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PURPOSE OF REVIEW: Nuts in general and walnuts in particular are in the limelight for the association of their consumption with improved health outcomes. Walnuts have an optimal composition in bioactive nutrients and recent clinical and experimental studies have uncovered a number of beneficial effects of walnut micronutrients, working in isolation or in concert, on metabolic pathways and clinical outcomes that make this review timely and relevant.
RECENT FINDINGS: Alpha-linolenic acid, a critical walnut component, is metabolized into bioactive oxylipins, has been shown to protect microglial cells from inflammation, and is associated with lower fatal myocardial infarction rates through a putative antiarrhythmic effect. Phytosterols relate to the cholesterol-lowering effect of nut consumption. Nonsodium minerals are associated with better cardiometabolic health. Walnut phytomelatonin has anticancer effects that are shared by the main walnut polyphenols and their metabolites, ellagitannins and urolithins, respectively.
SUMMARY: This review highlights new evidence on the health-promoting properties of walnuts and their main micronutrient components. The conclusion is that walnuts are optimal healthful foods.
Rachel Clare Brown,1 Andrew Robert Gray, Lee Ching Yong, Alex Chisholm, Sook Ling Leong, and Siew Ling Tey
PeerJ. 2018; 6: e5500.
Published online 2018 Sep 11. doi: [10.7717/peerj.5500]
BACKGROUND: Nut consumption at the population level remains low despite the well-documented benefits of their consumption, including their cardioprotective effects. Studies have suggested that advice from health professionals may be a means to increase nut consumption levels. Understanding how nuts are perceived by the public and health professionals, along with understanding the public’s perceptions of motivators of and deterrents to consuming nuts, may inform the development of initiatives to improve on these low levels of consumption. The aim of this cross-sectional study was to compare perceptions of nuts among three groups of health professionals (dietitians, general practioners, and practice nurses) and the general public in New Zealand (NZ), along with motivators of and deterrents to consuming nuts amongst the general public and their experiences of receiving advice around nut consumption.
METHODS: The NZ electoral roll was used to identify dietitians, general practitioners (GPs), and practice nurses, based on their free-text occupation descriptions, who were then invited to complete a questionnaire with 318, 292, and 149 respondents respectively. 1,600 members of the general public were randomly selected from the roll with 710 respondents. Analyses were performed using chi-squared tests to look at differences in categorical variables and linear regression for differences in other variables between the four survey groups.
RESULTS: Although there were significant differences between the four groups regarding the perceptions of nuts, in general there was agreement that nuts are healthy, high in protein and fat, are filling, and some nuts are high in selenium. We noted frequent agreement that the general public participants would consume more if nuts: improved health (67%), were more affordable (60%), or improved the nutrient content (59%) and balance of fats (58%) within their diets. Over half the respondents reported they would eat more nuts if they were advised to do so by a dietitian or doctor, despite less than 4% reporting they had received such advice. The most frequently selected deterrents to increasing nut consumption were: cost (67%), potential weight gain (66%), and leading to eating too much fat (63%).
DISCUSSION: It is concerning that so few among the general public report receiving advice to consume more nuts from health professionals, especially given their apparent responsiveness to such advice. Health professionals could exploit the motivators of nut consumption, while also addressing the deterrents, to promote nut intake. These factors should also be addressed in public health messages to encourage regular nut consumption among the public. Educational initiatives could also be used to improve the nutritional knowledge of GPs and practice nurses with regard to nuts, although even dietitians were unsure of their knowledge in some cases.
The proportion of adults aged over 60 years in the world is expected to reach 20% by the year 2050. Ageing is associated with several physiological changes that increase the risk of malnutrition among this population. Malnutrition is characterized by deficiencies or insufficiencies of macro- and micronutrients. Malnutrition has detrimental effects on the health, wellbeing, and quality of life in older adults. Nuts are rich in energy, unsaturated fats, and protein, as well as other nutrients that provide a range of health benefits. While the effects of nuts on overnutrition have been studied extensively, very few studies have been specifically designed to understand the role of nuts in mitigating undernutrition in the elderly. Therefore, this review explores the potential role of nuts in improving the nutritional status of older adults who are at risk of undernutrition. Several properties of whole nuts, some of which appear important for addressing overnutrition, (e.g., hardness, lower-than-expected nutrient availability, satiety-enhancing effects) may limit their effectiveness as a food to combat undernutrition. However, we propose that modifications such as transforming the physical form of nuts, addressing the timing of nut ingestion, and introducing variety may overcome these barriers. This review also discusses the feasibility of using nuts to prevent and reverse undernutrition among older adults. We conclude with a recommendation to conduct clinical studies in the future to test this conceptual framework.
BACKGROUND: The beneficial effect of nut consumption preventing cardio-metabolic diseases and cancer suggests that nuts might also protect from physical function impairment in older people, since aging-related functional decline shares biological pathways with these chronic diseases. The objective was to examine the association between nut consumption and impairment of physical function in older adults.
METHODS: Prospective study with 3,289 individuals aged ≥60 years from the Seniors-ENRICA cohort. In 2008-2010 and 2012 nut consumption was measured with a validated diet history. Participants were followed-up until 2015 to ascertain incident impaired physical function, specifically impaired agility, mobility, grip strength, gait speed and overall physical function. Statistical analyses were performed with Cox regression and adjusted for the main confounders, including a wide set of socioeconomic, lifestyle, dietary and morbidity variables.
RESULTS: Overall, 65.7% of participants consumed any type of nuts. The mean intake among nut consumers was 15.1 g/d in men and 14.6 g/d in women. Median consumption of nuts was 11.5 g/d in both sexes. Men consuming ≥11.5 g/d of nuts had lower risk of impaired agility and mobility than those who did not consume nuts; the hazard ratios (95% confidence interval; p for linear trend) were 0.59 (0.39-0.90; p=0.01) and 0.50 (0.29-0.90; p=0.02), respectively. In women, compared to non-consumers, the hazard ratio (95% confidence interval; p for linear trend) of impaired overall physical function for nut intake ≥11.5 g/d was 0.65 (0.48-0.87; p=0.004). No association was observed between nut consumption and low grip strength and slow gait speed.
CONCLUSIONS: Nut consumption was associated with half the risk of impaired agility and mobility in men and with lower risk of overall physical function impairment in women. The suggested protective effect of nut consumption on physical functioning merits further examination.
Tucker LA. Consumption of Nuts and Seeds and Telomere Length in 5,582 Men and Women of the National Health and Nutrition Examination Survey (NHANES).J Nutr Health Aging. 2017;21(3):233-240. doi: 10.1007/s12603-017-0876-5.
OBJECTIVES: Consumption of nuts and seeds is associated favorably with all-cause mortality. Nuts and seeds could reduce disease and prolong life by influencing telomeres. Telomere length is a good indicator of the senescence of cells. The purpose of the present study was to determine the relationship between nuts and seeds intake and leukocyte telomere length, a biomarker of biologic aging.
