|Butts, Christopher - Chris|
Submitted to: Clinical and Experimental Allergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2006
Publication Date: 6/2/2006
Citation: Pomes', A., Butts, C.L., Chapman, M. 2006. Quantification of ara h 1 in peanuts: roasting makes a difference. Journal of Clinical and Experimental Allergy. 36:824-830.
Interpretive Summary: Certain proteins in peanuts have been identified as causing most of the allergic reactions by sensitive individuals. One of those proteins is called Ara h 1 and is used in assays to quantify the allergenicity of peanuts. This study showed that allergenicity of runner type peanuts reached a maximum if roasted for 10-15 minutes. If peanuts were roasted for 20 minutes or more, the allergenicity decreased to much lower levels and approached the same level as raw peanuts. The study also showed that levels of Ara h 1 were essentially the same for four different runner peanut varieties. It also verified work by other researchers that immature peanuts did not have as much Ara h 1 as mature peanuts. This work also showed that a relatively simple test can be used to specifically measure Ara h 1, one of the allergens in peanut, instead of detecting the presence of all peanut proteins.
Technical Abstract: Increased allergenicity of roasted versus raw peanut has been reported by showing higher IgE binding to roasted peanut extracts. The objective was to study differences in Ara h 1 quantification between raw and roasted peanut using a specific monoclonal antibody-based ELISA, and to compare the Ara h 1 content from different peanut varieties and kernel sizes. Raw or oven-roasted (350°F for 5-30 minutes) runner peanuts were crushed and extracted at 60°C. Inhibition ELISA was used to study binding of Ara h 1 purified from raw or roasted peanut. Runner peanuts of four different cultivars were collected, shelled, sized and roasted for 15 minutes at 350°F. Ara h 1 in the extracts was compared by ELISA. Ara h 1 levels were up to 22 fold higher in roasted than in raw peanuts (820 versus 37 'g/ml, in a representative experiment) with an Ara h 1 peak at 10-15 minutes of roasting. Inhibition ELISA indicated that this increase was not due to conformational changes in the Ara h 1 monoclonal antibody epitopes. Ara h 1 was found at lower levels in number 1 than in jumbo and medium sized peanuts, and no differences were found among cultivars. These results suggest that roasting increases the efficiency of Ara h 1 extraction, and/or that the monoclonal antibody binding epitopes were more accessible in roasted peanut. Expression of Ara h 1 is associated with peanut maturity.