Bioavailability assessment of essential and toxic metals in edible nuts and seeds.
Bioavailability of essential and toxic metals in edible nuts and seeds has been assessed by using an in vitro dialyzability approach. The samples studied included walnuts, Brazil nuts, Macadamia nuts, pecans, hazelnuts, chestnuts, cashews, peanuts, pistachios and seeds (almond, pine, pumpkin and sunflower). Metals were measured by inductively coupled plasma-mass spectrometry in dialyzates and also in samples after a microwave assisted acid digestion pre-treatment. Low dialyzability percentages were found for Al, Fe and Hg; moderate percentages were found for Ba, Ca, Cd, Co, Cu, K, Li, Mg, Mn, Mo, P, Pb, Se, Sr, Tl and Zn; and high dialyzability ratios were found for As, Cr and Ni. The highest dialyzability percentages were found in raw chestnuts and raw hazelnuts. Metal dialyzability was found to be negatively affected by fat content. Positive correlation was found between carbohydrate content and metal dialyzability ratios. Protein and dietary fibre content did not influence metal bioavailability. Predicted dialyzability for some metals based on fat and protein content could also be established.
Is Microarray Analysis Really Useful and Sufficient to Diagnose Nut Allergy in the Mediterranean Area?
BACKGROUND: Component-based diagnosis on multiplex platforms is widely used in food allergy but its clinical performance has not been evaluated in nut allergy. OBJECTIVE: To assess the diagnostic performance of a commercial protein microarray in the determination of specific IgE (sIgE) in peanut, hazelnut, and walnut allergy. METHODS: sIgE was measured in 36 peanut-allergic, 36 hazelnut-allergic, and 44 walnut-allergic patients by ISAC 112, and subsequently, sIgE against available components was determined by ImmunoCAP in patients with negative ISAC results. ImmunoCAP was also used to measure sIgE to Ara h 9, Cora 8, and Jug r 3 in a subgroup of lipid transfer protein (LTP)-sensitized nut-allergic patients (positive skin prick test to LTP-enriched extract). sIgE levels by ImmunoCAP were compared with ISAC ranges. RESULTS: Most peanut-, hazelnut-, and walnut-allergic patients were sensitized to the corresponding nut LTP (Ara h 9, 66.7%; Cor a 8, 80.5%; Jug r 3, 84% respectively). However, ISAC did not detect sIgE in 33.3% of peanut-allergic patients, 13.9% of hazelnut-allergic patients, or 13.6% of walnut-allergic patients. sIgE determination by ImmunoCAP detected sensitization to Ara h 9, Cor a 8, and Jug r 3 in, respectively, 61.5% of peanut-allergic patients, 60% of hazelnut-allergic patients, and 88.3% of walnut-allergic patients with negative ISAC results. In the subgroup of peach LTP-sensitized patients, Ara h 9 sIgE was detected in more cases by ImmunoCAP than by ISAC (94.4% vs 72.2%, P < .05). Similar rates of Cora 8 and Jug r 3 sensitization were detected by both techniques. CONCLUSIONS: The diagnostic performance of ISAC was adequate for hazelnut and walnut allergy but not for peanut allergy. sIgE sensitivity against Ara h 9 in ISAC needs to be improved.
Detection by real time PCR of walnut allergen coding sequences in processed foods.
A quantitative real-time PCR (RT-PCR) method, employing novel primer sets designed on Jug r 1, Jug r 3, and Jug r 4 allergen-coding sequences, was set up and validated. Its specificity, sensitivity, and applicability were evaluated. The DNA extraction method based on CTAB-phenol-chloroform was best for walnut. RT-PCR allowed a specific and accurate amplification of allergen sequence, and the limit of detection was 2.5pg of walnut DNA. The method sensitivity and robustness were confirmed with spiked samples, and Jug r 3 primers detected up to 100mg/kg of raw walnut (LOD 0.01%, LOQ 0.05%). Thermal treatment combined with pressure (autoclaving) reduced yield and amplification (integrity and quality) of walnut DNA. High hydrostatic pressure (HHP) did not produce any effect on the walnut DNA amplification. This RT-PCR method showed greater sensitivity and reliability in the detection of walnut traces in commercial foodstuffs compared with ELISA assays.
Prospective investigation on the transfer of Ara h 2, the most potent peanut allergen, in human breast milk.
