Peanut Protein Research Articles

Effect of pH-Shift Treatment on IgE-Binding Capacity and Conformational Structures of Peanut Protein

Hypoallergenic processing is an area worthy of continued exploration. In the treatment of the peanut protein (PP), pH shift was applied by acidic (pH 1.0–4.0) and alkaline (pH 9.0–12.0) treatment, after which the pH was adjusted to 7.0. Following pH-shift treatment, PP showed a larger particle size than in neutral solutions. SDS-PAGE, CD analysis, intrinsic fluorescence, UV spectra, and surface hydrophobicity indicated the protein conformation was unfolded with the exposure of more buried hydrophobic residues. Additionally, the IgE-binding capacity of PP decreased after pH-shift treatment on both sides. Label-free LC–MS/MS results demonstrated that the pH-shift treatment induced the structural changes on allergens, which altered the abundance of peptides after tryptic digestion. Less linear IgE-binding epitopes were detected in PP with pH-shift treatment. Our results suggested the pH-shift treatment is a promising alternative approach in the peanut hypoallergenic processing. This study also provides a theoretical basis for the development of hypoallergenic food processing.

Safety and adherence of early oral immunotherapy for peanut allergy in a primary care setting: a retrospective cross-sectional study

BackgroundPeanut allergy is a common food allergy with potentially life-threatening implications. Early oral immunotherapy for peanut allergy (P-EOIT) has been shown to be effective and safe in research and specialty clinic settings. Provision of P-EOIT in primary care would make it available to more patients. We sought to assess the safety of P-EOIT in a primary care setting by documenting the rates of peanut-related allergic reactions leading to emergency department (ED) visits and use of epinephrine. We also examined adherence by assessing the percentage of patients reaching maintenance phase and continuing ingestion after one year of P-EOIT.MethodsThis retrospective study included all patients aged less than 36 months who started P-EOIT at a primary care allergy clinic in New Brunswick, Canada, from 2016 to 2020. The population included patients who (1) had a history of an allergic reaction to peanuts with a positive skin prick test or positive peanut specific IgE level (ps-IgE) or (2) no history of ingestion and a baseline ps-IgE ≥5 kU/L. Patients had biweekly clinic visits with graded increases in peanut protein up to a maintenance dose of 300 mg of peanut protein daily. A blinded retrospective review of paper charts and electronic medical records was conducted along with phone interviews regarding ED visits and epinephrine use.ResultsAll 69 consented patients reached maintenance dose over a median of 29 weeks, and 66 patients (95.7%) were still regularly consuming peanut protein after 1 year of maintenance. One patient had a peanut ingestion-related ED visit requiring epinephrine during the escalation phase of peanut protein dosing (1.4%). During the first year of maintenance phase, no patients had peanut ingestion-related ED visits nor required epinephrine.ConclusionEarly oral immunotherapy for peanut allergy in a primary care setting appears to be safe and our findings suggest that it does not lead to an increased burden of emergency department visits. Our population had high adherence rates, with the majority achieving maintenance dose and staying on this dose for one year.

The effects of ultrasound-assisted glycation on the allergenicity and functional properties of peanut proteins

This study investigated the effects of ultrasound-assisted glycation on the allergenicity and functional properties of peanut proteins. Results showed that ultrasound-assisted glycation increased the degree of glycation reaction of peanut proteins significantly (P < 0.05). ELISA results indicated that the binding of peanut allergens with serum immunoglobulin G (IgG) and immunoglobulin E (IgE) was significantly decreased (P < 0.05). Furthermore, secondary structure analysis revealed a significant increase in β-sheet content, alongside decreases in α-helix, β-turn, and random coil contents (P < 0.05). In addition, intrinsic fluorescence intensity, surface hydrophobicity, and ultraviolet (UV) spectra intensity were diminished (P < 0.05), indicating notable changes in both secondary and tertiary structures of peanut proteins. Moreover, emulsification property, antioxidant activity and in vitro digestibility of peanut proteins showed the most obvious improvements following ultrasound-assisted glycation, and the solubility was increased while turbidity was decreased significantly (P < 0.05). In conclusion, this study demonstrated that ultrasound-assisted glycation not only effectively reduced the allergenicity of peanut allergens, but also improved the overall functional properties of peanut proteins, and the changes in sensitization and functional properties might be closely related to structural changes. This study will provide a theoretical basis for the development of peanut products.

