Browsing by Author "Samman, Norma"
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- Antioxidant activity and characterization of antioxidants from Argentina OcaPublication . Rego, Andreia; André, Catarina; Delgado, Inês; Samman, Norma; Castanheira, IsabelOverview: - Objectives - Introduction • Oca • Phenolic compounds - Methods • Sample • Extraction Method • Antioxidant activity • Total Phenolic Content • UPLC-PDA - Results and Discussion • DPPH • TPC • UPLC-PDA - Conclusions
- Assessment of Digestion Methods to Assist Mineral Analysis of Purple Corn, Quinoa, Amaranth and Buckwheat by ICP-OESPublication . Nascimento, Ana Cláudia; Santiago, Susana; Santos, Mariana; Coelho, Inês; Gueifão, Sandra; Castanheira, Isabel; Samman, Norma; Calhau, Maria AntóniaPurple corn (Zea mays L.), quinoa (Chenopodium Quinoa) and amaranth (Amaranthus caudatus) are a cereal and pseudocereals of Andean origin, largely consumed in North of Argentina. Buckwheat (Fagopyrum esculentum) is a pseudocereal with an important role in food diets around the world, especially in Asia and Eastern Europe. They gained increasing attention of scientific community, specially due to their high nutritional value and health benefits. Mineral concentrations in cereals and pseudocereals can differ with genotype, type of soil, fertilizer application, region’s mineral composition and treatments applied, that can even cause the loss of some minerals. Analytical values must be obtained by applying high quality criteria, such as criteria on sample handling, appropriate sample preparation and subsequent analytical method and, an effective internal and external quality control program. Inductively Couple Plasma Atomic Emission Spectrometry – ICP-OES is a high specific technique which allows a rapid and simultaneous multi-elemental analysis of several elements, in a numerous and wide scale of sample matrices, with good detection limits. A previous sample decomposition through its dissolution is required which can be undertaken by different methods, namely microwave digestion, dry-ashing, wet digestion. The destruction of organic matter is a slow step of overall analytical process largely dependent on the content of major components. The purpose of this work was to compare the performances of microwave and dry-ashing digestion procedures, including the optimization of microwave conditions to assist ICP-OES analysis. The optimized digestion method was applied on determination, of copper, manganese, iron, zinc, magnesium, calcium, phosphorus, sodium and potassium contents in purple corn, quinoa, amaranth, buckwheat and rice. Samples were dry ashed within platinum capsules in a furnace at 470 ºC during 40 h and microwave digested using a closed-vessel system digestion with a mixture of concentrated acid nitric, hydrogen peroxide and deionised water. The accuracy of analytical procedure was verified by analyzing a NIST 1548a reference material. Mineral profiles of purple corn, pseudocereals and rice were compared. Copper ranged from 0.07 mg/100g (rice) to 0.59 mg/100g (quinoa), manganese ranged from 0.64 mg/100g (purple corn) to 1.73 mg/100g (quinoa), iron ranged from 0.2 mg/100g (rice) to 8.8 mg/100g (amaranth), zinc ranged from 1 mg/100g (rice) to 5.1 mg/100g (amaranth), magnesium ranged from 27 mg/100g (rice) to 211 mg/100g (amaranth), calcium ranged from < 10 mg/100g (rice) to 154 mg/100g (amaranth), phosphorus ranged from 105 mg/100g (rice) to 480 mg/100g (amaranth), potassium ranged from 90 mg/100g (rice) to 587 mg/100g (quinoa). By comparing purple corn and pseudocereals with rice, pseudocereals presented the highest mineral content as expected. Also, for almost all minerals, purple corn showed higher mineral amounts than rice. These results showed that purple corn and pseudocereals understudy can be added to diets, with already known improved nutritional benefits. Statistically there was no evidence that the two different digestion methods applied have influenced final results, as P value was considered to be not significant (P > 0.05). However, microwave digestion enabled a more effective control of contamination or losses than dry-ashing, with less time consuming dispended.
- A chemometric approach: characterization of quality and authenticity of artisanal honeys from ArgentinaPublication . Rios, Francisco; Sanchez, Ana Carina; Lobo, Manuel; Lupo, Liliana; Coelho, Inês; Castanheira, Isabel; Samman, NormaThe demand of honey with defined quality has increased around the world; therefore, an adequate description of the traceability and authenticity of honeys is necessary. The pollen and physicochemical characteristics of 58 honey samples collected from five different environmental units (EUs) of the Jujuy province (Argentine) were determined,in order to differentiate them by geographical origin through the application of chemometric methods. A qualitative pollen analysis was performed by microscopy. The physicochemical characteristics were determined by Association of Official Analytical Chemists methods. Correspondence analysis (CA), principal component analysis (PCA) and linear discriminant analysis (LDA) were performed. Forty-five per cent of honeys were monofloral; nearly half of them correspond to native species—among which, Salix humboldtiana, Baccharis sp. and Ziziphus mistol stood out. Physicochemical and microbiological analysis showed acceptable quality for honeys. CA characterized significantly honeys from four different EUs using all pollen data. While forward stepwise coupled to LDA identified 14 significant variables to build a discriminatory model with three significant discriminant functions, a cumulative variance of 94% was reached. Thus, 86%of the samples were correctly classified. PCA and LDA applied to physicochemical data allowed to distinguish three different groups with a significant function (p<0.01) that explained 90% of the total variability. Honey corresponding to EU III Subandean Hills of Santa Bárbara was the most accurately classified by pollen and physicochemical data. The application of chemometric methods to pollen data and physicochemical parameters may be a useful tool to determine honey geographical origin.
