María Castro-Puyana

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

This review work presents and discusses the main applications of capillary electromigration methods in food analysis and Foodomics. Papers that were published during the period February 2013–February 2015 are included following the previous review by Garcia‐Cañas et al. (Electrophoresis, 2014, 35, 147–169). Analysis by CE of a large variety of food‐related molecules with different chemical properties, including amino acids, hazardous amines, peptides, proteins, phenols, polyphenols, lipids, carbohydrates, DNAs, vitamins, toxins, contaminants, pesticides, residues, food additives, as well as small organic and inorganic compounds. This work includes recent results on food quality and safety, nutritional value, storage, bioactivity, as well as applications of CE for monitoring food processing. The use, among other CE developments, of microchips, CE‐MS, and chiral CE in food analysis and Foodomics is also discussed.

Extraction and Characterization of Bioactive Compounds with Health Benefits from Marine Resources: Macro and Micro Algae, Cyanobacteria, and Invertebrates

The occurrence and incidence of different diseases such as cancer, cardiovascular diseases, obesity, and diabetes may be related to the consumption of high calorie calorie-containing diets combined with sedentary lifestyles. The concept of functional foods first appeared in Japan where it was considered to be a tool to promote health and well-being. In 1992, the Japanese government established a policy of “Foods of Specific Health Uses” (FOSHU). This concept was further developed in Europe within the “Functional Food Science in Europe” (FUFOSE) project supported by the European Commission (EC) and co-ordinated by the International Life Sciences Institute (ILSI). Several interesting points were observed at the end of this project (Bellisle, F., A.T. Diplock, G. Hornstra, B. Koletzko, M. Roberfroid, S. Salminen, et al. 1998. Functional food science in Europe. British Journal of Nutrition 80:1–193; Diplock, A.T., P.J. Agget, M. Ashwell, F. Bornet, E.B. Fern, M.B. Roberfroid. 1999. Scientific concepts of functional foods in Europe: Consensus document. British Journal of Nutrition 81:S1–S27), including a definition of a functional food as “a food which is demonstrated to positively affect one or more physiological functions, so that it is able to increase the well-being and/or to reduce the risk to suffer a disease” (Diplock, A.T., P.J. Agget, M. Ashwell, F. Bornet, E.B. Fern, M.B. Roberfroid. 1999. Scientific concepts of functional foods in Europe: Consensus document. British Journal of Nutrition 81:S1–S27). This definition implies that a functional food must maintain the shape of the food (thereby excluding pills and capsules) and that the functional food must impart a physiological effect following consumption that is above and beyond any observed nutritional effects.

Global Foodomics strategy to investigate the health benefits of dietary constituents.

A global methodology, called Foodomics, which allows carrying out a comprehensive evaluation of the health benefits of food ingredients is presented in this work. The new methodology is based on the combination of several analytical platforms and data processing for Transcriptomics, Proteomics and Metabolomics studies, allowing the determination of changes induced by food ingredients at molecular level. Both, the whole methodological development and its potential are presented through the investigation of a case study following a hypothesis-free strategy. Namely, the chemopreventive effect of polyphenols from rosemary was examined on the total gene, protein and metabolite expression in human HT29 colon cancer cells. Conclusions on the bioactivity of polyphenols against colon cancer cells based on the results from each single platform (Transcriptomics, Proteomics or Metabolomics) are compared with the conclusions based on the integration of the whole results from the three platforms, corroborating the interest of using a global integrative strategy as Foodomics. To our knowledge, although many papers and reviews have been published on this topic, this is the first time that Transcriptomics, Proteomics and Metabolomics platforms are put together to study the health benefits from dietary ingredients against colon cancer cells at gene, protein and metabolite level. Advantages, drawbacks and current challenges of this global analytical strategy are discussed in this work. The results from our study provide new insights on the biological mechanisms involved in the cancer risk reduction properties of dietary constituents.

Metabolomics, peptidomics and proteomics applications of capillary electrophoresis-mass spectrometry in Foodomics: A review

In the current post-genomic era, Foodomics has been defined as a discipline that studies food and nutrition through the application of advanced omics approaches. Foodomics involves the use of genomics, transcriptomics, epigenetics, proteomics, peptidomics, and/or metabolomics to investigate food quality, safety, traceability and bioactivity. In this context, capillary electrophoresis-mass spectrometry (CE-MS) has been applied mainly in food proteomics, peptidomics and metabolomics. The aim of this review work is to present an overview of the most recent developments and applications of CE-MS as analytical platform for Foodomics, covering the relevant works published from 2008 to 2012. The review provides also information about the integration of several omics approaches in the new Foodomics field.

About the role of enantioselective selector-selectand interactions and the mobilities of diastereomeric associates in enantiomer separations using CE

It is generally accepted that the selective binding of enantiomers of the chiral analyte to a chiral selector is necessary for enantioseparations in CE, whereas the role of mobility differences between the temporary diastereomeric associates formed between the enantiomers and the chiral selector has been commonly neglected. One of the authors of this study suggested in 1997 that the mobility difference between the diastereomeric associates of two enantiomers with the chiral selector may be solely responsible for a separation of enantiomers in CE and enantioselective selector–selectand binding may be not necessarily required. Several indirect confirmations of this hypothesis have been described in the literature within the last few years but a dedicated study proving this concept has not been published yet. The present data obtained for the two chiral antimycotic drugs ketoconazole and terconazole by CE and NMR spectroscopy unequivocally support this concept.