Breakthrough in allergy mitigation using an innovative steam pressure-based processing technique

Peanuts are recognized as one of the most common allergenic foods, known to induce severe Th2-mediated allergic reactions. The resulting global health concern has fostered the necessity to design innovative technologies capable of mitigating allergenicity. This study investigated the effect of an innovative thermomechanical process, “Intensification of Vaporization by Decompression to the Vacuum” (IVDV), on the protein content and immunogenicity of whole peanuts. Through animal studies using peanut allergy BALB/c mouse models, this research revealed a clear reduction in allergic symptoms once challenged with IVDV-treated peanut protein extract, compared to those receiving raw or deep-fried peanut protein extracts. Significant changes in immune response markers in animals were observed, including reduced levels of histamine, Th1/Th2 cytokines, and antibodies, thus confirming the efficacy of IVDV in mitigating allergenicity in peanuts. Saturated steam pressure was demonstrated to have a highly significant positive effect on the reduction of protein content in IVDV-treated samples through degradation, with a noteworthy reduction ranging from 42.3% to 89.2%. This pilot study embarked on a pioneering exploration into the ability of IVDV to offer a viable solution in reducing peanut allergenicity, opening new avenues for enhanced food safety and inclusivity. The ease of scalability of IVDV technology to an industrial level, along with its cost-efficiency, further enhance its appeal for widespread adoption.

Spray Drying of Inca Peanut Meal Protein Hydrolysate to Produce Protein Powder Drink Mix

The optimal conditions (maltodextrin concentration and inlet air temperature) for spray drying Inca peanut meal protein hydrolysate (IMPH) were determined. The maltodextrin concentration was varied at 5, 10 and 15 % by weight, and inlet air temperature was varied at 150, 160 and 170 °C. The IMPH was subjected to spray drying, where the feed solution was atomized into fine droplets and exposed to a hot air stream, leading to rapid drying and the formation of powder. The moisture, protein, yield, water activity and water solubility index (WSI) of IMPH powder were analyzed. The optimal condition for spray drying IMPH powder utilized 10 % maltodextrin and an inlet air temperature of 160 °C. Under these conditions, the moisture, protein, yield and WSI of IMPH powder were 2.93, 36.93, 38.95 and 99.59 %, respectively, while water activity was 0.41. IMPH powder particles were spherical and non-agglomerate. Inca peanut meal protein powder drink mix (IMPD) with cocoa flavor was the most acceptable. The IMPD with cocoa flavor could be promoted as a high protein and high dietary fiber product. It could be kept at 35 ± 2 °C for 12 weeks, whilst retaining good microbiological properties. HIGHLIGHTS The optimal conditions for spray drying Inca peanut meal protein hydrolysate (IMPH) were determined to be 10% maltodextrin and an inlet air temperature of 160 °C. This resulted in high yield, protein content, and water solubility, while keeping moisture and water activity low. IMPH powder had spherical, non-agglomerated particles, and cocoa-flavored Inca peanut protein powder drink mix (IMPD) was the most preferred in sensory evaluations. The IMPD with cocoa flavor was identified as a high-protein, high-dietary-fiber product, suitable for storage at 35 °C for up to 12 weeks while maintaining good microbiological quality. The study highlights the nutritional benefits of the cocoa-flavored IMPD, which includes essential amino acids, omega-3 fatty acids, and antioxidant properties. GRAPHICAL ABSTRACT

Interactions with peanut protein isolate regulate the bioaccessibility of cyanidin-3-O-glucoside: Multispectral analysis, simulated digestion, and molecular dynamic simulation

