Comparison of the phytohaemagglutinin from red kidney bean (Phaseolus vulgaris) purified by different affinity chromatography

Galactose-functionalized methacrylate polymers as affinity sorbents for extraction of food allergen lectins

In this study, glycidyl methacrylate (GMA)-based materials functionalized with different galactose derivatives were prepared to be used as affinity sorbents for solid-phase extraction (SPE) of several food allergen lectins (such as phytohemagglutinin (PHA)). First, GMA-based polymers were synthesized and then galactose derivatives were immobilized onto the GMA surface using two different synthetic routes. In the first approach, the bare polymer was modified with ethylenediamine and glutaraldehyde, and subsequently two galactose derivatives were immobilized. In the second strategy, the starting polymer was modified with cystamine and gold nanoparticles (AuNPs), on which a thiolated galactose derivative was subsequently anchored. The resulting materials were characterized by scanning electron microscopy and used as SPE sorbents for the isolation of PHA (as probe protein) from food matrices. Different SPE parameters (sample pH, eluent solution composition, binding capacity, sample volume, selectivity and reusability) were evaluated. The material that provided the best PHA recovery (98%) was the one obtained in the second approach, being this material successfully applied to the selective extraction of PHA and other similar lectins from different foods (red and lima dried beans, fresh soybeans and biscuits containing soybean protein traces as indicated in their label). After SDS-PAGE of eluates, all samples only exhibited the characteristic PHA band around 30 kDa, suggesting the high potential of the developed material for application in food allergy field.

Detection of Lectin Protein Allergen of Kidney Beans (Phaseolus vulgaris L.) and Desensitization Food Processing Technology

With the increase of food allergy events related to not properly cooked kidney beans (Phaseolus vulgaris L.), more and more researchers are paying attention to the sensitization potential of lectin, one of the major storage and defensive proteins with the specific carbohydrate-binding activity. The immunoglobulin E (IgE), non-IgE, and mixed allergic reactions induced by the lectins were inducted in the current paper, and the detection methods of kidney bean lectin, including the purification strategies, hemagglutination activity, specific polysaccharide or glycoprotein interactions, antibody combinations, mass spectrometry methods, and allergomics strategies, were summarized, while various food processing aspects, such as the physical thermal processing, physical non-thermal processing, chemical modifications, and biological treatments, were reviewed in the potential of sensitization reduction. It might be the first comprehensive review on lectin allergen detection from kidney bean and the desensitization strategy in food processing and will provide a basis for food safety control.

Effects of Soaking on the Functional Properties of Yellow-Eyed Bean Flour and the Acceptability of Chocolate Brownies

Dried beans are an excellent source of protein, soluble fiber, and resistant starch. In spite of their beneficial properties, the presence of off-flavors limits their use as alternate flour sources in food applications. Soaking and then masking with flavor compounds are effective methods to remove off-flavors in pulses; however, these strategies are not often combined in a single-food application. The objective of this study was to determine the effect of these combined strategies on the acceptability of brownies made with bean flour and whether soaking affected the functional properties of the flour samples. Yellow-eyed (YE) beans were soaked for 24 hr, dried in an oven (treated), and then ground to form flour using a kitchen mill. The check-all-that-apply scores revealed that brownies made with 100% YE flour had nutty and beany flavors. However, consumer liking of brownies made with 50:50 and 25:75 all-purpose (AP):YE-treated flour blends, respectively, were not significantly different from the control brownies made with AP flour. Starch content varied significantly among the treated (42.9 ± 3.2%, P < 0.05) and untreated YE bean flour samples (35.3 ± 1.9%). The treated YE flour showed the highest water absorption index, 3.69 ± 0.12. Overall, combining soaking and the use of chocolate were successful strategies to reduce off-flavors in cake-style brownies, which suggest that up to 50% treated YE flours may be used as a suitable partial replacer of AP flour in chocolate brownies. PRACTICAL APPLICATION: Soaking yellow-eyed (YE) beans prior to milling, combined with the use of chocolate were successful strategies to mask off-flavors in cake-style brownies. The significance of the findings of this study lies in the fact that treated YE flours may be used as a suitable partial replacer of AP flour in chocolate brownies. The use of these strategies has the potential to increase the consumption of pulse flours in Canada.

