•Caramelization & Maillard paths were clarified for glucose and leucine as precursors.•12 markers were measured quantitatively in a model cake versus baking time.•Kinetic data consolidated the ...reaction scheme.•The impact of temperature, convection and formula on the reactions was studied.•The importance of isomerization of glucose to fructose was highlighted.
Understanding the mechanisms leading to the multitude of newly–formed compounds generated during the thermal processing of food is important for the reasoned construction of quality. Thanks to a solid food model with a structure and technological history comparable to that of a real sponge cake and containing only known amounts of precursors (glucose with or without leucine), an adapted reaction scheme unravelling Maillard and caramelization reactions was built and then compared to experimental kinetic data measured on numerous reaction markers (precursors, α–dicarbonyl intermediates and furanic compounds). For caramelization, this study showed that glucose mainly formed 1,2–enediol and then fructose rather than glucosone and glyoxal. 5–hydroxymethylfurfural started to form when there were sufficient quantities of fructose, and 3,4–dideoxyoglucosone was not generated until after this step. Furfural was mainly formed via 3–deoxyglucosone. The involvement of leucine tended to accelerate the breakdown of sugars as more degradation pathways (via enaminols) were added.
The use of standards for the measurement of photoluminescence quantum yields (QYs) in dilute solutions is reviewed. Only three standards can be considered well established. Another group of six ...standards has been investigated by several independent researchers. A large group of standards is frequently used in recent literature, but the validity of these is less certain. The needs for future development comprise: (i) confirmation of the validity of the QY values of many commonly used standard materials, preferably in the form of SI traceable standards; (ii) extension of the set of standard materials to the UV and near-IR spectral ranges; and (iii) good standards or robust protocols for the measurements of low QYs.
This recommendation proposes a definition for the term “chalcogen bond”; it is recommended the term is used to designate the specific subset of inter- and intramolecular interactions formed by ...chalcogen atoms wherein the Group 16 element is the electrophilic site.
The history of the IUPAC Photochemistry Committee since its creation in 1976 and its transition in 2001 to the IUPAC Photochemistry Sub-Committee are reviewed as well as the connections of Committee ...and Sub-Committee to the various photochemical associations (
uropean
hotochemical
ssociation,
,
nter-
merican
hotochemical
ociety,
and
sian and Oceanian
hotochemistry
ssociation,
). The participants in both the Commission and the Sub-Committee over the years are listed as well as the Recommendations and Technical Reports produced since the creation of the Committee until the present days.
•Photo-reduction of 4-Chloro-2-methylphenoxyacetic acid (MCPA) by UV/Sulfite reduction process is the subject of this study.•MCPA decomposed to simple and detoxified such as C5H8O3, C5H10O and ...C6H8.•zone inhibition surrounding reduced from 31 mm (without treatment) to 5 mm after treatment.•When MCPA concentration increase from 50 to 200. mg L−1, Kobs and robs decreased from 0.299 to 0.029 min−1 and 14.95 to 5.80 mg L−1, respectively.•With the increase in the concentration of MCPA from 50 to 200 mg L−1, the amount of EEO from 0.821 to 6.54 kwh.m−3
This study focuses on the MCPA reduction in sulfite excitation under UV irradiation (US process). After 20 min of reaction time, the ideal pH was 11, and the MCPA: sulfite molar ratio was 3:1. in the PFO kinetic model kobs and robs, range, reach 0. 299 to 0. 029 min−1 and 14.95 to 5.80 mgL−1. Additionally, kinetics and IUPAC methods were used to calculate EEO, which demonstrates that EEO increases from 1.54 to 8.02 kWh as MCPA concentration rises from 50 to 200 mg L−1. m− 3. In order to study intermediate products and the decomposition of MCPA, LC-MS was used and intermediates were detected include C5H8O3 and C5H10O and C6H8. These basic substances have a lot of potential to transform into carbon dioxide and water. Before treatment, the inhibition zone was 39 mm; after 30 min of reaction time, it decreased to 11.4 mm. The reduction in bacterial growth inhibition and intermediate production is evidence that the US process causes effluent environmental toxicity. The US process produces effluent toxicity to the environment, as evidenced by the decrease in bacterial growth inhibition and intermediates production. The US process produces decreasing effluent toxicity to the environment, as evidenced by the decrease in bacterial growth inhibition and intermediates production.
This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into ...four sections – precursors, gels, solids, and processes – and the terms have been restricted to those most commonly encountered. For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas.
Procedures for the determination of photoluminescence quantum yields with optical
methods are addressed, and challenges associated with these measurements are
discussed. Special emphasis is dedicated ...to relative measurements of fluorescent
(i.e., short excited-state lifetime), transparent, dilute dye solutions in
conventional cuvettes in a 0°/90° measurement geometry.
Recommendations on the selection of suitable quantum yield standards are
presented, and requirements for the documentation of photoluminescence quantum
yields are derived.
This recommendation proposes a definition for the term “pnictogen bond”; the term pnictogen bond designates a subset of the attractive interactions between an
region on a
atom in a
and a
region in ...another, or the same, molecular entity.
This glossary of terms covers phenomena considered under the very wide terms
and
. A clear distinction is made between phenomena related to either photochemistry and photocatalysis or radiation ...chemistry and radiation catalysis. The term “radiation” is used here as embracing electromagnetic radiation of all wavelengths, but in general excluding fast-moving particles. Consistent definitions are given of terms in the areas mentioned above, as well as definitions of the most important parameters used for the quantitative description of the phenomena. Terms related to the up-scaling of photocatalytic processes for industrial applications have been included. This Glossary should be used together with the
, 3
edition, IUPAC Recommendations 2006: (doi:10.1351/pac200779030293) as well as with the
, 2
ed. (the “Gold Book”, 2006– doi:10.1351/goldbook) because many terms used in photocatalysis are defined in these documents.
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