Recent approaches in sensitive enantioseparations by CE.

The latest strategies and instrumental improvements for enhancing the detection sensitivity in chiral analysis by CE are reviewed in this work. Following the previous reviews by García‐Ruiz et al. (Electrophoresis 2006, 27, 195–212) and Sánchez‐Hernández et al. (Electrophoresis 2008, 29, 237–251; Electrophoresis 2010, 31, 28–43), this review includes those papers that were published during the period from June 2009 to May 2011. These works describe the use of offline and online sample treatment techniques, online sample preconcentration techniques based on electrophoretic principles, and alternative detection systems to UV–Vis to increase the detection sensitivity. The application of the above‐mentioned strategies, either alone or combined, to improve the sensitivity in the enantiomeric analysis of a broad range of samples, such as pharmaceutical, biological, food and environmental samples, enables to decrease the limits of detection up to 10−12 M. The use of microchips to achieve sensitive chiral separations is also discussed.

Development of a CE-MS2 method for the enantiomeric separation of L/D-carnitine: Application to the analysis of infant formulas

A new chiral analytical method based on CE‐MS is proposed for the identification and simultaneous quantification of D/L‐carnitine in infant formulas. Previous derivatization of carnitine with FMOC enabled the optimization of the chiral separation using CE with UV detection. An optimization of electrospray‐MS parameters using a partial filling of the non‐volatile chiral selector (succinyl‐γ‐CD) was performed. A selective fragmentation using MS2 experiments with an ion trap analyser was carried out to confirm the identity of D/L‐carnitine according to the current legislation. Satisfactory results were obtained in terms of linearity, precision, and accuracy. Interestingly, the CE‐MS2 method developed allowed a sensitivity enhancement with respect to UV detection of 100‐fold, obtaining an LOD of 100 ng/g for D‐carnitine. The determination of L‐carnitine and its enantiomeric purity in 14 infant formulas supplemented with carnitine was successfully achieved, sample preparation only requiring an ultrafiltration with centrifugal filter devices to retain the components with the highest molecular weights.

Recovering bioactive compounds from olive oil filter cake by advanced extraction techniques.

The potential of by-products generated during extra-virgin olive oil (EVOO) filtration as a natural source of phenolic compounds (with demonstrated bioactivity) has been evaluated using pressurized liquid extraction (PLE) and considering mixtures of two GRAS (generally recognized as safe) solvents (ethanol and water) at temperatures ranging from 40 to 175 °C. The extracts were characterized by high-performance liquid chromatography (HPLC) coupled to diode array detection (DAD) and electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) to determine the phenolic-composition of the filter cake. The best isolation procedure to extract the phenolic fraction from the filter cake was accomplished using ethanol and water (50:50, v/v) at 120 °C. The main phenolic compounds identified in the samples were characterized as phenolic alcohols or derivatives (hydroxytyrosol and its oxidation product), secoiridoids (decarboxymethylated and hydroxylated forms of oleuropein and ligstroside aglycones), flavones (luteolin and apigenin) and elenolic acid derivatives. The PLE extraction process can be applied to produce enriched extracts with applications as bioactive food ingredients, as well as nutraceuticals.

Enantiomeric separation of bupropion enantiomers by electrokinetic chromatography: quantitative analysis in pharmaceutical formulations.

The first CE method enabling the quantitation of the two enantiomers of bupropion was developed in this work. Electrokinetic chromatography (EKC) mode using cyclodextrins as chiral selectors was employed. A study on the enantiomeric separation ability of different neutral and anionic CDs was carried out. Sulfated-beta-CD was shown to provide the highest values for the enantiomeric resolution. The influence of some experimental conditions, such as pH, chiral selector concentration, temperature, and separation voltage on the enantiomeric separation of bupropion was also studied. The use of 10 mM sulfated-beta-CD in 50 mM borate buffer (pH 9.0) with an applied voltage of 30 kV and a temperature of 30 degrees C enabled the separation of the enantiomers of bupropion with high resolution (Rs > 7) and short analysis time (approximately 3.5 min). Finally, the method was successfully applied to the quantitation of bupropion in two pharmaceutical formulations.

Potential of vancomycin for the enantiomeric resolution of FMOC‐amino acids by capillary electrophoresis‐ion‐trap‐mass spectrometry

The potential of the antibiotic vancomycin (VC) as chiral selector for the enantiomeric separation of amino acids by CE‐ESI‐MS/MS2 was investigated for the first time in this work. Derivatization of amino acids with FMOC‐Cl was carried out to enable their interaction with VC as well as the formation of precursor ions with larger m/z which were employed in MS2 experiments. The partial filling of a coated capillary was employed to avoid the loss in MS sensitivity originated by the introduction of VC in the ionization source. Under optimized conditions, the simultaneous enantiomeric separation and unequivocal identification of 17 amino acids (two of them being nonprotein amino acids) took place in about 20 min with LODs in the micromolar range.