An evaluation of the brewing attributes of maize (Zea mays )

An evaluation of the brewing attributes of maize was investigated, with the aim of providing the best substitute for barley which is an expensive and scarce ingredient in brewing industry, particularly in the tropics. White maize kernels (sourced from Minna central market, Nigeria) were malted to activate amylase enzymes in the grains, and the malted grains were subjected to non enzymatic mashing process. Analysis of the selected physico-chemical parameters of the resulting samples were carried out using standard analytical methods. The malting analysis showed that maize has 98 % germinative power, 99.0 % germinative capacity and 0.91 % per hour water uptake characteristics. The maize malt was found to have moisture content of 8.05 %, a diastatic power of 28.2 oLintner , crude protein of 10.03 %, fat (ether extract) content of 1.82 %, malting loss of 4.02 %, nitrogen content of 1.7 %, and carbohydrate content of 80.07 %. On mashing, analysis of the wort obtained shows that it has the following characteristics; good clarity, pH of 5.61, colour of 8.5 EBC, gravity of 4.15 oPlato, humid and dry extract yields of 35 % and 38 % respectively. The study revealed that maize is endowed with good brewing attributes, and can be substituted for barley effectively, but requires the use of external source of amylase enzymes as supplement to its enzymatic power; and a reduction of the malted maize moisture content to curb slack characteristics.Keywords: Brewering, attributes, maiz

Characterization of Al2O3–ZrO2 Mixed Oxide Supported Mo Hydrotreating Catalyst

A series of molybdenum catalysts supported on Al2O3–ZrO2 mixed oxide containing 50% ZrO2 and 50% Al2O3 were prepared by incipient wetness technique and characterized by BET surface area, X-ray diffraction, temperature programmed reduction and oxygen chemisorption. The catalytic activities for hydrodesulphurization (HDS), hydrogenation (HYD), and hydrocracking (HYC) were determined using thiophene, cyclohexene, and cumene as model compounds, respectively. Results indicate that up to 8wt% Mo loading, the catalyst is well dispersed and crystallite growth occurre

Optimization of a two stage process for biodiesel production from shea butter using response surface methodology

The challenges of biodiesel production from high free fatty acid (FFA) shea butter (SB) necessitated this study. The reduction of %FFA of SB by esterification and its subsequent utilization by transesterification for biodiesel production in a two stage process for optimization studies was investigated using response surface methodology based on a central composite design (CCD). Four operating conditions were investigated to reduce the %FFA of SB and increase the %yield of shea biodiesel (SBD). The operating conditions were temperature (40–60°C), agitation speed (200–1400 rpm), methanol (MeOH): oil mole ratio: 2:1–6:1 (w/w) for esterification and 4:1–8:1 (w/w) for transesterification and catalyst loading: 1–2% (H2SO4, (v/v) for esterification and KOH, (w/w) for transesterification. The significance of the parameters obtained in linear and non-linear form from the models were determined using analysis of variance (ANOVA). The optimal operating conditions that gave minimum FFA of 0.26% were 52.19°C, 200 rpm, 2:1 (w/w) and 1.5% (v/v), while those that gave maximum yield of 92.16% SBD were 40°C, 800 rpm, 7:1 (w/w) and 1% (w/w). The p-value of <0.0001 for each of the stages showed that the models were significant with R2 of 0.96 each. These results indicate the reproducibility of the models and showed that the RSM is suitable to optimize the esterification and transesterification of SB for SBD production. Therefore, RSM is a useful tool that can be employed in industrial scale production of SBD from high FFA SB

Comparative kinetic studies of delignification of sugarcane bagasse using Hydrogen Peroxide and Sodium Hydroxide

Delignification kinetics of sugarcane bagasse by hydrogen peroxide and sodium hydroxide were studied and results compared. A reactor equipped with pH and temperature controls was used to study effects of de-lignifying agent concentration (3 and 6%), bagasse particle diameter (0.3, 0.6 and 1.2 mm), temperature (30, 40, and 50 oC) and pH (8, 9, 10 and 11) on de-lignification of sugarcane bagasse over 48 h period. A pseudo-first order kinetics of 64.4 kJ/mol and 44.04 kJ/mol activation energies were found to represent delignification kinetics using hydrogen peroxide and sodium hydroxide respectively. Statistical analysis of the experimental and predicted results using MathCard software to simulate model equation for degree of delignification indicated positive correlations (0.874-0.993) for both hydrogen peroxide and sodium hydroxide. Results showed increase degree of delignification with temperature and pH values. