Determination of protein, lipid and sugar contents of bakery products by using Fourier-transform near infrared spectroscopy

The use of Fourier-transform near infrared spectroscopy (FT-NIR) to measure the content of protein, lipid and sugar contents of bakery products was investigated. The samples were dried, homogenized, sieved and measured in the wavelength range of 780–2500 nm. The calibration was based on partial least squares (PLS) regression with cross-validation. The performance of the final model was evaluated according to root mean square of cross-validation (RMSECV), root mean square error of estimation (RMSEE) and the determination coefficient (R2).The developed models use the ranges of 1100–1245 nm and 1590–2600 nm for protein determination, 1330–1840 nm and 2170–2350 nm for lipid, 1400–1630 nm, 2000–2170 nm and 2230–2570 nm for sugar determination, respectively. Protein, lipid and sugar could be determined directly with R2 values of 98.93, 99.07 and 98.81, and RMSECV values of 0.16 m/m%, 0.79 m/m% and 0.28 m/m%, respectively. It can be concluded that FT-NIR spectroscopy can be used for the routine determination of protein, lipid and sugar content of bakery products and it can contribute to the estimation of calorie content in a fast and non-destructive way

Identification of anionic selenium species in Se-rich yeast by electrospray QTOF MS/MS and hybrid linear ion trap/orbitrap MSn

An analytical approach allowing the identification Of unknown selenium metabolites ill selenium-rich yeast was described. Anion-exchange HPLC of the Se-metabolome fraction co-eluting with salts ill size-exclusion chromatography allowed the separation of nine selenium species (excluding isomers and selenate) as monitored by inductively Coupled plasma mass spectrometry (ICP MS). The individual fractions were analyzed by electrospray QTOF MS/MS and hybrid linear ion trap/Orbitrap MSn after sample introduction by reversed-phase nanoHPLC and by hydrophilic interaction LC (HILIC), respectively. Out of the nine detected species. eight were identified oil the basis of accurate mass measurements and collision induced dissociation/fragmentation information. Seven Se-species (selenohomolanthionine, gamma-Glu-selenocystathionine, 2,3-DHP-selenocystathionine, N-acetyl-selenocystathionine, 2,3-DHP-selenohomolanthionine Se-methyl-selenoglutathione, and 2,3-DHP-Se-methylselenocysteine) were reported for the first time in Se-rich yeast. five of them have never been reported in any biological sample before

A sequential extraction procedure for an insight into selenium speciation in garlic

International audienceA sequential extraction procedure was developed for the fractionation of different classes of selenium species present in garlic. The consecutive steps included leaching with water, extraction of cell-wall bound species after lysis with a mixture of cellulase, chitinase and β-glucanase completed by a proteolytic attack, extraction with HCl to liberate the residual organic bound species and finally, extractions with sulfite solution and CS2 to complete the mass balance by the recovery of Se0 and Se2-, respectively. Selenium speciation in the aqueous fractions was probed by anion-exchange and ion-pairing reversed-phase HPLC-ICP MS after purification by preparative size-exclusion LC. It was found to be strongly affected by the sample redox conditions. The peak identity was matched with a mixture of 9 compounds expected to be present in allium plants; electrospray QTOF MS turned out to be unsuccessful. Selenite, selenate and selenomethionine were the dominating species present

Application of FT-NIR spectroscopy on the determination of the fat and protein contents of lyophilized cheeses

Fourier transform near infrared spectroscopy (FT-NIR) has been developed for determining the fat and protein contents of hard, semi-hard and processed cheeses. Multivariate calibration models were carried out by partial least squares (PLS) regression. The diffuse reflection spectra of different type of lyophilized cheeses were measured by FT-NIR analyser in the 800–2500 nm spectral range. The calibration set of 62 samples were validated by leave-oneout cross-validation and by prediction set of 31 samples. The optimal result for fat content (root mean square error of cross-validation (RMSECV)=1.0; R2>=99.1%, PLS factor= 6) was obtained when the spectra were preprocessed by first derivation (FD) combined with multiplicative scatter correction (MSC) and smoothing. The optimal result for protein content (RMSECV=1.4, R2=97.2%, PLS factor=6) was observed when the first derivation combined with straight line subtraction (SLS) and smoothing spectral preprocessing method was applied

