Prebiotic potential of a new sweetener based on galactooligosaccharides and modified mogrosides

This study was conducted to investigate the sweetness intensity and the potential fecal microbiome modulation of galactooligosaccharides in combination with enzymatically modified mogrosides (mMV-GOS), both generated through a patented single-pot synthesis. Sweetness intensity was performed in vivo by trained sensory panelists. The impact on the human fecal microbiome was evaluated by in vitro pH-controlled batch fermentation, and bacterial populations and organic acid concentrations were measured by qPCR and GC-FID, respectively. Significant growth (p ≤ 0.05) during the fermentation at 10 h of bacterial populations includes Bifidobacterium (8.49 ± 0.44 CFU/mL), Bacteroides (9.73 ± 0.32 CFU/mL), Enterococcus (8.17 ± 0.42 CFU/mL), and Clostridium coccoides (6.15 ± 0.11 CFU/mL) as compared to the negative control counts for each bacterial group (7.94 ± 0.27, 7.84 ± 1.11, 7.52 ± 0.37, and 5.81 ± 0.08 CFU/mL, respectively) at the same time of fermentation. Likewise, the corresponding significant increase in production of SCFA in mMV-GOS at 10 h of fermentation, mainly seen in acetate (20.32 ± 2.56 mM) and propionate (9.49 ± 1.44 mM) production compared to a negative control at the same time (8.15 ± 1.97 and 1.86 ± 0.24 mM), is in line with a positive control (short-chain fructooligosaccharides; 46.74 ± 12.13 and 6.51 ± 1.91 mM, respectively) revealing a selective fermentation. In conclusion, these substrates could be considered as novel candidate prebiotic sweeteners, foreseeing a feasible and innovative approach targeting the sucrose content reduction in food. This new ingredient could provide health benefits when evaluated in human studies by combining sweetness and prebiotic fiber functionality

1-Alil-3-metilimidazolio bis(trifluorometanosulfonil)amida como fase estacionaria en Cromatografía de Gases. Preparación de columnas capilares abiertas, caracterización y aplicaciones

Trabajo fin de máster presentado por Plácido Galindo.Peer Reviewe

Exploring the effect of alkyl end group on poly(L-lactide) oligo-esters. Synthesis and characterization

10 páginas, 9 figuras, 1 esquema, 4 tablas.-- Trabajo original publicado on-line.-- El pdf es el borrador del artículo.Poly(L-lactide) (PLLA) oligo-esters with α-hydroxyl-ω-alkyl (alkyl = −CH2−[CH2−CH2]m−CH3, where m = 1, 2, 4, 5, 6, 7, 8, 9, and 10) end groups were synthesized by ring-opening polymerization of L-lactide (L-LA) catalyzed by tin(II) 2-ethylhexanoate Sn(Oct)2 in the presence of aliphatic alcohols as initiators (HO−CH2−[CH2−CH2]m−CH3, where m = 1, 2, 4, 5, 6, 7, 8, 9, and 10). High yields (~ 62 to 71%) and M n(NMR) in the range of 2120–2450 Da (PLLA) were obtained. Effects of alkyl end groups on thermal properties of the oligo-esters were analyzed by DSC, TGA and SAXS. Glass transition temperature (T g) gradually decreases with increase in the percent of−CH2−[CH2−CH2]m−CH3 end group, as results alkyl end group provides most flexibility to PLLA. An important effect of alkyl end group on a double cold crystallization (T c1 and T c2) was observed, and is directly related with the segregation phase between alkyl end group and PLLA. TGA analysis revealed that PLLA oligo-esters are more thermally stable with docosyl (−C22H45) respect to the butyl (−C4H9) end group, probably is due to steric hindrance of the end group (docosyl respect to butyl) toward intermolecular and intramolecular transesterification. SAXS analysis showed that alkyl end group as docosyl restricted the growth of lamellae thickness (D) due to steric hindrance. Characterization of hydroxyl and alkyl end groups in the PLLA oligo-esters was determined by MALDI-TOF, GPC, FT-IR and 1 H and 13 C NMR.J.E.B. is much indebted to the Instituto de Ciencia y Tecnología de Polímeros (CSIC), Consejo Nacional de Ciencia y Tecnología (CONACYT, México) and Sistema Nacional de Investigadores (SNI, México). A.M.F. and J.E.B. thanks the Ministerio de Educación y Ciencia for its financial support in accessing the Synchrotron.Peer reviewe

