Proteomic Profiling of Major Peanut Allergens and Their Post-Translational Modifications Affected by Roasting

Physicochemical, techno-functional, biochemical and structural characterization of a protein isolate from groundnut (Arachis hypogaea L.) paste treated with high-intensity ultrasound

The objective of this research was to evaluate the effect of ultrasound (HISound) (200, 400 and 600 W; 15-30 min) on the physicochemical, biochemical and structural techno-functional properties of a groundnut paste protein isolate (GPPI). HISound increased the contents of free sulfhydryls (552.22 %), total sulfhydryls (124.68 %) and α-helix (389.75 %), as well as molecular flexibility (50.91 %), hydrophobic surface (38.99 %), and particle size (171.45 %) of GPPI, which improved protein solubility by 8.05 %, oil holding capacity by 73.54 %, emulsifying stability index by 226.25 % and foaming capacity by 216.00 %, compared with non-sonicated GPPI. Also, the microstructure analysis revealed smooth structures, with molecular weights in the range of 13.88-67.07 kDa. Pearson analysis determined some highly significant correlations (r ≥ 0.90, p < 0.01) between some GPPI protein properties. The improvement of GPPI properties by HISound could contribute to its use as an ingredient for human consumption.

Shrimp allergen extract immunotherapy induces prolonged immune tolerance in a gastro-food allergy mouse model

Food allergies are a global health problem that continues to grow annually, with a prevalence of more than 10%. Shrimp allergy is the most common and life-threatening allergy. There is no cure for food allergies, but shrimp allergen extract (SAE) offers promise as a treatment through allergen-specific immunotherapy (AIT). However, whether SAE induces immunological tolerance in seafood allergies remains to be established. This study aimed to determine the effectiveness of SAE in inducing immunological tolerance in a gastro-food allergy mouse model. For the immunotherapy evaluation, mice (n = 24) were intraperitoneally (i.p.) sensitized with 1 mg alum and 100 μg SAE in PBS on days 0, 7, and 14 and randomly divided into four groups of six: a negative control (NC) and high- to low-dose immunotherapy (HI, MI, and LI). The untreated group (n = 6) only received 1 mg alum in PBS (i.p.). All groups were challenged with 400 μg SAE (i.g.) on days 21, 22, 23, 53, and 58. Following the challenge, SAE-sensitized mice from the immunotherapy group were treated (i.p.) with 10 μg SAE for LI, 50 μg SAE for MI, and 100 μg SAE for HI on days 32, 39, and 46. The untreated and NC groups only received PBS (i.p.). All mice were euthanized on day 59. As the results, we found that SAE immunotherapy reduced systemic allergy symptom scores, serum IL-4 levels, IL-4 and FcεR1α mRNA relative expression, and mast cell degranulation in ileum tissue in allergic mice while increasing Foxp3 and IL-10 mRNA relative expression. Notably, we observed an increased ratio of IL-10 to IL-4 mRNA expression, demonstrating the efficacy of SAE immunotherapy in promoting desensitization. Thus, SAE can be developed as an immunotherapeutic agent for food allergies by inducing prolonged allergy tolerance with a wide range of allergen targets.

Mass Spectrometry Analysis on the Breakage of Allergens in High-Molecular-Mass Polymer of Roasted Peanuts

Peanut allergy is a prevalent and concerning food allergy. Roasting can introduce structural changes to peanut allergens, affecting their allergenicity, but the structure on the primary structure is unclear. Here, the breakage sites were identified by mass spectrometry and software tools, and structural changes were simulated by molecular dynamics and displayed by PyMOL software. Results revealed that the appearance frequencies of L, Q, F, and E were high at the N-terminal of the breakage site, while S and E were dominant at the C-terminal. In the conformational structure, breakage sites were found close to disulfide bonds and the Cupin domains of Ara h 1 and Ara h 3. The breakage of allergens destroyed linear epitopes and might change the conformation of epitopes, which could influence peanuts' potential allergenicity.

Antioxidant Properties of Protein-Rich Plant Foods in Gastrointestinal Digestion—Peanuts as Our Antioxidant Friend or Foe in Allergies

Thermally processed peanuts are ideal plant models for studying the relationship between allergenicity and antioxidant capacity of protein-rich foods, besides lipids, carbohydrates and phytochemicals. Peanut is highly praised in the human diet; however, it is rich in allergens (>75% of total proteins). One-third of peanut allergens belong to the products of genes responsible for the defence of plants against stress conditions. The proximate composition of major peanut macromolecules and polyphenols is reviewed, focusing on the identity and relative abundance of all peanut proteins derived from recent proteomic studies. The importance of thermal processing, gastrointestinal digestion (performed by INFOGEST protocol) and their influence on allergenicity and antioxidant properties of protein-rich plant food matrices is elaborated. Antioxidant properties of bioactive peptides from nuts were also considered. Moreover, there are no studies dealing simultaneously with the antioxidant and allergenic properties of protein- and polyphenol-rich foods, considering all the molecules that can significantly contribute to the antioxidant capacity during and after gastrointestinal digestion. In summary, proteins and carbohydrates are underappreciated sources of antioxidant power released during the gastrointestinal digestion of protein-rich plant foods, and it is crucial to decipher their antioxidant contribution in addition to polyphenols and vitamins before and after gastrointestinal digestion.

Peanut Allergenicity: An Insight into Its Mitigation Using Thermomechanical Processing

Peanuts are the seeds of a legume crop grown for nuts and oil production. Peanut allergy has gained significant attention as a public health issue due to its increasing prevalence, high rate of sensitization, severity of the corresponding allergic symptoms, cross-reactivity with other food allergens, and lifelong persistence. Given the importance of peanuts in several sectors, and taking into consideration the criticality of their high allergic potential, strategies aiming at mitigating their allergenicity are urgently needed. In this regard, most of the processing methods used to treat peanuts are categorized as either thermal or thermomechanical techniques. The purpose of this review is to provide the reader with an updated outlook of the peanut’s allergens, their mechanisms of action, the processing methods as applied to whole peanuts, as well as a critical insight on their impact on the allergenicity. The methods discussed include boiling, roasting/baking, microwaving, ultrasonication, frying, and high-pressure steaming/autoclaving. Their effectiveness in alleviating the allergenicity, and their capacity in preserving the structural integrity of the treated peanuts, were thoroughly explored. Research data on this matter may open further perspectives for future relevant investigation ultimately aiming at producing hypoallergenic peanuts.