Standardless identification of selenocystathionine and its γ-glutamyl derivatives in monkeypot nuts by 3D liquid chromatography with ICP-MS detection followed by nanoHPLC-Q-TOF-MS/MS

International audienceA three-step chromatographic procedure using orthogonal separation mechanisms (size-exclusion, cation-exchange and ion-pairing reversed phase) was developed to purify three low molecular weight selenospecies, including the major compound, from the aqueous extract of monkeypot (Lecythis minor) nuts. The following reversed-phase nanoHPLC-electrospray Q-TOF-MS/MS allowed the formal standardless identification of selenocystathionine and two isoforms of γ-glutamyl-selenocystathionine. This is the first MS and MS/MS-based formal evidence of the presence of these compounds in a biological sample

Analogy in selenium enrichment and selenium speciation between selenized yeast Saccharomyces cerevisiae and Hericium erinaceus (lion's mane mushroom)

International audienceHuman selenium supplementation is vastly dominated by selenized yeasts based products not only due to regulation issues but due to the fact that yeasts convert inorganic selenium into organic forms up to 2000 μg g-1 through a well characterized selenium metabolism. Though both yeasts and the higher mushroom Agaricomycetes belong to the kingdom of fungi, their selenometabolic pathways are different. Agaricomycetes, the most widely researched higher fungi tend to store the excess of selenium in inorganic forms. A sample of Hericium erinaceus (lion's mane mushroom), also belonging to Agaricomycetes, was examined in our study after moderate selenium enrichment from inorganic selenium source. Enzymatic digestion and ion-pairing chromatography coupled to ICP-MS revealed that nearly 50% of the selenium was in organic forms: selenomethionine and Se-methylselenocysteine. To explore the background of this, directed orthogonal chromatographic purification was executed in search for Se-adenosyl compounds, typical for yeast metabolism. After HPLC-ESI-QTOFMS analyses three Se-adenosyl-compounds were identified: Se-methyl-5-selenoadenosine, Se-methyl-5-selenoadenosine-Se-oxide and the previously unreported Se-dimethyl-5-selenonium-adenosine. Two of these species have been linked only to the selenium metabolism of yeasts. The high selenomethionine content and the presence of Se-adenosyl compounds in Hericium erinaceus open the possibility for a functional food alternative to selenized yeast based dietary supplements. © 2015 Elsevier Ltd

The Use of Ion Mobility Mass Spectrometry for Isomer Composition Determination Extracted from Se-Rich Yeast

peer reviewedThe isomer ratio determination of a selenium-containing metabolite produced by Se-rich yeast was performed. Electrospray Ionization and Ion Mobility Mass Spectrometry (IM-MS) were unsuccessfully used in order to resolve the isomers according to their Collisional Cross Section (CCS) difference. The isomer ratio determination of 2,3-dihydroxypropionylselenocystathionine was performed after multidimensional liquid chromatography preconcentration from a water extract of Se-rich yeast using preparative size exclusion, anion exchange and capillary reverse phase columns coupled to IM-MS. 4’-nitrobenzo-15-crown-5 ether, a Selective Shift Reagent (SSR), was added after the last chromatographic dimension in order to specifically increase the CCS of one of the isomers by the formation of a stable host-guest system with the crown-ether . Both isomers were consequently fully resolved by IM-MS and the relative ratio of the isomers was determined: 11-13% and 87-89%. The present data compared favorably with literature to support the analytical strategy despite the lack of authentic standard for method validation. In addition, computational chemistry methods were successfully applied to design the SSR and to support the experimental data

Growth light substantially affects both primary and secondary metabolic processes in Catharanthus roseus plants

Common periwinkle (Catharanthus roseus L.) is an important medicinal plant used by the pharmaceutical industry. The present work aimed to determine the effect of low light intensity on the primary and secondary metabolic processes, using various photosynthesis and targeted and untargeted analytical techniques. Growth light had only limited effects on the photosynthetic electron transport processes, although membrane stability seemed slightly higher in plants growing under higher light conditions. The reduced growth light caused a reduction in certain primary metabolites, including amino acids and sugars, and it also reduced the contents of most of the phenolic compounds investigated in the present experiments. Interestingly, the differences in the growth light caused a much less pronounced difference in the alkaloid contents than that found in the flavonoid contents. However, besides the growth light, genotypic differences, most evident in flower colour, also affected some metabolic processes, including primary and secondary processes