Browsing by Autor "Juan Alvarado"

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Changes in phenolic antioxidants during chuño production (traditional Andean freeze and sun-dried potato)
(Elsevier BV, 2010) J. Mauricio Peñarrieta; Trinidad G Salluca; Leslie Tejeda; Juan Alvarado; Björn Bergenståhl
Chemical composition, antioxidant capacity and content of phenolic compounds in meals collected in hospitals in Bolivia and Sweden.
(National Institutes of Health, 2013) Leslie Tejeda; Magdalena Dębiec; Lars Nilsson; J. Mauricio Peñarrieta; Juan Alvarado
The objective of this study was to evaluate the proximal composition, as well as Total Antioxidant Capacity (TAC) and Total Phenols (TPH) in meals that represent a complex food matrix, from different hospitals in Bolivia and Sweden. Protein, fat, ash, dietary fiber and carbohydrate contents were measured in 29 samples: 20 from two Bolivian hospitals and 9 from the university hospital in Lund, Sweden. The antioxidant capacity was measured by three spectrophotometric methods: the ferric reducing antioxidant power (FRAP) method, the 2, 2'- azinobis-3-ethylbenzotiazoline-6-sulfonic acid (ABTS) method and Total Phenolic Compounds (TPH) using the Folin-Ciocalteu reagent. The results show that fat, protein, carbohydrate and dietary fiber in Bolivian and Swedish hospital meals are following internationally established recommendations. Regarding the main courses, TPH contents in both countries were in the same range. However, TAC and dietary fiber content were higher in Swedish meals than in Bolivian meals and the TAC was far lower, in both cases, in comparison with the value obtained from individual food items reported from literature. The results show that antioxidant levels can be easily overestimated by considering only individual uncooked ingredients. An interesting consideration is, the fiber content in the meals, which can be an important source of antioxidants and non-extractable phenolic compounds.
CONTENT OF TRACE ELEMENTS IN FOUR ANDEAN VEGETABLE SPECIES OF BOLIVIA
(Universidad Autónoma del Estado de México, 2008) Felipe Chuquimia; Juan Alvarado; J. Mauricio Peñarrieta; Björn Bergenståhl
"In the present work the determination of iron, zinc and copper of four vegetable species of the Andean region of Bolivia was carried out. The plants are: the rhizomes of chijura (Stangea rhizantha); the roots of the cactus achacana (Neowerdermannia vorwerckii), the white basal leaves in form of rose of siki (Hipochoeris meyeniana var.brachylepis) and the shaft of the flower of amañoke (Ombrophytum subterraneum Asplund), the eatable part of a Balanophoraceae that parasites on the roots of thola (Lepidophillum quadrangulare) and it is also used as a medicine. The selected plants are used as foodstuffs, in particular in times of famine. The quantification by AAS was carried out in triplicate. Several interesting results regarding the trace element content of the studied species were obtained. All the species presented high Fe values, and the highest values were obtained for chijura (10.9 mg/100 g). Regarding Zn, achacana presented the higher value (2.6 mg/100 g), amañoke gave (1.5 mg/100 g) and chijura gave (1.8 mg/100 g). Regarding the content of Cu, amañoke stands out with 0.46 mg/100 g./ En el trabajo presente se llevó a cabo la cuantificación de hierro, cinc y cobre de cuatro especies de la verdura de la región andina de Bolivia. Las plantas estudiadas fueron: los rizomas de chijura (Stangea rhizantha); las raíces del cactus achacana (Neowerdermannia vorwerckii), el blanco de las hojas basales en forma de rosa de la planta de siki (Hipochoeris meyeniana var.brachylepis) y el tallo de la flor de amañoke (Ombrophytum subterraneum Asplund), la parte comestible de una balanoforacea que parásita las raíces de thola (Lepidophillum quadrangulare) y que también se usa como medicina. Las plantas seleccionadas se usan como comestibles, en particular en tiempos de hambre. La cuantificación por AAS se llevó a cabo por triplicado. Varios resultados interesantes con respecto al contenido de elementos traza de las especies estudiadas se obtuvieron. Todas las especies presentaron valores altos de Fe, y los valores más altos se obtuvieron para la chijura (10.9 mg/100 g). Con respecto a Zn, la achacana (2.6 mg/100 g) presentó el valores más alto, el amañoke dio (1.5 mg/100 g) y la chijura dio (1.8 mg/100 g). Con respecto al contenido de Cu, el amañoke destaca con 0.46 mg/100 g."