BACKGROUND: Peanut allergy is one of the most severe food allergies. Whether breast feeding induces tolerance to peanuts or on the contrary, predisposes at risk-babies to occult allergic sensitization to peanuts is still a matter of discussion. We sought to investigate the transfer of the most potent peanut allergen Ara h 2 into human breast milk in a German breast milk study and to shed light on the time kinetics of Ara h 2 appearance. METHODS: We recruited 32 lactating, non-peanut allergic women, and collected breast milk samples at different time points after consumption of 100 g dry roasted peanuts. Breast milk samples were investigated for Ara h 2 with different immunological methods: by 2D immunoblotting with a patient's serum, by affinity enrichment using a monoclonal antibody against Ara h 2 followed by LC-MS/MS based detection and by a competitive inhibition ELISA for the detection of Ara h 2 and its digestion resistant peptides (DRP-Ara h 2). RESULTS: In a qualitative analysis Ara h 2 could be identified in a breast milk sample by 2D immunoblot by means of a patient's serum and furthermore by immunoaffinity enrichment followed by LC-MS/MS analysis. In a semi-quantitative analysis Ara h 2 and its digestion-resistant peptides were detected in the breast milk of 9 out of 32 subjects. Evidence suggests that Ara h 2 is excreted individually either rapidly (after 1 h, 2 h, 3 h or 4 h) or delayed (after 8 h or 12 h) and in different concentrations. CONCLUSIONS: Time and concentration of secreted Ara h 2 in breast milk appears to be individually regulated. The identification of Ara h 2 in breast milk is the prerequisite for the investigation of its sensitizing or tolerogenic properties. This article is protected by copyright. All rights reserved.
Peanuts as functional food: a review.
Peanut is an important crop grown worldwide. Commercially it is used mainly for oil production but apart from oil, the by-products of peanut contains many other functional compounds like proteins, fibers, polyphenols, antioxidants, vitamins and minerals which can be added as a functional ingredient into many processed foods. Recently it has also revealed that peanuts are excellent source of compounds like resveratrol, phenolic acids, flavonoids and phytosterols that block the absorption of cholesterol from diet. It is also a good source of Co-enzyme Q10 and contains all the 20 amino acids with highest amount of arginine. These bioactive compounds have been recognized for having disease preventive properties and are thought to promote longevity. The processing methods like roasting and boiling have shown increase in the concentration of these bioactive compounds. In the present paper an overview on peanut bioactive constituents and their health benefits are presented.
Effects of Diet Composition and Insulin Resistance Status on Plasma Lipid Levels in a Weight Loss Intervention in Women.
BACKGROUND: Optimal macronutrient distribution of weight loss diets has not been established. The distribution of energy from carbohydrate and fat has been observed to promote differential plasma lipid responses in previous weight loss studies, and insulin resistance status may interact with diet composition and affect weight loss and lipid responses. METHODS AND RESULTS: Overweight and obese women (n=245) were enrolled in a 1-year behavioral weight loss intervention and randomly assigned to 1 of 3 study groups: a lower fat (20% energy), higher carbohydrate (65% energy) diet; a lower carbohydrate (45% energy), higher fat (35% energy) diet; or a walnut-rich, higher fat (35% energy), lower carbohydrate (45% energy) diet. Blood samples and data available from 213 women at baseline and at 6 months were the focus of this analysis. Triglycerides, total cholesterol, and high- and low-density lipoprotein cholesterol were quantified and compared between and within groups. Triglycerides decreased in all study arms at 6 months (P<0.05). The walnut-rich diet increased high-density lipoprotein cholesterol more than either the lower fat or lower carbohydrate diet (P<0.05). The walnut-rich diet also reduced low-density lipoprotein cholesterol in insulin-sensitive women, whereas the lower fat diet reduced both total cholesterol and high-density lipoprotein cholesterol in insulin-sensitive women (P<0.05). Insulin sensitivity and C-reactive protein levels also improved. CONCLUSIONS: Weight loss was similar across the diet groups, although insulin-sensitive women lost more weight with a lower fat, higher carbohydrate diet versus a higher fat, lower carbohydrate diet. The walnut-rich, higher fat diet resulted in the most favorable changes in lipid levels. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01424007.
