Oils and fats on food: is it possible to have a healthy diet?

Oils and fats are an important part of our diet as components of many food formulations. Thus, they are retailed for domestic or hostelry uses and broadly used by food industry for the elaboration of margarines, ice cream, canned food, pre-cooked dishes, bakery, confectionary, chocolates, etc. Chemically, the main component of oils and fats are triacylglycerols (TAGs), which account for up to 95% of their total weight. They consisted of a molecule of glycerol esterified with three fatty acids, usually the saturated, palmitic and stearic, the monounsatu�rated oleic, and the polyunsaturated, linoleic or linolenic, all with 18 carbons excepting the palmitic which has 16 carbons. Out of those most common fatty acids, we can found other fatty acids present only in certain oils such as saturated medium chained fatty acids like lauric and myristic, which contain 12 and 14 carbons respectively

Oils and fats on food: is it possible to have a healthy diet?

Oils and fats are an important part of our diet as components of many food formulations. Thus, they are retailed for domestic or hostelry uses and broadly used by food industry for the elaboration of margarines, ice cream, canned food, pre-cooked dishes, bakery, confectionary, chocolates, etc. Chemically, the main component of oils and fats are triacylglycerols (TAGs), which account for up to 95% of their total weight. They consisted of a molecule of glycerol esterified with three fatty acids, usually the saturated, palmitic and stearic, the monounsatu�rated oleic, and the polyunsaturated, linoleic or linolenic, all with 18 carbons excepting the palmitic which has 16 carbons. Out of those most common fatty acids, we can found other fatty acids present only in certain oils such as saturated medium chained fatty acids like lauric and myristic, which contain 12 and 14 carbons respectively

NTMC2T5: lipid transfer proteins at ER-chloroplast contact sites involved in plant stress.

Chloroplasts are the site of fatty acid synthesis in plants; however, these fatty acids are assembled into glycerolipids at the ER. Later on, some of these ER-assembled glycerolipids will be transferred back to the chloroplasts to be further modified and to form part of the chloroplastic membranes. Previous reports have shown that under some abiotic stresses, these plastid membranes suffer a large lipid remodelling and new precursors massively need to be transported from the ER to the chloroplast or vice versa. It has been suggested that the newly synthetized ER lipids are delivered to chloroplast via a non-vesicular pathway, likely through lipid transport proteins (LTP). These LTP would be localized in membrane contact sites (MCS). Some LTP at MCS contain particular domains, as the synaptotagmin-like mitochondrial lipid-binding (SMP) domain. We have studied the occurrence of SMP proteins in A. thaliana and S. lycopersicum. By using transient expression in N. benthamiana leaves and confocal microscopy, we have identified the NTMC2T5 family with two homologs in A. thaliana and only one in S. lycopersicum. They are anchored to the chloroplast outer membrane, and they interact in trans with the ER (ER-chloroplast MCS). We have observed that clustering of chloroplasts around the nucleus occurred when we overexpressed these proteins and Arabidopsis double knock-out mutant for these proteins showed less chloroplasts attached to nuclei at control conditions. And, we have investigated the NTMC2T5 protein domains involved in this clustering. Moreover, our analysis has demonstrated that Arabidopsis simple mutants show lower germination rates in media supplemented with NaCl and lower rates of expanded cotyledons in media supplemented with ABA. We have also performed biotinylation-based proximity labelling proteomics experiments in order to identify interactors of these proteins. Finally, we have performed lipidomic analysis to understand the role of these proteins.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

New Insights Into Sunflower (Helianthus annuus L.) FatA and FatB Thioesterases, Their Regulation, Structure and Distribution

Sunflower seeds (Helianthus annuus L.) accumulate large quantities of triacylglycerols (TAG) between 12 and 28 days after flowering (DAF). This is the period of maximal acyl-acyl carrier protein (acyl-ACP) thioesterase activity in vitro, the enzymes that terminate the process of de novo fatty acid synthesis by catalyzing the hydrolysis of the acyl-ACPs synthesized by fatty acid synthase. Fatty acid thioesterases can be classified into two families with distinct substrate specificities, namely FatA and FatB. Here, some new aspects of these enzymes have been studied, assessing how both enzymes contribute to the acyl composition of sunflower oil, not least through the changes in their expression during the process of seed filling. Moreover, the binding pockets of these enzymes were modeled based on new data from plant thioesterases, revealing important differences in their volume and geometry. Finally, the subcellular location of the two enzymes was evaluated and while both possess an N-terminal plastid transit peptide, only in FatB contains a hydrophobic sequence that could potentially serve as a transmembrane domain. Indeed, using in vivo imaging and organelle fractionation, H. annuus thioesterases, HaFatA and HaFatB, appear to be differentially localized in the plastid stroma and membrane envelope, respectively. The divergent roles fulfilled by HaFatA and HaFatB in oil biosynthesis are discussed in the light of our data.España MINECO y FEDER Projects AGL2014- 53537-R y AGL2017-83449-

NTMC2T5: a newly identified lipid transfer proteins at ER-chloroplast contact sites involved in development and stress response.

