Submitted to: Food and Bioprocess Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/8/2014
Publication Date: 9/3/2014
Publication URL: http://handle.nal.usda.gov/10113/59557
Citation: Zhao, X., Yang, W., Chung, S., Sims, C.A., Otwell, S.W., Rababah, T.M. 2014. Reduction of IgE immunoreactivity of whole peanut (Arachis hypogaea L.) after pulsed light illumination. Food and Bioprocess Technology. 7(9):2637-2645. Interpretive Summary: Pulsed light (PL) is an emerging food processing technology which has a potential to destruct microorganisms, and therefore, decontaminate food products. Previously we have shown that PL is also capable of reducing the levels of allergens from different food extracts (for example, peanut extract). In this study, we further tested the efficacy of PL in reducing peanut allergens from a whole peanut kernel (i.e., a solid phase rather than previous liquid phase). We tested different illumination durations and sample distances from the lamp. After PL treatment, we extracted the proteins from the whole peanut, and compared them to untreated proteins in terms of their allergenic capacity using immunochemical techniques that involved human serum containing antibodies (called IgE) that reacted with peanut allergens. Results showed that the allergen levels along with the reactions or binding between the allergens and IgE antibodies were reduced as a result of PL treatment. The degree of reduction in allergenic potential (i.e., binding of IgE to allergens) of the PL-treated peanut kernel was 80%, compared to the untreated. We concluded that PL treatment could lead to a marked reduction in the allergenic capacity of whole peanut kernel. If confirmed by clinical or animal studies, the research would find applications in the development of hypoallergenic peanut kernel.
Technical Abstract: Pulsed light (PL), a novel food processing and preservation technology, has been shown in literature to reduce allergen levels on peanut, soybean, almond, and shrimp protein extracts. This study investigated how PL affected the immunoreactivity of whole peanut kernels at two sample-to-lamp distances (7 and 10 cm) and a PL frequency of 3 pulses/s. A combination of different illumination durations and distances were tested to explore the effective conditions for PL roasting of whole peanuts. After the PL treatments, crude proteins of the whole peanuts were extracted and compared to that of the raw peanuts (control) in vitro for allergen reactivity using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, dot blot, and enzyme-linked immunosorbent assay (ELISA) with pooled plasma of allergenic patients. The SDS-PAGE, Western blot, dot blot results all showed that PL was capable of mitigating all major allergens of whole peanut kernels to an undetectable level. Indirect ELISA results showed 80% signal reduction for the PL-treated peanut as compared to raw peanut. A closer distance (7 cm) between the PL lamp and the sample resulted in stronger reduction of IgE immunoreactivity than 10 cm.