Effects of Extrusion, Boiling, Autoclaving, and Microwave Heating on Lupine Allergenicity

Abstract

Lupine flour has been reported as a causative agent of allergic reactions. However, the allergenicity of lupine after thermal processing is not well-known. For this purpose, the allergenic characteristics of lupine seeds after boiling (up to 60 min), autoclaving (121 degrees C, 1.18 atm, up to 20 min and 138 degrees C, 2.56 atm, up to 30 min), microwave heating (30 min), and extrusion cooking were studied. The IgE-binding capacity was analyzed by IgE-immunoblotting and CAP inhibition using a serum pool from 23 patients with lupine-specific IgE. Skin testing was carried out in four patients. An important reduction in allergenicity after autoclaving at 138 degrees C for 20 min was observed. IgE antibodies from two individual sera recognized bands at 23 and 29 kDa in autoclaved samples at 138 degrees C for 20 min. Autoclaving for 30 min abolished the IgE binding to these two components. A previously undetected band at 70 kDa was recognized by an individual serum. Therefore, prolonged autoclaving might have an important effect on the allergenicity of lupine with the majority of patients lacking IgE reactivity to these processed samples.

Immunoreactivity changes during lupin seed storage proteins digestion

“…During digestion peptide bonds are cleavaged, which results in protein structure changes. Such changes may cause the formation of new epitopes or uncovering antigenic determinants, initially hidden inside protein structures [11]. The trypsin activity resulted in complete loss of immunoreactivity of lupin seed proteins (Fig.…”

“…There is limited information describing change of antigenicity of lupin proteins during technological processing. The available data provide insight into immunoreactivity changes during heat treatment of lupin seed proteins [11]. Álvarez-Álvarez et al [11] analysed the effect of extrusion cooking, boiling, autoclaving, and microwave heating on the lupin seed proteins stability.…”

“…However, similar effects may also be caused by other lupin proteins characterised by different molecular weight, i.e., 13 kDa [6], 29 kDa [11], 34 kDa [12], 38 kDa [8], and 66 kDa [13]. The large heterogeneity of lupin seed proteins that exhibits Abstract Lupin seeds are already widely used as an ingredient in different food products.…”

Digestion susceptibility of seed globulins isolated from different lupin species

“…The main protein binding IgE of allergic characterised by molecular weights in the range of: 45-42 kDa [10,13,14]. Other potential allergens may be a protein with the molecular weight of 13 kDa [10], 29 kDa [15], 34 kDa [16], 38 kDa [12] and 66 kDa [17].…”

“…Álvarez-Álvarez et al [15] analysed the influence of extrusion cooking, autoclaving and microwave heating on the stability of lupin seed proteins. On the basis of the immunoblotting analysis, they found that only the autoclaving process causes a significant change in the amount of proteins that interact with the antibodies of people who were allergic to lupin.…”