Nutritional quality of chestnut (Castanea sativa Mill.) cultivars from Portugal

Protected Designation of Origin (PDO), Protected Geographical Indication (PGI) and Traditional Speciality Guaranteed (TSG): A bibiliometric analysis

Despite the importance of the literature on food quality labels in the European Union (PDO, PGI and TSG), our search did not find any review joining the various research topics on this subject. This study aims therefore to consolidate the state of academic research in this field, and so the methodological option was to elaborate a bibliometric analysis resorting to the term co-occurrence technique. Analysis was made of 501 articles on the ISI Web of Science database, covering publications up to 2016. The results of the bibliometric analysis allowed identification of four clusters: "Protected Geographical Indication", "Certification of Olive Oil and Cultivars", "Certification of Cheese and Milk" and "Certification and Chemical Composition". Unlike the other clusters, where the PDO label predominates, the "Protected Geographical Indication" cluster covers the study of PGI products, highlighting analysis of consumer behaviour in relation to this type of product. The focus of studies in the "Certification of Olive Oil and Cultivars" cluster and the "Certification of Cheese and Milk" cluster is the development of authentication methods for certified traditional products. In the "Certification and Chemical Composition" cluster, standing out is analysis of the profiles of fatty acids present in this type of product.

Effects of Ultrasound on the Physicochemical Properties and Antioxidant Activities of Chestnut Polysaccharide

A comparison of chestnut polysaccharide extraction using ultrasound-assisted extraction (UAE) and hot water extraction (HWE) demonstrated that UAE is superior to HWE due to its higher extraction efficiency. Scanning electron microscopy (SEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the ultrasound-assisted-extracted polysaccharide (UAEP) and hot water-extracted polysaccharide (HWEP). SEM images revealed that the UAEP and chestnut residue were crushed, with particle sizes that were smaller than those of the HWEP, which was related to the breakage of long-chain polysaccharides. TGA-DSC showed a higher transition temperature and enthalpy value for the UAEP than the HWEP, and the FTIR spectrum revealed typical characteristics of polysaccharides, with some differences between the UAEP and HWEP. The evaluation of antioxidant activities showed that the UAEP had stronger antioxidant capacities than the HWEP, regardless of the reducing power and DPPH-, ABTS- and hydroxyl radical-scavenging activities, suggesting that ultrasound is an optimal method to rapidly extract chestnut polysaccharide, a potential natural antioxidant.

Starch characterization in seven raw, boiled and roasted chestnuts (Castanea sativa Mill.) cultivars from Portugal

Changes occurring in seven chestnut (Castanea sativa sp.) cultivars, caused by boiling and roasting, on starch content, cell and starch granules dimension were evaluated, and morphological changes were characterized by scanning electron microscopy. Three clear patterns of variation were detected after processing, namely: i) decrease of starch content with processing; ii) starch increase with the applied treatments; iii) increase of starch with boiling and decrease with roasting. Starch granules of raw chestnuts presented round, oval or elliptical form, external smooth surface and eccentric hilum, with rather ellipsoid-shaped growth rings. Processing resulted in modifications of the granules, with fusion of individual granules, and gelatinization taking place with the formation of elongated clusters. The present results indicate that boiling and roasting, besides changing the starch content of chestnut, causes important modifications in the starch granules, which can affect the sensory, rheological and chemical characteristics of chestnuts.

Promising new applications of Castanea sativa shell: nutritional composition, antioxidant activity, amino acids and vitamin E profile