SETTING AND PARTICIPANTS: A total of 5,582 randomly selected men and women from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, were studied.
MEASUREMENTS: DNA was obtained via blood samples. Telomere length was assessed using the quantitative polymerase chain reaction method. A validated, multi-pass, 24-h recall dietary assessment, administered by NHANES, was employed to quantify consumption of nuts and seeds.
RESULTS: Nuts and seeds intake was positively and linearly associated with telomere length. For each 1-percent of total energy derived from nuts and seeds, telomere length was 5 base pairs longer (F=8.6, P=0.0065). Given the age-related rate of telomere shortening was 15.4 base pairs per year (F=581.1, P<0.0001), adults of the same age had more than 1.5 years of reduced cell aging if they consumed 5% of their total energy from nuts and seeds.
CONCLUSIONS: Consumption of nuts and seeds accounts for meaningful decreases in biologic aging and cell senescence. The findings reinforce the recommendations of the 2015-2020 Dietary Guidelines for Americans, which encourage the consumption of nuts and seeds as part of a healthy diet.
Kranz S, Hill AM, Fleming JA, Hartman TJ, West SG, Kris-Etherton PM.Nutrient displacement associated with walnut supplementation in men. J Hum Nutr Diet. 2014 Apr;27 Suppl 2:247-54.
BACKGROUND: Dietary guidance issued by various global government agencies recommends nut consumption within the context of a healthy-eating pattern. Nuts are nutrient dense and may promote nutrient adequacy. As an energy-dense food, nuts must replace other foods in the diet to prevent an excess of calories.
METHODS: We evaluated how recommending the inclusion of walnuts (75 g day(-1) ) in the diet affected energy and nutrient intake in men (45-75 years; mean body mass index = 27.6 kg m(-2) ; n = 19) at risk for developing prostate cancer. Guidance was provided about incorporating walnuts isocalorically in a healthy diet. Three-day food records and body weight were collected at baseline and after two 8-week diet periods (usual versus walnut supplement diets).
RESULTS: Energy intake on the walnut supplement diet exceeded the usual diet, although body weight was maintained. Energy intake was lower on the actual walnut supplement diet than the calculated walnut diet [10,865 kJ (2595 kcal) versus 11,325 kJ (2705 kcal) per day, respectively] and contributed 23% less energy than 75 g of walnuts. Approximately, 86% and 85% of the total fat and saturated fatty acids from walnuts were not displaced, whereas the increase in fibre from the usual diet to the actual walnut supplement diet represented less than one-half (39%) of the fibre provided by 75 g of walnuts. Walnuts were substituted, in part, for other foods, and the nutrient profile of the diet was improved, however, the beneficial effect of walnuts on the diet quality was not optimized.
CONCLUSIONS: Individuals do not optimally implement food-based guidance. Consequently, nutrition professionals play a key role in teaching the implementation of food-based recommendations.
Brittain C, Kremen C, Garber A, Klein AM.Pollination and plant resources change the nutritional quality of almonds for human health. PLoS One. 2014 Feb 27;9(2):e90082.
Insect-pollinated crops provide important nutrients for human health. Pollination, water and nutrients available to crops can influence yield, but it is not known if the nutritional value of the crop is also influenced. Almonds are an important source of critical nutrients for human health such as unsaturated fat and vitamin E. We manipulated the pollination of almond trees and the resources available to the trees, to investigate the impact on the nutritional composition of the crop. The pollination treatments were: (a) exclusion of pollinators to initiate self-pollination and (b) hand cross-pollination; the plant resource treatments were: (c) reduced water and (d) no fertilizer. In an orchard in northern California, trees were exposed to a single treatment or a combination of two (one pollination and one resource). Both the fat and vitamin E composition of the nuts were highly influenced by pollination. Lower proportions of oleic to linoleic acid, which are less desirable from both a health and commercial perspective, were produced by the self-pollinated trees. However, higher levels of vitamin E were found in the self-pollinated nuts. In some cases, combined changes in pollination and plant resources sharpened the pollination effects, even when plant resources were not influencing the nutrients as an individual treatment. This study highlights the importance of insects as providers of cross-pollination for fruit quality that can affect human health, and, for the first time, shows that other environmental factors can sharpen the effect of pollination. This contributes to an emerging field of research investigating the complexity of interactions of ecosystem services affecting the nutritional value and commercial quality of crops.
Kiefl J, Pollner G, Schieberle P. Sensomics Analysis of Key Hazelnut Odorants ( Corylus avellana L. ‘Tonda Gentile’) Using Comprehensive Two-Dimensional Gas Chromatography in Combination with Time-of-Flight Mass Spectrometry (GC×GC-TOF-MS). J Agric Food Chem. 2013 May 21. [Epub ahead of print]
Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) has been used a few times to identify and quantitate single aroma-active compounds, but the capability of this technique to monitor a complete set of key odorants evoking the aroma of a given food in one run has not been exploited so far. A fast, multiodorant analysis using GC×GC-TOF-MS in combination with stable isotope dilution assays (SIDA) was developed to quantitate the entire set of aroma compounds, the sensometabolome, of raw and roasted hazelnuts ( Corylus avellana L. ‘Tonda Gentile’) previously established by GC-olfactometry. The capability of the method to evaluate the aroma contribution of each sensometabolite was evaluated by introducing a new term, the limit of odor activity value (LOAV), indicating whether a given aroma compound can be determined down to an odor activity value (OAV) of 1 (odor activity value = ratio of concentration to odor threshold). The advantage of the new method was proven by comparing the performance parameters with a traditional one-dimensional approach using GC-ion trap mass-spectrometry (GC-IT-MS). The results showed that the detector linearity and sensitivity of GC×GC-TOF-MS was on average higher by a factor of 10 compared to GC-IT-MS, thus enabling the quantitation of the aroma relevant amounts of 22 key odorants of hazelnuts in one run of the 30 aroma-active compounds. Seven novel isotopically labeled internal standards were synthesized to meet the analytical requirements defined by electron impact ionization in TOF-MS, that is, to keep the label. On the basis of the quantitative results obtained, it was possible to closely mimic the aroma of raw and roasted ‘Tonda Gentile’ hazelnuts by preparing an aroma recombinate containing the key odorants at their natural concentrations occurring in the nuts.
Handy SM, Timme RE, Jacob SM, Deeds JR. Development of a locked nucleic acid real-time polymerase chain reaction assay for the detection of Pinus armandii in mixed species pine nut samples associated with dysgeusia. J Agric Food Chem. 2013 Feb 6;61(5):1060-6.
Recent work has shown that the presence of the species Pinus armandii , even when occurring as species mixtures of pine nuts, is correlated with taste disturbance (dysgeusia), also referred to as “pine mouth”. Because of this known possibility of pine nut mixtures, a need was identified for a rapid streamlined assay to detect the presence of this species in the presence of other types of pine nuts. A locked nucleic acid probe was employed in a real-time polymerase chain reaction (RT-PCR) format to detect a single nucleotide polymorphism (SNP) unique to this species. This assay was able to detect P. armandii in homogenates down to ∼1% concentration (the lowest level tested) in the presence of several commonly co-occurring and closely related species of pine and should prove to be a useful tool for the detection of this species in food products.
