Los pigmentos como marcadores de trazabilidad del aceite de oliva

XIV Simposium Científico-Técnico del Aceite de Oliva= XIV Scientific-Technical Symposium of Olive Oil. (Jáén, 13-15 mayo, 2009). EXPOLIVA 2009.Se discute la utilidad de los pigmentos clorofílicos y carotenoides como marcadores químicos para la trazabilidad del aceite de oliva en los siguientes puntos: 1.-Marcadores para rastrear el origen varietal del aceite: la presencia de pigmentos exclusivos tales como derivados clorofílicos desesterificados y/o xantofilas esterificadas se puede aplicar para diferenciar aceites de las variedades Arbequina y Blanqueta. Así mismo, el contenido total en pigmentos y los porcentajes de las xantofilas violaxanteno y luteína son de utilidad como variables clasificatorias en un modelo de rastreo del origen varietal. 2.- Marcadores de condiciones térmicas en el procesado y/o almacenamiento: el porcentaje de ciertos pigmentos clorofílicos oxidados como pirofeofitina “a” puede indicar malas prácticas de procesado y/o almacenamiento. Se propone la aplicación de un modelo matemático para predecir la formación de pirofeofitina “a” en aceite de oliva virgen, en función del tiempo y temperatura de almacenamiento como herramienta para su trazabilidad. 3.-Marcadores de adulteración en el producto envasado: la presencia de pigmentos ajenos a la oliva o la alteración de las relaciones cuantitativas entre ciertos pigmentos se proponen como marcadores de adulteración.Sergio Alcañiz (Ayudante de Laboratorio) Dirección General de Investigación por la financiación de los Proyectos de Investigación: OLI97-2151 AGL 2000-0699 AGL 2004-07623-C03-02 AGL 2007-66139-C02-01.Peer reviewe

A rapid spectrophotometric method for the determination of peroxide value in food lipids with high carotenoid content

ABSTRACT: A rapid and sensitive ultraviolet-visible spectrophotometric method for determination of peroxide value (PV) in foods with high carotenoid content (e.g., paprika oleoresin, paprika powder, red palm oil) has been developed. The proposed protocol [modified International Dairy Federation (IDF) method] was established from the IDF Fe(II)-oxidation-based spectrophotometric method, and the main one of the introduced modifications consisted of a clean-up extraction step of pigments before determining the PV by complexing Fe(III) ions with thiocyanate. Fe(II) oxidation time, reaction medium, and Fe(III)-thiocyanate complex formation time were optimized. The modified IDF method was compared with and was validated by iodometric AOAC official method with a good correlation (R 2 = 0.957) between data obtained by both analytical methods. The high sensitivity of the method allows the use of only about 0.010-0.015 g of sample, with a detection limit of 0.044 mequiv peroxide/kg of sample. Therefore, an improved spectrophotometric method for assessing PV in food lipids with high carotenoid content is now available and can be applied to any kind of sample, independent of oil and pigment content

Correlación entre unidades asta-concentración carotenoide en pimentones. Predicción de la estabilidad del color durante el almacenamiento

Paprika obtained through the traditional process, from fruits dried in oak ovens, is stored at room temperature for 18 months. Samples are taken at 2-3 months time intervals and color quantity is evaluated, measuring it as ASTA units and carotenoid content. Values obtained from both measurements are compared, achieving a good correlation between ASTA units and total carotenoid content. As a result two equations are proposed, one linking both parameters and another which predicts the remaining ASTA unit as a function of storage time. ASTA values after 18 months of storing time are ca. 55 % of the initial values.El pimentón obtenido de forma tradicional, a partir de frutos secados en hornos de leña, se ha almacenado a temperatura ambiente durante 18 meses. Se han tomado muestras de los mismos a intervalos de 2-3 meses y se ha evaluado la cantidad de color extractable como unidades ASTA y, en paralelo, se ha controlado la concentración carotenoide. Se comparan los valores obtenidos por cada uno de los dos procedimientos, observándose que se da una buena correlación entre las unidades ASTA y la concentración total de carotenoides. Se postula una ecuación que relaciona ambos parámetros y otra ecuación que permite predecir el valor remanente de ASTA con el tiempo de conservación. La retención de color a los 18 meses se sitúa en torno al 55 % del valor inicial

Astaxanteno procedente de cangrejo (Procambarus clarkii) como ingrediente colorante en la alimentación de gallinas ponedoras