Anthocyanins are susceptible to degradation owing to environmental factors. Combining them with proteins can improve their stability; however, the interaction mechanism is difficult to elucidate. This study used multispectral and molecular dynamics simulations and molecular docking methods to investigate the interaction mechanism between peanut protein isolate (PPI) and cyanidin-3-O-glucoside (C3G). The UV absorption peak and PPI turbidity increased, while the fluorescence intensity decreased with greater C3G content. Protein secondary structure changes suggested that PPI and C3G coexisted in spontaneous covalent and non-covalent interactions via static quenching. The complex structures were stable over time and C3G stably bound to the peanut globulin Ara h 3 cavity through hydrogen bonding and hydrophobic interactions. Furthermore, PPI enhanced the C3G antioxidant activity and bioaccessibility by increasing its retention rate during in-vitro simulated digestion. This study elucidates the binding mechanism of PPI and C3G and provides insight into applications of the complex in food development.

Identification of digestion-resistant peptides in various processed peanut reveals their distinct allergenicity

Peanut protein is a significant food allergen that can trigger severe reactions. The allergenicity of peanut protein may be affected by the thermal processing method and matrices, and its anti-digestibility may also change accordingly. This study investigated how three heat treatment techniques affect the allergenicity and digestibility of peanut proteins and compared the differences in anti-digestive peptide segments by Mass spectrometry. Results showed that boiling and frying reduced sensitization, while roasting potentially increased it. After gastric digestion, allergenicity of Ara h 1 decreases due to breakdown of allergenic peptide segments. Hydrophobic regions of Ara h 1 where monomers interact resist degradation. Compared to boiling and frying, roasting can retain more allergenic peptides containing PGQFEDFF, YLQGFSRN, QEERGQRR, HRIFLAGDKD, and KDLAFPGSGE allergenic epitopes even after prolonged digestion. Meanwhile, digestion-resistant epitopes were affected by matrix and thermal treatments. These findings underscore the potential implications for food processing and allergy management strategies.

Effect of legume proteins on the structure and digestibility of wheat starch-lauric acid complexes

The effect of legume proteins (soy protein (SP), chickpea protein (CP) and peanut protein (PP)) on the properties of wheat starch-lauric acid (WS-LA) system and its intrinsic mechanism were investigated. RVA, digestion experiment and TGA results showed that legume proteins prompted the viscosity peak formation during cooling stage and increased anti-digestion and thermal stability of WS-LA system. FT-IR, Raman, XRD and 13C NMR results indicated that legume proteins improved the long-range and short-range ordering degree and single-helix structure of WS-LA system. SP had greater influence on the properties of WS-LA system than that of CP and PP. Proteins with high solubility, emulsifying properties and β-sheet content were conducive to starch-based complexes formation. Molecular dynamics simulation results indicated that major forces for WS-LA-SP formation were hydrogen bonding and van der Waals forces. This study offered crucial information on starch-fatty acid-protein complexes formation for proteins selection in starch-based products development.

Homologous mapping yielded a comprehensive predicted protein–protein interaction network for peanut (Arachis hypogaea L.)

BackgroundProtein–protein interactions are the primary means through which proteins carry out their functions. These interactions thus have crucial roles in life activities. The wide availability of fully sequenced animal and plant genomes has facilitated establishment of relatively complete global protein interaction networks for some model species. The genomes of cultivated and wild peanut (Arachis hypogaea L.) have also been sequenced, but the functions of most of the encoded proteins remain unclear.ResultsWe here used homologous mapping of validated protein interaction data from model species to generate complete peanut protein interaction networks for A. hypogaea cv. ‘Tifrunner’ (282,619 pairs), A. hypogaea cv. ‘Shitouqi’ (256,441 pairs), A. monticola (440,470 pairs), A. duranensis (136,363 pairs), and A. ipaensis (172,813 pairs). A detailed analysis was conducted for a putative disease-resistance subnetwork in the Tifrunner network to identify candidate genes and validate functional interactions. The network suggested that DX2UEH and its interacting partners may participate in peanut resistance to bacterial wilt; this was preliminarily validated with overexpression experiments in peanut.ConclusionOur results provide valuable new information for future analyses of gene and protein functions and regulatory networks in peanut.