Hampton RL, Scully C, Gandhi S, Raber-Durlacher J. Cacogeusia following pine nut ingestion: a six patient case series. Br J Oral Maxillofac Surg. 2013 Jan;51(1):e1-3.
This is a retrospective case series of 6 patients complaining of a bad taste (cacogeusia) specifically metallogeusia, following the ingestion of pine nuts.(1) The taste arose always within 48h of ingestion, and in all but one patient spontaneously resolved within 14 days. Pine nuts also have a potential for triggering anaphylaxis.(2).
Russo P, Siani A. The role of nuts in the optimal diet: time for a critical appraisal? Nutr Metab Cardiovasc Dis. 2012 Dec;22(12):1019-23.
During the last decades, nuts have attracted the attention of researchers for their potential benefits in cardiovascular prevention. We discuss here some aspects of the assumed beneficial effects of nuts, weighing them against potential harm. Epidemiological observations and controlled intervention trials consistently suggest that nuts consumption is associated with improved serum lipid profile, thus helping decrease cardiovascular risk. Being nuts an energy dense food, their impact on energy balance and body weight should be considered. In particular, the claim that adding nuts to the habitual diet, thus increasing calorie intake, does not cause body fat accumulation still needs evidence and biological plausibility. The potential risk associated with the relatively frequent occurrence of allergic reactions following the consumption of nuts is also discussed.
Munk MD. Pine mouth (pine nut) syndrome: description of the toxidrome, preliminary case definition, and best evidence regarding an apparent etiology. Semin Neurol. 2012 Nov;32(5):525-7.
Pine mouth syndrome (PMS), otherwise known as pine nut syndrome, is a relatively new condition. At least several thousand cases have now been described in the literature. The author describes the PMS toxidrome, offers a preliminary case definition, and discusses current best evidence regarding the etiology and risk factors related to the development of PMS.A clinically compatible case of PMS must include taste disturbance, usually characterized as bitter or metallic, following the ingestion of affected pine nuts by 1 to 3 days. Affected nuts would appear to include all, or some portion, of nuts harvested from species Pinus armandii (Chinese white pine), but could include nuts from other species. The specific toxin that is apparently present in affected nuts has not yet been isolated, and the mechanism of toxicity and factors determining PMS susceptibility need to be further detailed. There are no proven therapies for PMS. The only treatment is to cease ingesting implicated nuts and to wait for symptoms to abate.
Robbins WA, Xun L, FitzGerald LZ, Esguerra S, Henning SM, Carpenter CL. Walnuts improve semen quality in men consuming a Western-style diet: randomized control dietary intervention trial. Biol Reprod. 2012 Oct 25;87(4):101.
We tested the hypothesis that 75 g of whole-shelled walnuts/day added to the Western-style diet of healthy young men would beneficially affect semen quality. A randomized, parallel two-group dietary intervention trial with single-blind masking of outcome assessors was conducted with 117 healthy men, age 21-35 yr old, who routinely consumed a Western-style diet. The primary outcome was improvement in conventional semen parameters and sperm aneuploidy from baseline to 12 wk. Secondary endpoints included blood serum and sperm fatty acid (FA) profiles, sex hormones, and serum folate. The group consuming walnuts (n = 59) experienced improvement in sperm vitality, motility, and morphology, but no change was seen in the group continuing their usual diet but avoiding tree nuts (n = 58). Comparing differences between the groups from baseline, significance was found for vitality (P = 0.003), motility (P = 0.009), and morphology (normal forms; P = 0.04). Serum FA profiles improved in the walnut group with increases in omega-6 (P = 0.0004) and omega-3 (P = 0.0007) but not in the control group. The plant source of omega-3, alpha-linolenic acid (ALA) increased (P = 0.0001). Sperm aneuploidy was inversely correlated with sperm ALA, particularly sex chromosome nullisomy (Spearman correlation, -0.41, P = 0.002). Findings demonstrated that walnuts added to a Western-style diet improved sperm vitality, motility, and morphology.
Ballin NZ. A trial investigating the symptoms related to pine nut syndrome. J Med Toxicol. 2012 Sep;8(3):278-80.
During the last few years, thousands of cases of pine nut-related dysgeusia have been reported. The symptoms involved are predominantly related to taste disturbances such as a constant bitter or metallic taste. The taste disturbance has been reported to occur 1-2 days after ingestion of pine nuts from the species of Pinus armandii. This paper describes a small trial where six volunteers consumed six to eight pine nuts suspected to cause dysgeusia. Incubation periods, symptoms and their duration were recorded. The trial showed that all subjects had developed symptoms of pine nut-related dysgeusia. Four out of six subjects experienced the classical bitter and metallic taste 1-2 days after ingestion. Two subjects experienced minor symptoms such as dryness and a sensation of enlarged tonsils. After the disappearance of symptoms, laboratory tests determined the pine nuts to originate from the species of P. armandii. A follow-up conversation with the subjects after 1 year showed no recurrent symptoms.
Stockler-Pinto MB, Lobo J, Moraes C, Leal VO, Farage NE, Rocha AV, Boaventura GT, Cozzolino SM, Malm O, Mafra D. Effect of Brazil nut supplementation on plasma levels of selenium in hemodialysis patients: 12 months of follow-up. J Ren Nutr. 2012 Jul;22(4):434-9.
BACKGROUND: Large amounts of reactive oxygen species are produced in hemodialysis (HD) patients, and, at higher concentrations, reactive oxygen species are thought to be involved in the pathogenesis of cardiovascular disease. It has been proposed that selenium (Se) may exert an antiatherogenic influence by reducing oxidative stress. The richest known food source of Se is the Brazil nut (Bertholletia excelsa, family Lecythidaceae), found in the Amazon region.
OBJECTIVE: The objective of this work was to determine if Se plasma levels in HD patients submitted to a program of supplementation during 3 months with 1 Brazil nut by day could be sustained after 12 months.
METHODS: A total of 21 HD patients (54.2 ± 15.2 years old; average time on dialysis, 82.3 ± 51.6 months; body mass index, 24.4 ± 3.8 kg/m(2)) from the RenalCor Clinic in Rio de Janeiro, Brazil, were followed up 12 months after the supplementation study ended. The Se plasma levels were determined by atomic absorption spectrophotometry with hydride generation.
RESULTS: The Se Plasma levels (17.3 ± 19.9 μg/L) were below the normal range (60 to 120 μg/L) before nut supplementation, and after 3 months of supplementation, the levels increased to 106.8 ± 50.3 μg/L (P < .0001). Twelve months after supplementation, the plasma Se levels decreased to 31.9 ± 14.8 μg/L (P < .0001). CONCLUSIONS: The data showed that these patients were Se deficient and that the consumption of Brazil nut was effective to increase the Se parameters of nutritional status. Se levels 12 months after the supplementation period were not as low as presupplementation levels but yet significantly lower, and we needed to motivate patients to adopt different dietary intake patterns.