Chicken egg yolks generally owe their color to yellow carotenoids. The addition of synthetic red pigments allows changes in color, from the original yellow to red hues which may be more appealing to consumers in certain markets.Our aim has been to test whether ground crayfish shells, which are a rich and natural source of astaxanthin, produce detectable changes in the coloration of egg yolks through the accumulation of this carotenoid. Laying hens were fed with a commercial feed mixed with crayfish powder and the carotenoid profiles of the yolks in the eggs laid during the trial were monitored by HPLC. The analyses showed a progressive increase in the astaxanthin concentration in the egg yolks, reaching similar levels to those obtained for the rest of present carotenoid pigments.La yema de huevo de gallina debe su coloración a la presencia de carotenoides de tonalidad amarilla. La adición de colorantes sintéticos de tonalidades rojas permite modificar e incrementar la coloración de la yema desde el amarillo original a tonos rojos que pueden ser demandados en ciertos mercados según las preferencias del consumidor. El objetivo del trabajo fue probar si un triturado obtenido a partir de caparazones de cangrejo, que es una fuente natural y rica en astaxanteno, produce cambios detectables en la coloración de la yema de huevo por la acumulación de dicho carotenoide. Las gallinas ponedoras se alimentaron con un pienso comercial al que se adicionó triturado de caparazón de cangrejo. Se realizó un seguimiento de los cambios en la composición carotenoide (mediante HPLC) de la yema de los huevos puestos durante el periodo de alimentación suplementada. Los análisis mostraron una progresiva incorporación de astaxanteno que alcanzó niveles similares al resto de carotenoides presentes inicialmente en la yema

Carotenoid composition and carotenogenic gene expression during Ipomoea petal development

Japanese morning glory (Ipomoea nil) is a representative plant lacking a yellow-flowered cultivar, although a few wild Ipomoea species contain carotenoids in their petals such as Ipomoea sp. (yellow petals) and I. obscura (pale-yellow petals). In the present study, carotenoid composition and the expression patterns of carotenogenic genes during petal development were compared among I. nil, I. obscura, and Ipomoea sp. to identify the factors regulating carotenoid accumulation in Ipomoea plant petals. In the early stage, the carotenoid composition in petals of all the Ipomoea plants tested was the same as in the leaves mainly showing lutein, violaxanthin, and β-carotene (chloroplast-type carotenoids). However, in fully opened flowers, chloroplast-type carotenoids were entirely absent in I. nil, whereas they were present in trace amounts in the free form in I. obscura. At the late stage of petal development in Ipomoea sp., the majority of carotenoids were β-cryptoxanthin, zeaxanthin, and β-carotene (chromoplast-type carotenoids). In addition, most of them were present in the esterified form. Carotenogenic gene expression was notably lower in I. nil than in Ipomoea sp. In particular, β-ring hydroxylase (CHYB) was considerably suppressed in petals of both I. nil and I. obscura. The CHYB expression was found to be significantly high in the petals of Ipomoea sp. during the synthesis of chromoplast-type carotenoids. The expression levels of carotenoid cleavage genes (CCD1 and CCD4) were not correlated with the amount of carotenoids in petals. These results suggest that both I. obscura and I. nil lack the ability to synthesize chromoplast-type carotenoids because of the transcriptional down-regulation of carotenogenic genes. CHYB, an enzyme that catalyses the addition of a hydroxyl residue required for esterification, was found to be a key enzyme for the accumulation of chromoplast-type carotenoids in petals

Impact assessment of mechanical harvest on fruit physiology and consequences on oil physicochemical and sensorial quality from ‘Manzanilla de Sevilla’ and ‘Manzanilla Cacereña’ super-high density hedgerows. A preliminary study

BACKGROUND Super-intensive cultivation facilitates olive mechanized harvesting, allowing substantial savings in the production cost of virgin olive oil (VOO). However, the number of varieties adapted to this type of cultivation is small. This study explores the impact that harvesting with a grape straddle harvester of ‘Manzanilla de Sevilla’ and ‘Manzanilla Cacereña’ olives grown in super-intensive cultivation has on the physiology of the fruit and the quality of the oil subsequently extracted. RESULTS For both cultivars, fruits harvested mechanically showed higher respiration and ethylene production and lower firmness than fruits harvested by hand. Their oils exhibited lower phenol contents, lower oxidative stability and lower presence of positive sensory attributes. However, in these oils the values of parameters used to assess the level of quality of VOO remained within the limits required for the best commercial category. CONCLUSION Mechanical harvesting of ‘Manzanilla de Sevilla’ and ‘Manzanilla Cacereña’ super-high-density hedgerows induced physiological alterations in the fruits and a reduction in the contents of natural antioxidants and flavour components in the oils, though it did not result in a loss of the ‘Extra’ level of quality. © 2014 Society of Chemical IndustryFEDER AGL2011-30371-C02-0