CUANTIFICACION DE RESVERATROL EN VINOS MEDIANTE HPLC
(Universidad Autónoma del Estado de México, 2012) Atma‐Sol Bustos; Juan C. Calisaya; Carolina Paredes; Gimena Duran; Marco Taquichiri; Juan Alvarado; J. Mauricio Peñarrieta
"Resveratrol, a phenolic compound, was quantified in wines from Tarija - Bolivia by a method by Reverse Phase High Performance Liquid Chromatography (HPLC). The method was validated considering parameters such as standard deviation (S), coefficient of variation (CV), linear correlation coefficient (R), limit of detection (LOD) and limit of quantitation (LOQ). The amount of resveratrol found in the wines analyzed is somewhat high compared to valúes reported worldwide, giving an average of 7.7 ± 0.9 mg/L."
CUANTIFICACION DE SAPONINAS EN MUESTRAS DE CAÑIHUA CHENOPODIUM PALLIDICAULE AELLEN
(Universidad Autónoma del Estado de México, 2013) Bianca Guzmán; Dora L. Cruz; Juan Alvarado; Patricia Mollinedo
"The quantification of the saponin contents of grains of Chenopodium pallidicaule was carried out through UV/VIS analyses."
DETERMINACIÓN DE LA CAPACIDAD ANTIOXIDANTE Y LA CUANTIFICACIÓN DE COMPUESTOS FENÓLICOS Y FLAVONÓIDICOS DE CUATRO ESPECIES VEGETALES DE LA REGIÓN ANDINA DE BOLIVIA
(Universidad Autónoma del Estado de México, 2008) Felipe Chuquimia; Juan Alvarado; J. Mauricio Peñarrieta; Björn Bergenståhl; Björn kesson
"In the present work the measurement of the antioxidant capacity and the quantification of flavonoids and phenolic compounds are carried out in four vegetable species of the Andean region of Bolivia with the purpose of revaluing our ancestral foods and in this way, in a future to be able to take advantage of its nutritious and biological properties. The selected plants are used as foodstuf, in particular in times of famine. The selected plants are: the rhizome of Chijura (Stangea rhizantha); the root of the cactus Achacana (Neowerdermannia vorwerckii) and the white basal leaves in form of rose of Siki (Hipochoeris meyeniana var. brachylepis) and Amañoke (Ombrophytum subterraneum Asplund), a parasite eatable plant that grows on roots of Lepidophillum quadrangulare. The Total Antioxidant Capacity TAC was determined by two methods ABTS (2,2' Azinobis-3-etil-benzotiazolin-6-sulfonic acid) and FRAP (Ferric Reduction Ability of Plasma). The Total Poliphenols were determined by the method of Folin Ciocalteau and the Total Flavonoids were determined as catechin equivalents. The higher values of antioxidant activity were observed in amañoke./ En el presente trabajo se realizó la determinación de la capacidad antioxidante y la cuantificación de compuestos fenólicos y flavonóidicos de cuatro especies vegetales de la región andina de Bolivia con el fin de revalorizar algunos de nuestros alimentos ancestrales y, de esta manera, en un futuro poder aprovechar sus propiedades alimenticias y biológicas. Las plantas seleccionadas son utilizadas en la alimentación humana de la región, en particular en épocas de escasez. Las plantas son: Chijura (Stangea rhizantha), un rizoma comestible; Achacana (Neowerdermannia vorwerckii), una cactácea andina, cuya raíz se utiliza como alimento; Siki (Hipochoeris meyeniana var.brachylepis), planta con hojas basales en forma de roseta, cuyas bases blancas son comestibles; Amañoke (Ombrophytum subterraneum Asplund), una balanoforácea comestible parásita de las raíces de Lepidophyllum quadrangulare. La Capacidad Antioxidante Total TAC fue determinada por los métodos ABTS (2,2’ Azinobis-3-etil- benzotiazolina-6-acido sulfonico) y FRAP (poder antioxidante de reducción férrica). Los Polifenoles Totales fueron determinados por el método de Folin-Ciocalteau y los Flavonoides Totales fueron determinados como equivalente de catequina. Los valores mas altos de actividad antioxidante encontrados corresponden al amañoke."
