FTIR Fingerprint Research Articles

Antifungal mechanism of cinnamaldehyde and citral combination against Penicillium expansum based on FT-IR fingerprint, plasma membrane, oxidative stress and volatile profile.

Cinnamaldehyde (Cin) and citral (Cit) have been studied as antimicrobial agents and natural preservatives, but their action modes are controversial, and the knowledge of their antifungal mechanism against P. expansum is still incomplete. The present study was conducted to evaluate the antifungal mechanism of the combination of Cin and Cit (Cin/Cit) against P. expansum by observing the cellular ultrastructure, fourier transform infrared spectroscopy (FT-IR) fingerprints, plasma membrane, oxidative stress and volatile profile. Cin/Cit caused membrane invaginations, organelles and cytoplasm destruction, as shown by transmission electron microscopy (TEM) observations. The FT-IR spectra and followed principle component analysis (PCA) presented the significant differences in chemical compounds, particularly phospholipid, protein and fatty acids of cells exposed to Cin/Cit. Compared to controls, Cin/Cit induced a decrease of ergosterol by 39.40%, an increase of unsaturated fatty acid, and protein release level (3.5 times). Besides, membrane damage was further verified through the reduction of the membrane integrity by using a flow cytometer. Moreover, the increase of malondialdehyde (MDA) (40.09%) and reactive oxygen species (ROS) accumulation indicated an induction of oxidative stress in cells by Cin/Cit. To resist the unfavorable stress caused by Cin/Cit, P. expansum metabolized Cin or Cit to the predominant detoxification compounds, cinnamic alcohol, nerol, and geraniol. The alterations in volatile profile demonstrated the influences on specific metabolisms in P. expansum caused by Cin/Cit.

The chemical fingerprint of hair melanosomes by infrared nano-spectroscopy.

In situ characterization of the chemical and structural properties of black and white sheep hair was performed with a spatial resolution of 25 nm using infrared nano-spectroscopy. Comparing data sets from two types of hair allowed us to isolate the keratin FTIR fingerprint and so mark off chemical properties of the hair's melanosomes. From a polarization sensitive analysis of the nano-FTIR spectra, we showed that keratin intermediate filaments (IFs) present anisotropic molecular ordering. In stark contrast with white hair which does not contain melanosomes, in black hair, we spatially resolved single melanosomes and achieved unprecedented assignment of the vibrational modes of pheomelanin and eumelanin. The in situ experiment presented here avoids harsh chemical extractive methods used in previous studies. Our findings offer a basis for a better understanding of the keratin chemical and structural packing in different hair phenotypes as well as the involvement of melanosomes in hair color and biological functionality.

Structural studies of the arabinogalactans in Mangifera indica L. fruit exudate

The arabinogalactan of ‘Nam Dokmai’ mango (Mangifera indica L.) fruit exudate was studied to elucidate major structural characteristics in comparison with commercially available type-II-arabinogalactans from acacia (gum arabic) and larch wood. From the latter two, the purified polysaccharide was distinguished by its FTIR, 1H NMR, and 13C NMR spectra and its strikingly low polydispersity around a peak molecular weight of ∼22,000. As regards carbohydrate composition and FTIR fingerprint, it ranged between the two comparison samples. The molar ratio of its major components galactose, arabinose, rhamnose, and glucuronic acid was 84:9:4:4. In the FTIR spectra, absorbance maxima ascribed to β-galactans (1076–1070 cm−1) and arabinans (1043–1032 cm−1) always predominated, but their ratios differed. 2D NMR analyses of the purified mango fruit exudate polymer revealed 11 components, including the (1→3)-linked and the (1→6)-linked β-galactopyranosyl residues of type-II-arabinogalactans. α-Arabinofuranosyl moieties, α-l-rhamnopyranosyl-(1→4)–β-glucopyranosyluronic acid, and 4-O-methyl-β-glucopyranosyluronic acid were on terminal positions. Unlike the comparison samples and various Anacardiaceae tree exudate gums, this polysaccharide had internal (1→6)-linked β-galactopyranosyl residues in abundance and internal β-arabinofuranosyl units besides a remarkable number of different α-arabinofuranosyl moieties. Its higher sensitivity to partial acid hydrolysis, which left polymeric glucuronogalactan fragments (overall molar galactose/glucuronic acid ratio: 97:3) within a broad molecular-weight range, suggested greater accessibility to internal cleavage of this polymer. 2D NMR showed these fragments to contain β-glucopyranosyluronic acid and its 4-O-methyl derivative terminally, besides the aforesaid internal β-galactopyranosyl moieties. The still prevalent (1→6)-linked β-galactopyranosyl units and limited increase in terminal β-galactopyranosyl residues indicated longer β-1,6-galactan sequences compared to larch gum.