Fardin-Kia AR, Handy SM, Rader JI. Characterization of pine nuts in the U.S. market, including those associated with “pine mouth”, by GC-FID. J Agric Food Chem. 2012 Mar 14;60(10):2701-11.
Taste disturbances following consumption of pine nuts, referred to as “pine mouth”, have been reported by consumers in the United States and Europe. Nuts of Pinus armandii have been associated with pine mouth, and a diagnostic index (DI) measuring the content of Δ5-unsaturated fatty acids relative to that of their fatty acid precursors has been proposed for identifying nuts from this species. A 100 m SLB-IL 111 GC column was used to improve fatty acid separations, and 45 pine nut samples were analyzed, including pine mouth-associated samples. This study examined the use of a DI for the identification of mixtures of pine nut species and showed the limitation of morphological characteristics for species identification. DI values for many commercial samples did not match those of known reference species, indicating that the majority of pine nuts collected in the U.S. market, including those associated with pine mouth, are mixtures of nuts from different Pinus species.
Redal-Baigorri AB. [Pine mouth syndrome: a global problem].[Article in Danish] Ugeskr Laeger. 2011 Dec 5;173(49):3184-6.
Pinemouth syndrome is characterised by the development of metallogeusia two days after the ingestion of Chinese pine nuts. The symptoms disappear 7-14 days later. The distribution of Chinese pine nuts not suitable for human consumption, is caused by an increasing demand due to price differences. The reason for the taste disturbances is unknown, some suggest turpentine-based products in its composition, and others have studied the fatty acid content of pine nuts and the properties of pinolenic acid. So far the presence of pesticides or mycotoxins is been ruled out, but the puzzle remains unsolved.
Handy SM, Parks MB, Deeds JR, Liston A, de Jager LS, Luccioli S, Kwegyir-Afful E, Fardin-Kia AR, Begley TH, Rader JI, Diachenko GW. Use of the chloroplast gene ycf1 for the genetic differentiation of pine nuts obtained from consumers experiencing dysgeusia. J Agric Food Chem. 2011 Oct 26;59(20):10995-1002.
Pine nuts are a part of traditional cooking in many parts of the world and have seen a significant increase in availability/use in the United States over the past 10 years. The U.S. Food and Drug Administration (US FDA) field offices received 411 complaints from U.S. consumers over the past three years regarding taste disturbances following the consumption of pine nuts. Using analysis of fatty acids by gas chromatography with flame ionization detection, previous reports have implicated nuts from Pinus armandii (Armand Pine) as the causative species for similar taste disturbances. This method was found to provide insufficient species resolution to link FDA consumer complaint samples to a single species of pine, particularly when samples contained species mixtures of pine nuts. Here we describe a DNA based method for differentiating pine nut samples using the ycf1 chloroplast gene. Although the exact cause of pine nut associated dysgeusia is still not known, we found that 15 of 15 samples from consumer complaints contained at least some Pinus armandii, confirming the apparent association of this species with taste disturbances.
Flesch F, Rigaux-Barry F, Saviuc P, Garnier R, Daoudi J, Blanc I, Tellier SS, Lasbeur L. Dysgeusia following consumption of pine nuts: more than 3000 cases in France. Clin Toxicol (Phila). 2011 Aug;49(7):668-70.
INTRODUCTION: In March 2008, French poison centres (PCs) recorded the first calls reporting persistent bitterness following the ingestion of pine nuts.
METHODS: The French toxic exposure surveillance system (French-Tess) was searched and a descriptive analysis of cases was performed on data recorded from 13 March 2008 to 31 January 2010.
RESULTS: Some 3111 cases of bitterness were reported to PCs. The number of cases rose sharply from May 2009 to reach a peak in August 2009 with 697 cases. The median time to onset of dysgeusia was 24 hours and it lasted less than 14 days in 95% of cases. Raw as well as cooked or processed pine nuts were implicated.
DISCUSSION: The delayed onset and persistence of dysgeusia suggest that the toxin may act via an unknown toxic mechanism on the receptor. The aetiological agent could be an unidentified toxin present in some varieties of non-edible pine nuts.
CONCLUSION: The high incidence of the event and the lack of understanding of the nature of the toxin and its pathophysiological mechanism require continued monitoring of poison cases, botanical and biochemical analysis, and experimental studies.
Kobler H, Monakhova YB, Kuballa T, Tschiersch C, Vancutsem J, Thielert G, Mohring A, Lachenmeier DW. Nuclear magnetic resonance spectroscopy and chemometrics to identify pine nuts that cause taste disturbance. J Agric Food Chem. 2011 Jul 13;59(13):6877-81.
Nontargeted 400 MHz (13)C and (1)H nuclear magnetic resonance (NMR) spectroscopy was used in the context of food surveillance to reveal Pinus species whose nuts cause taste disturbance following their consumption, the so-called pine nut syndrome (PNS). Using principal component analysis, three groups of pine nuts were distinguished. PNS-causing products were found in only one of the groups, which however also included some normal products. Sensory analysis was still required to confirm PNS, but NMR allowed the sorting of 53% of 57 samples, which belong to the two groups not containing PNS species. Furthermore, soft independent modeling of class analogy was able to classify the samples between the three groups. NMR spectroscopy was judged as suitable for the screening of pine nuts for PNS. This process may be advantageous as a means of importation control that will allow the identification of samples suitable for direct clearance and those that require further sensory analysis.
Piluzza G, Bullitta S. Correlations between phenolic content and antioxidant properties in twenty-four plant species of traditional ethnoveterinary use in the Mediterranean area. Pharm Biol. 2011 Mar;49(3):240-7.
CONTEXT: Scientific information on antioxidant properties and phenolic content of less widely used plants can be useful. Therefore, the assessment of such properties remains an interesting and useful task, particularly for finding new sources for natural antioxidants, functional foods, and nutraceuticals.
OBJECTIVE: As knowledge about antioxidant properties and phenolic content of many plant species used as traditional plant remedies is limited, we determined in vitro the total antioxidant activity and the phenolic content of several plant species traditionally used for ethnoveterinary practices.
MATERIALS AND METHODS: For 24 extracts (70% acetone) from wild and cultivated plant species traditionally used for health care of animals we determined the Trolox equivalent antioxidant capacity (TEAC) by the two assays 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS). The phenolic content was determined by the Folin Ciocalteu method.
RESULTS: Total phenolics, calculated as gallic acid equivalent (GAE), showed variation ranging from 3.18 (Allium sativum L. (Liliaceae)) to 147.68 (Pistacia lentiscus L. (Anacardiaceae)) mgGAE/g dry weight (DW). High TEAC values corresponded to high phenolic content, while plants with low antioxidant activity exhibited low total phenolic content. The TEAC determined through each assay and total phenolic content were positively correlated, R² = 0.9152 and R² = 0.8896, respectively, for DPPH and ABTS assay.