DETERMINATION OF TOTAL PHENOLIC COMPOUNDS CONTENT AND THE ANTIOXIDANT CAPACITY OF ANDEAN TUBERS AND ROOTS (ISAÑO, OCA, ULLUCO AND ARRACACHA)
(Universidad Autónoma del Estado de México, 2008) Trinidad G Salluca; J. Mauricio Peñarrieta; Juan Alvarado; Björn Bergenståhl
"Four species of Andean tubers, isaño (Tropaeolum tuberosum), oca (Oxalis tuberosa), ulluco (Ullucus tuberosus) and roots of arracacha (Arracacia xanthorrhiza), were studied for the quantification of the Total Antioxidant Capacity (TAC) and determination of Total Phenolic Compounds (TPH). The total antioxidant capacity was measured using ABTS and FRAP methods, and the total phenolics compounds were measured using the Folin & Ciocalteu reagent. The antioxidant capacity found in the tubers and root studied ranged from 0.35 to 11.8 μmol trolox equiv/g dry sample, and phenolics ranged from 0.002 to 0.02 μmol gallic acid equiv./g dry sample. In general black isaño tubers showed the highest values of antioxidant capacity and phenolic compounds compared with the other tubers./ Cuatro especies de tubérculos andinos, isaño (Tropaeolum tuberosum), oca (Oxalis tuberosa), ulluco (Ullucus tuberosus) y raíces de arracacha (Arracacia xanthorrhiza) fueron estudiados para la cuantificación de la capacidad antioxidante total (TAC) y la determinación de compuestos fenólicos totales (TPH). La capacidad antioxidante fue medida mediante el uso de los métodos ABTS y FRAP, los compuestos fenólicos fueron medidos mediante el uso del reactivo de Folin & Ciocalteau.La capacidad antioxidante encontrada en los tubérculos estudiados tienen un rango de 0.35 a 11.8 μmol equiv. de trolox/g de muestra seca, el rango de compuestos fenolicos es de 0.002 a 0.02 μmol equiv. de ácido gálico/g de muestra seca. En general el isaño oscuro muestra los valores mas altos de capacidad antioxidante y compuestos fenólicos comparados con los otros tubérculos."
High Levels of Resveratrol in Grapes Cultivated at High Altitude Valleys in Bolivia
(Taylor & Francis, 2014) Marco Taquichiri; Ruth Ayarde; Pastor Gutierrez; Atma‐Sol Bustos; Carolina Paredes; Juan Carlos Callisaya; Juan Carlos Surco; Eduardo Palenque; Flavio Ghezzi; Juan Alvarado
Trans-resveratrol, total antioxidant capacity (TAC), and total phenolic compounds were assessed in Bolivian grape cultivars collected at high altitude valleys. The TAC of the grapes ranged from 0.8 to 22 μmol Trolox equivalents/g dry matter determined by 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), and from 0.6 to 10 determined by the ferric reduction antioxidant power. In the present study, we observed that under certain conditions trans-resveratrol levels in Bolivian grapes are 10-fold higher than the reported data from the literature. Additionally, the temporal evolution in three different solar ultraviolet-B radiation levels was carried out to understand their effect on the oxidative processes.
PHENOLIC COMPOUNDS FROM BACCHARIS PAPILLOSA SUBSP. PAPILLOSA
(Universidad Autónoma del Estado de México, 2009) Zilma Escobar; Yonny Flores; Leslie Tejeda; Juan Alvarado; Olov Sterner; Giovanna R. Almanza
"Cuatro compuestos fenólicos fueron aislados Ermanine 1, Isokamferine 2, Drupanine 3 and 5,7,5 ,4 - tetrahidroxi- 3-metoxiflavona 4 a partir de las hojas secas de Baccharis papillosa subsp. papillosa. Sus estructuras fueron determinadas por métodos espectroscópicos y comparados con datos bibliográficos. El material vegetal fue colectado en dos estaciones; invierno y verano, en ambos casos fueron determinados los mismos compuestos pero con diferentes rendimientos, incrementandose la cantidad de los compuestos 2, 3 y 4 en verano. Además, se evaluó la actividad antioxidante de cada compuesto puro mediante dos métodos: ABTS y FRAP, determinandose una potente actividad para el compuesto 4, una significante actividad para el compuesto 2 y una débil actividad para los compuestos 1 y 3."
Relating genes in the biosynthesis of the polyphenol composition of <scp>A</scp>ndean colored potato collection
(Wiley, 2013) Leslie Tejeda; Juan Alvarado; Magdalena Dębiec; J. Mauricio Peñarrieta; Oscar Cárdenas; María Teresa Álvarez; Aakash Chawade; Lars Nilsson; Björn Bergenståhl
The objective of this study was to evaluate total antioxidant capacity (TAC), total phenolic content (TPH), and the identification of anthocyanidin and polyphenolic compounds in 13 colored potatoes collected from the Andean region of Bolivia, and understand how the chemical composition correlated with the botanical classification and molecular characterization of genes, ans (anthocyanidin synthase) and stan1 (Solanum tuberosum anthocyanidin synthase), associated with the synthesis of anthocyanidins. The results show the existence of a limited correlation between botanical classification, based on morphological identification and polyphenol composition. No association between genetic grouping of the ans and stan genes and botanical classification was found. However, it was possible to identify a correlation between the ans gene clades and the levels of anthocyanidins as well as of other polyphenols. Thus, this result confirms the concept that potato color can be used in the search for high polyphenol potato cultivars.