Application of FTIR spectroscopy to the characterization of archeological wood

Two archeological wood samples were studied by attenuated total reflectance Fourier transform infrared (FTIR–ATR) spectroscopy. They originate from a shipwreck in Ribadeo Bay in the northwest of Spain and from a beam wood of an old nave of the Cathedral of Segovia in the central Spain. Principal component analysis was applied to the transposed data matrix (samples as columns and spectral bands as rows) of 43 recorded spectra (18 in the shipwreck and 25 in the beam wood). The results showed differences between the two samples, with a larger proportion of carbohydrates and smaller proportion of lignin in the beam than in the shipwreck wood. Within the beam wood, lignin content was significantly lower in the recent than the old tree rings (P=0.005). These variations can be attributed to species differences between the two woods (oak and pine respectively), with a mixture of guaiacyl and syringyl in hardwood lignin, whereas softwood lignin consists almost exclusively of guaiacyl moieties. The influence of environmental conditions on the FTIR fingerprint was probably reflected by enhanced oxidation of lignin in aerated conditions (beam wood) and hydrolysis of carbohydrates in submerged-anoxic conditions (shipwreck wood). Molecular characterization by analytical pyrolysis of selected samples from each wood type confirmed the interpretation of the mechanisms behind the variability in wood composition obtained by the FTIR–ATR.

Monitoring the Evolution of Major Chemical Compound in Dairy Products During Shelf-Life by FTIR

Fourier-transform infrared (FTIR) spectroscopy is considered to be a comprehensive and sensitive method to characterize the chemical composition and for detection of molecular changes in different samples. In this study, FTIRspectroscopy was employed as an rapid and low-cost technique in order to characterize the FTIR spectra and identify appropriate spectral regions for dairy product fermented by a lactic culture consisting by species of Lactococcus lactis and Leuconostoc mesenteroides . A second objective was to monitore the key chemical compounds (lactose, lactic acid, flavors) during fermentation and refrigerated storage (1-21 days, at 4-6°C). By FT-IR fingerprint during fermentation we identified changes of the spectra pattern with specific increasing or decreasing peaks for lactose, lactic acid, esters, aromatic compounds, aminoacids, fatty acids. Also the technique was able to identify chemical compounds involved in the microbial activity such as phosphates and phosphorylated carbohydrates during fermentation and dairy product shelf-life. All the major chemical compounds recorded significant increaments during fermentation and refrigerated storage comparing with the raw milk.

Liquid Hydrocarbon Production Potential of a Novel Strain of the Microalga Botryococcus braunii: Assessing the Reliability of in Situ Hydrocarbon Recovery by Wet Process Solvent Extraction

Botryococcus braunii is considered a promising source of non-oxygenated liquid biofuels. Harvesting and pre-extraction processing of the algal biomass are among the major challenges for commercial sustainability of algae-based biofuel production. An energy-efficient and cost-effective method of in situ recovery of the hydrocarbon-rich oil from the harvest aqueous culture of B. braunii without pre-extraction processing is an attractive proposition. In this study, in situ recovery of lipid-hydrocarbons by wet process solvent extraction (WPSE) was assessed using the harvest aqueous culture of a novel strain B. braunii GUBIOTJTBB1. The strain yielded 56.3% (w/w) total lipids, 42.6% of which was Soxhlet n-hexane extractable. The recovery of lipid contents was found to vary significantly (P < 0.001) with the extraction solvent. Fractionation of the total lipids using silica gel column chromatography with n-hexane as eluent yielded lipids (24.9%), which revealed the presence of mostly aliphatic hydrocarbons by GC-MS analysis. In situ recovery rate of the hydrocarbon-rich oil by WPSE, which varies significantly (P < 0.05) with the method of pretreatments, was the maximum (88.99%) with autoclave-assisted WPSE followed by microwave-assisted WPSE (80%). Applications of multivariate chemometrics in FTIR fingerprint assessment confirmed the reliability of the method. Besides rapidity and minimizing the use of toxic solvents, the principal fate of the method was on the fact that the hydrocarbon-rich oil could be recovered from the harvest aqueous culture, which circumvents the energy intensive pre-extraction processing of the algal biomass.

