Influence of Instant Controlled Pressure Drop (DIC) on Allergenic Potential of Tree Nuts

Abstract

Pistachio and cashew contain allergenic proteins, which causes them to be removed from the diet of allergic people. Former evidences have demonstrated that food processing (thermal and non-thermal) can produce structural and/or conformational changes in proteins by altering their allergenic capacity. In this study, the influence of Instant Controlled Pressure Drop (DIC) on the pistachio and cashew allergenic capacity has been studied. Western blot was carried out using IgG anti-11S and anti-2S and IgE antibodies from sera of patients sensitized to pistachio and cashew. DIC processing causes changes in the electrophoretic pattern, reducing the number and intensity of protein bands, as the pressure and temperature treatment increment what results in a remarkable decrease of detection of potentially allergenic proteins. The harshest conditions of DIC (7bar, 120s) markedly reduce the immunodetection of allergenic proteins, not only by using IgG (anti 11S and anti 2S) but also when IgE sera from sensitized patients were used for Western blots. Such immunodetection is more affected in pistachio than in cashew nuts, but it not completely removed. Therefore, cashew proteins are possibly more resistant than pistachio proteins. According these findings, Instant Controlled Pressure Drop (DIC) can be considered a suitable technique in order to obtain hypoallergenic tree nuts flour to be used in food industry.

Immunoglobulin E-Binding Pattern of Canadian Peanut Allergic Children and Cross-Reactivity with Almond, Hazelnut and Pistachio

“…Other resolved pistachio protein bands Pi1/Pi2 may correspond to Pis v 1 (2S albumin, 7 and 17 kDa); Pi3 band for Pis v 4; Pi4, Pi6 and Pi7 to Pis v 2 subunits, a superoxide dismutase of 26 kDa and Pi8 band for Pis v3 [ 50 , 51 , 52 ]. In addition, the location and molecular weight of the SDS-PAGE-resolved pistachio bands agreed well with the pistachio allergen identifications by liquid chromatography-mass spectrometry (LC/MS/MS) recently reported by Vicente et al [ 53 ]. Moreover, the SDS-PAGE analysis of the prepared extracts showed that the utilization of optimal nondenaturing protein extraction conditions that are specific to peanut and to each selected tree nut [ 23 ] allows for a representative extraction of allergens, thereby facilitating a comprehensive investigation of sIgE-binding to a majority of peanut, almond, hazelnut and pistachio allergens.…”

Effect of Instant Controlled Pressure Drop (DIC) Treatment on the Detection of Nut Allergens by Real Time PCR

“…This tested Real-Time PCR assay, especially in the case of cashew, allowed the authors to potentially detect traces of the nuts treated by heat and pressure at 7 bar and 2 min, which resulted in the appearance of an immunoreactive response in sensitive patients. In that study [ 26 ], pistachio proteins were also more susceptible to DIC processing than cashew ones, and, according to our results, it was possible to detect and quantify treated cashew with good efficiency, much better than pistachio ( Figure S3 ).…”

“…As mentioned with pistachio, Vicente and collaborators [ 26 ] showed, for the first time, by mass spectrometry, that major cashew allergens (Ana o 2 and Ana o 3) survived to DIC 7b 120 s processing, and triggered IgE immunoreactivity in patients, although a reduction in the capacity to bind IgE was noticeable. This tested Real-Time PCR assay, especially in the case of cashew, allowed the authors to potentially detect traces of the nuts treated by heat and pressure at 7 bar and 2 min, which resulted in the appearance of an immunoreactive response in sensitive patients.…”

“…Recently, Vicente and collaborators [ 26 ] studied the effect of DIC 7b 120 s treatment on the in vitro IgE binding capacity of pistachio, using sera from Spanish allergic patients. This treatment allowed the authors to reduce pistachio’s capacity to bind IgG and IgE, although it was able to trigger IgE immunoreactivity in several patients.…”

“…Treatment based on instantaneous controlled pressure drop (DIC) on foods and its effect on allergenicity has not been extensively analysed. Together with the recent study in cashew and pistachio [ 26 ], which have already been discussed, the studies about the influence of this treatment on the IgE reactivity of legumes and milk must be mentioned [ 31 , 32 ]. In the case of legumes [ 18 , 19 , 32 ], the application of DIC treatment at 6 bar for 3 min did not eliminate the immunoreactive capacity of peanut, chickpea and lentil allergens, but in the case of soybeans and lupin, it was markedly reduced.…”