Poly(L-lactide) macrodiols (HOPLLAOH): Influence of linear alkyl diols as initiators: Synthesis and characterization

A series of ¿,¿-hydroxy telechelic poly(L-lactide)s (HOPLLAOHs) were synthesized by ring-opening polymerization (ROP) of L-lactide (L-LA) using tin octoate [Sn(Oct)2] as catalyst and a family of linear alkyl diols as initiators [HO¿[CH2]m¿OH, where m¿2, 4, 6, 8, 10, and 12]. A systematic analysis of these HOPLLAOHs species in terms of their thermal properties was realizedby DSC. In this sense, the linear alkyl group had an important influence on the glass transition temperature (Tg); a relatively high content of alkyl group on the HOPLLAOH increased the flexibility of the polyester, evidenced by a value of Tg inversely proportional to the weight percent of the alkyl group. Besides, the alkyl groups had an effect on the crystallization temperature (Tc), melting temperature (Tm), and crystallinity (xi). Additionally, HOPLLAOHs were characterized by 1H and 13C NMR, FT-IR, MALDI-TOF, and GPC.Peer Reviewe

Poly(-caprolactone) diols (HOPCLOH) and their poly(ester-urethane)s (PEUs): The effect of linear aliphatic diols [HO-(CH2)m-OH] as initiators

α,ω-Hydroxy telechelic poly(ε-caprolactones) were prepared by ring-opening polymerization of the ε-caprolactone catalyzed by ammonium decamolybdate in the presence of different aliphatic diols [HO–(CH2)m–OH, where m ¼ 2, 4, 6, 8, 10, 12, 14, and 16] as initiators to obtain a family of α,ω- hydroxy telechelic poly(ε-caprolactone) [HO–PCL–O–(CH2)m–O–PCL–OH, m ¼ 2, 4, 6, 8, 10, 12, 14, and 16]. The content of the alkyl group (AG) (–(CH2)m–) had an important effect on the crystallinity (xi) of α,ω-hydroxy telechelic poly(ε-caprolactone), showing a proportional relationship. In poly (ester-urethanes) derived from α,ω-hydroxy telechelic poly(ε-caprolactones) and 1,6- hexamethylene diisocyanate, the AG also showed a similar effect on the xi and eventually on the mechanical properties, increasing the values of the modulus. Therefore, AG content was a factor to induce a plastic behavior in poly(ester-urethanes). The effect of AG on the water uptake of poly(ester-urethanes) after 1 week was negligible.José E. Báez thanks the “Programa para el Desarrollo Profesional Docente (PRODEP, Protocolo 166155)”, Dirección de Apoyo a la Investigación y al Posgrado (DAIP) at University of Guanajuato (UG), Consejo Nacional de Ciencia y Tecnología (CONACYT) and “Sistema Nacional de Investigadores (SNI)” in Mexico for financial support of the work. José E. Báez also thanks Ángel Marcos-Fernández for believing in these ideas and providing financial support for the reagents. José E. Báez also thanks the UG for the recent opportunity to work as an Assistant Professor. Marvin was used for drawing, displaying, and characterizing chemical structures, substructures, and reactions (Marvin Sketch 6.1.3, 2013, ChemAxon; http://www.chemaxon.com); a free software program with an academic license was provided by ChemAxon. Finally, José E. Báez thanks to MSc Paulina Lozano and Dr. Ricardo Navarro Mendoza for the acquisition of SEM micrographs in the “National Laboratory for the Characterization of Physicochemical Properties and Molecular Structure” at the University of Guanajuato. Ángel Marcos-Fernández would like to thank the Ministry of Economy and Competitiveness (MINECO) for the financial support of this work within the framework of the Plan Nacional de IþDþI through the research project MAT2014-52644-R.Peer Reviewe

Congener-specific determination of hydroxylated polychlorinated biphenyls by polar-embedded reversed-phase liquid chromatography-tandem mass spectrometry