Mishra N, Dubey A, Mishra R, Barik N. Study on antioxidant activity of common dry fruits. Food Chem Toxicol. 2010 Dec;48(12):3316-20.
This study investigates the antioxidant activity of different dry fruits (almonds, walnut, cashew nut, raisins, chironji) through several chemical and biochemical assays: reducing power, lipid peroxidation damage in biomembranes, determination of antioxidant enzymes activity (SOD and CAT). To estimate the total phenolic content, the assay using Folin-Ciocalteu reagent was used. The EC(50) values were calculated for all the methods in order to evaluate the antioxidant efficiency of each dry fruit. The results obtained were quite heterogenous, revealing significant differences among the dry fruits. The methanolic extract of walnut showed the higher value of antioxidant activity based on lipid peroxidation assay. The higher phenolic content was found in walnuts followed by almonds cashew nut, chironji and least phenolic content was found in raisins. Walnut revealed the best antioxidant properties, presenting lower EC(50) values in all assays except in antioxidant enzymatic activity.
Pérez-Jiménez J, Neveu V, Vos F, Scalbert A. Identification of the 100 richest dietary sources of polyphenols: an application of the Phenol-Explorer database. Eur J Clin Nutr. 2010 Nov;64 Suppl 3:S112-20.
BACKGROUND/OBJECTIVES: The diversity of the chemical structures of dietary polyphenols makes it difficult to estimate their total content in foods, and also to understand the role of polyphenols in health and the prevention of diseases. Global redox colorimetric assays have commonly been used to estimate the total polyphenol content in foods. However, these assays lack specificity. Contents of individual polyphenols have been determined by chromatography. These data, scattered in several hundred publications, have been compiled in the Phenol-Explorer database. The aim of this paper is to identify the 100 richest dietary sources of polyphenols using this database.
SUBJECTS/METHODS: Advanced queries in the Phenol-Explorer database (www.phenol-explorer.eu) allowed retrieval of information on the content of 502 polyphenol glycosides, esters and aglycones in 452 foods. Total polyphenol content was calculated as the sum of the contents of all individual polyphenols. These content values were compared with the content of antioxidants estimated using the Folin assay method in the same foods. These values were also extracted from the same database. Amounts per serving were calculated using common serving sizes.
RESULTS: A list of the 100 richest dietary sources of polyphenols was produced, with contents varying from 15,000 mg per 100 g in cloves to 10 mg per 100 ml in rosé wine. The richest sources were various spices and dried herbs, cocoa products, some darkly coloured berries, some seeds (flaxseed) and nuts (chestnut, hazelnut) and some vegetables, including olive and globe artichoke heads. A list of the 89 foods and beverages providing more than 1 mg of total polyphenols per serving was established. A comparison of total polyphenol contents with antioxidant contents, as determined by the Folin assay, also showed that Folin values systematically exceed the total polyphenol content values.
CONCLUSIONS: The comprehensive Phenol-Explorer data were used for the first time to identify the richest dietary sources of polyphenols and the foods contributing most significantly to polyphenol intake as inferred from their content per serving.
Alasalvar C, Pelvan E, Topal B. Effects of roasting on oil and fatty acid composition of Turkish hazelnut varieties (Corylus avellana L.). Int J Food Sci Nutr. 2010 Sep;61(6):630-42.
A total of 18 natural and roasted hazelnut varieties (namely, Aci, Cavcava, Cakildak, Foşa, Ham, Incekara, Kalinkara, Kan, Karafindik, Kargalak, Kuş, Mincane, Palaz, Sivri, Tombul, Uzunmusa, Yassi Badem, and Yuvarlak Badem), grown in the Giresun province of Turkey, were compared for their differences in oil content and fatty acid profiles. The oil content in natural and roasted hazelnut varieties ranged from 57.85% for Kargalak to 68.31% for Incekara and from 61.37% for Kargalak to 71.72% for Incekara, respectively. A total of 20 fatty acids were identified in oils extracted from different varieties of natural and roasted hazelnuts. Among the identified fatty acids in natural hazelnut oils, 18:1omega9 was the dominant fatty acid (ranging from 77.77 to 86.91%). Roasting had minor influence on the fatty acid profiles. These results suggest that semi-commercial hazelnut varieties are as good source of oils and possess valuable fatty acid profiles as commercial varieties (Tombul, Cakildak, Foşa, Karafindik, Mincane, Palaz, and Sivri).
Martínez ML, Labuckas DO, Lamarque AL, Maestri DM. Walnut (Juglans regia L.): genetic resources, chemistry, by-products. J Sci Food Agric. 2010 Sep;90(12):1959-67.
Walnut (Juglans regia L.) is the most widespread tree nut in the world. There is a great diversity of genotypes differing in forestry, productivity, physical and chemical nut traits. Some of them have been evaluated as promising and may serve as germplasm sources for breeding. The nutritional importance of the nut is related to the seed (kernel). It is a nutrient-dense food mainly owing to its oil content (up to 740 g kg(-1) in some commercial varieties), which can be extracted easily by screw pressing and consumed without refining. Walnut oil composition is dominated largely by unsaturated fatty acids (mainly linoleic together with lesser amounts of oleic and linolenic acids). Minor components of walnut oil include tocopherols, phospholipids, sphingolipids, sterols, hydrocarbons and volatile compounds. Phenolic compounds, present at high levels in the seed coat but poorly extracted with the oil, have been extensively characterised and found to possess strong antioxidant properties. The oil extraction residue is rich in proteins (unusually high in arginine, glutamic and aspartic acids) and has been employed in the formulation of various functional food products. This review describes current scientific knowledge concerning walnut genetic resources and composition as well as by-product obtainment and characteristics.
Yamori Y, Taguchi T, Hamada A, Kunimasa K, Mori H, Mori M. Taurine in health and diseases: consistent evidence from experimental and epidemiological studies. J Biomed Sci. 2010 Aug 24;17 Suppl 1:S6.
