Maillard reactions lead to changes in food color, organoleptic properties, protein functionality, and protein digestibility Numerous different strategies for controlling Maillard reactions in foods have been attempted during the past decades In this paper, recent advances in strategies for controlling the Maillard reaction and subsequent downstream reaction products in food systems are critically reviewed The underlying mechanisms at play are presented, strengths and weaknesses of each strategy are discussed, and reasonable reaction mechanisms are proposed to reinforce the evaluations The review includes strategies involving addition of functional ingredients, such as plant polyphenols and vitamins, as well as enzymes The resulting trapping or modification of Maillard targets, reactive intermediates, and advanced glycation endproducts (AGEs) are presented with their potential unwanted side effects Finally, recent advances in processing for control of Maillard reactions are discussed

http://pubs.acs.org/doi/pdf/10.1021/acs.jafc.7b00882

Control of Maillard Reactions in Foods: Strategies and Chemical Mechanisms

Biochar can benefit human society as a carbon-negative material and soil amendment. However, negative biochar impacts on plant germination and growth have been observed, and they have not been fully explained. Therefore, protocols to avoid these risks cannot be proposed. We hypothesized that the free radicals generated during charring may inhibit plant germination and growth. Significant electron paramagnetic resonance (EPR) signals were observed in the biochars derived from several types of common biomass (corn stalk, rice, and wheat straws) and the major biopolymer components of biomass (cellulose and lignin), but not in the original materials, suggesting the ubiquitous presence of free radicals in biochars. EPR signal intensity increased with increasing pyrolysis temperature, and it was dominantly contributed by oxygen centered in the mixture of oxygen- and carbon-centered free radicals as the temperature increased. The free radicals in biochars induced strong ·OH radicals in the aqueous phase. Significant germination inhibition, root and shoot growth retardation and plasma membrane damage were observed for biochars with abundant free radicals. Germination inhibition and plasma membrane damage were not obvious for biochars containing low free radicals, but they were apparent at comparable concentrations of conventional contaminants, such as heavy metals and polyaromatic hydrocarbons. The potential risk and harm of relatively persistent free radicals in biochars must be addressed to apply them safely.

Detecting Free Radicals in Biochars and Determining Their Ability to Inhibit the Germination and Growth of Corn, Wheat and Rice Seedlings

Reactive oxygen species (ROS) generated by environmentally persistent free radicals (EPFRs) of 2-monochlorophenol, associated with CuO/silica particles, were detected using the chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy. Yields of hydroxyl radical (•OH), superoxide anion radical (O2•–), and hydrogen peroxide (H2O2) generated by EPFR–particle systems were reported. Failure to trap superoxide radicals in aqueous solvent, formed from reaction of EPFRs with molecular oxygen, results from fast transformation of the superoxide to hydrogen peroxide. However, formation of superoxide as an intermediate product in hydroxyl radical formation in aprotic solutions of dimethyl sulfoxide (DMSO) and acetonitrile (AcN) was observed. Experiments with superoxide dismutase (SOD) and catalase (CAT) confirmed formation of superoxide and hydrogen peroxide, respectively, in the presence of EPFRs. The large number of hydroxyl radicals formed ...

/pdf/environmentally-persistent-free-radicals-epfrs-1-generation-1835j22uny.pdf

Environmentally Persistent Free Radicals (EPFRs). 1. Generation of Reactive Oxygen Species in Aqueous Solutions

Formation, characteristics, and applications of environmentally persistent free radicals in biochars: A review

Stereochemical aspects of phosphor-1,1-dithiolato metal complexes (dithiophosphates, dithiophosphinates): Coordination patterns, molecular structures and supramolecular associations—I

Identification of irradiation treatment of aromatic herbs, spices and fruits by electron paramagnetic resonance and thermoluminescence.

The purpose of the present review is to collect some results available in the literature in order to focus the attention of the world EPR community and thus to stimulate their activity on solving the problems of quantitative EPR spectrometry.

Quantitative EPR spectrometry — “State of the art”

A new approach for extension of the identification period of irradiated cellulose-containing foodstuffs by EPR spectroscopy

The knowledge about the physico-chemical properties of the stable free radical DPPH as a primary standard for the Quantitative EPR spectrometry is summarized. It is shown how to calibrate DPPH in order to use it as a primary EPR standard for quantitative estimations. It is expected that the reported data will be useful for the EPR community specially in calibration and also for periodical checking of the standards used.

Nicola D. Yordanov

Papers

Identification of irradiation treatment of aromatic herbs, spices and fruits by electron paramagnetic resonance and thermoluminescence.

Quantitative EPR spectrometry — “State of the art”

A new approach for extension of the identification period of irradiated cellulose-containing foodstuffs by EPR spectroscopy

Is our knowledge about the chemical and physical properties of DPPH enough to consider it as a primary standard for quantitative EPR spectrometry

EPR and UV spectral study of gamma-irradiated white and burned sugar, fructose and glucose.