This paper reports the development of an LC-ESI-MS method for the sensitive determination of hydroxylated polychlorinated biphenyls (OH-PCBs) in human serum samples. Congener-specific separation was achieved by using a polar-embedded stationary phase, previously optimized for the working group, which provided better separation of isobaric compounds than the common octadecylsilane phases. MS fragmentation patterns and energies showed differences among OH-PCB congeners, mainly depending on the position of OH-group and the number of chlorine atoms in the molecule, although the most intense transitions were always those corresponding to the neutral loss of an HCl group from the quasi-molecular ion cluster. The method allowed the determination of OH-PCBs with good linearity (dynamic linear range of four orders of magnitude with R higher than 0.995) and precision (relative standard deviations of absolute areas lower than 10%), and with better sensitivity than other similar methods previously described in the literature. Matrix effect has been evaluated and reduced to less than 10% by the addition of isotopically labeled standards and a 10-fold dilution of the final sample extract. The low iLODs provided by the developed method (from 1.2 to 5.4 fg µL for all the OH-PCBs studied, except 4′-OH[sbnd]CB108, whose iLOD was 61 fg µL) allows dilution without losses of detected peaks. Finally, the applicability of the method has been demonstrated by analyzing human serum samples belonging to an interlaboratory exercise.Authors thank Comunidad of Madrid and European funding from FSE and FEDER program (S2018/BAA-4393–AVANSECAL-II- CM) and the Spanish Ministry of Economy and Competitiveness (projects AGL2012–37201 and AGL2016–80475-R) for the financial support. We are particularly grateful to Laura Herrero and Sagrario Calvarro for their technical ai

Green subcritical water extraction of Mentha x rotundifolia leaves collected in different annuities

im: In this work, the development for the first time of a green and efficient method to obtain bioactive extracts from Mentha x rotundifolia leaves has been investigated. Methods: The efficiency of three techniques [microwave-assisted extraction (MAE), subcritical water extraction (SWE), and ultrasound-assisted extraction (UAE)] was compared in terms of total phenolic content (TPC) and antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzthioazoline-6-sulfonic acid) (ABTS) assays]. Results: Under similar operating conditions, SWE outperformed MAE and UAE for providing M. rotundifolia extracts with improved antioxidant activity. Further in-depth optimization of the SWE method by means of a Box-Behnken experimental design showed 120°C, 5 min, 0.08 g dry sample: 1 mL water and 2 extraction cycles as optimal experimental parameters to provide the maximum yield of phenolics and the highest bioactivity. The application of the developed SWE method to M. rotundifolia leaves collected in different annuities (2014–2017) showed, in general, no significant differences regarding both composition and antioxidant capacity, as expected from plant samples grown in field under drip irrigation conditions. Conclusions: The SWE method here optimized is shown as a sustainable and efficient alternative for providing bioactive M. rotundifolia extracts with application as functional ingredients, natural preservatives, etc. in the food industry, amongAuthors thank Dr. Julia Navarro Rocha for providing the M. rotundifolia samples under study, Dr. Mar Villamiel for her assistance on the use of UAE facilities, and Drashti Mansukhani for her technical support on SWE experiment

Analysis of glycated sodium caseinate proteins by MALDI-MS and LC-ESI-MS

Resumen del póster presentado al 28th International Symposium on Chromatography celebrado en Valencia (España) del 12 al 16 de septiembre de 2010.Sodium caseinate (SC) is extensively used in the food industry as a functional ingredient due to its simple production, excellent nutritional value and versatile functional properties such as thickening, emulsifying and foaming properties. However, in spite of this, the food industry is moving towards the search of procedures to obtain new multifunctional ingredients. Over the past few years, there has been an increased interest in deliberately promoted Maillard reaction to obtain glycoconjugates with improved functionalities in relation to the initial proteins. Because of glycation-induced modifications in proteins can influence their functional properties, more precise and detailed information on structure of glycated proteins is essential to gain knowledge about their structure-function relationship. In this respect, the power of both matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI-MS) for the monitoring and characterization of protein glycation has been demonstrated. However, as far as we know, no studies on the advantages and disadvantages of both techniques for characterization of glycated SC have been carried out. Thus, the aim of this work was to compare the type of information that can be derived from the spectra of both MALDI-MS and LC-ESI-MS and determine the most suitable technique for the analysis of SC after its glycation via Maillard reaction with galactose and lactose. Following MALDI analyses, the less abundant k- and as2-caseins showed a low response, which impaired the accurate determination of the glycation degree of both proteins. Regarding the major caseins, as1- and b-casein, MALDI-MS spectra of glycated SC were characterized by an unique and broad Gaussian peak shape without good resolution, due to the great heterogeneity of the glycated forms of both caseins. LC-ESI-MS allowed the chromatographic separation of the four casein fractions, either in native or in glycated forms, within only nine minutes. ESI mass spectra were recorded in the negative ion mode due to the high content of SC in phosphorylated serine residues. As it occurred for MALDI, as2-casein also showed a low response by ESI, impairing its identification. Nevertheless, ESI-MS spectra corresponding to the unglycated and glycated forms of as1-, b- and k-casein were characterized by multiply charged molecular ions which allowed their identification, providing an accurate estimation of the number of carbohydrate molecules attached to each casein fraction. In conclusion, LC-ESI-MS was found to be a more efficient technique than MALDI-MS to determine the degree of glycation of SC.This work was supported by projects Consolider Ingenio 2010 FUN-C-FOOD CSD2007-00063 (MICINN) and ALIBIRD S2009/AGR-1469 (CAM). M. Corzo-Martínez thanks the CSIC for an I3P PhD-grant.Peer Reviewe

