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At least 361 records · Page 20Linked to original sources
PubMed2006

Mixed-up nuts: identification of peanuts and tree nuts by children.

BACKGROUND: Peanuts and tree nuts frequently cause severe allergic reactions. Nut avoidance is the key treatment, and accurate identification of nuts is essential for successful avoidance. OBJECTIVES: To determine the age at which nut-allergic and nonallergic children can accurately identify various nuts and whether nut-allergic children can identify nuts they should avoid. METHODS: A "nut box" was constructed containing samples of 11 common nuts and pine nuts. Nut-allergic and nonallergic children were asked to identify the nuts, and their responses were compared and correlated by age. Nut-allergic children were asked to identify the nut(s) that they should not eat. RESULTS: One hundred children (37 allergic and 63 nonallergic) were enrolled. The mean number of nuts correctly identified was only 2.7 per child and increased with age, but there was large variation. Fifty-nine children identified 2 or fewer nuts. Peanuts in the shell were identified most often (89% of children), followed by peanuts out of the shell (52%). Other nuts were identified less commonly, ranging from 32% for pistachios to 0% for Brazil nuts. Nut-allergic children were not better able to correctly identify tree nuts and were less able in the case of peanuts. Of the nut-allergic children, 10 (27%) could not identify the peanut or tree nut to which they were allergic. CONCLUSIONS: In general, children, including those who are allergic to nuts, can identify few nuts. This lack of recognition could put them at increased risk for unintentional ingestion. As part of an overall educational plan, nut-allergic children should be taught not only to avoid but also to identify the nut to which they are allergic.

Adolescent↗
PubMed2002

Accelerated shelf life testing of whey-protein-coated peanuts analyzed by static headspace gas chromatography.

Four different formulations of whey-protein-based coatings were used to coat peanuts. Four controls were used to investigate the effects of different ingredients in the coating formulation on the peanut shelf life. Untreated peanuts were designated as the reference. The peanut samples were stored in duplicate at 40, 50, and 60 degrees C for storage durations of up to 31 weeks. The analysis of hexanal indicated that the coated samples were oxidized significantly slower than the reference; hence, the predicted shelf life was longer for the coated samples. However, the investigation of the control ingredients revealed that even when only water was applied onto the peanuts the oxidation was delayed.

Aldehydes↗
PubMed2002

Physicochemical and sensory characteristic changes in fortified peanut spreads after 3 months of storage at different temperatures.

Three amino acid-balanced, vitamin- and mineral-fortified peanut spreads were stored at 4, 23, and 40 degrees C for 3 months. These were 69.6% peanut/19% soybean-40.5% fat, 61.9% peanut/19% soybean-44.5% fat, and 74.1% peanut/14% nonfat dry milk (NFDM)-40% fat. The peanut spreads were fortified with vitamin A, thiamin, riboflavin, vitamin B(6), vitamin C, calcium, and iron to provide 33.3% of the Recommended Dietary Allowances for children. Water-soluble vitamins were quite stable in deaerated peanut spreads. The antioxidant activity of phytochemicals in soybean prevented vitamin A degradation in soy-containing spreads, whereas the NFDM spread lost 70% of the initial content. Instron analysis detected major changes in texture when peanut spreads were stored at 40 degrees C, suggesting that the polymorphic form of lipid transformed and the proper crystallization of stabilizer was destroyed. Panelists did not detect the texture changes in peanut spreads stored at different temperatures. At 40 degrees C, the primary deteriorative changes in sensory quality were increased browning and the development of "soybean" and "oxidized" flavors as well as decreased "roasted peanutty" flavor.

Adult↗
PubMed2004

Confirmation of the allergenic peanut protein, Ara h 1, in a model food matrix using liquid chromatography/tandem mass spectrometry (LC/MS/MS).

Enzymatic digestion of total protein along with liquid chromatography/tandem mass spectrometry (LC/MS/MS) was used to confirm the presence of a major peanut allergen in food. Several peptides obtained from the enzymatic digestion of the most abundant peanut allergen, Ara h 1, were identified as specific peptide biomarkers for peanut protein. Using ice cream as a model food matrix, a method was developed for the detection of the allergen peptide biomarkers. A key component of the method was the use of molecular mass cutoff filters to enrich the Ara h 1 in the protein extracts. By applying the method to ice cream samples containing various levels of peanut protein, levels as low as 10 mg/kg of Ara h 1 could routinely be detected. This method provides an unambiguous means of confirming the presence of the peanut allergen, Ara h 1, in foods and can easily be modified to detect other food allergens.