Unraveling the role of peanut protein in baijiu-peanut pairing flavor complexity: A focus on ethanol-induced denaturation

Food processing, cooking, and consumption introduce various factors that affect food flavor, distinguishing it from its objective composition. This study focuses on liquor-accompanying food pairing, investigating the interaction between baijiu aroma compounds and peanut proteins, and the effect of ethanol on it. Peanut globulins significantly inhibited the release of baijiu aroma compounds through hydrogen bonding (2.63–3.23 Å), hydrophobic interactions, and covalent reactions (−2.85 to −5.64 kcal/mol), resulting in flavor modification. In the presence of ethanol, peanut globulins adopt a more compact and aggregated structure, reducing their affinity for binding aroma compounds. Surprisingly, this structural change promotes a salting-out effect, significantly promoting the release of aldehydes, phenols, and aromatic compounds, enhancing the grassy, floral, and sweet aroma of baijiu. This finding improves the understanding of alcohol pairing and proposes a novel strategy for enhancing the overall flavor profile of baijiu by modifying accompanying food choices.

Comparison of formation and structural characteristics of amyloid fibrils of peanut protein isolate after hydration treatment at different pH

In this paper, the process of fibrillation and the structure of fibrils formed from peanut protein after hydration treatment at pH 5.0 (group Q) and pH 2.0 (group S) were studied. The results showed that compared with the peanut protein obtained after hydration at pH 5.0, the particle size of the peanut protein obtained after hydration at pH 2.0 increased, and the surface hydrophobicity and intrinsic fluorescence intensity decreased, indicating that the protein aggregated. During fibrillation, the maximum Thioflavin T fluorescence intensity of protein in group Q was higher than that in group S, and the time for group S protein to reach the maximum fluorescence intensity was slower than that in group Q protein. Besides, the group Q protein first formed short worm-like fibrils and then long flexible fibrils, and the group S protein first formed short rigid fibrils and then worm-like fibrils. In conclusion, hydration treatment at pH 2.0 led to the aggregation of peanut protein, reduced the fibrils forming ability of peanut protein and affected subsequent self-assembly processes. This study could provide new insights of the fibril formation mechanism and structural properties of peanut protein after hydration treatment at different pH.

Successful Introduction of Peanut in Sensitized Infants With Reported Reactions at Home

Background and objectivePrevious studies have shown efficacy of early introduction of peanut to prevent peanut allergy. It is currently unknown which diagnostic pathway is optimal after parental-reported reactions to peanut at home after early introduction. MethodsThe PeanutNL cohort study included high-risk infants that were referred for early introduction of peanut. A subgroup of 186 infants with reactions to peanut at home underwent peanut skin prick tests and a supervised open oral food challenge (OFC) at a median age of 8 months. After a negative OFC, peanut was introduced at home. ResultsSensitization to peanut was detected in 69% of 186 infants, of which 80% had > 4mm wheals in skin prick tests. An OFC with a cumulative dose of 4.4 gr peanut protein was performed in 163 infants with Sampson severity score grade I-III reactions at home; 120 challenges were negative. Peanut was subsequently introduced at home in infants with a negative challenge outcome. After 6 months, 96% were still eating peanut and 81% ate single portions of 3.0 gr peanut protein. One patient was considered to be peanut allergic after reintroduction of peanut at home. ConclusionThese data show that 65% of infants with reported reactions to peanut at home have negative OFCs. In those children, peanut could be introduced safely and 96% were able to consume peanut regularly without reactions. Challenging infants under 12 months of age prevents the misdiagnosis of peanut allergy, and enables safe continued exposure to peanut and the induction of long-term tolerance.

Isolation, identification, and chelation mechanism of ferrous-chelating peptide from peanut protein hydrolysate.

