Thermal Processing of Peanut Grains Impairs Their Mimicked Gastrointestinal Digestion While Downstream Defatting Treatments Affect Digestomic Profiles

The Rising Incidence of Food Allergies and Infant Food Allergies

Infant food allergies have become a continually rising global health issue. There is a lack of global standardized recommendations on measures for prevention and treatment of infant food allergies because of the variations in ethnic, social, educational, and healthcare practices that affect the outcomes of research studies. Food allergies can cause mild to severe reactions and can affect social and emotional aspects of life up to the adolescent stage and are sometimes never outgrown. Maternal factors such as in utero supply of antibodies, dietary diversity, genetics, food allergen consumption during pregnancy, gut microbiota, and breastfeeding characteristics are the cornerstones of the development of an infant's immune system. In this review, we discuss how prenatal and postnatal factors affect the gut microbiota and development of an infant's immune system, and the current therapies available. The importance of food processing and education of stakeholders in the care of infants with food allergies is also discussed.

Effect of Peanut Protein Treated with Alkaline Protease and Flavorzyme on BALB/c Mice

This article aims to analyze the effects of enzyme treatment concentration, temperature, and time on peanut protein so as to obtain an optimal enzymatic hydrolysis condition for flavorzyme (Fla) and alkaline protease (Alk). The results were as follows: enzymatic hydrolysis temperature 60 °C and 55 °C, enzyme concentration 10% and 4%, enzymatic hydrolysis time 80 min and 60 min, and double enzyme hydrolysis ratio 2% Fla + 5% Alk, respectively. The BALB/c mice were sensitized with gavage of peanut protein before and after enzyme treatment to evaluate the effects of different enzyme treatments on peanut allergenicity. Compared with the mice sensitized with raw peanuts, the weight growth rate of the mice sensitized with enzyme treatment peanut increased but not as much as the control, the degranulation degree of mast cell and basophils decreased, the inflammatory infiltration and congestion in jejunum and lung tissue decreased, the expression of proinflammatory factors and thymic stromal lymphopoietin (TSLP) gene decreased, and the secretion of specific antibodies (IgE, and IgG) decreased, and the binding ability of peanut protein with peanut-specific IgE antibodies decreased as well. The results above indicate that the allergenicity of peanut protein decreases after enzyme treatment and the dual enzyme (Fla + Alk) treatment can be much more efficient.

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.

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

Post-translational modifications (PTMs) are covalent changes occurring on amino acid side chains of proteins and yet are neglected structural and functional aspects of protein architecture. The objective was to detect differences in PTM profiles that take place after roasting using open PTM search. We conducted a bottom-up proteomic study to investigate the impact of peanut roasting on readily soluble allergens and their PTM profiles. Proteomic PTM profiling of certain modifications was confirmed by Western blotting with a series of PTM-specific antibodies. In addition to inducing protein aggregation and denaturation, roasting may facilitate change in their PTM pattern and relative profiling. We have shown that Ara h 1 is the most modified major allergen in both samples in terms of modification versatility and extent. The most frequent PTM was methionine oxidation, especially in roasted samples. PTMs uniquely found in roasted samples were hydroxylation (Trp), formylation (Arg/Lys), and oxidation or hydroxylation (Asn). Raw and roasted peanut extracts did not differ in the binding of IgE from the serum of peanut-sensitised individuals done by ELISA. This study provides a better understanding of how roasting impacts the PTM profile of major peanut allergens and provides a good foundation for further exploration of PTMs.

INFOGEST Digestion Assay of Raw and Roasted Hazelnuts and Its Impact on Allergens and Their IgE Binding Activity

Most of the food allergens sensitized via the gastrointestinal tract resist thermal treatments and digestion, particularly digestion by pepsin. Roasted hazelnuts are more commonly consumed than raw ones. Since no studies have characterized gastric digestion protein fragments of raw and roasted hazelnuts nor their IgE binding properties, we compared these aspects of raw and roasted hazelnuts’ gastric digesta obtained by INFOGEST protocol. Their electrophoretically resolved profiles were probed with hazelnut allergic patients’ sera in 1D and 2D immunoblots. Electrophoretic profiles demonstrated pepsin digestion of all hazelnut allergens to varying extents. While 2D immunoblots indicated that roasting slightly reduced allergenicity, IgE ELISA with the pool of sera showed a slight significant (10%) increase in IgE binding in both gastric digesta. Cor a 9 isolated from the raw and roasted hazelnuts, characterized by far and near CD, remained stable after roasting, with preserved IgE reactivity. Its immunoreactivity contribution by inhibitory ELISA was noticeable in raw and roasted hazelnut digesta; its activity was slightly stronger in the roasted preparations. Roasting has a visible impact on proteins; however, it did not affect overall IgE reactivity. Gastric digestion slightly increases the overall IgE reactivity in raw and roasted hazelnuts, and may therefore impact the profiles of allergens and their fragments available to interact with the immune system in the small intestine.