Hazelnut and neuroprotection: Improved memory and hindered anxiety in response to intra-hippocampal Aβ injection.
Objectives Corylus avellana L. (hazelnut) is known to be a delicious and nutritious food. This study was carried out to evaluate the use of hazelnut as a therapy for memory impairment because in Iranian traditional medicine, it is recommended for those suffering from a particular type of dementia, with symptoms of Alzheimer's disease. Methods In this study, rats were fed with hazelnut kernel [(without skin) 800 mg/kg/day] during 1 week before stereotaxic surgery to 24 hours before behavioral testing (in general, for 16 consecutive days) and the effect of hazelnut eating on memory, anxiety, neuroinflammation and apoptosis was assessed in the amyloid beta-injected rat. Results The results of this study showed that feeding with hazelnut improved memory, (which was examined by using Y-maze test and shuttle box apparatus), and reduced anxiety-related behavior, that was evaluated using elevated plus maze. Also, western blotting analysis of cyclooxygenase-2, interleukin-1β, tumor necrosis factor-α, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, and caspase-3 showed that hazelnut has an ameliorating effect on the neuroinflammation and apoptosis caused by Aβ. Discussion These findings suggest that hazelnut, as a dietary supplement, improves healthy aging and could be a beneficial diet for the treatment of AD.
Review of dried fruits: Phytochemicals, antioxidant efficacies, and health benefits.
Dried fruits, which serve as important healthful snacks worldwide, provide a concentrated form of fresh fruits. They are nutritionally equivalent to fresh fruits in smaller serving sizes, ranging from 30 to 43 g depending on the fruit, in current dietary recommendation in different countries. Daily consumption of dried fruits is recommended in order to gain full benefit of essential nutrients, health-promoting phytochemicals, and antioxidants that they contain, together with their desirable taste and aroma. Recently, much interest in the health benefits of dried fruits has led to many in vitro and in vivo (animal and human intervention) studies as well as the identification and quantification of various groups of phytochemicals. This review discusses phytochemical compositions, antioxidant efficacies, and potential health benefits of eight traditional dried fruits such as apples, apricots, dates, figs, peaches, pears, prunes, and raisins, together with dried cranberries. Novel product formulations and future perspectives of dried fruits are also discussed. Research findings from the existing literature published within the last 10 years have been compiled and summarised.
Comparative evaluation of methods for the detection of 2-alkylcyclobutanones as indicators for irradiation treatment of cashew nuts and nutmeg.
Irradiation of food products and ingredients must be indicated by proper labeling. This study evaluated the appropriateness of the European Standard EN 1785:2003 for the detection of 2-alkylcyclobutanones, which are radiolysis products of fatty acids, in cashew nuts and nutmeg and confirmed its suitability to detect irradiation of cashew nut samples at average absorbed doses of 1kGy and above. An alternative method was developed, which is based on matrix solid phase dispersion and subsequent separation and detection of oxime derivatives of 2-alkylcyclobutanones by high performance-high resolution mass spectrometry. It is more rapid, less resource consuming, and more sensitive than EN 1785:2003. This method allowed detection of 2-alkylcyclobutanones in cashew nuts irradiated at 100 Gray and in nutmeg irradiated at 400 Gray. None of the 26 cashew nut and 14 nutmeg samples purchased in different EU Member States contained traces of 2-alkylcyclobutanones.
Allergenicity Attributes of Different Peanut Market Types.
Four different market classes of peanut (Runner, Virginia Spanish, and Valencia) are commonly consumed in Western countries, but for some consumers peanuts are a main cause of food-induced anaphylaxis. Limited information is available on the comparative allergenicity of these distinct market classes. The aim of this study was to compare allergenicity attributes of different peanut cultivars. The protein content and protein profiles were highly comparable for all tested cultivars. All cultivar samples contained the major allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6, as assessed by SDS-PAGE and RP-HPLC, although some minor differences in major allergen content were found between samples. All samples were reactive in commercial ELISAs for detection and quantification of peanut protein.. IgE-binding potency differed between samples with a maximum factor of 2, indicating a highly comparable allergenicity. Based on our observations, we conclude that peanuts from the main market types consumed in Western countries are highly comparable in their allergenicity attributes, indicating that safety considerations with regard to peanut allergy are not dependent on the peanut cultivar in question.