Cake Flour Chlorination and Alternative Treatments (Review)

In order to produce satisfactory cake, ingredients must be balanced accurately. Flour acts as building structure that contributes in the crumb properties. Chlorine treatment of soft wheat flour has been widely used since the 1920s. The functional effect of chlorination is partially de-polymerizing and oxidizing of flour starch. Oxidized starch granules are able to swell more rapidly after the starch reaches the gelatinization temperature and the resulting batter system will be adequately viscous to support the cake’s structure without collapsing. Batter expansion is superior for treated flours, even at the lowest chlorination rate, than for untreated flour. Alternatives to chlorine treatment need to be developed because of the potential carcinogenic effect of chlorination. Egg albumin contributes strength to cake crumb and improves cake volume. Acceptable cake volume can be achieved by heating but the dryer, stiffer crumb that springs back upon compression is not produced by heated flours. Xanthan gum L-cysteine, and hydrogen peroxide plus peroxidase to heat-treated flour and obtained volumes equivalent to cakes produced using chlorine-treated flour. Ozone treatments also are applied in cake flour with some benefits instead of chlorination.

Modeling bromide effects on the speciation of trihalomethanes formation in chlorinated drinking water

Speciation behavior of trihalomethanes formation in chlorinated waters due to the effects of bromide is mathematically modeled by a three-tier scheme. Equations for the mole fractions of the mono-, di-, and trihalo-intermediates at each tier level in terms of the initial bromide to chlorine molar ratio are derived and verified by comparison with results of other theoretical studies based on an assumption of constant bromination to chlorination reaction reactivity ratio. It is identified that the usage of applied chlorine concentration or available chlorine concentration for calculation of the relative initial bromide to chlorine concentration would yield different reactivity ratio and should be used consistently. The model equations are also tested by laboratory experiments done with source water at a local plant. It is found that equations with an overall bromination to chlorination rate constant ratio of 18.66 can capture the THM speciation behavior of all four tested incubation periods well.

Recovery of Niobium from Baogang Tailings by Carbochlorination

Carbochlorination of niobium in the tailings of Baogang concentrator was experimentally studied, and the activated carbon was used as the reducing agent and chlorine gas as the chlorinating agent. The effects of the reaction time and the temperature on chlorination rate of niobium in tailings were investigated. The result showed that when the tailings were chlorinated at 800 for 2 h,96.15% of niobium was yield.

NADPH as a co-substrate for studies of the chlorinating activity of myeloperoxidase

The reinvestigation of the kinetics of myeloperoxidase (MPO) activity with the use of NADPH as a probe has allowed us to determine the effects of H2O2, Cl- ion and pH on the MPO-dependent production of HOCl. The chlorination rate of NADPH did not depend on NADPH concentration and was entirely related to the rate of production of HOCl by MPO. The overall oxidation of NADPH occurred similarly in the absence of O2 and was insensitive to scavengers of the superoxide radical anion. Experiments performed on the direct oxidation of NADPH by MPO in the presence and the absence of H2O2 showed that neither the rate nor the stoichiometry of the reaction could interfere in the NADPH oxidation process involved in the steady-state chlorination cycle. The oxidation of NADPH was characterized by a decrease in the A339 of the reduced nicotinamide with the concomitant appearance of a new chomophore with absorbance maximum at 274 nm, characterized by isosbestic points at 300 and 238 nm. The reaction product did not possess any enzymic properties with dehydrogenases and led to a metabolite other than NADP+. Its amount accounted for a stoichiometric conversion of H2O2 into HOCl. Analyses of the NADPH reaction allowed the determination of both kinetic (kcat and Km) and thermodynamic (Kd) parameters. When the values of kinetic parameters were compared with previously published ones, the main discrepancy was found with data obtained with the chlorination of monochlorodimedon and a better agreement with diethanolchloramine formation or H2O2 consumption. Variations in the extent of NADPH oxidation with Cl- concentration enabled us to determine the dissociation constant for the enzyme-Cl- complex. In the course of titration studies, the spectral properties of NADPH reacting with either HOCl or the MPO/H2O2/Cl- system were quantitatively similar in terms of stoichiometry and absorbance coefficient and thus led to identical chlorinated products. However, no spectral modification occurred with NADP+ and adenine nucleotide analogues under the same conditions. A quantitative comparison of difference spectra obtained with NADPH and NMNH indicated that chlorination occurred on the nicotinamide part of the molecule.