Development of 2D and 3D front face fluorescence spectroscopy for monitoring ultrasound treatment in the removal of pesticides residues from fresh lettuces at the laboratory and pilot scales.

Pesticide residues in vegetables are potentially toxic components to humans and can cause serious health problems. To remove pesticide residues from fresh agricultural products and improve consumer food safety, various pesticide removal methods have been investigated over the past decades. In this study, the effectiveness of laboratory and pilot scale ultrasonic cleaning on the removal of boscalid and pyraclostrobin residues from lettuce was examined.

Impact of storage period and lipid unsaturation on the kinetic of 5-hydroxymethylfurfural and furfural generation in pound cakes.

This work aimed at studying the influence of formulation and storage on the formation of Maillard compounds called 5-hydroxymethylfurfural (HMF) and furfural in pound cakes formulated with rapeseed oil (RO) and palm oil (PO). A progressive humidification of the crust and a dryness of the crumb were observed during storage. Lightness (L*) decreased for both PO and RO pound cakes in crumb as well as crust.

Potentiality of front-face fluorescence and mid-infrared spectroscopies coupled with partial least square regression to predict lipid oxidation in pound cakes during storage.

The potentialities of front-face fluorescence (FFF) and mid-infrared (MIR) spectroscopies coupled with partial least square regression (PLSR) were compared to predict the lipid oxidation of pound cakes. The level of lipid oxidation in pound cakes determined using classical methods showed some changes. Similarly, the fluorescence emission (305-490 nm) and excitation (252-390 nm) spectra and MIR spectra scanned in the 4000-700 cm region showed some changes in pound cakes as a function of both storage time and the type of oil used in the formulation.

Use of front face fluorescence for monitoring lipid oxidation during ageing of cakes.

Front face fluorescence spectroscopy coupled with chemometric tools was used as a useful tool for the monitoring of sponge cakes freshness, produced at the pilot scale, during ageing (i.e. 1, 3, 6, 9, 16, and 20days).

Monitoring changes in sponge cakes during aging by front face fluorescence spectroscopy and instrumental techniques.

In the present study, sponge cakes, produced at the pilot scale, were monitored during aging (i.e., 1, 3, 6, 9, 16, and 20 days) by three different analytical techniques.

Analytical model for site-specific isotope fractionation in 13C during sorption: determination by isotopic 13C NMR spectrometry with vanillin as model compound.

The aim of this study was to conceive a reactive transport model capable of providing quantitative site-specific enrichment factors for fractionation in (13)C isotopic content during sorption. As test compound the model treats vanillin, for which the (13)C isotopic content at natural abundance at each of the 8 carbon positions can be measured by quantitative (13)C nuclear magnetic resonance spectrometry. This technique determines the isotope ratios with a resolution better than ±1‰ (0.

Antibody-Hapten Recognition at the Surface of Functionalized Liposomes Studied by SPR: Steric Hindrance of Pegylated Phospholipids in Stealth Liposomes Prepared for Targeted Radionuclide Delivery.

Targeted PEGylated liposomes could increase the amount of drugs or radionuclides delivered to tumor cells. They show favorable stability and pharmacokinetics, but steric hindrance of the PEG chains can block the binding of the targeting moiety. Here, specific interactions between an antihapten antibody (clone 734, specific for the DTPA-indium complex) and DTPA-indium-tagged liposomes were characterized by surface plasmon resonance (SPR).

Evidence of 13C non-covalent isotope effects obtained by quantitative 13C nuclear magnetic resonance spectroscopy at natural abundance during normal phase liquid chromatography.

Quantitative isotopic (13)C NMR at natural abundance has been used to determine the site-by-site (13)C/(12)C ratios in vanillin and a number of related compounds eluted from silica gel chromatography columns under similar conditions. Head-to-tail isotope fractionation is observed in all compounds at the majority of carbon positions. Furthermore, the site-specific isotope deviations show signatures characteristic of the position and functionality of the substituents present.

Quantitative isotopic 13C nuclear magnetic resonance at natural abundance to probe enzyme reaction mechanisms via site-specific isotope fractionation: the case of the chain-shortening reaction for the bioconversion of ferulic acid to vanillin.

Isotope fractionation is a powerful technique by which to probe the reaction mechanism of enzymes. The effect of a heavy isotope on the reaction energetics can be used to predict transition state architecture and reaction mechanism. In order to examine simultaneously the isotope fractionation in (13)C at multiple sites within the substrate and product molecules without any need for site-selective isotope enrichment, a technique exploiting quantitative isotopic nuclear magnetic resonance (NMR) spectrometry at natural abundance (NAQ-NMR) has been developed.

Accurate quantitative 13C NMR spectroscopy: repeatability over time of site-specific 13C isotope ratio determination.

The stability over time (repeatability) for the determination of site-specific 13C/12C ratios at natural abundance by quantitative 13C NMR spectroscopy has been tested on three probes: enriched bilabeled [1,2-13C2]ethanol; ethanol at natural abundance; and vanillin at natural abundance. It is shown in all three cases that the standard deviation for a series of measurements taken every 2-3 months over periods between 9 and 13 months is equal to or smaller than the standard deviation calculated from 5-10 replicate measurements made on a single sample. The precision which can be achieved using the present analytical 13C NMR protocol is higher than the prerequisite value of 1-2 per thousand for the determination of site-specific 13C/12C ratios at natural abundance (13C-SNIF-NMR).