Metal analysis and standardization of crude extracts from Nigella sativa seeds and Terminalia chebula fruits

Nigella sativa seeds and Terminalia chebula fruits are the concentrated sources of energy and nutrition and are used by indigenous communities in Pakistan to cure various ailments. Despite their widespread use, by people of all age and income groups, no study exists reporting their metal contents and standardization. Current investigation has been designed to explore their metal contents and to establish their identity profiles by using HPLC chromatograms and FTIR fingerprint studies. HPLC studies indicated 5 and 10 peaks indicating possible presence of different compounds in N. sativa seeds and T. chebula fruits, respectively. Fourteen and ten peaks were identified in FTIR fingerprint analysis of N. sativa seeds and T. chebula fruits, respectively. Metal analysis using atomic absorption spectrometer and flame photometer indicated that investigated extracts contained sufficient amounts of important metals like sodium, calcium and iron. Concentration of most of metals in both extracts was in the optimum level as set by regulatory bodies. Key words: Nigella sativa, Terminalia chebula, FTIR, metal analysis.

Changes in the infrared microspectroscopic characteristics of DNA caused by cationic elements, different base richness and single-stranded form.

BackgroundThe infrared (IR) analysis of dried samples of DNA and DNA-polypeptide complexes is still scarce. Here we have studied the FT-IR profiles of these components to further the understanding of the FT-IR signatures of chromatin and cell nuclei.Methodology/Principal FindingsCalf thymus and salmon testis DNA, and complexes of histone H1, protamine, poly-L-lysine and poly-L-arginine (histone-mimic macromolecules) with DNA were analyzed in an IR microspectroscope equipped with an attenuated total reflection diamond objective and Grams software. Conditions including polypeptides bound to the DNA, DNA base composition, and single-stranded form were found to differently affect the vibrational characteristics of the chemical groups (especially, PO2 −) in the nucleic acid. The antisymmetric stretching (νas) of the DNA PO2 − was greater than the symmetric stretching (νs) of these groups and increased in the polypeptide-DNA complexes. A shift of the νas of the DNA PO2 − to a lower frequency and an increased intensity of this vibration were induced especially by lysine-rich histones. Lysine richness additionally contributed to an increase in the vibrational stretching of the amide I group. Even in simple molecules such as inorganic phosphates, the vibrational characteristics of the phosphate anions were differently affected by different cations. As a result of the optimization of the DNA conformation by binding to arginine-rich polypeptides, enhancements of the vibrational characteristics in the FT-IR fingerprint could be detected. Although different profiles were obtained for the DNA with different base compositions, this situation was no longer verified in the polypeptide-DNA complexes and most likely in isolated chromatin or cell nuclei. However, the νas PO2 −/νs PO2 − ratio could discriminate DNA with different base compositions and DNA in a single-stranded form.Conclusions/SignificanceFT-IR spectral profiles are a valuable tool for establishing the vibrational characteristics of individualized chromatin components, such as DNA and DNA-polypeptide complexes in dried samples.

Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate

The results of a study on the analytical identification and quantification of migration of chemicals from plastics baby bottles found in the European Union market made of materials that are now present as substitutes for polycarbonate (PC) are reported. A total of 449 baby bottles with a focus on first age or sets of bottles were purchased from 26 European Union countries, Canada, Switzerland and the USA. From this collection, which contained several duplicates, a total of 277 baby bottles were analysed. The materials included different types of plastic such as PC, polyamide (PA), polyethersulphone (PES), polypropylene (PP), but also silicone, and from the United States a co-polyester marketed under the trade name Tritan™. The bottles were subjected to the conventional migration test for hot fill conditions, i.e. 2 h at 70°C. The simulant used was that specified in European Union legislation (2007/19/EC) for milk, i.e. 50% ethanol. In a first phase 1, migration was conducted since the scope of this investigation was a screening rather than a true compliance testing check. Second and third migrations were performed on selected articles when migrated substances exceeded limits specified in the legislation. In order to verify some materials, a portion of the bottle was cut to run an FT-IR fingerprint to confirm the nature of the polymer. The migration solutions in general showed a low release of substances. Results showed that bottles made of PP and silicones showed a greater number of substances in the migration solutions and in greater quantity. Chemicals from PP included alkanes, which could be found in >65% of the bottles at levels up to 3500 µg kg−1; and benzene derivatives in 17% of the baby bottles and found at levels up to 113 µg kg−1. Some substances were found on a regular basis such as plasticisers, esters and antioxidants (e.g. tris(2,4-di-tert-butylphenyl)phosphate, known as Irgafos 168. Some substances found were not included in the Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25 µg kg−1, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400 µg kg−1). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene – DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50–150 µg kg−1 and DEHP at levels 25–50 µg kg−1.