Taurine (T) was first noted as beneficial for stroke and cardiovascular diseases (CVD) prevention in genetic rat models, stroke-prone spontaneously hypertensive rats (SHRSP). The preventive mechanisms of T were ascribed to sympathetic modulation for reducing blood pressure (BP) and anti-inflammatory action. Recent epidemiological surveys revealed the involvement of inflammatory mediators in the pathogenesis of stroke and also atherosclerosis for which T was proven to be effective experimentally. Arterio-lipidosis prone rats, a substrain of SHRSP selectively bred for higher reactive hypercholesterolemia, quickly develop not only arterial fat deposition but also fatty liver which could be attenuated by dietary T supplementation. CARDIAC (CVD and Alimentary Comparison) Study was a WHO-coordinated multi-center epidemiological survey on diets and CVD risks and mortalities in 61 populations. Twenty-four-hour urinary (24U) T was inversely related significantly with coronary heart disease mortality. Higher 24U-T excreters had significantly lower body mass index, systolic and diastolic BP, total cholesterol (T-Cho), and atherogenic index (AI: T-Cho/high density lipoprotein-cholesterol) than lower T excreters. T effects on CVD risks were intensified in individuals whose 24U-T and -magnesium (M) excretions were higher. Furthermore, higher Na excreters with higher heart rate whose BP were significantly higher than those with lower heart rate were divided into two groups by the mean of 24U-T, high and low T excreters. Since the former showed significantly lower BP than the latter, T may beneficially affect salt-sensitive BP rise. Included among the typical 61 populations, were Guiyang, China or St. John’s, Newfoundland, Canada where in which the means of both 24U-T and -M were high or low, respectively. The former and the latter had low and high CVD risks, respectively. Australian Aboriginals living at the coastal area in Victoria were supposed to eat T- and M-rich bush and sea foods and be free from CVD 200 years ago, but they presently have nearly the highest CVD risks indicating that T- and/or M-containing seafood, vegetables, fruits, nuts, milk, etc, similar to prehistoric hunters’ and gatherers’ food should be good for CVD prevention. The preventive effects of T, good for health and longevity, first noted experimentally, were also proven epidemiologically in humans.
Arráez-Román D, Fu S, Sawalha SM, Segura-Carretero A, Fernández-Gutiérrez A. HPLC/CE-ESI-TOF-MS methods for the characterization of polyphenols in almond-skin extracts. Electrophoresis. 2010 Jul;31(13):2289-96.
We have developed two rapid methods using CE and HPLC coupled to ESI-TOF-MS and both these methods have been compared for the separation and characterization of antioxidant phenolic compounds in almond-skin extract. Under optimum CE-ESI-TOF-MS conditions we achieved the determination of nine compounds from the polar fraction in 35 min. Furthermore, by using the HPLC-ESI-TOF-MS method, a total of 23 compounds corresponding to phenolic acids and the flavonoid family were identified from almond skin in only 9 min. The sensitivity, together with mass accuracy and true isotopic pattern of TOF-MS, allowed the identification of a broad series of known phenolic compounds present in almond-skin extracts using HPLC and CE as separation techniques.
de Jong WH, Post WJ, Kerstens MN, de Vries EG, Kema IP. Elevated Urinary Free and Deconjugated Catecholamines after Consumption of a Catecholamine-Rich Diet. J Clin Endocrinol Metab. 2010 Jun;95(6):2851-5
CONTEXT: The biochemical diagnosis of pheochromocytoma depends on the demonstration of elevated levels of catecholamines (i.e. epinephrine, norepinephrine, and dopamine) and their metabolites.
OBJECTIVE: The aim of the study was to determine the preanalytical influence of a catecholamine-rich diet on urinary free and deconjugated catecholamines in healthy volunteers with a highly specific and sensitive analytical technique.
DESIGN, SETTING AND PARTICIPANTS: We conducted a crossover study involving 27 healthy adults in a specialist medical center.
INTERVENTIONS: Subjects consumed catecholamine-rich nuts and fruits at fixed times on one day (about 35 micromol dopamine and 1 micromol norepinephrine) and catecholamine-poor products on another day. Urine samples were collected at timed intervals before, during, and after experimental and control interventions.
MAIN OUTCOME MEASURES: We performed automated online sample preparation coupled to isotope-dilution mass spectrometry measurements of urinary concentrations of free and deconjugated catecholamines.
RESULTS: The catecholamine-rich diet had substantial effects on urinary excretions of deconjugated dopamine (up to 20-fold increases) and norepinephrine (up to 10-fold). Dietary catecholamines had less but significant effects on urinary excretion of free dopamine and norepinephrine (up to 1.5-fold increases). Outputs of urinary free and deconjugated epinephrine remained unaffected.
CONCLUSIONS: Urinary excretion of deconjugated norepinephrine and dopamine is strongly affected by consumption of catecholamine-rich food products, thereby increasing the likelihood of a false-positive test result during hormonal evaluation for pheochromocytoma. Measurement of deconjugated catecholamines should therefore preferably be avoided, in favor of measurement of urinary free catecholamines. In case of demonstrating increased urinary excretion of deconjugated norepinephrine and dopamine, repeated measurements are warranted with dietary restrictions prior to sample collection.
Sharma GM, Su M, Joshi AU, Roux KH, Sathe SK. Functional Properties of Select Edible Oilseed Proteins. J Agric Food Chem. 2010 May 12;58(9):5457-64.Trox J, Vadivel V, Vetter W, Stuetz W, Scherbaum V, Gola U, Nohr D, Biesalski HK. Bioactive Compounds in Cashew Nut (Anacardium occidentale L.) Kernels: Effect of Different Shelling Methods. J Agric Food Chem. 2010 May 12;58(9):5341-6.
In the present study, the effects of various conventional shelling methods (oil-bath roasting, direct steam roasting, drying, and open pan roasting) as well as a novel “Flores” hand-cracking method on the levels of bioactive compounds of cashew nut kernels were investigated. The raw cashew nut kernels were found to possess appreciable levels of certain bioactive compounds such as beta-carotene (9.57 microg/100 g of DM), lutein (30.29 microg/100 g of DM), zeaxanthin (0.56 microg/100 g of DM), alpha-tocopherol (0.29 mg/100 g of DM), gamma-tocopherol (1.10 mg/100 g of DM), thiamin (1.08 mg/100 g of DM), stearic acid (4.96 g/100 g of DM), oleic acid (21.87 g/100 g of DM), and linoleic acid (5.55 g/100 g of DM). All of the conventional shelling methods including oil-bath roasting, steam roasting, drying, and open pan roasting revealed a significant reduction, whereas the Flores hand-cracking method exhibited similar levels of carotenoids, thiamin, and unsaturated fatty acids in cashew nuts when compared to raw unprocessed samples.
Sharma GM, Su M, Joshi AU, Roux KH, Sathe SK. Functional Properties of Select Edible Oilseed Proteins. J Agric Food Chem. 2010 May 12;58(9):5457-64.
Borate saline buffer (0.1 M, pH 8.45) solubilized proteins from almond, Brazil nut, cashew nut, hazelnut, macadamia, pine nut, pistachio, Spanish peanut, Virginia peanut, and soybean seeds were prepared from the corresponding defatted flour. The yield was in the range from 10.6% (macadamia) to 27.4% (almond). The protein content, on a dry weight basis, of the lyophilized preparations ranged from 69.23% (pine nut) to 94.80% (soybean). Isolated proteins from Brazil nut had the lightest and hazelnut the darkest color. Isolated proteins exhibited good solubility in aqueous media. Foaming capacity (<40% overrun) and stability (<1 h) of the isolated proteins were poor to fair. Almond proteins had the highest viscosity among the tested proteins. Oil-holding capacity of the isolated proteins ranged from 2.8 (macadamia) to 7 (soybean) g of oil/g of protein. Least gelation concentrations (% w/v) for almond, Brazil nut, cashew, hazelnut, macadamia, pine nut, pistachio, Spanish peanut, Virginia peanut, and soybean were, respectively, 6, 8, 8, 12, 20, 12, 10, 14, 14, and 16.
