Effect of wet and dry milling on the functional properties of whole sorghum grain flour and kafirin.

The effect of wet and dry milling on the functional properties of whole sorghum grain flour (SF) and extracted kafirin were assessed. White sorghum landrace was used to prepare two SFs by wet milling (SF1) or dry milling (SF2) and to extract their respective kafirins SK1 and SK2. Protein contents of SK1 and SK2 were 90.07 and 94.23%. Wet milling of SF allowed increasing the oil binding capacity, the least gelling concentration and the instant foam capacity and decreasing the water binding capacity and foam stability. The emulsifying activity index of SF1 and SF2 were in the same range, while emulsion stability was two time higher in SF2. Functional properties of SK1 and SK2 showed an appropriate water binding capacity of 2.20 ± 0.10 and 1.82 ± 0.22 (g water/g dry mater), respectively. Both SK1 and SK2 showed higher oil binding capacity than SF1 and SF2 with no gel and foam formation. The wet milling improved water and oil binding capacities of SK1 by 17 and 5%. The emulsifying activity indexes were approximately similar for SK1 and SK2 with emulsion stability exceeding 60%. Fourier transform infrared spectroscopy of SK1 and SK2 showed that wet milling induced a decrease of α-helical structure and an increase of intermolecular ß-sheet and ß-turns and no change in the anti parallel ß-sheet. This study showed that wet milling could allow extracting kafirin with preserving the most important functional properties of SF and kafirin and could constitute an interesting method for protein recovery and starch isolation.

Determination of the just suspended speed for solid particle in torus reactor.

With the considerable use of pipelines and reactors in the engineering industry, determining the deposition velocity enabling hydraulic transport is of utmost importance. This has been investigated throughout the years, scrupulously in several types of reactors used in water treatment and solid transport. The primary focus has been extended to torus reactors, due to their significant advantage in chemical, biochemical and mixing processes. In the present work, we have studied the solid-liquid suspension in a torus reactor. We elaborated an experimental method based on visual assessment SBAM (Steady Bed Angle Method), which enabled us to analytically determine the just suspended speed 'Njs' at which no solid remains stationary at the bed and further parametrically study the effect of several parameters including solid loadings, particle sizes and densities. The just suspended speed values obtained experimentally have been compared to a modified Zwietering's correlation.

Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide catalyzed by copper oxide.

This work is dedicated to the removal of free cyanide from aqueous solution through oxidation with hydrogen peroxide H2O2 catalyzed by copper oxide nanoparticles. Effects of initial molar ratio [H2O2]0/[CN-]0, catalyst dose, temperature, pH and the catalyst stability on cyanide removal have been investigated. The use of copper oxide has improved the reaction rate showing catalytic activity. The cyanide removal efficiency was increased from 60% to 94% by increasing in the dose of catalyst from 0.5 g/L to 5.0 g/L. Increasing the temperature from 20 °C to 35 °C promotes cyanide removal and the four successive times re-use of catalyst shows good stability. Kinetics of cyanide removal was found to be of pseudo-first-order with respect to cyanide. The rate constants have been determined.

In vitro starch digestion in sorghum flour from Algerian cultivars.

This work aims to evaluate starch digestion in whole sorghum grains. Nine sorghum cultivars were sampled from the Sahara of Algeria. The structural characteristics of sorghum grains were measured. Total starch (TS) varied between 67.67% and 74.82%, digestible starch (DS) between 64.34% and 69.70%, and resistant starch (RS) ranged from 2.55% to 7.98%. The kinetic of starch digestion displayed first-order model. For all sorghum cultivars, starch were digested with different extents, DS at infinite time (D ∞) ranged from 52.58 to 102.13 g/100 g dry starch, while the hydrolysis index (HI) ranged from 41.55% to 76.93% and high average glycemic index (GIavg) ranged from 65.97 to 94.14. The results showed that there are differences in grain quality of Algerian sorghum cultivars. The starch fractions have acceptable nutritional value with good in vitro digestibility characteristics suitable for human health and nutrition.

Algerian pearl millet ( Pennisetum glaucum L.) contains XIP but not TAXI and TLXI type xylanase inhibitors.

An XIP (xylanase inhibiting protein) type xylanase inhibitor was purified from Algerian pearl millet ( Pennisetum glaucum L.) grains and characterized for the first time. Cation exchange and affinity chromatography with immobilized Trichoderma longibrachiatum glycoside hydrolase (GH) family 11 xylanase resulted in electrophoretically pure protein with a molecular mass of 27-29 kDa and a pI value of 6.7. The experimentally determined N-terminal amino acid sequence of the purified XIP protein is 87.5%, identical to that of sorghum ( Sorghum bicolor L.) XIP and 79.2% identical to that of wheat ( Triticum aestivum L.) XIP-I. The biochemical properties of pearl millet XIP are comparable to those described earlier for sorghum XIP, except for the higher specific activity toward a T. longibrachiatum GH family 11 xylanase. On the basis of immunoblot neither TAXI nor TLXI type xylanase inhibitors were detected in pearl millet grains.