Peanut peptides can chelate iron but their chelation mechanism remains unclear. The purpose of this study is to separate peanut ferrous-chelating peptides and explore the chelation mechanism of peanut peptides with iron. Peanut peptide component F-122, which had a higher chelation rate, was separated using ultrafiltration, gel filtration chromatography, and ion exchange chromatography, achieving a ferrous chelation rate of 90.7%. Six peptide segments were screened and their amino acid sequences were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Spectral analysis confirmed that the chelation between peanut peptides and ferrous ions occurred and a new substance was formed. Molecular docking simulation indicated that the amino acids in peanut peptides involved in the chelating reaction were glutamic acid, arginine, glycine, threonine, phenylalanine, and lysine. The binding sites included the main chain oxygen atom, side chain oxygen atom, and carboxyl oxygen atom of amino acid. The isolated peanut peptide had a higher ferrous-chelation rate. The chelating mechanism of peanut peptide with ferrous ion was elucidated. This study provides a theoretical basis for the development of new peptide-ferrous preparations. © 2024 Society of Chemical Industry.

Comparison of intestinal absorption of soybean protein isolate-, glutenin- and peanut protein isolate-bound Nε-(carboxymethyl) lysine after in vitro gastrointestinal digestion

Advanced glycation end products (AGEs), a heterogeneous compound existed in processed foods, are related to chronic diseases when they are accumulated excessively in human organs. Protein-bound Nε-(carboxymethyl) lysine (CML) as a typical AGE, is widely determined to evaluate AGEs level in foods and in vivo. This study investigated the intestinal absorption of three protein-bound CML originated from main food raw materials (soybean, wheat and peanut). After in vitro gastrointestinal digestion, the three protein-bound CML digests were ultrafiltered and divided into four fractions: less than 1 kDa, between 1 and 3 kDa, between 3 and 5 kDa, greater than 5 kDa. Caco-2 cell monolayer model was further used to evaluate the intestinal absorption of these components. Results showed that the absorption rates of soybean protein isolate (SPI)-, glutenin (Glu)-, peanut protein isolate (PPI)-bound CML were 30.18%, 31.57% and 29.5%, respectively. The absorption rates of components with MW less than 5 kDa accounted for 19.91% (SPI-bound CML), 22.59% (Glu-bound CML), 23.64% (PPI-bound CML), respectively, and these samples were absorbed by paracellular route, transcytosis route and active route via PepT-1. Taken together, these findings demonstrated that all three protein-bound CML digests with different MW can be absorbed in diverse absorption pathways by Caco-2 cell monolayer model. This research provided a theoretical basis for scientific evaluation of digestion and absorption of AGEs in food.

Proteomic characterization of peanut flour fermented by Rhizopus oryzae

Fermentation alters the protein content and composition of foods. To characterize fungal catabolism of peanut proteins, defatted peanut flour was fermented by Rhizopus oryzae (R. oryzae) for up to 48 h and evaluated by SDS-PAGE, mass spectrometry, and antibody binding. A clear change in peanut protein migration was observed by SDS-PAGE after 16 h of fermentation. Mass spectrometric analysis indicated changes in allergen peptides and R. oryzae proteins. Several low molecular weight allergen fragments produced during fermentation were identified by mass spectrometry. Immunoassays using anti-peanut allergen antibodies demonstrated reduced allergen content as early as 16 h of fermentation. However, ELISA with peanut allergic IgE indicated only slightly reduced allergen binding even after 48 h. These results indicate that while R. oryzae fermentation efficiently metabolizes peanut allergens, significant IgE binding remains in lower molecular mass peptides, and therefore R. oryzae fermented peanut products would not be safe for peanut allergic individuals.

Angiotensin-Converting Enzyme and Renin-Inhibitory Activities of Protein Hydrolysates Produced by Alcalase Hydrolysis of Peanut Protein.