The present study was aimed to assess the macronutrient composition and the amino acid and vitamin E profiles of Castanea sativa shell from different production regions of Portugal (Minho, Trás-os-Montes and Beira-Alta). The nutritional composition was similar for all samples, with a high moisture content and low fat amounts. Arginine and leucine were the predominant essential amino acids (EAA) accounting for 3.55-7.21% and 1.59-2.08%, respectively, for samples of the different production zones. All the shells presented high contents of vitamin E (481.5 mg per 100 g sample, 962.8 mg per 100 g sample and 567.5 mg per 100 g sample, respectively, for Minho, Trás-os-Montes and Beira-Alta). The predominant vitamer was γ-tocopherol (670 mg per 100 g sample for Trás-os-Montes). The antimicrobial and antioxidant activities of C. sativa shell were also determined. Trás-os-Montes extracts displayed the highest antioxidant activity (EC50 = 31.8 ± 1.3 μg mL(-1) for DPPH; 8083.5 ± 164.8 μmol per mg db for FRAP). The total phenolic content (TPC) varied from 241.9 mg to 796.8 mg gallic acid equivalents (GAE) per g db sample, the highest TPC being obtained for Trás-os-Montes. The total flavonoid content (TFC) varied from 31.4 to 43.3 mg of catechin equivalents (CEQ) per g db sample. No antimicrobial activity was observed. The results showed the potentialities of C. sativa shell extracts.

Nutraceutical properties of chestnut flours: beneficial effects on skeletal muscle atrophy

Plants contain a wide range of non-nutritive phytochemicals, many of which have protective or preventive properties for human diseases. The aim of the present work has been to investigate the nutraceutical properties of sweet chestnut flour extracts obtained from fruits collected from 7 geographic areas of Tuscany (Italy), and their ability in modulating skeletal muscle atrophy. We found that the cultivars from different geographic areas are characterized by the composition and quantity of various nutrients and specific bioactive components, such as tocopherols, polyphenols and sphingolipids. The nutraceutical properties of chestnut sweet flours have been evaluated in C2C12 myotubes induced to atrophy by serum deprivation or dexamethasone. We found that the pretreatment with both total extracts of tocopherols and sphingolipids is able to counterbalance cell atrophy, reducing the decrease in myotube size and myonuclei number, and attenuating protein degradation and the increase in expression of MAFbx/atrogin-1 (a muscle-specific atrophy marker). By contrast, polyphenol extracts were not able to prevent atrophy. Since we also found that γ-tocopherol is the major form of tocopherol in sweet flour and its content differs depending on the procedure of sweet flour preparation, the mechanisms by which γ-tocopherol as well as sphingolipids affect skeletal muscle cell atrophy have been also investigated. This is the first evidence that chestnut sweet flour is a natural source of specific bioactive components with a relevant role in the prevention of cell degeneration and maintenance of skeletal muscle mass, opening important implications in designing appropriate nutritional therapeutic approaches to skeletal muscle atrophy.

Transcriptomic identification and expression of starch and sucrose metabolism genes in the seeds of Chinese chestnut (Castanea mollissima)

The Chinese chestnut (Castanea mollissima) seed provides a rich source of carbohydrates as food and feed. However, little is known about starch biosynthesis in the seeds. The objectives of this study were to determine seed composition profiles and identify genes involved in starch and sucrose metabolism. Metabolite analysis showed that starch was the major component and rapidly accumulated during seed endosperm development. Amylopectin was approximately 3-fold of amylose content in chestnut starch. Illumina platform-based transcriptome sequencing generated 56671 unigenes in two cDNA libraries from seed endosperms collected at 45 and 75 days after flowering (DAF). A total of 1537 unigenes showed expression differences ≥2-fold in the two stages of seeds including 570 up-regulated and 967 down-regulated unigenes. One hundred and fifty-two unigenes were identified as involved in starch and sucrose metabolism, including 1 for glycogenin glucosyltransferase, 4 for adenylate transporter (brittle1-type), 3 for ADP-glucose pyrophosphorylase (AGP, not brittle2- or shrunken2-type), 3 for starch synthase (SS), 2 for starch branching enzyme, 5 for starch debranching enzyme, 11 for sucrose synthase, and 3 for sucrose-phosphate synthase. Among them, 58 unigenes showed a ≥2-fold expression difference between the 45 and 75 DAF seeds including 11 up- and 47 down-regulated unigenes. The expression of 21 unigenes putatively coding for major enzymes in starch and sucrose metabolism was validated by qPCR using RNA from five seed stages. Expression profiles and correlation analysis indicated that the mRNA levels of AGP (large and small subunits), granule-bound SS2, and soluble SS1 and SS4 were well-correlated with starch accumulation in the seeds. This study suggests that the starch biosynthesis pathway in Chinese chestnut is similar to that of potato tuber/Arabidopsis leaf and differs from that of maize endosperm. The information provides valuable metabolite and genetic resources for future research in starch and sucrose metabolism in Chinese chestnut tree.