Allergens↗
PubMed2005

Germination of peanut kernels to enhance resveratrol biosynthesis and prepare sprouts as a functional vegetable.

Bioactive benefits of resveratrol in the diets have attracted extensive interests of the public. Peanut is one of the potent natural sources of resveratrol. In this study, germination of peanut kernels to enhance resveratrol biosynthesis and preparation of sprouts as a functional vegetable was conducted. When the rehydrated kernels of three peanut cultivars were germinated at 25 degrees C and relative humidity 95% in dark for 9 days, resveratrol contents increased significantly from the range of 2.3 to 4.5 microg/g up to the range of 11.7 to 25.7 mug/g depending upon peanut cultivar. In comparison with the sprout components, resveratrol contents were highest in the cotyledons, slightly lower in the roots, and not detected in the stems. When the sprouts were heated in boiling water for 2 min, resveratrol contents varied in a limited range. Methanol extracts of the freeze-dried sprouts exhibited potent 1,1-diphenyl-2-picryl-hydrazyl scavenging activity and antioxidative potency against linoleic acid oxidation. These activities increased with an increase of germination time. After 9 days of germination, total free amino acid, sucrose, and glucose contents increased significantly while crude protein contents decreased and the large sodium dodecyl sulfate polyacrylamide gel electrophoresis protein molecules of the kernels were extensively degraded. From a practical viewpoint, it is of potency to prepare peanut sprouts as a functional vegetable.

Antioxidants↗
PubMed2005

Elicitation of resveratrol in peanut kernels by application of abiotic stresses.

Application of no postharvest stress or by size reduction, grinding, chopping, or slicing and exposure to UV light or ultrasound were investigated for the elicitation of trans-resveratrol, total phenolic compounds, and antioxidant activity (AOA) in peanut kernels. AOA and total phenolic compounds did not increase in stressed peanuts over incubation times 0-48 h at 25 degrees C; however, an increase in trans-resveratrol concentration over time occurred. Slicing (2 mm), ultrasound exposure for 4 min at 25 degrees C, and incubation for 36 h produced the highest level of trans-resveratrol synthesis in peanuts, increasing concentrations from 0.48 +/- 0.08 microg/g in untreated peanuts to 3.96 +/- 0.96 microg/g. AOA in stressed peanuts was negatively correlated with trans-resveratrol concentration, indicating that as AOA decreased trans-resveratrol concentration increased.

Antioxidants↗
PubMed2007

Transglutaminase polymerization of peanut proteins.

Transglutaminase promotes protein cross-linking reactions through an acyl transferase mechanism involving protein-bound glutaminyl residues and primary amines including the epsilon-amino group of lysine residues in soy, myosin, gluten, oat globulin, casein, and whey. Herein, we present a first report of exogenous transglutaminase catalysis of several peanut protein fractions, including purified Ara h 1. In most cases, SDS-PAGE banding patterns revealed the formation of high molecular weight polymers while catalysis of Ara h 1 resulted in distinct dimer formation. Cross-linking effects were accomplished in the presence and absence of the reducing reagent, dithiothreitol. Ortho-phthaldialdehyde assays, used to quantify the degree of polymerization, indicated approximately 21% and approximately 30% coupling over a similar time interval, using either cold hexane extracted peanut protein fractions or lightly roasted flour dispersions, respectively. Rheological measurements established that transglutaminase-modified peanut extracts exhibited lowered viscosity readings compared to nontreated dispersions. Peanut protein polymers and glycoprotein conjugates, created by covalent linkage between protein substrates and monosaccharide amino sugars, exhibited similar IgE binding activity, compared to control solutions. These results suggested that potential allergic responses were not enhanced after enzymatic modification. Ultimately, these approaches may provide novel peanut-based food ingredients with unique functional characteristics for expanded applications within the world marketplace.

Allergens↗
PubMed2000

Investigations into genotypic variations of peanut carbohydrates.

Carbohydrates are known to be important precursors in the development of roasted peanut quality. However, little is known about their genotypic variation. A better understanding of the role of carbohydrates in roasted peanut quality requires first an understanding of the genotypic variation in the soluble carbohydrate components. Ion exchange chromatography was used to isolate 20 different carbohydrate components in 52 genotypes grown in replicated trials at two locations. Inositol, glucose, fructose, sucrose, raffinose, and stachyose were quantitated, and 12 unknown peaks were evaluated on the basis of the peak height of the unknown relative to the cellobiose internal standard peak height. Peaks tentatively identified as verbascose and ajugose could not be properly integrated because of tailing. Of the 18 carbohydrates that were estimated, 9 exhibited significant variation between test environments, 5 among market types, 14 among genotypes within market types, and 11 exhibited some significant form of genotype x environment interaction. Genotypes accounted for 38-78% of the total variation for the known components, suggesting that broad-sense heritability for these components is high. The observed high genotypic variation in carbohydrate components is similar to the high genotypic variation observed for the sweetness attribute in roasted peanuts, which raises the question regarding possible interrelationships. The establishment of such interrelationships could be most beneficial to peanut breeding programs to ensure the maintenance of flavor quality in future peanut varieties.

