergen stability. The PUV-treated samples remained less-reactive under simulated gastric and intestinal digestive conditions. Lastly, treating shrimp extract with HHP did not change allergen reactivity under the treatment conditions tested in this study. In conclusion, although HHP has little effect on shrimp allergen reactivity, PUV and NTP may be promising methods to reduce the allergenic potential of Atlantic white shrimp for the future manufacturing of less-allergenic food products. ( en )