- Physicochemical Properties and Mineral Profile of Honeys from Argentina, Portugal and AngolaPublication . Santos, Mariana; Mota, Carla; Nascimento, Ana Cláudia; Rios, Francisco; Samman, Norma; Coelho, Inês; Gueifão, Sandra; Castanheira, IsabelHoney is a natural sweet product which gained increasing interest of scientific community, specially due to its high nutritional value and health benefits. Honey composition is highly influenced by type of flowers, regional and climatic conditions and its quality also depends on proper producing and processing technology. These explain the differences presented by honeys from different regions. In this work proximal and mineral profile of multi-floral honeys from selected regions of Argentina, Portugal, and Angola were determined and reported for the first time. Therefore the nutrient analysis and chemical properties with the purpose to be included in national Food Composition Databank and disseminated through EuroFIR e-search platform was carried out. Ash, Moisture, °Brix sugar, pH and electrical conductivity were determined by AOAC methods. Manganese. iron, magnesium, calcium, phosphorus, sodium and potassium were analyzed by ICP-OES and, copper, zinc, cadmium, lead and selenium by IC P-MS. Analyzed honeys showed °Brix sugar ranged 77-82 at 20ºC. Moisture content and acidity is according with legislation, <18% and < 50mEq respectively, showing the good quality of tested samples. Ash content ranged 0.08-0.40 g/100g. Potassium was the most abundant mineral content ranging from 53-171mg/100g, phosphorus values varies between 5-12mg/100g, calcium from 4-8 mg/100g, magnesium from 2-5 mg/100g and manganese from 0.10-0.15mg/100g. Selenium and cadmium contents were below 23 µg/kg and 11 µg/kg respectively. Lead values ranged from <23-178 µg/kg. Based on these results honeys under study can be considered a good source of minerals, with numerous health benefits associated. Also, as expected, results showed differences in composition among honeys obtained from different regions. The use of EuroFIR guidelines for determination of proximate, mineral and trace elements contents reveled that data obtained could be used as a contribution to honey quality and authenticity.
- Protein and Amino Acids Profile of Andean Cereals from North of ArgentinaPublication . Mota, Carla; Mauro, Raul; Samman, Norma; Santos, Mariana; Castanheira, IsabelQuinoa (Chenopodium Quinoa) amaranth (Amaranthus caudatus) and corn purple (Zea mays L.) are crops with large genetic variability adapted to diverse habitats agro-climatic and edaphic conditions. Few Food Composition Databanks include data on their amino acid profile (AAP). The aim of work was characterized AAP of Quinoa, Amaranth and Corn purple consumed in the North of Argentina and originated from Jujuy Province and Salta and compare with rice as the most consumed gluten free cereal in Europe. Study was framed by EuroFIR quality criteria to guarantee comparability of results that enter in Argentine, LATINFOODS Food Composition Data and EuroFIR e-search platform. Samples in triplicate were collected from local market of Salta and Jujuy. Rice was collected from most representative Portuguese rice producers. Protein quantification was carried out by Kjeldahl method (AOAC920.87). Amino acids (AA) were analyzed by UPLC system equipped with diode array detector (260 nm), using pre-column derivatization preceded by acid hydrolysis (6N HCl) in microwave system. The method was used for determination of aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, arginine, methionine and cysteine. Total Protein content varies from 16.3 g/100g (quinoa) to 10.5 g/100g (purple corn) lower values were found in rice samples (6.7 g/100g). Most abundant essential AA was aromatic amino acids (AAA). Quinoa presents the highest content in AAA (153.5 mg/100g). Amaranth was found the cereal with a major methionine content (28.9 mg/100g). Purple corn has the minor content in lysine (6.4 mg/100g) and major in leucine (106.6 mg/100g). Rice presents the lowest content for all AA. The research showed that Andeans cereals are a better source of AA than rice. EuroFIR guidelines proved to be a crucial tool to guarantee the comparability of data.
- Protein and amino acids profile of andean cereals from North of ArgentinaPublication . Mota, Carla; Mauro, Raul; Samman, Norma; Santos, Mariana; Torres, Duarte; Castanheira, Isabel
- Proximate and Mineral profile of Quinoa (Chenopodium quinoa), and kiwicha (Amaranthus caudatus) consumed in north of ArgentinaPublication . Coelho, Inês; Gueifão, Sandra; Nascimento, Ana Cláudia; Lobo, Manuel; Gimenez, Gimenez; Samman, Norma; Castanheira, IsabelQuinoa (Chenopodium quinoa), and kiwicha (Amaranthus caudatus) are pseudo-cereals largely consumed in North of Argentina. They gained special attention by scientific community in part due to high nutritional value. Therefore the nutrient analysis with the purpose to be included in Argentinean Food Composition Databank is urgent. In this work proximal and mineral profile of Quinoa consumed in the North of Argentina was determined and reported for the first time, for the purpose to be included in national Food Composition Databank and disseminated through EuroFIR e-search platform. Ash, Moisture, Dietary Fibre, Protein, and Fat content were determined by AOAC methods and Calcium, Copper, Iron, Sodium, Potassium, Phosphorus, Magnesium, were analyzed by or ICP-OES and Selenium by ICP-MS. The values were obtained applying quality criteria as defined by EuroFIR guidelines for laboratory analysis. This required criteria on sample handling, an appropriate analytical method in terms of precision and accuracy, limit of quantification selectivity, and an effective internal and external quality control program including appropriate use of Certified Reference Materials and participation in adequate Proficiency Testing Schemes carried out by laboratories hold ISO/EN 17025. Guidelines for laboratory performance are paramount to guarantee the acceptability of values in LATINFOODS and others Food Data Organizations. This provides the necessary information to the users of Food Composition Databanks who wish to have an overview of the parameters, which influence the estimation of nutrient intake, and may affect the diet-disease relationship.