Chemical composition and functional properties of native chestnut starch (Castanea sativa Mill)

Starch isolation methods can change their physico-chemical and functional characteristics hindering the establishment of a starch-food functionality relation. A simple high yield and soft isolation method was applied for chestnut (Castanea sativa Mill) starch consisting in steeping and fruit disintegration in a 25 mM sodium bisulfite solution and purification by sedimentation. Starch integrity, physico-chemical composition, morphology and functional properties were determined, being observed significant differences from previous described methods for chestnut starch isolation. The X-ray pattern was of B-type, with a degree of crystallinity ranging from 51% to 9%, dependent on the starch moisture content. The onset, peak, and conclusion gelatinization temperatures were 57.1°C, 61.9°C and 67.9°C, respectively. Total amylose content was 26.6%, and there was not found any evidence for lipid complexed amylose. Swelling power at 90°C was 19 g/g starch, and the amount of leached amylose was 78% of the total amylose content. Native chestnut starch presents a type B pasting profile similar to corn starch but with a lower gelatinization (56.1°C) and peak viscosity (79.5°C) temperatures, making native chestnut starch a potential technological alternative to corn starch, especially in application where lower processing temperatures are needed.

Effects of electron-beam radiation on nutritional parameters of Portuguese chestnuts (Castanea sativa Mill.)

Chestnuts are a widely consumed fruit around the world, with Portugal being the fourth biggest producer in Europe. Storage of these nuts is an important step during processing, and the most widely used fumigant was banned in the European Union under the Montreal Protocol because of its toxicity. Recently, radiation has been introduced as a cheap and clean conservation method. Previous studies of our research group proved that γ radiation had no negative effect on the nutritional value of chestnuts; in fact, storage time had a much bigger influence on the chestnut quality. In the present study, we report the effect of a less ionizing radiation, electron beam, with doses of 0, 0.5, 1, 3, and 6 kGy in the nutritional value of chestnuts (ash, energy, fatty acids, sugars, and tocopherols), previously stored at 4 °C for 0, 30, and 60 days. The storage time seemed to reduce fat and energetic values but reported a tendency for higher values of dry matter. With regard to fatty acids, there was a higher detected quantity of C20:2 in non-irradiated samples and four fatty acids were only detected in trace quantities (C6:0, C8:0, C10:0, and C12:0). γ-Tocopherol decreased during storage time but did not alter its quantity for all of the radiation doses (as like α-, β-, and δ-tocopherol); in fact, these compounds were present in higher concentrations in the irradiated samples. Sucrose and total sugars were lower in non-irradiated samples, and raffinose was only detected in irradiated samples. Electron-beam irradiation seems to be a suitable methodology, because the effects on chemical and nutritional composition are very low, while storage time seems to be quite important in chestnut deterioration.

Comparative effects of gamma and electron beam irradiation on the antioxidant potential of Portuguese chestnuts (Castanea sativa Mill.)

Chestnuts (Castanea sativa Mill.) are widely consumed all over the world, and have been recently studied for their antioxidant potential. The present study reports the effect of e-beam and gamma radiation (doses of 0, 0.5, 1 and 3 kGy) on the antioxidant potential of Portuguese chestnuts. Irradiation might be an alternative preservation method, since Methyl Bromide, a widely used fumigant, was banished by the European Union in 2010 due to its toxicity. The antioxidant activity was evaluated through 2,2-diphenyl-1-pycrylhydrazyl (DPPH) free radical scavenging activity assay, reducing power by the Ferricyanide/Prussian blue assay, and lipid peroxidation inhibition by β-carotene/linoleate and thiobarbituric acid reactive substances (TBARS) assays. The analysis of total phenolics and flavonoids was performed by spectrophotometric assays. Irradiated samples preserved total phenolics content (but not flavonoids) and revealed higher antioxidant activity (lower EC50 values) than the control samples. The most indicated doses to maintain antioxidants content, and to increase antioxidant activity were 1 and 3 kGy for electron beam and gamma radiation, respectively.

