Pulsed ultraviolet light and pulsed electric fields reduce peanut allergenic potency.

Peanut allergy is one of the most serious hypersensitivity reactions to foods and imposes a growing threat to a certain population. Research indicates that roasting peanuts can increase the allergenic potency of the product.

In research at Alabama A&M University, investigators examined the effects of two non-thermal techniques--pulsed electric fields (PEFs) and pulsed ultraviolet (PUV) light--on the allergenic potency of raw peanut protein extracts. The results of these treatments were compared to roasting the peanuts at 165 C for 15 minutes. PUV light alone or PEFs in combination with PUV light helped reduce the allergenic potency of peanut extracts. These techniques could facilitate the development of hypoallergenic peanut-based products.

For PEF, 60 mL of extract were treated in a 4 J PEF processor at 43.2 KV per cm of field strength for 47 [micro]s. Several PUV light treatments were used: PUV1 was a 3-mL extract subjected to a Xenon RS-3000 C for 4 minutes; PUV2 was the same treatment for 2 minutes. A third treatment, PUV3, incorporated PEF and PUV2.

The scientists analyzed the resultant supernatants for changes in allergen levels and immunoglobulin E (IgE) binding. To do this, they used sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and a competitive inhibition Elisa, respectively. SDS-PAGE showed that levels of two major peanut allergens, Ara h 1 and Ara h 3, were reduced in all of the treated extracts except the first one. Another major peanut allergen, Ara h 2, was unaffected by the PEF or PUV light treatments.

Analyses of IgE binding revealed a seven-fold decrease in the allergenic potency of the PUV1 and PUV3 extracts, compared to the allergenic potency of a roasted extract. The degree of allergenic potency of each extract varied. The roasted extract had a greater allergenic potency than did the untreated raw extract. The allergenic potency of the PEF treatment was greater than that of PUV2. The extract with the least allergenic potency was the one that underwent the PUV3 treatment.

Further information. Wade Yang, Department of Food and Animal Sciences, Alabama A&M University, A-108, Carver Complex Thomas Wing, Normal, AL 35762; phone: 256-372-4158; fax: 256-372-5432; email: weihua.yang@email.aamu.edu.