Transglycosylation of Steviol Glycosides and Rebaudioside A: Synthesis Optimization, Structural Analysis and Sensory Profiles

To improve flavor profiles, three cyclodextrin glucosyltransferases (CGTases) from different bacteriological sources, Paenibacillus macerans, Geobacillus sp. and Thermoanaerobacter sp., were used with an extract of steviol glycosides (SVglys) and rebaudioside A (RebA) as acceptor substrates in two parallel sets of reactions. A central composite experimental design was employed to maximize the concentration of glucosylated species synthesized, considering temperature, pH, time of reaction, enzymatic activity, maltodextrin concentration and SVglys/RebA concentration as experimental factors, together with their interactions. Liquid chromatography coupled to a diode-array detector (LC-DAD), liquid chromatography-mass spectrometry (LC-ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) were used to characterize and identify the chemical structures obtained along the optimization. To assess the impact on the sensory properties, a sensory analysis was carried out with a group of panelists that evaluated up to 16 sensorial attributes. CGTase transglucosylation of the C-13 and/or C-19 led to the addition of up to 11 glucose units to the steviol aglycone, which meant the achievement of enhanced sensory profiles due to a diminution of bitterness and licorice appreciations. The outcome herein obtained supposes the development of new potential alternatives to replace free sugars with low-calorie sweeteners with added health benefits.This research was funded by Optibiotix Health PLC (York, UK), by the Spanish Ministry of Science, Innovation and Universities (projects AGL2017-84614-C2-1-R) and by FEDER-Spanish Ministry of Science and Innovation (Project RTI2018-101273-J-I00).Peer reviewe

Poly(<i>ε</i>-caprolactone) Diols (HOPCLOH) and Their Poly(ester-urethanes) (PEUs): The Effect of Linear Aliphatic Diols [HO–(CH₂)_<i>m</i>–OH] as Initiators

<p><i>α</i>,ω-Hydroxy telechelic poly(<i>ε</i>-caprolactones) were prepared by ring-opening polymerization of the <i>ε</i>-caprolactone catalyzed by ammonium decamolybdate in the presence of different aliphatic diols [HO–(CH₂)_<i>m</i>–OH, where <i>m</i> = 2, 4, 6, 8, 10, 12, 14, and 16] as initiators to obtain a family of <i>α</i>,ω-hydroxy telechelic poly(<i>ε</i>-caprolactone) [HO–PCL–O–(CH₂)_<i>m</i>–O–PCL–OH, <i>m</i> = 2, 4, 6, 8, 10, 12, 14, and 16]. The content of the alkyl group (AG) (–(CH₂)_<i>m</i>–) had an important effect on the crystallinity (<i>x</i>_i) of <i>α</i>,ω-hydroxy telechelic poly(<i>ε</i>-caprolactone), showing a proportional relationship. In poly(ester-urethanes) derived from <i>α</i>,ω-hydroxy telechelic poly(<i>ε</i>-caprolactones) and 1,6-hexamethylene diisocyanate, the AG also showed a similar effect on the <i>x</i>_i and eventually on the mechanical properties, increasing the values of the modulus. Therefore, AG content was a factor to induce a plastic behavior in poly(ester-urethanes). The effect of AG on the water uptake of poly(ester-urethanes) after 1 week was negligible.</p