Probiotic fermentation improves the bioactivities and bioaccessibility of polyphenols in Dendrobium officinale under in vitro simulated gastrointestinal digestion and fecal fermentation

The objective of the research was to investigate and compare the bioactivities and bioaccessibility of the polyphenols (PPs) from Dendrobium officinale (DO) and probiotic fermented Dendrobium officinale (FDO), by using in vitro simulated digestion model under oral, gastric and intestinal phases as well as colonic fermentation. The results indicated that FDO possessed significantly higher total phenolic contents (TPC) and total flavonoid contents (TFC) than DO, and they were released most in the intestinal digestion phase with 6.96 ± 0.99 mg GAE/g DE and 10.70 ± 1.31 mg RE/g DE, respectively. Using high-performance liquid chromatography (HPLC), a total of six phenolic acids and four flavonoids were detected. In the intestinal phase, syringaldehyde and ferulic acid were major released by DO, whereas they were p-hydroxybenzoic acid, vanillic acid, and syringic acid for FDO. However, apigenin and scutellarin were sustained throughout the digestion whether DO or FDO. As the digestive process progressed, their antioxidant ability, α-amylase and α-glucosidase inhibitory activities were increased, and FDO was overall substantially stronger in these activities than that of DO. Both DO and FDO could reduce pH values in the colonic fermentation system, and enhance the contents of short-chain fatty acids, but there were no significantly different between them. The results of the 16S rRNA gene sequence analysis showed that both DO and FDO could alter intestinal microbial diversity during in vitro colonic fermentation. In particular, after colonic fermentation for 24 h, FDO could significantly improve the ratio of Firmicutes to Bacteroidetes, and enrich the abundancy of Enterococcus and Bifidobacterium (p < 0.05), which was most likely through the carbohydrate metabolism signal pathway. Taken together, the PPs from DO and FDO had good potential for antioxidant and modulation of gut bacterial flora during the digestive processes, and FDO had better bioactivities and bioaccessibility. This study could provide scientific data and novel insights for Dendrobium officinale to be developed as functional foods.

Effect of Sample Preparation on the Detection and Quantification of Selected Nuts Allergenic Proteins by LC-MS/MS

The detection and quantification of nut allergens remains a major challenge. The liquid chroma-tography tandem mass spectrometry (LC-MS/MS) is emerging as one of the most widely used methods, but sample preparation prior to the analysis is still a key issue. The objective of this work was to establish optimized protocols for extraction, tryptic digestion and LC-MS analysis of almond, cashew, hazelnut, peanut, pistachio and walnut samples. Ammonium bicar-bonate/urea extraction (Ambi/urea), SDS buffer extraction (SDS), polyvinylpolypyrroli-done (PVPP) extraction, trichloroacetic acid/acetone extraction (TCA/acetone) and chloro-form/methanol/sodium chloride precipitation (CM/NaCl) as well as the performances of con-ventional tryptic digestion and microwave-assisted breakdown were investigated. Overall, the protein extraction yields ranged from 14.9 ± 0.5 (almond extract from CM/NaCl) to 76.5 ± 1.3% (hazelnut extract from Ambi/urea). Electrophoretic profiling showed that the SDS extraction method clearly presented a high amount of extracted proteins in the range of 0-15 kDa, 15-35 kDa, 35-70 kDa and 70-250 kDa compared to the other methods. The linearity of the LC-MS methods in the range of 0 to 0.4 µg equivalent defatted nut flour was assessed and recovery of internal standards GWGG and DPLNV(d8)LKPR ranged from 80 to 120%. The identified bi-omarkers peptides were used to relatively quantifier selected allergenic protein form the inves-tigated nut samples. Considering the overall results, it can be concluded that SDS buffer allows a better protein extraction from almond, peanut and walnut samples while PVPP buffer is more appropriate for cashew, pistachio and hazelnut samples. It was also found that conventional overnight digestion is indicated for cashew, pistachio and hazelnut samples, while microwave assisted tryptic digestion is recommended for almond, hazelnut and peanut extracts.