Volatile fingerprinting of chestnut flours from traditional Emilia Romagna (Italy) cultivars

The volatile profile of nine monocultivar chestnut flours, obtained from fruits grown in Italy (Parma province), was characterised by a head-space solid-phase microextraction (HS-SPME) coupled with GC-MS technique. The volatile fraction was composed of 44 main compounds belonging to different classes, mainly aldehydes, ketones, alcohols, furans and terpenes. Aldehydes, in particular hexanal, are the most abundant components. In order to better understand the origin of the different volatile compounds during the drying and milling processes, samples of fresh fruit were also analysed by the same technique and the data obtained were statistically and critically compared in order to get a picture of the volatile evolution in chestnut from fresh fruit to flour. Finally, the nine monocultivar flours were chemometrically classified on the basis of the main odour descriptors associated with the volatile fingerprinting.

Composition of European chestnut (Castanea sativa Mill.) and association with health effects: fresh and processed products

Chestnut fruits are highly regarded and widely consumed throughout Europe, America and Asia. Various commercial forms are available, e.g. fresh and industrially processed. There have been various reviews on the composition of chestnut fruits but there has not been a comprehensive review of the different health benefits that this fruit can provide. This review is focused on the composition and associated health effects of European fresh chestnut (Castanea sativa Mill.) fruits and their home-processed and industrial products, e.g. boiled, roasted, frozen, and 'marron glacées'. We also expand the knowledge of chestnut uses by presenting data for other chestnut materials that have potential applications as new foods, as sources of antioxidants, and as sources of other useful bioactives. There is considerable literature data on nutrients in fresh chestnut fruits but less information on bioactive non-nutrients such as phenolics. Chestnuts are mostly consumed as processed forms, and the different types of processing clearly affect the nutrient and non-nutrient composition of the fruits. The benefits that this fruit can provide for human and animal health are numerous, but it is clear that improvements can be made for both production and quality of chestnut products, e.g. genetic selection and optimizing industrial processing.

Chemical profiling of Portuguese Pinus pinea L. nuts

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.

CONCLUSION

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.

Composição química de nozes e sementes comestíveis e sua relação com a nutrição e saúde

Esta revisão sistemática compara a composição química em nutrientes e outros compostos bioativos entre diferentes nozes e sementes comestíveis, relacionando-a com a nutrição e saúde. Foi realizada pesquisa bibliográfica nas bases Biological Abstracts, CAB Abstracts, Food Science and Technology Abstracts, Medline e Lilacs segundo os critérios de seleção: artigos de pesquisa original publicados nos últimos cinco anos em periódicos nacionais ou internacionais das áreas de Ciência de Alimentos, Medicina I e Medicina II, indexados no Institute for Scientific Information. Os artigos foram analisados conforme critérios de qualidade pré-estabelecidos. Nozes verdadeiras (amêndoas, avelãs, castanhas, castanhas-de-caju, castanhas-do-pará, macadâmias, nozes e pistaches) e sementes comestíveis (amendoim e amêndoa de baru) são boas fontes de lipídeos e proteínas. As frações lipídicas são compostas especialmente pelos ácidos graxos oléico (C18:1) e linoléico (C18:2), com destaque para a relação ω-6:ω-3 da macadâmia, noz, castanha e amêndoa de baru, perfil favorável à redução do risco de doenças cardiovasculares. As proteínas apresentam perfil de aminoácidos que atende grande parte das necessidades de escolares, contendo teores mais elevados de sulfurados que as leguminosas como feijões. Essas nozes e sementes comestíveis também são boas fontes de fitoesteróis, especialmente de β-sitoesterol; de minerais, sobretudo cálcio, ferro, zinco, selênio e potássio; de tocoferóis, com ênfase para o α-tocoferol, e de fibras alimentares insolúveis. Esses alimentos contêm alta densidade de nutrientes e de substâncias bioativas que potencializam seus efeitos benéficos à saúde e, portanto, o estudo e o consumo deles devem ser estimulados.

Sugars profiles of different chestnut (Castanea sativa Mill.) and almond (Prunus dulcis) cultivars by HPLC-RI

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.