In plants, fatty acid synthesis takes place at chloroplasts, and they are assembled into glycerolipids and sphingolipids at the endoplasmic reticulum (ER). Then, the newly ER synthetized lipids are sent back to the chloroplast to form part of their membranes. Since, no vesicular transport has been described between these two organelles, lipid transport might be mediated by lipid transport proteins (LTP) via a non-vesicular pathway.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

NTMC2T5 protein family: newly identified ER-chloroplast contact site proteins involved in abiotic stress.

Plants are sessile organisms and therefore they have perfected a complex molecular signalling network to detect and respond to the different environmental stresses such as high temperatures, salinity, or drought. In plants, fatty acid synthesis takes place at chloroplasts, and they are assembled into glycerolipids and sphingolipids at the endoplasmic reticulum (ER). Then, the newly synthetized lipids in the ER are delivered to chloroplast via a non-vesicular pathway, likely through lipid transport proteins (LTP). These LTP would be localized in ER-chloroplast membrane contact sites (MCS). Synaptotagmin-like mitochondrial-lipid-binding (SMP) domain proteins are evolutionarily conserved LTP in eukaryotes that localize at MCS. They are involved in tethering of these MCS through interaction with other proteins/membrane lipids and in transferring of glycerolipids between these two membranes. We have studied the occurrence of SMP proteins in A. thaliana and S. lycopersicum by searching remote orthologs of human E-Syt1 (SMP protein). By using transient expression in N. benthamiana leaves and confocal microscopy, we have identified the NTMC2T5 family with two homologs in A. thaliana and only one in S. lycopersicum that are anchored to the chloroplast outer membrane and are interacting with the ER (at ER-chloroplast MCS). Our preliminary data have unequivocally demonstrated that NTMC2T5 proteins are anchored to the chloroplast, and they bind in trans the ER. Additionally, it is predicted that these proteins contain a SMP domain which is a lipid-transfer domain, indicating that these proteins could be responsible for some of the lipid transferring events at ER-chloroplast MCS that are still unknown. Our preliminary phenotypic analyses have shown that these proteins are involved in salt tolerance. Finally, we have observed that clustering of chloroplasts around the nucleus occurred when we overexpressed these proteins in Nicotiana benthamiana leaves.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Caracterización de diferentes aceites de girasol ozonizados I. Cambios químicos durante la ozonización

Vegetable oils are usually rich in unsaturated fatty acids which are susceptible to oxidation. The oxidation of vegetable oils has been one of the most widely studied fields within lipid chemistry, because it alters their properties and nutritive value, inducing the formation of harmful compounds and off-flavors. Moreover, oxidized vegetable oils display altered physical and chemical properties which are conferred by the newer oxy-genated compounds they contain. This is the case of ozonized oils. Ozone is a powerful oxidizing agent that mainly acts on olefinic compounds which generate ozonides and other peroxidic species that can decompose into carbonilic fragments. The action of the oxidant and the later reactions depend on the chemical environment of the reaction as well as the carbonyl termination products resulting from peroxide cleavage. In recent years, sunflower oils with different fatty acid compositions have been developed by breeding and mutagenesis. They displayed higher contents of oleic, stearic or palmitic acids, which mainly alters their triacylglycerol composi-tion. Therefore, four different sunflower oils, common, high oleic, high stearic-high oleic and high palmitic-high oleic, were oxidized with ozone and the progress of the reaction was monitored by measuring the level of oil peroxygenation and the changes in the oils’ fatty acid compositions. The peroxidated species formed during ozonation were studied by FT-IR spectroscopy. The main conclusions of this work were that ozonation caused linear oxidation rates that were similar in all the oils assayed. The addition of water accelerated oxidation, which tended to occur in linoleic polyunsaturated fatty acid The FT-IR pointed to the presence of ozonide-derived peroxides as the major oxygenated species.Los aceites vegetales son generalmente ricos en ácidos grasos insaturados susceptibles de oxidación. La oxi-dación de aceites vegetales ha sido un campo de estudio intensivo dentro de la química de lípidos ya que este proceso altera sus propiedades y valor nutritivo, induciendo la formación de compuestos perjudiciales y olores y sabores indeseados. Además, los aceites vegetales oxidados muestran propiedades físicas alteradas conferidas por los nuevos compuestos oxigenados que contienen. Este es el caso de los aceites ozonizados. El ozono es un agente oxidante enérgico que actúa sobre los compuestos olefínicos generando ozónidos y otras especies peroxídicas que se descomponen en fragmentos carbonílicos. La acción del oxidante y las reacciones posteriores dependen del entorno químico de la reacción además de los productos carbonílicos de terminación resultante de la rotura de los peróxidos. El aceite de girasol común es rico en oleico y linoleico, susceptibles de ataque oxida-tivo por parte del ozono. En los últimos años, aceites de girasol con composiciones diferentes de ácidos grasos se han desarrollado por selección y mutagénesis. Estos aceites muestran altos contenidos en oleico, esteárico o palmítico, los cuales alteran de manera importante su composición de triglicéridos. Este trabajo es el primero de una serie de dos en los cuales se estudian los cambios físico-químicos que dichos aceites de girasol experimentan durante la ozonización. Así, se oxidaron con ozono cuatro aceites de girasol diferentes, girasol común, alto oleico, alto esteárico-alto oleico y alto palmítico-alto oleico. Se monitorizaron las cantidades absorbidas de ozono, los niveles de peroxidación y los ácidos grasos que experimentaron oxidación. Las especies formadas en el proceso se estudiaron mediante espectroscopía FT-IR. El modo en que la composición de ácidos grasos del aceite afectó a las cinéticas de oxidación y los productos resultantes se comentaron a la vista de los resultados.Consejo Superior de Investigaciones Científicas (CSIC) ICOOPCOOPB2015