Hypertension is a major controllable risk factor associated with cardiovascular disease (CVD) and overall mortality worldwide. Most people with hypertension must take medications that are effective in blood pressure management but cause many side effects. Thus, it is important to explore safer antihypertensive alternatives to regulate blood pressure. In this study, peanut protein concentrate (PPC) was hydrolyzed with 3-5% Alcalase for 3-10 h. The in vitro angiotensin-converting enzyme (ACE) and renin-inhibitory activities of the resulting peanut protein hydrolysate (PPH) samples and their fractions of different molecular weight ranges were determined as two measures of their antihypertensive potentials. The results show that the crude PPH produced at 4% Alcalase for 6 h of hydrolysis had the highest ACE-inhibitory activity with IC50 being 5.45 mg/mL. The PPH samples produced with 3-5% Alcalase hydrolysis for 6-8 h also displayed substantial renin-inhibitory activities, which is a great advantage over the animal protein-derived bioactive peptides or hydrolysate. Remarkably higher ACE- and renin-inhibitory activities were observed in fractions smaller than 5 kDa with IC50 being 0.85 and 1.78 mg/mL. Hence, the PPH and its small molecular fraction produced under proper Alcalase hydrolysis conditions have great potential to serve as a cost-effective anti-hypertensive ingredient for blood pressure management.

Effects of enzymatic hydrolysis combined with glycation on the emulsification characteristics and emulsion stability of peanut protein isolate

Peanut protein isolate (PPI) has high nutritional value, but its poor function limits its application in the food industry. In this study, peanut protein isolate was modified by enzymatic hydrolysis combined with glycation. The structure, emulsification and interface properties of peanut protein isolate hydrolysate (HPPI) and dextran (Dex) conjugate (HPPI-Dex) were studied. In addition, the physicochemical properties, rheological properties, and stability of the emulsion were also investigated. The results showed that the graft degree increased with the increase of Dex ratio. Fourier transform infrared spectroscopy (FTIR) confirmed that the glycation of HPPI and Dex occurred. The microstructure showed that the structure of HPPI-Dex was expanded, and the molecular flexibility was enhanced. When the ratio of HPPI to Dex was 1:3, the emulsifying activity and the interface pressure of glycated HPPI reached the highest value, and the emulsifying activity (61.08 m2/g) of HPPI-Dex was 5.28 times that of PPI. The HPPI-Dex stabilized emulsions had good physicochemical properties and rheological properties. In addition, HPPI-Dex stabilized emulsions had high stability under heat treatment, salt ion treatment and freeze–thaw cycle. According to confocal laser scanning microscopy (CLSM), the dispersion of HPPI-Dex stabilized emulsions was better after 28 days of storage. This study provides a theoretical basis for developing peanut protein emulsifier and further expanding the application of peanut protein in food industry.

Effects of genetic diversity on the allergenicity of peanut (Arachis hypogaea) proteins: identification of the hypoallergenic accessions using BALB/c mice model and in silico analysis of Ara h 3 allergen cross-reactivity

This study investigated the effects of genetic diversity in the allergenicity of peanut and assessed the allergenic capacity of six Arachis hypogaea accessions using a Balb/c mouse model. It also explored potential cross-reactivities between Ara h 3 (peanut allergen) and Gly m (soybean allergen) using computational tools. Female Balb/c mice were injected with peanut protein extracts and alum. Serum-specific antibodies (IgE, IgGt, IgG1, IgG2a) were measured using ELISA, and allergic protein profiles were examined via western blot. Structural homology, B cell epitopes, and molecular interactions between Ara h 3 and Gly m with human IgE were also investigated. The mice developed high sIgE and sIgG1 responses, with antibodies recognizing 19 bands on western blot. Notably, Saharan accessions showed unique features such as no bands on western blot profiles, reduced anaphylactic symptoms, lower IgE titers, and less intestinal tissue damage. Molecular docking results suggest significant cross-allergenicity, supported by allergenicity predictions and structural homology analysis. This comprehensive analysis provides insights into shared epitopes, potential competition for binding sites, and molecular dynamics of cross-reactive responses, enhancing understanding of food allergen interactions. The study recommends using Algerian Sahara peanut accessions in breeding, genomics studies, and industry for safer peanut options for individuals with allergies. SignificanceThe significance of this study lies in its contribution to addressing a major public health issue: peanut allergy, which represents a significant cause of anaphylaxis affecting numerous individuals and families worldwide. By exploring the genetic diversity of peanut proteins and identifying hypoallergenic accessions through experimental and computational approaches, this research offers valuable insights for mitigating allergic reactions. The findings highlight that certain accessions from the Saharan region exhibit reduced allergenicity, resulting in attenuated anaphylactic symptoms, lower IgE levels, and reduced intestinal damage in murine models. Furthermore, the study's in silico analysis sheds light on the issue of cross-reactivity between peanut and soybean allergens, providing crucial information for understanding allergen interactions at the molecular level. Overall, this research contributes to advancing knowledge in the field of food allergen research and has practical implications for improving the quality of life for individuals allergic to peanuts, particularly through the selection of safer peanut varieties and their cultivation.