Kornsteiner Krenn M et al Lipid components of 10 different nut types FASEB J April 6, 2010 24:721.5
No abstract available
Pravst I, Zmitek K, Zmitek J. Coenzyme Q10 contents in foods and fortification strategies. Crit Rev Food Sci Nutr. 2010 Apr;50(4):269-80. Nutr Res. 2008;28(3):151-5.
Coenzyme Q10 (CoQ(10)) is an effective natural antioxidant with a fundamental role in cellular bioenergetics and numerous known health benefits. Reports of its natural occurrence in various food items are comprehensively reviewed and critically evaluated. Meat, fish, nuts, and some oils are the richest nutritional sources of CoQ(10), while much lower levels can be found in most dairy products, vegetables, fruits, and cereals. Large variations of CoQ(10) content in some foods and food products of different geographical origin have been found. The average dietary intake of CoQ(10) is only 3-6 mg, with about half of it being in the reduced form. The intake can be significantly increased by the fortification of food products but, due to its lipophilicity, until recently this goal was not easily achievable particularly with low-fat, water-based products. Forms of CoQ(10) with increased water-solubility or dispersibility have been developed for this purpose, allowing the fortification of aqueous products, and exhibiting improved bioavailability; progress in this area is described briefly. Three main fortification strategies are presented and illustrated with examples, namely the addition of CoQ(10) to food during processing, the addition of this compound to the environment in which primary food products are being formed (i.e. animal feed), or with the genetic modification of plants (i.e. cereal crops).
Dong Q, Banaich MS, O’Brien PJ. Cytoprotection by almond akin extracts or catechins of hepatocyte cytotoxicity induced by hydroperoxide (oxidative stress model) versus glyoxal or methylglyoxal (carbonylation model). Chem Biol Interact. 2010 Apr 29;185(2):101-9
Oxidative and carbonyl stress are detrimental in the pathogenesis of diabetic complications, as well as in other chronic diseases. However, this process may be decreased by dietary bioactive compounds. Almond skin is an abundant source of bioactive compounds and antioxidants, including polyphenolic flavonoids, which may contribute to the decrease in oxidative and carbonyl stress. In this study, four Almond Skin Extracts (ASEI, ASEII, ASEIII, and ASEIV) were prepared by different methods and evaluated for their antioxidant activity. The order of the polyphenol content (total muM gallic acid equivalents) of the four extracts was found to be, in decreasing order of effectiveness: ASEI>ASEIII>ASEIV>ASEII. The order of Ferric-reducing antioxidant power (FRAP, microM FeSO(4)/g) value, in decreasing order was ASEI (216)>ASEIII (176)>ASEIV (89)>ASEII (85). The order of ASE effectiveness for decreasing protein carbonyation induced by the copper Fenton reaction was ASEI>ASEIV>ASEII>ASEIII. The order of antioxidant effectiveness for inhibiting tertiary-butyl hydroperoxide (TBH) induced microsomal lipid peroxidation was ASEI>ASEIV>ASEII, ASEIII. Also, the order of ASE effectiveness for inhibiting TBH induced hepatocyte cell death was: ASEIII, ASEIV>ASEI, ASEII. Catechin also protected hepatocytes from TBH induced hepatocyte, lipid peroxidation and cytotoxicity. In a cell free model, equimolar concentrations of catechin or epicatechin rescued serum albumin from protein carbonylation induced by methylglyoxal (MGO). Catechin, epicatechin and ASEI all decreased gloxal induced hepatocyte cell death and reactive oxygen species (ROS) formation in GSH-depleted hepatocytes. Catechin and epicatechin protected against GO or MGO induced hepatocyte cell death, protein carbonylation and ROS formation. Catechin was more effective than epicatechin. Our results suggest that (a) bioactive almond skin constituents in the non-lipophilic polyphenol extract were the most effective at protecting hepatocytes against hydroperoxide induced hepatocyte oxidative stress and in protecting against dicarbonyl induced cytotoxicity; (b) catechins, the major polyphenol in the extract, were also effective at preventing GO or MGO cytotoxicity likely by trapping GO and MGO and/or rescuing hepatocytes from protein carbonylation.
Sharma M, Li L, Celver J, Killian C, Kovoor A, Seeram NP. Effects of Fruit Ellagitannin Extracts, Ellagic Acid, and Their Colonic Metabolite, Urolithin A, on Wnt Signaling (dagger). J Agric Food Chem. 2010 Apr 14;58(7):3965-9.
Recent data suggest that ellagitannins (ETs), a class of hydrolyzable tannins found in some fruits and nuts, may have beneficial effects against colon cancer. In the stomach and gut, ETs hydrolyze to release ellagic acid (EA) and are converted by gut microbiota to urolithin A (UA; 3,8-dihydroxy-6H-dibenzopyran-6-one) type metabolites, which may persist in the colon through enterohepatic circulation. However, little is known about the mechanisms of action of either the native compounds or their metabolites on colon carcinogenesis. Components of Wnt signaling pathways are known to play a pivotal role in human colon carcinogenesis, and inappropriate activation of the signaling cascade is observed in 90% of colorectal cancers. This study investigated the effects of UA, EA, and ET-rich fruit extracts on Wnt signaling in a human 293T cell line using a luciferase reporter of canonical Wnt pathway-mediated transcriptional activation. The ET extracts were obtained from strawberry (Fragaria annassa), Jamun berry (Eugenia jambolana), and pomegranate (Punica granatum) fruit and were all standardized to phenolic content (as gallic acid equivalents, GAEs, by the Folin-Ciocalteu method) and to EA content (by high-performance liquid chromatography methods): strawberry = 20.5% GAE, 5.0% EA; Jamun berry = 20.5% GAE, 4.2% EA; pomegranate = 55% GAE, 3.5% EA. The ET extracts (IC(50) = 28.0-30.0 microg/mL), EA (IC(50) = 19.0 microg/mL; 63 microM), and UA (IC(50) = 9.0 microg/mL; 39 microM) inhibited Wnt signaling, suggesting that ET-rich foods have potential against colon carcinogenesis and that urolithins are relevant bioactive constituents in the colon.
Evaristo I, Batista D, Correia I, Correia P, Costa R. Chemical profiling of Portuguese Pinus pinea L. nuts. J Sci Food Agric. 2010 Apr 30;90(6):1041-9.
BACKGROUND: The first detailed chemical characterisation of Portuguese pine nut (Pinus pinea L.) is reported concerning proximate composition, fatty acid, mineral and vitamin contents.