Metabolic Activity and Behavior of Lactobacillus Casei During Fermentation and Microencapsulation

The metabolic activity and behavior of Lactobacillus casei were investigated during lactic fermentation and after microencapsulation. L.casei metabolic activity in vitro was investigated by HPLC and Infrared spectrometry (FTIR). Following the fermentation during 78 h, we identified lactic acid (retention time at 4.59 min) and its synthesis to begin after 3h and increasing gradually, up to a productivity of 6.89 mg mL-1 after 78 h. We noticed a high activity in the first 6 hours, and the media was totally consumed before 12 hours. By FT-IR fingerprint during fermentation we identified changes of the spectra pattern, specific increasing peaks of lactic acid (1127 cm-1) during fermentation (from 3 to 78 h) and other specific absorption peaks at 1420 cm-1, 2845 and 2929 cm-1. &#x0D; The comparative behavior of L.casei microencapsulated in different matrices, in simulated gastric and intestinal juice were also studied. L.casei was microencapsulated in sodium alginate (AG), chitosan (CH), alginate: guar gum (AG:GU) and alginate: xanthan gum (AG:XA). The microencapsulation effects on the changes in survival rate of bacteria, during exposure in simulated gastric and intestinal juice were studied. The survivability of the strains, were expressed as the destructive value (decimal reduction time). The alginate beads 2% prevented acid-induced reduction of the cell density in simulated gastric juice, resulting in significant (P

Morphology, FTIR fingerprint and survivability of encapsulated lactic bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) in simulated gastric juice and intestinal juice

SummaryMicroencapsulation of bacteria in hydrocolloid beads is known as a potential way to enhance and protect their survivability in the digestive tract. We encapsulated a mix of two lactic bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) in sodium alginate (AG) and chitosan (CH) matrices. The morphological parameters of beads containing bacteria were comparatively measured. The FTIR fingerprint can discriminate the presence of bacteria into the beads, identifying specific absorption peaks for bacteria located at 1750, 2852 and 2926 cm−1. To check the survivability of bacteria, beads were incubated in simulated gastric juice (pH 1.5) and intestinal juice (pH 7.2) for different periods of time, up to 120 min. The 2% AG beads, better than CH beads, provided best protection of bacterial survivability. Encapsulated mix of S. thermophilus and L. delbrueckii subsp. bulgaricus can behave as a probiotic bacteria, viable, surviving in the simulated gastric and intestinal juice.

HPLC characterization of lactic acid formation and FTIR fingerprint of probiotic bacteria during fermentation processes.

Lactic acid production during growth of several probiotic bacteria (Lactobacillus plantarum, Bifidobacterium infantis, Lactobacillus casei, Bifidobacterium breve and mix of them) in model MRS media has been monitored using HPLC and the bacterial fingerprint was detected using FTIR. FTIR spectroscopy was able to fingerprint the bacteria identify specific markers located at 900-1300 cm-1 (carbohydrates and proteins, nucleic acids from DNA of bacteria), 1300-1900 cm-1 (C=O stretching vibrations) and large band (for water) at 3100-3700 cm-1. HPLC evaluation showed that Lactobacillus plantarum achieved lactic acid concentration (after 78 h of fermentation) close to 6.08g L-1, Bifidobacterium infantis 7.09 g L-1, Lactobacillus casei 6.16 g L-1, Bifidobacterium breve 6.17 g L-1, while mix of them 7.12 g L-1. Pearsons analysis showed that the level of lactic acid in mix of probiotics bacteria was positively and significantly correlated, with lactic acid level of Lactobacillus plantarum (r2=0.965), Bifidobacterium infantis (r2=0.9846), Lactobacillus casei (r2=0.9904), Bifidobacterium breve (r2=0.9958), when P<0.0001.

EFFECT OF GLYCEROL ON PHYSICAL PROPERTIES OF CASSAVA STARCH FILMS

ABSTRACT In this work, the effect of glycerol on the physical properties of edible films were identified by X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared (FTIR) and microwave spectroscopy. According to XRD diffractograms, films with 0 and 15% glycerol displayed an amorphous character, and a tendency to semicrystallization, for films with 30% and 45% glycerol. From DSC thermograms, the glass transition (Tg) of the films decreased with glycerol content. However, two Tgs were observed for samples with 30% and 45% glycerol, due to a phase separation. The intensity and positions of the peaks in FTIR fingerprint region presented slight variations due to new interactions arising between glycerol and biopolymer. Microwave measurements were sensitive to moisture content in the films, due to hydrophilic nature of the glycerol. The effect of plasticizer plays, then, an important rule on the physical and functional properties of these films, for applications in food technology. PRACTICAL APPLICATIONS Edible and/or biodegradable films are thin materials used mainly in food recovering, food packaging and other applications, in substitution of the films obtained by synthetic ways. In view of these applications, these films must satisfy some of the exigencies in order to increase the food shelf-life, or in other words, they must be flexible, transparent, resistant to some gases such as oxygen, as well as resistant to water vapor. The addition of plasticizers alters the functional properties of the films. Thus, the physical characterization of these films becomes fundamental in order to increase their potential use in industry.