Accidental allergic reactions to immediate-type food allergens in Japanese children: A single-center study.

Few studies have assessed the nature of accidental allergic reactions (AAR). We assessed the prevalence and risk factors for AAR in Japanese children. This study included children with immediate-type hen's egg (HE), cow's milk (CM), wheat, or peanut allergy who developed allergic reactions within at least 2 years and were followed up regularly at a single national allergy center in Japan. From January to December 2020, low-dose reactivity was defined as allergic reactions to ≤250, ≤102, ≤53, or ≤ 133 mg of HE, CM, wheat, or peanut protein, respectively. The annualized AAR rate showed the number of reactions per patient per year (95% confidence interval). AAR risk factors were analyzed using multiple logistic regression. Of the 1096 participants, 609, 457, 138, and 90 had HE, CM, wheat, and peanut allergies, respectively. The median (interquartile range) age was 5.0 (2.3-8.6) years, 39% had completely eliminated allergenic food, and 24% had low-dose reactivity. The annualized AAR rate was 0.130 (0.109-0.153) in all sub-cohorts. Moderate and severe symptoms occurred in 50% and 0.7%, respectively, of children who experienced AAR. Multiple logistic regression revealed that low-dose reactivity was a significant risk factor for AAR in the overall and CM cohorts, respectively (p < .001 and p = .036). In this single-center study in Japan, the annualized AAR rate was relatively low during the COVID-19 pandemic; however, half of the participants with AAR had moderate to severe symptoms. Especially in the case of low-dose reactivity, children would require careful AAR risk management.

Potential of Marine Bacterial Metalloprotease A69 in the Preparation of Peanut Peptides with Angiotensin-Converting Enzyme (ACE)-Inhibitory and Antioxidant Properties.

Marine bacterial proteases have rarely been used to produce bioactive peptides, although many have been reported. This study aims to evaluate the potential of the marine bacterial metalloprotease A69 from recombinant Bacillus subtilis in the preparation of peanut peptides (PPs) with antioxidant activity and angiotensin-converting enzyme (ACE)-inhibitory activity. Based on the optimization of the hydrolysis parameters of protease A69, a process for PPs preparation was set up in which the peanut protein was hydrolyzed by A69 at 3000 U g-1 and 60 °C, pH 7.0 for 4 h. The prepared PPs exhibited a high content of peptides with molecular weights lower than 1000 Da (>80%) and 3000 Da (>95%) and contained 17 kinds of amino acids. Moreover, the PPs displayed elevated scavenging of hydroxyl radical and 1,1-diphenyl-2-picryl-hydrazyl radical, with IC50 values of 1.50 mg mL-1 and 1.66 mg mL-1, respectively, indicating the good antioxidant activity of the PPs. The PPs also showed remarkable ACE-inhibitory activity, with an IC50 value of 0.71 mg mL-1. By liquid chromatography mass spectrometry analysis, the sequences of 19 ACE inhibitory peptides and 15 antioxidant peptides were identified from the PPs. These results indicate that the prepared PPs have a good nutritional value, as well as good antioxidant and antihypertensive effects, and that the marine bacterial metalloprotease A69 has promising potential in relation to the preparation of bioactive peptides from peanut protein.