Arachis↗
PubMed1997

Expression of a Bacillus thuringiensis cryIA(c) gene in transgenic peanut plants and its efficacy against lesser cornstalk borer.

The invasion of peanut (Arachis hypogaea L.) pods and seeds by aflatoxin-forming species of Aspergillus is linked to injury by the lesser cornstalk borer and frequently causes a severe reduction in crop quality. The lesser cornstalk borer is susceptible to the lepidopteran-active Bacillus thuringiensis insecticidal crystal protein. We have introduced a codon-modified Bacillus thuringiensis cryIA(c) gene into peanut using microprojectile bombardment. The toxin-coding region of a Bt cryIA(c) gene was reconstructed for expression in plants and the resulting 3.4 kb gene cassette (promoter: 1.8 kb coding: 3') was directly cloned into the BglII site of plant transformation vectors. The vectors contained the hph gene, conferring resistance to the antibiotic hygromycin. Somatic embryos initiated from immature peanut cotyledons of two cultivars were used as the target for bombardment. DNA from hygromycin-resistant embryogenic cell lines, regenerated plants, and a progeny plant showed the presence and integration of hph and Bt genes by PCR and/or Southern blot analyses. ELISA immunoassay of the CryIA(c) protein from the hygromycin-selected plants showed the expression of CryIA(c) protein up to 0.18% of total soluble protein. Insect feeding bioassay of transformed plants indicated various levels of resistance to the lesser cornstalk borer, from complete larval mortality to a 66% reduction in larval weight. A negative correlation between percent survival or larval weight and the amount of Bt CryIA(c) protein was recorded indicating in general that the higher the protein level the lower the survival or larval weight of the insect. Based on leaf bioassay, transformation of peanut with vectors containing the Bt cryIA(c) gene may be effective in protecting the peanut plants from damage by lepidopteran insect larvae of lesser cornstalk borer.

Animals↗
PubMed2003

Sensory and physical properties of peanut brittle prepared in different types of cookware and with different levels of sodium bicarbonate.

Two studies to evaluate peanut brittle containing either raw or roasted peanuts were conducted. In the first study, brittles were prepared in iron, aluminum, stainless steel and nonstick stainless steel pans. In the second study, brittles containing 0, 2 or 4 g of sodium bicarbonate prepared in either stainless steel or nonstick stainless steel pans were evaluated. All brittles were evaluated for color, shear strength and sensory properties at 0, 30 and 60 days. Products prepared in a nonstick stainless steel pan and those with added sodium bicarbonate were lighter, more yellow and slightly greener than other products. Pan type did not affect shear force but increasing sodium bicarbonate was associated with decreasing force needed to shear brittles. Peanut and caramel aromas were not affected by pan type or sodium bicarbonate level but were greater (p < 0.05) in products containing roasted peanuts. Burned flavors were more prevalent in products prepared in iron or stainless steel pans with roasted peanuts. More intense sweet and buttery flavors were detected as level of sodium bicarbonate increased.

Arachis↗
PubMed2026

Pan-genome-based resequencing of 2,320 accessions reveals structural variations and accelerates breeding advances in cultivated peanut.

The cultivated peanut is a crucial global legume crop that is essential for food security and nutrition, particularly in developing regions. However, its limited genetic variation hampers breeding progress and yield improvement. Here we constructed a graph-based pan-genome for peanut, incorporating 14 genomes that represent all 6 peanut varieties. Using this pan-genome, we genotyped 2,320 accessions, covering 88.03% of ICRISAT and 59.21% of USDA core germplasm, enriching valuable resources for genomic studies and breeding. We cataloged genomic structural variations and investigated the role of homoeologous exchanges in population divergence. Through our pan-genome approach, we overcame the challenges of genotyping posed by homoeologous exchanges and identified key genes associated with flowering and dwarfism in peanut. By integrating superior haplotypes and germplasm resources guided by the pan-genome, we further developed high-yield dwarf lines. This work provides essential genomic resources to accelerate functional gene discovery and modern peanut breeding.

Journal Article↗
PubMed2001

Isolation and molecular characterization of the first genomic clone of a major peanut allergen, Ara h 2.