Radiation degradation studies of carrageenans

The radiation degradation yield ( G d) of kappa, iota and lambda carrageenans was compared in solid and in 1% aqueous solution in air at ambient temperature. G ds obtained in solid and aqueous form did not vary with the different types of carrageenan. The chemical structural changes of carrageenans were accompanied by appearance of UV absorbance peak at 260 nm and a characteristic FT-IR band at 1728 cm −1. Changes in the FT-IR finger print regions were observed at high doses of the aqueous solution. Radiation-induced desulfation increased the acidity of the carrageenans. The number of reducing end groups increased with dose with greater susceptibility in κ-carrageenan.

The Crystal Chemistry of Ferric Oxyhydroxyapatite

Ferric hydroxyapatites (Fe-HAp) and oxyapatites (Fe-OAp) of nominal composition [Ca(10-x)Fe(x)(3+)][(PO(4))(6)][(OH)(2-x)O(x)] (0 < or = x < or = 0.5) were synthesized from a coprecipitated precursor calcined under flowing nitrogen. The solid solubility of iron was temperature-dependent, varying from x = 0.5 after firing at 600 degrees C to x approximately 0.2 at 1000 degrees C, beyond which Fe-OAp was progressively replaced by tricalcium phosphate (Fe-TCP). Crystal size (13-116 nm) was controlled by iron content and calcination temperature. Ferric iron replaces calcium by two altervalent mechanisms in which carbonate and oxygen are incorporated as counterions. At low iron loadings, carbonate predominantly displaces hydroxyl in the apatite channels (Ca(2+) + OH(-) --> Fe(3+) + CO(3)(2-)), while at higher loadings, "interstitial" oxygen is tenanted in the framework (2Ca(2+) + (vac) --> 2Fe(3+) + O(2+)). Although Fe(3+) is smaller than Ca(2+), the unit cell dilates as iron enters apatite, providing evidence of oxygen injection that converts PO(4) tetrahedra to PO(5) trigonal bipyramids, leading to the crystal chemical formula [Ca(10-x)Fe(x)][(PO(4))(6-x/2)(PO(5))(x/2)][(OH)(2-y)O(2y)] (x < or = 0.5). A discontinuity in unit cell expansion at x approximately 0.2 combined with a substantial reduction of the carbonate FTIR fingerprint shows that oxygen infusion, rather than tunnel hydroxyl displacement, is dominant beyond this loading. This behavior is in contrast to ferrous-fluorapatite where Ca(2+) --> Fe(2+) aliovalent replacement does not require oxygen penetration and the cell volume contracts with iron loading. All of the materials were paramagnetic, but at low iron concentrations, a transition arising from crystallographic modification or a change in spin ordering is observed at 90 K. The excipient behavior of Fe-OAp was superior to that of HAp and may be linked to the crystalline component or mediated by a ubiquitous nondiffracting amorphous phase. Fe-HAp and Fe-OAp are not intrinsically suitable magnetic agents for drug delivery but may be useful in reactive cements that promote osteoblast proliferation.

FT-IR Investigation of Cell Wall Polysaccharides from Cereal Grains. Arabinoxylan Infrared Assignment

The FT-IR fingerprint of wheat endosperm arabinoxylan (AX) was investigated using a set of polysaccharides exhibiting variation of their degree of substitution and xylo-oligosaccharides comprising xylose units mono- or disubstituted by arabinose residues. Substitution of the xylose backbone by arabinose side units was more particularly studied in the 1000-800 cm(-1) spectral region, by taking advantage of second-derivative enhancement. The 920-1020 cm(-1) spectral region revealed two absorption bands at 984 and 958 cm(-1), the intensities of which varied according to the degree of substitution. Whereas the intensity of the band at 958 cm(-1) increased with the degree of substitution, that at 984 cm(-1) decreased. The second-derivative spectral data of xylo-oligosaccharides indicated that these changes could be attributed to substitution of the xylan backbone by arabinose residues, and the band at 958 cm(-1) was ascribed to the presence of disubstituted xylose residues. Principal component analysis of FT-IR spectra of model mixtures of AX, beta-glucans, and arabinogalactans suggested that it is possible to evaluate the relative proportions of the polymers and degree of substitution of AX in complex mixtures such as the cell wall of cereal grains.