Tag Archives: food-science

Exopolysaccharides from olive brines could reduce the adhesion of ETEC K88 to intestinal epithelial cells

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Zhu, Yanan, Gemma González-Ortiz, Rufino Jiménez-Díaz, Míriam Pérez-Trujillo, Teodor Parella, Paola López-Colom & Susana María Martín-Orúe. 2018. Exopolysaccharides from olive brines could reduce the adhesion of ETEC K88 to intestinal epithelial cells. Food & Function 9(7). 3884–3894. DOI: https://doi.org/10.1039/c8fo00690c

This study aims to explore the biological functions of the isolated exopolysaccharides (EPSs) produced during the industrial fermentation of olives against enterotoxigenic E. coli (ETEC) K88. Exopolysaccharides were isolated from five industrial fermenters. Analysis of their monosaccharide composition by GLC revealed that the main components were glucose (27%–50%) and galactose (23%–33%) followed by rhamnose (4–23%) and arabinose (6–17%). The 1H NMR spectrum showed a very similar profile between samples, and a more in-depth analysis revealed the presence of an α-pyranose in the form of α-D-Glcp-(1→) and two different α-furanoses, with chemicals shift values, suggesting the presence of α-D-Glcf and α-D-Galf. Miniaturized in vitro tests demonstrated the ability of EPS samples to attach specifically to ETEC K88 (P < 0.05) with variable intensities. The competition test did not show the ability to block the ETEC K88 adhesion to IPEC-J2 cells; however, in the displacement test, all EPS samples were shown to effectively remove the pathogens attached to the cells (P < 0.01).

These results suggest that the EPSs produced during the fermentation of table green olives could interfere with the attachment of opportunistic pathogens onto the intestinal epithelial cells. This would open the possibility of novel functional properties for this traditional Mediterranean fermented food and for the isolated EPSs as candidates for nutraceutics to be used in human and/or animal diets in the prevention and treatment of ETEC diarrhoea.

Free sugars quantification in intact plant tissue by HR-MAS NMR.

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Planta - Journal cover“Assessment of a 1H high-resolution magic angle spinning NMR spectroscopy procedure for free sugars quantification in intact plant tissue” Teresa Delgado-Goñi, Sonia Campo, Juana Martín-Sitjar, Miquel E. Cabañas, Blanca San Segundo, Carles Arús; Planta, 238:397-413, 2013 (PDF file). DOI: 10.1007/s00425-013-1924-y

In most plants, sucrose is the primary product of photosynthesis, the transport form of assimilated carbon, and also one of the main factors determining sweetness in fresh fruits. Traditional methods for sugar quantification (mainly sucrose, glucose and fructose) require obtaining crude plant extracts, which sometimes involve substantial sample manipulation, making the process time-consuming and increasing the risk of sample degradation. Here, we describe and validate a fast method to determine sugar content in intact plant tissue by using high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR). Continue reading Free sugars quantification in intact plant tissue by HR-MAS NMR. →

Sodium mobility on dry-cured ham studied by T2 relaxation times

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“High pressure processing of dry-cured ham: Ultrastructural and molecular changes affecting sodium and water dynamics” Pierre A. Picoueta, Xavier Sala, Núria Garcia-Gila, Pau Nolis, Maddalena Colleo, Teodor Parella, Jacint Arnau. Innovative Food Science & Emerging Technologies. Available online 4 August 2012. DOI: 10.1016/j.ifset.2012.07.008

High pressure processing (HPP) has become a popular method to reduce bacterial load on dry-cured ham. However, HPP processed hams tend to present higher saltiness than non-processed ones. In this study was evaluated the effect of processing Biceps femoris samples of 9 dry-cured hams aged for 15 months at a pressure of 0.1, 300, 600 and 900 MPa. 23Na-Nuclear Magnetic Resonance (NMR) relaxation values were used to determine the mobility of sodium. Continue reading Sodium mobility on dry-cured ham studied by T2 relaxation times →

Identification of compounds of biological significance in foodstuffs by LC-NMR/MS. Olive oil

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There is a great interest in understanding the biochemical basis for the reported beneficial health effects of particular diets or food groups. Characterising the wide variety of nutrients in the things we eat and drink in detail is a substantial analytical challenge, especially when numerous sets of molecules in such mixtures may have very similar chemical structures.

Continue reading Identification of compounds of biological significance in foodstuffs by LC-NMR/MS. Olive oil →

Analysis of phenolic compounds in Extra Virgin Olive Oil by LC-NMR/MS. Differentiation and identification of diastereoisomeric molecules

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“Separation and Identification of Phenolic Compounds of Extra-Virgin Olive Oil from Olea Europaea L. by HPLC-DAD-SPE-NMR/MS. Identification of a New Diastereoisomer of the Aldehydic Form of Oleuropein Aglycone”, by Míriam Pérez-Trujillo, Ana María Gómez-Caravaca, Antonio Segura-Carretero, Alberto Fernández-Gutiérrez, Teodor Parella; Journal of Agricultural and Food Chemistry 58, 9129-9136 (2010). DOI: 10.1021/jf101847e

The phenolic fraction of a monovarietal extra virgin olive oil (EVOO) from Olea europaea L. var. Cornezuelo was studied by the hyphenated HPLC-DAD-SPE-NMR/MS techniques. This survey led to the identification of 25 main compounds. One was identified as a new diastereoisomer of the aldehydic form of oleuropein aglycone (AOA) and characterized by 1D and 2D NMR techniques. Continue reading Analysis of phenolic compounds in Extra Virgin Olive Oil by LC-NMR/MS. Differentiation and identification of diastereoisomeric molecules →