Food allergens are mainly naturally-occurring proteins with immunoglobulin E (IgE)-binding epitopes. Understanding the structural and immunogenic characteristics of allergenic proteins is essential in assessing whether and how food processing techniques reduce allergenicity. We here discuss the impacts of food processing technologies on the modification of physicochemical, structural, and immunogenic properties of allergenic proteins. Detection techniques for characterizing changes in these properties of food allergens are summarized. Food processing helps to reduce allergenicity by aggregating or denaturing proteins, which masks, modif ies, or destroys antigenic epitopes, whereas, it cannot eliminate allergenicity completely, and sometimes even improves allergenicity by exposing new epitopes. Moreover, most food processing techniques have been tested on purif ied food allergens rather than food products due to potential interference of other food components. We provide guidance for further development of processing operations that can decrease the allergenicity of allergenic food proteins without negatively impacting the nutritional profile.

Food allergy as a global health problem threatens food industry. Bee pollen (BP) is a typical food with allergenic potentials, although it performs various nutritional/pharmacological functions to humans. In this study, lactic acid bacteria (LAB) were used to ferment Brassica napus BP for alleviating its allergenicity. Four novel allergens (glutaredoxin, oleosin-B2, catalase and lipase) were identified with significant decreases in LAB-fermented BP (FBP) than natural BP by proteomics. Meanwhile, metabolomics analysis showed significant increases of 28 characteristic oligopeptides and amino acids in FBP versus BP, indicating the degradation of LAB on allergens. Moreover, FBP showed alleviatory effects in BALB/c mice, which relieved pathological symptoms and lowered production of allergic mediators. Microbial high-throughput sequencing analysis showed that FBP could regulate gut microbiota and metabolism to strengthen immunity, which were closely correlated with the alleviation of allergic reactivity. These findings could contribute to the development and utilization of hypoallergenic BP products.

Bee pollen has potential in preventing metabolic syndrome (MetS). The present study aimed to investigate the effect of yeast-fermented wall-broken bee pollen (YB) intervention on ICR mice with MetS induced with a high-fat (HF) diet. After YB intervention in mice for 16 weeks, the effect on alleviating MetS was evaluated based on MetS serum parameters, hepatic oxidant status markers and gut microbial populations. The results of animal experiment showed that YB intervention attenuated MetS. Based on multivariate statistical analysis results, YB treatment significantly increased glutathione S-transferase (GST) and catalase (CAT) activities and decreased the malondialdehyde (MDA) level in the liver. Further investigation showed that YB restored the Nrf-2-Keap-1 pathway to alleviate oxidative stress. Additionally, gut microbial community analysis revealed that YB restored the increase in the Firmicutes to Bacteroidetes (F/B) ratio (6.94 for the HF group and 3.74 for HF+YB group) and improved Lactobacillus and Lactococcus abundance induced by the HF diet. Overall, YB improved function and prevented MetS by modulating the gut microbiota and alleviating oxidative stress.