A Combined Proteomic and Metabolomic Strategy for Allergens Characterization in Natural and Fermented Brassica napus Bee Pollen.

Shuting Yin,Liuwei Zhao,Yusuo Jiang,Yuxiao Tao,Qiangqiang Li,Liming Wu,Xiaofeng Xue,Lifeng Meng

doi:10.3389/fnut.2022.822033

Abstract

Bee pollen is consumed for its nutritional and pharmacological benefits, but it also contains hazardous allergens which have not been identified. Here, we identified two potential allergens, glutaredoxin and oleosin-B2, in Brassica napus bee pollen using mass spectrometry-based proteomics analyses, and used bioinformatics to predict their antigenic epitopes. Comparison of fermented (by Saccharomyces cerevisiae) and unfermented bee pollen samples indicated that glutaredoxin and oleosin-B2 contents were significantly decreased following fermentation, while the contents of their major constituent oligopeptides and amino acids were significantly increased based on metabolomics analyses. Immunoblot analysis indicated that the IgE-binding affinity with extracted bee pollen proteins was also significantly decreased after fermentation, suggesting a reduction in the allergenicity of fermented bee pollen. Furthermore, fermentation apparently promoted the biosynthesis of L-valine, L-isoleucine, L-tryptophan, and L-phenylalanine, as well as their precursors or intermediates. Thus, fermentation could potentially alleviate allergenicity, while also positively affecting nutritional properties of B. napus bee pollen. Our findings might provide a scientific foundation for improving the safety of bee pollen products to facilitate its wider application.

Highlights

Bee pollen, plant pollen grains collected by honeybees and aggregated by salivary gland secretions and flower nectar, has been widely considered a complete food of abundant nutrients and bioactive compounds [1]
To identify potential allergens in B. napus bee pollen, we used a label-free proteomics strategy based on the NCBI and Uniprot protein databases for Brassica
Method uses two specific comparison rules: [1] the word matching rule requires that proteins with more than six consecutive amino acids matching the sequence of a known allergen are considered potential allergens; [2] the sliding window matching rule requires proteins with more than 35%

Summary

Introduction

Plant pollen grains collected by honeybees and aggregated by salivary gland secretions and flower nectar, has been widely considered a complete food of abundant nutrients and bioactive compounds [1]. Puumalainen et al identified 2S albumins, or napins, as potential allergens in B. napus pollen [6]. Another eight potential allergens of B. napus pollen were detected using immunoblot method their primary structures have not been determined [7]. The studies investigating allergens of bee pollen from B. napus remain limited, thereby resulting in a threat to its consumption

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Conclusion