Pistachio (Pistacia vera L.) Detection and Quantification Using a Murine Monoclonal Antibody-Based Direct Sandwich Enzyme-Linked Immunosorbent Assay

Abstract

A commercially available direct sandwich enzyme-linked immunosorbent assay (ELISA) (BioFront Technologies, Tallahassee, FL, USA) using murine anti-pistachio monoclonal antibodies (mAbs) as capture and detection antibodies was evaluated. The assay was sensitive (limit of detection = 0.09 ± 0.02 ppm full fat pistachio, linear detection range = 0.5-36 ppm, 50% maximum signal concentration = 7.9 ± 0.7 ppm), reproducible (intra- and inter-assay variability < 24% CV), and rapid (post-extraction testing time ∼ 1.5 h). The target antigen was stable and detectable in whole pistachio seeds subjected to autoclaving (121 °C, 15 psi, 15, 30 min), blanching (100 °C, 5, 10 min), frying (191 °C, 1 min), microwaving (500, 1000 W, 3 min), and dry roasting (140 °C, 30 min; 168 °C, 12 min). No cross-reactivity was observed in 156 food matrices, each tested at 100,000 ppm, suggesting the ELISA to be pistachio specific. The pistachio recovery ranges for spiked (10 ppm) and incurred (10-50000 ppm) food matrices were 93.1-125.6% and 35.7-112.2%, respectively. The assay did not register any false-positive or -negative results among the tested commercial and laboratory prepared samples.

Effects of the Maillard Reaction on the Immunoreactivity of Amandin in Food Matrices

“…Thermal processing, particularly in presence of reducing sugar, significantly reduced amandin immunoreactivity in several food matrices such as cookies, sponge cakes, almond bars, and almond brittles (Table ). Decreased amandin immunoreactivity was also found in almond‐incurred chocolate and cornflakes, which was in agreement with our previous observations (Su and others ; Liu and others ). The reduction in amandin immunoreactivity may be attributed to epitope masking or degradation due to presence of sugars in the system, loss of disulfide bonds in amandin, and/or loss of protein solubility due to thermal aggregation or matrix effect (for example, protein–polyphenol insoluble complex formation).…”

“…Preparation of thermally processed almond seeds and almond containing food have been reported (Su and others ; Liu and others ).…”

Pistachio nut allergy: An updated overview

“…In some cases, the immunoreactivity of pistachio nut proteins seemed to increase (like in blanching and frying conditions), which can probably be explained by a better accessibility of a buried epitope. The murine anti-pistachio monoclonal antibody recognised protein fractions of 50, 40 and 31 kDa that are likely to correspond to albumin and 11S globulin polypeptides in the pistachio nut (Liu, Chhabra, and Sathe 2015).…”

Comparison of Laboratory‐Developed and Commercial Monoclonal Antibody‐Based Sandwich Enzyme‐Linked Immunosorbent Assays for Almond (Prunus dulcis) Detection and Quantification

“… Almond incurred corn flakes: Forty five grams of sweet corn kernels (78% moisture) was ground in an Osterizer blender (speed setting “grind”; Galaxy model 869‐18R, Jaden Consumer Solutions, Boca Raton, Fla., U.S.A.) for 30 s with 50 mL of distilled water. Almond full fat flour was incurred at 0.5%, 1%, 2%, and 5% (w/w) final concentration and blended for another 30 s. The mixture was baked at 120 °C in a KitchenAid Architect II oven (KitchenAid, Benton Harbor, Mich., U.S.A.) until dry (Liu and others ). Typical yield of the final dry product was approximately 10 g. Almond incurred sponge cakes: Eggs (17 g) were beaten by a KitchenAid hand mixer (speed setting “1”) for 4 min.…”