BACKGROUND: Peanuts have been identified as potent food allergens responsible for life-threatening IgE reactions among hypersensitive individuals. With the current increase of peanut allergies, there is an urgent need to molecularly characterize the genes encoding the target proteins and to understand the nature of their regulation. OBJECTIVES: The objectives of this study were to isolate, sequence, and characterize at least one full-length genomic clone encoding the major peanut allergen Ara h 2. METHODS: A peanut genomic library, constructed in a Lambda Fix II vector, was screened with an 80-bp oligonucleotide probe constructed on the basis of the 5' end of a published Ara h 2 cDNA partial sequence. One putative positive lambda clone was isolated, digested with Bam HI to release its 16-kb insert, and confirmed by means of dot blot and Southern hybridization. The positive clone was subcloned in pBluescript SK+ vector, sequenced, and characterized. RESULTS: Sequence analysis revealed a full-length genomic clone with an open reading frame starting with an initiation codon (ATG) at position 1 and ending with a termination codon (TGA) at position 622. One putative polyadenylation signal (AATAAA) is identified at positions 951 in the 3' untranslated region, and 6 additional stop codons are located at positions 628, 769, 901, 946, 967, and 982 downstream from the start codon. In the 5' promoter region, a putative TATA box (TATTATTA) is located at position -72 upstream from the start codon. The deduced amino acid sequence has 207 residues and includes a putative signal peptide of 21 residues. CONCLUSIONS: The results reveal for the first time information on the structure of a major peanut allergen, Ara h 2. Comparison of the cDNA and genomic sequences revealed the absence of an intron but the presence of 2 isoforms of Ara h 2 or different members of the same gene family.

2S Albumins, Plant↗
PubMed2001

A voluntary registry for peanut and tree nut allergy: characteristics of the first 5149 registrants.

BACKGROUND: A voluntary registry of individuals with peanut and/or tree nut allergy was established in 1997 to learn more about these food allergies. OBJECTIVE: The purpose of this study was to elucidate a variety of features of peanut and tree nut allergy among the first 5149 registry participants. METHODS: The registry was established through use of a structured questionnaire distributed to all members of the Food Allergy and Anaphylaxis Network and to patients by allergists. Parental surrogates completed the forms for children under the age of 18 years. RESULTS: Registrants were primarily children (89% of registrants were younger than 18 years of age; the median age was 5 years), reflecting the membership of the Network. Isolated peanut allergy was reported by 3482 registrants (68%), isolated tree nut allergy by 464 (9%), and allergy to both foods by 1203 (23%). Registrants were more likely to have been born in October, November, or December (odds ratio, 1.2; 95% CI, 1.18-1.23; P <.0001). The median age of reaction to peanut was 14 months, and the median age of reaction to tree nuts was 36 months; these represented the first known exposure for 74% and 68% of registrants, respectively. One half of the reactions involved more than 1 organ system, and more than 75% required treatment, frequently from medical personnel. Registrants with asthma were more likely than those without asthma to have severe reactions (33% vs 21%; P <.0001). In comparison with initial reactions, subsequent reactions due to accidental ingestion were more severe, more common outside the home, and more likely to be treated with epinephrine. CONCLUSIONS: Allergic reactions to peanut and tree nut are frequently severe, often occur on the first known exposure, and can become more severe over time.

Adolescent↗
PubMed2004

Degradation of aflatoxins in peanut kernels/flour by gaseous ozonation and mild heat treatment.

Aflatoxins occur naturally in many agricultural crops causing health hazards and economic losses. Despite improved handling, processing and storage, they remain a problem in the peanut industry. Therefore, new ways to detoxify contaminated products are needed to limit economic/health impacts and add value to the peanut industry. The study was conducted (1) to evaluate the effectiveness of ozonation and mild heat in breaking down aflatoxins in peanut kernels and flour, and (2) to quantify aflatoxin destruction compared with untreated samples. Peanut samples were inoculated with known concentrations of aflatoxins B1, B2, G1 and G2. Samples were subjected to gaseous ozonation and under various temperatures (25, 50, 75 degrees C) and exposure times (5, 10, 15 min). Ozonated and non-ozonated samples were extracted in acetonitrile/water, derivatized in a Kobra cell and quantified by high-performance liquid chromatography. Ozonation efficiency increased with higher temperatures and longer treatment times. Regardless of treatment combinations, aflatoxins B1 and G1 exhibited the highest degradation levels. Higher levels of toxin degradation were achieved in peanut kernels than in flour. The temperature effect lessened as the exposure time increased, suggesting that ozonation at room temperature for 10-15 min could yield degradation levels similar to those achieved at higher temperatures while being more economical.