Self-complementary nickel halides enable multifaceted comparisons of intermolecular halogen bonds : fluoride ligands vs other halides

The syntheses of three series of complexes designed with self-complementary motifs for formation of halogen bonds between an iodotetrafluorophenyl ligand and a halide ligand at square-planar nickel are reported, allowing structural comparisons of halogen bonding between all four halides C6F4IX–Ni (X = F, Cl, Br, I). In the series, trans-[NiX(2,3,5,6-C6F4I)(PEt3)2] 1pX and trans-[NiX(2,3,4,5-C6F4I)(PEt3)2] (X = F, Cl, Br, I) 1oX, the iodine substituent on the benzene ring was positioned para and ortho to the metal, respectively. The phosphine substituents were varied in the series, trans-[NiX(2,3,5,6-C6F4I)(PEt2Ph)2] (X = F, I) 2pX. Crystal structures were obtained for the complete series 1pX, and for 1oF, 1oCl, 1oI and 2pI. All these complexes exhibited halogen bonds in the solid state, of which 1pF exhibited unique characteristics with a linear chain, the shortest halogen bond d(C6F4IF–Ni) = 2.655(5) Å and the greatest reduction in halogen bond distance (IF) compared to the sum of the Bondi van der Waals radii, 23%. The remaining complexes form zig-zag chains of halogen bonds with distances also reduced with respect to the sum of the van der Waals radii. The magnitude of the reductions follow the pattern F > Cl ~ Br > I, 1pX > 1oX, consistent with the halogen bond strength following the same order. The variation in the IX–Ni angles is consistent with the anisotropic charge distribution of the halide ligand. The temperature dependence of the X-ray structure of 1pF revealed a reduction in halogen bond distance of 0.055(7) Å on cooling from 240 to 111 K. Comparison of three polymorphs of 1oI shows that the halogen bond geometry may be altered significantly by the crystalline environment. The effect of the halogen bond on the 19F NMR chemical shift in the solid state is demonstrated by comparison of the magic-angle spinning NMR spectra of 1pF and 1oF with that of a complex incapable of halogen bond formation, trans-[NiF(C6F5)(PEt3)2] 3F. Halogen bonding causes deshielding of iso in the component of the tensor perpendicular to the nickel coordination plane. The results demonstrate the potential of fluoride ligands for formation of halogen bonds in supramolecular structures

Allelic Variation, Alternative Splicing and Expression Analysis of Psy1 Gene in Hordeum chilense Roem. et Schult

Background: The wild barley Hordeum chilense Roem. et Schult. is a valuable source of genes for increasing carotenoid content in wheat. Tritordeums, the amphiploids derived from durum or common wheat and H. chilense, systematically show higher values of yellow pigment colour and carotenoid content than durum wheat. Phytoene synthase 1 gene (Psy1) is considered a key step limiting the carotenoid biosynthesis, and the correlation of Psy1 transcripts accumulation and endosperm carotenoid content has been demonstrated in the main grass species. Methodology/Principal findings: We analyze the variability of Psy1 alleles in three lines of H. chilense (H1, H7 and H16) representing the three ecotypes described in this species. Moreover, we analyze Psy1 expression in leaves and in two seed developing stages of H1 and H7, showing mRNA accumulation patterns similar to those of wheat. Finally, we identify thirtysix different transcripts forms originated by alternative splicing of the 59 UTR and/or exons 1 to 5 of Psy1 gene. Transcripts function is tested in a heterologous complementation assay, revealing that from the sixteen different predicted proteins only four types (those of 432, 370, 364 and 271 amino acids), are functional in the bacterial system. Conclusions/Significance: The large number of transcripts originated by alternative splicing of Psy1, and the coexistence of functional and non functional forms, suggest a fine regulation of PSY activity in H. chilense. This work is the first analysis of H. chilense Psy1 gene and the results reported here are the bases for its potential use in carotenoid enhancement in duru