Geological, geochemical and mineralogical characteristics of REE-bearing Las Mercedes bauxite deposit, Dominican Republic

Bauxite deposits, traditionally the main source of 'aluminum, have been recently targeted for their remarkable contents in rare earth elements (REE). With Sigma REE (lanthanoids + Sc + Y) concentrations systematically higher than similar to 1400 ppm (ay. = 1530 ppm), the Las Mercedes karstic bauxites in the Dominican Republic rank as one of the REE-richest deposits of its style.The bauxitic ore in the Las Mercedes deposit is mostly unlithified and has a homogeneous-massive lithostructure, with only local cross-stratification and graded bedding. The dominant arenaceous and round-grained texture is composed of bauxite particles and subordinate ooids, pisoids and carbonate clasts. Mineralogically, the bauxite ore is composed mostly of gibbsite and lesser amounts of kaolinite, hematite, boehmite, anatase, goethite, chromian spinel and zircon. Identified REE-minerals include cerianite and monazite-Ce, whose composition accounts for the steady enrichment in light-relative to medium-and heavy-REE of the studied bauxites.Considering the paleo-geomorphology of the study area, we propose that bauxites in the Las Mercedes deposit are the product of the erosion and deposition of lithified bauxites located at higher elevations in the Bahoruco ranges. Based on the available data, we suggest a mixed lithological source for the bauxite deposits at the district scale: bedrock carbonates and an igneous source of likely mafic composition. (C) 2017 Elsevier B.V. All rights reserved

High stearic sunflower oil: Latest advances and applications☆

Regular sunflower oil is rich in linoleic acid. To improve its properties for different applications several genotypes with modified fatty acid compositions have been developed. Amongst them, the most remarkable have been high oleic and high stearic types. High stearic sunflower lines reported to date have been produced by traditional methods of breeding and mutagenesis. The mutations affected the expression of enzymes responsible for stearate desaturation in developing seeds. This trait has been combined with standard and high oleic backgrounds, giving high stearic lines with high contents of linoleic or oleic acids and thus different physical properties, increasing their functionality and potential applications. Nevertheless, for applications requiring plastic or confectionery fats, the oils have to be fractionated to obtain derived fats and butters with higher levels of solids. In the present review we present recent advances for the above mentioned topics related to high stearic sunflower oils

Functional Characterization of Lysophosphatidylcholine: Acyl-CoA Acyltransferase Genes From Sunflower (Helianthus annuus L.)

Lysophosphatidylcholine acyltransferase (LPCAT, EC 2.3.1.23) is an evolutionarily conserved key enzyme in the Lands cycle that catalyzes acylation of lysophosphatidylcholine (LPC) to produce phosphatidylcholine (PC), the main phospholipid in cellular membranes. In this study, three LPCAT genes from sunflower were identified and the corresponding proteins characterized. These HaLPCAT genes encoded functionally active enzymes that were able to complement a deficient yeast mutant. Moreover, enzymatic assays were carried out using microsomal preparations of the yeast cells. When acyl specificities were measured in the forward reaction, these enzymes exhibited a substrate preference for unsaturated acyl-CoAs, especially for linolenoyl-CoA, while in the reverse reaction, linoleoyl or linolenoyl acyl groups were transferred from PC to acyl-CoA to a similar extent. Expression levels of LPCAT genes were studied revealing distinct tissue-specific expression patterns. In summary, this study suggests that the combined forward and reverse reactions catalyzed by sunflower LPCATs facilitate acyl-exchange between the sn-2 position of PC and the acyl-CoA pool. Sunflower LPCATs displayed different characteristics, which could point to different functionalities, favoring the enrichment of seed triacylglycerols (TAGs) with polyunsaturated fatty acid (PUFA)España, AEI and FEDER Project AGL2017- 83449-R. R