RESULTS: Based on the analysis of 27 different populations, pine nuts were characterised by high contents of fat (47.7 g per 100 g dry matter (DM)), protein (33.8 g per 100 g DM) and phosphorus (1130 mg per 100 g DM) and low contents of moisture (5.9 g per 100 g DM) and starch (3.5 g per 100 g DM). They were also found to be a good source of zinc, iron and manganese.
CONCLUSIONS: Mineral composition seemed to be most prone to variation, suggesting its potentially useful role in discriminating Mediterranean pine nuts. A significant variability was found in the nut composition of Portuguese P. pinea populations.
Harris W. Omega-6 and omega-3 fatty acids: partners in prevention. Curr Opin Clin Nutr Metab Care. 2010 Mar;13(2):125-9.
PURPOSE OF REVIEW: This review addresses the cardiovascular benefits of the two families of essential polyunsaturated fatty acids (FAs): omega-6 and omega-3. The former (and the shorter chain species of the latter) are found in vegetable oils and nuts, whereas the longer chain omega-3 FAs are found in fish oils. Although most clinicians understand that the omega-3 FAs are beneficial, there have been calls in the popular press to reduce the intake of the omega-6 FAs because of presumed proinflammatory and prothrombotic effects.
RECENT FINDINGS: The American Heart Association’s Nutrition Committee has published two ‘Science Advisories’, one in 2002 on omega-3 FAs and a new one on omega-6 FAs. Both considered a wide variety of data regarding their effects on cardiac risk.
SUMMARY: The AHA concludes that Americans need to increase their intake of long-chain omega-3 FAs and that they should maintain (and possibly even increase) their intakes of omega-6 FAs. For the omega-3 FAs, a healthy target intake is about 500 mg per day (whether from oily fish or fish oil capsules) and for linoleic acid, approximately 15 g per day (12 g for women and 17 g for men). Achieving healthy intakes of both omega-6 and omega-3 FAs is an important component of the nutritional prevention and treatment of coronary heart disease.
Barreira JC, Pereira JA, Oliveira MB, Ferreira IC. Sugars Profiles of Different Chestnut (Castanea sativa Mill.) and Almond (Prunus dulcis) Cultivars by HPLC-RI. Plant Foods Hum Nutr. 2010 Mar;65(1):38-43.
Sugar profiles of different almond and chestnut cultivars were obtained by high-performance liquid chromatography (HPLC), by means of a refractive index (RI) detector. A solid-liquid extraction procedure was used in defatted and dried samples. The chromatographic separation was achieved using a Eurospher 100-5 NH(2) column using an isocratic elution with acetonitrile/water (70:30, v/v) at a flow rate of 1.0 ml/min. All the compounds were separated in 16 min. The method was optimized and proved to be reproducible and accurate. Generally, more than 95% of sugars were identified for both matrixes. Sugars profiles were quite homogeneous for almond cultivars; sucrose was the main sugar (11.46 +/- 0.14 in Marcona to 22.23 +/- 0.59 in Ferragnes g/100 g of dried weight), followed by raffinose (0.71 +/- 0.05 in Ferraduel to 2.11 +/- 0.29 in Duro Italiano), glucose (0.42 +/- 0.12 in Pegarinhos two seeded to 1.47 +/- 0.19 in Ferragnes) and fructose (0.11 +/- 0.02 in Pegarinhos two seeded to 0.59 +/- 0.05 in Gloriette). Commercial cultivars proved to have higher sucrose contents, except in the case of Marcona. Nevertheless, chestnut cultivars revealed a high heterogeneity. Sucrose was the main sugar in Aveleira (22.05 +/- 1.48), Judia (23.30 +/- 0.83) and Longal (9.56 +/- 0.91), while glucose was slightly prevalent in Boa Ventura (6.63 +/- 0.49). The observed variance could serve for inter-cultivar discrimination.
Bolling, B.W., D.L. McKay, J. B. Blumberg. The phytochemical composition and antioxidant actions of tree nuts. Asia Pac J Clin Nutr. 2010;19(1):117-123 117. Nutr Res. 2008;28(3):151-5.
In addition to being a rich source of several essential vitamins and minerals, mono- and polyunsaturated fatty acids, and fiber, most tree nuts provide an array of phytochemicals that may contribute to the health benefits attributed to this whole food. Although many of these constituents remain to be fully identified and characterized, broad classes include the carotenoids, hydrolyzable tannins, lignans, naphthoquinones, phenolic acids, phytosterols, polyphenols, and tocopherols. These phytochemicals have been shown to possess a range of bioactivity, including antioxidant, antiproliferative, anti-inflammatory, antiviral, and hypocholesterolemic properties. This review summarizes the current knowledge of the carotenoid, phenolic, and tocopherol content of tree nuts and associated studies of their antioxidant actions in vitro and in human studies. Tree nuts are a rich source of tocopherols and total phenols and contain a wide variety of flavonoids and proanthocyanidins. In contrast, most tree nuts are not good dietary sources of carotenoids and stilbenes. Phenolic acids are present in tree nuts but a systematic survey of the content and profile of these compounds is lacking. A limited number of human studies indicate these nut phytochemicals are bioaccessible and bioavailable and have antioxidant actions in vivo.
Destaillats F, Cruz-Hernandez C, Giuffrida F, Dionisi F. Identification of the Botanical Origin of Pine Nuts Found in Food Products by Gas-Liquid Chromatography Analysis of Fatty Acid Profile. J Agric Food Chem. 2010 Feb 24;58(4):2082-7.
Pine nuts are traditionally used in various part of the world for the preparation of desserts or sauces or in salads. Local production is not sufficient to cope with the high demand of pine nuts around the world, and countries such as China or Pakistan are exporting much of their production to Western countries. Almost all the nuts that are traditionally consumed belong to the Pinus genus, but over the past years, the number of consumer complaints following consumption of commercial pine nuts increased. Some consumers experienced taste disturbance lasting for up to two weeks after consumption. Food safety agencies raised some concerns regarding pine nuts imported from Asia and their association with taste disturbance. However, even though a formal association has not been found to date, the Pinus genus comprises species that are not classified as edible and could be eventually used to adulterate edible species. Pinus spp. seed lipids are known to contain very specific polyunsaturated fatty acids know as Delta5-olefinic acids. Seed fatty acid profile of conifers had been used in the past as a taxonomic marker, and in the present study to identify the botanical origin of pine nut in nine commercial products. Fast gas-liquid chromatography (GLC) was used to resolve the complete fatty acid profile of Pinus spp. samples in less than 5 min. A diagnostic index based on the relative levels of the main fatty acids including distinctive Delta5-olefinic acids was used to identify botanical origins. Results revealed the occurrence of the following Pinus spp. in commercial products: P. pinea, P. koraiensis, P. gerardiana, P. armandii and P. massoniana. The later two species, known as Chinese white pine and Chinese red pine, are only cultivated in China and are not listed as common source of edible pine nuts by the Food and Agriculture Organization (FAO). The present study shows that the botanical origin of pine nuts can be identified in products based on the fatty acid profile.