Aflatoxin B1↗
PubMedDate not supplied

The occurrence of aflatoxins in peanuts imported into Czechoslovakia for human consumption.

Results of 492 analyses for aflatoxin in raw shelled peanuts imported into Czechoslovakia during 1982-1984 are presented. Most samples (55.3%) had aflatoxin content less than the detection limit of the radioimmunochemical screening method (0.8 micrograms/kg). Further analyses showed that 239 out of 410 samples of roasted peanuts contained aflatoxin below the detection limit. Only 1.9% of all peanut samples were found to have contamination level more than 5 micrograms/kg aflatoxin. The highest levels of aflatoxin observed were in a raw peanut sample containing 202.1 micrograms/kg and in a roasted peanut sample containing 32.6 micrograms/kg.

Aflatoxins↗
PubMedDate not supplied

Determination of aflatoxin B1 levels in peanut butter using an immunoaffinity column clean-up procedure: inter-laboratory study.

Ten United Kingdom laboratories participated in an evaluation of an immunoaffinity column sample preparation procedure used to prepare aflatoxin B1 containing extracts obtained from peanut butters contaminated by aflatoxins. Each laboratory was sent seven randomly numbered samples of roasted peanut butter which included two sets of undisclosed triplicates. These two peanut butters were naturally contaminated with aflatoxin B1 at levels of about 12 and 35 micrograms/kg. The other sample was a nominal blank peanut butter containing approximately 2 micrograms/kg of aflatoxin B1 which was also employed by participants for recovery experiments. Participating laboratories were instructed to follow a protocol regarding the use of the immunoaffinity columns for extract preparation, but were allowed a free choice of instrumental technique for quantification of aflatoxin levels. Mean recovery for spikes was 72%. Coefficients of variation for the results from the 10 participants for the two contaminated roasted peanut butters were, respectively, 45% (on a mean of 13.6 micrograms/kg) and 36% (on a mean of 37.2 micrograms/kg).

Aflatoxin B1↗
PubMed1984

Aflatoxin in respirable airborne peanut dust.

Laboratory shelling and pilot handling operations were conducted to determine if peanut dust generated by such operations contained significant amounts of aflatoxin. Air samples were collected from points of highest dust concentration. No aflatoxin B1 was detected in dust from uncontaminated lots. Aflatoxin B1 levels of 700 ppb and 7.6 ng/m3 were detected from highly contaminated lots. The contamination of the dust was directly proportional to the contamination of the lots handled or shelled. In the shelling tests, the level of contamination of the dust samples was about one-ninth of the level of contamination of the peanuts. In the handling tests, the level of contamination of the dust samples was about half the contamination level of the peanuts. These results indicate that most of the contaminated dust was probably removed by handling operations prior to shelling. Although workers are not routinely exposed to such levels of contaminated dust, these findings suggest the need for a more thorough study of peanut dust during handling or processing of contaminated peanuts.

Aflatoxin B1↗
PubMed1980

An apparent anomaly in peanut leaf conductance.

Conductance to gaseous transfer is normally considered to be greater from the abaxial than from the adaxial side of a leaf. Measurements of the conductance to water vapor of peanut leaves (Arachis hypogaea L.) under well watered and stress conditions in a controlled environment, however, indicated a 2-fold higher conductance from the adaxial side of the leaf than from the abaxial. Studies of conductance as light level was varied showed an increase in conductance from either surface with increasing light level, but conductance was always greater from the adaxial surface at any given light level. In contrast, measurements of soybean (Glycine max [L.] Merr.) and snapbean (Phaseolus vulgaris L.) leaf conductance showed an approximate 2-fold greater conductance from the abaxial surface than from the adaxial. Approximately the same number of stomata were present on both peanut leaf surfaces and stomatal size was similar. Electron microscopic examination of peanut leaves did not reveal any major structural differences between stomata on the two surfaces that would account for the differences in conductance. Light microscope studies of leaf sections revealed an extensive network of bundle sheaths with achloraplastic bundle sheath extensions; the lower epidermis was lined with a single layer of large achloraplastic parenchyma cells. Measurements of net photosynthesis made on upper and lower leaf surfaces collectively and individually indicated that two-thirds of the peanut leaf's total net photosynthesis can be attributed to diffusion of CO(2) through the adaxial leaf surface. Possibly the high photosynthetic efficiency of peanut cultivars as compared with certain other C(3) species is associated with the greater conductance of CO(2) through their upper leaf surfaces.

Journal Article↗