SEPARATION OF PHENOLIC COMPOUNDS FROM FOODS BY REVERSED-PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
(Universidad Autónoma del Estado de México, 2007) J. Mauricio Peñarrieta; Juan Alvarado; Björn Åkesson; Björn Bergenståhl
"As a part of a study on the content of antioxidants and phenolic compounds in Bolivian foods, a rapid high performance liquid chromatographic method using a reversed-phase column and a diode array detector (HPLC-DAD) method was established. It was used for the determination of phenolic compounds in foods and a good resolution of different standard compounds was achieved."
The influence of convection drying on the physicochemical properties of yacón (Smallanthus sonchifolius)
(Springer Science+Business Media, 2018) Juan Gabriel Salinas; Juan Alvarado; Björn Bergenståhl; Eva Tornberg
Yacón root is a natural source of fructans, which has many potential benefits. Convective drying has been applied to increase the shelf life of yacón roots. However, this processing may lead to detrimental effects on the physicochemical functionality. The drying was investigated using different conditions (drying temperatures of 45 °C, 50 °C and 55 °C at a drying air velocity of 2 m/s and 60 °C at a drying air velocity of 2 m/s, 3 m/s and 4 m/s). The dried samples were compared to the original yacón with regard to their physicochemical properties. From all the properties that were studied, the color of the dried material and the elastic modulus of the reconstituted yacón were the most important properties being minimized respectively. The results of this investigation indicate that the best drying conditions, where the physicochemical properties of the samples are kept closest to the original material, are obtained either by using temperatures of 55 °C and 2 m/s or using higher temperatures but increasing the air velocity.
Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (<i>Chenopodium pallidicaule</i>): An Andean pseudocereal
(Wiley, 2008) J. Mauricio Peñarrieta; Juan Alvarado; Björn Åkesson; Björn Bergenståhl
Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 m altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as micromol of Trolox equivalents/g dw. The content of TPH was 12.4-71.2 micromol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 micromol of catechin equivalents/g dw. The data obtained by the four methods showed several significant correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health.
Total Antioxidant Capacity and Content of Phenolic Compounds in Wild Strawberries (<i>Fragaria vesca</i>) Collected in Bolivia
(Taylor & Francis, 2009) J. Mauricio Peñarrieta; Juan Alvarado; Björn Bergenståhl; Björn Åkesson
To study the composition of wild strawberries grown at high altitude, total antioxidant capacity, total phenolic compounds, total flavonoids, and individual phenolic compounds were measured in wild strawberries (Fragaria vesca) collected between 2,650 and 3,300 m above sea level in Bolivia. Total antioxidant capacity, as assessed by the ferric-reducing antioxidant power and 2,2' -azino-bis(3-ethylbenzotiazoline-6-sulphonic acid) methods, was in the range 16-39 μmol of Trolox equivalents/g fw by both methods. The total phenolic content was 9.7–21 μmol gallic acid equivalents/g fw, and the flavonoid content ranged between 2.8 and 4.9 μmol of catechin equivalents/g fw. The data obtained by the four methods showed several significant linear correlations confirming that flavonoids and other phenolic compounds contributed significantly to the total antioxidant capacity values. Reversed-phase high performance liquid chromatography analysis of extracts subjected to acid hydrolysis showed the presence of seven major fractions, tentatively identified as ellagic acid, cyanidin, pelargonidin, quercetin, kaempferol, gallic acid derivatives, and catechin derivatives. The data indicated that wild strawberries have a somewhat higher total antioxidant capacity content in comparison with that reported for cultivated strawberries. No obvious difference to the composition reported for wild strawberries grown at low altitude could be found.
TOTAL ANTIOXIDANT CAPACITY IN ANDEAN FOOD SPECIES FROM BOLIVIA
(Universidad Autónoma del Estado de México, 2005) J. Mauricio Peñarrieta; Juan Alvarado; Björn kesson; Björn Bergenståhl
"As a part of a study on the content of antioxidants in Bolivian foods, the Total Antioxidant Capacity (TAC) in some Andean foods has been measured. Eight Andean foods were analyzed by two methods, ABTS and FRAP to assess TAC. The selected plants were : andean lupin (Lupinus mutabilis), quinoa (Chenopodium quinoa), amaranth (Amaranthus sp.), ulluco (Ullucus tuberosus), potato (Solanum tuberosum), arracacha (Arracacia xanthorrhiza), oca (Oxalis tuberosa) and canihua (Chenopodium pallidicaule). The highest TAC value was observed in canihua both in the water-soluble fraction and in the water-insoluble fraction. Intermediate values were found in oca, andean lupin and quinoa, and lower TAC values were demonstrated in potato, arracacha, ulluco and amaranth. TAC values obtained by the two methods showed significant linear correlations both for the water–soluble fractions (r=0.92) and water–insoluble fractions (r=0.95). Further studies are necessary to identify the compounds responsible for the antioxidant capacity of these foods."