Raymond Brouillard

Bio: Raymond Brouillard is an academic researcher from University of Paris. The author has contributed to research in topics: Temperature jump. The author has an hindex of 1, co-authored 2 publications receiving 112 citations.

Relaxation Amplitudes in Concentration Jump Experiments. Application to Anthocyanins

Abstract: The calculation of relaxation amplitudes by temperature jump is complex, except for very simple systems of the type A ⇋ B or A + B ⇋ C.1This is unlike their calculation by concentration jump, since, in this case, the perturbation occurs at constant Τ and P, and the equilibrium constants remain unchanged. Moreover, we show in this paper, that by proper use of the concentration jump method, one is able to measure the equilibrium constants of complicated as well as simple chemical systems. Whenever possible, the perturbation should be performed by rapidly modifying the concentration of a species that is characteristic of the type of reaction studied: H+ or OH- for proton transfer, nucleophile for nucleophilic addition or substitution, etc... Thus, one can always write \( \sum\limits_k {\left[ {{X_k}} \right]} (t) = {C_o} \), where Xk represents the different chemical forms that can be adopted by the compound studied. C0 is the analytical concentration. To calculate the relaxation amplitudes, it suffices to set up the following relationships: Aj. = [Xi]j. - [Xi]|j-1., where Aj is the amplitude at the ith mode of relaxation, and X. represents a species involved in the jth mode of relaxation but not in any faster one.

Effect of thermal processing on anthocyanin stability in foods; mechanisms and kinetics of degradation

Abstract: Anthocyanins are the most abundant flavonoid constituents of fruits and vegetables. The conjugated bonds in their structures, which absorb light at about 500 nm, are the basis for the red, blue and purple colours of fruits, vegetables and their products. Anthocyanin pigments readily degrade during thermal processing which can have a dramatic impact on colour quality and may also affect nutritional properties. This review attempts to summarize some important aspects of anthocyanin degradation during thermal processing. Conclusions regarding the mechanisms and kinetics of anthocyanin degradation during heat treatment are postulated based on current findings.

Food colorants: Anthocyanins

Abstract: Interest in food colorants as shown by the number of patents has doubled in recent years with natural pigments outnumbering synthetics by five to one The natural colorant area can be subdivided into anthocyanins, betalains, chlorophylls, carotenoids, flavonoids, polyphenols, Monascus, hemes, quinones, biliproteins, safflower, turmeric, and miscellaneous All involve different groups of chemical compounds which may be used directly as colorants, or may be chemically modified to produce different hues or increased stability All usually involve a method of collection, extraction, purification, possibly stabilization, and formulation A variety of hues can be obtained ranging from green through yellow, orange, red, blue, and violet, depending on the source of colorant Similarly, water or oil‐soluble formulations can be prepared depending on the type of colorant