Separation and Enrichment of Lectin from Zihua Snap-Bean (Phaseolus vulgaris) Seeds by PEG 600-Ammonium Sulfate Aqueous Two-Phase System

A fast and efficient method based on a polyethylene glycol (PEG) 600/(NH₄)₂SO₄ aqueous two-phase system for extracting lectin from Zihua snap-bean (Phaseolus vulgaris) seeds was established. According to a Box-Behnken design (BBD), involving four factors at three levels each subjected to analysis of variance (ANOVA) and response surface analysis, the protein recovery and the purification factor of lectin in the top phase were used as the response values of the variance analysis to acquire the multivariate quadratic regression model. SDS-PAGE electrophoresis and the hemagglutination test were used to detect the distribution of lectin in the aqueous two-phase system (ATPS). The obtained data indicated that lectin was preferentially partitioned into the PEG-rich phase, and the ATPS, composed of 15% (NH₄)₂SO₄ (w/w), 18% PEG 600 (w/w), 0.4 g/5 g NaCl and 1 mL crude extract, showed good selectivity for lectin when the pH value was 7.5. Under the optimal conditions, most of the lectin was assigned to the top phase in the ATPS, and the hemagglutination activity of the purified lectin in the top phase was 3.08 times that of the crude extract. Consequently, the PEG 600/(NH₄)₂SO₄ aqueous two-phase system was an effective method for separating and enriching lectin directly from the crude extract of Zihua snap-bean seeds.

Phaseolus vulgaris lectins: A systematic review of characteristics and health implications

Legume lectins are carbohydrate-binding proteins of non-immune origin. Significant amounts of lectins have been found in Phaseolus vulgaris beans as far back as in the last century; however, many questions about their potential biological roles still remain obscure. Studies have shown that lectins are anti-nutritional factors that can cause intestinal disorders. Owing to their ability to act as toxic allergens and hemagglutinins, the Phaseolus vulgaris lectins are of grave concern for human health and safety. Nonetheless, their potential beneficial health effects, such as anti-cancer, anti-human immunodeficiency virus (anti-HIV), anti-microbial infection, preventing mucosal atrophy, reducing type 2 diabetes and obesity, promoting nutrients absorption and targeting drugs, are of immense interest. The significance of Phaseolus vulgaris lectins in biological researches and the potential biomedical applications have placed tremendous emphasis on the development of purification strategies to obtain the protein in pure and stable forms. These purification strategies entail considerations such as effects of proteolysis, heating, gamma radiation, and high-hydrostatic-pressure that can have crucial outcomes in either eliminating or improving bioactivities of the lectins. Thus, up-to-date research findings of Phaseolus vulgaris lectins on different aspects such as anti-nutritional and health impacts, purification strategies and novel processing trends, are systematically reviewed.

Structure and Activity Changes of Phytohemagglutinin from Red Kidney Bean (Phaseolus vulgaris) Affected by Ultrahigh-Pressure Treatments

Phytohemagglutin (PHA), purified from red kidney beans (Phaseolus vulgaris) by Affi-Gel blue affinity chromatography, was subjected to ultrahigh-pressure (UHP) treatment (150, 250, 350, and 450 MPa). The purified PHA lost its hemagglutination activity after 450 MPa treatment and showed less pressure tolerance than crude PHA. However, the saccharide specificity and α-glucosidase inhibition activity of the purified PHA did not change much after UHP treatment. Electrophoresis staining by periodic acid-Schiff (PAS) manifested that the glycone structure of purified PHA remained stable even after 450 MPa pressure treatment. However, electrophoresis staining by Coomassie Blue as well as circular dichroism (CD) and differential scanning calorimetry (DSC) assay proved that the protein unit structure of purified PHA unfolded when treated at 0-250 MPa but reaggregates at 250-450 MPa. Therefore, the hemagglutination activity tends to be affected by the protein unit structure, while the stability of the glycone structure contributed to the remaining α-glucosidase inhibition activity.

Effects of high hydrostatic pressure treatments on haemagglutination activity and structural conformations of phytohemagglutinin from red kidney bean (Phaseolus vulgaris)

Red kidney beans were subjected to high hydrostatic pressure (HHP) treatment (50, 150, 250, 350, 450 MPa) and phytohaemagglutinin (PHA) was then extracted by affinity chromatography. It appeared that HHP treatment could increase crude extract yield and decrease its haemagglutination activity. For purified samples, PHA yield was not affected at pressures <450 MPa while the haemagglutination activity was noticeably reduced at 450 MPa. The structural changes were investigated using electrophoresis, size exclusion chromatography (SEC), Fourier transform infrared (FTIR) and differencial scanning calorimetry (DSC). Electrophoresis and SEC profiles revealed a new high molecular weight polymer after 450 MPa treatment. At pressures <450 MPa, FTIR showed an increase in β-sheet structure and a decrease in α-helix. At 450 MPa, the bands at 1688 cm(-1), representing aggregate strands and random coils, increased. The conclusions are that pressures <450 MPa can cause PHA unfolding and induce PHA aggregation at 450 MPa.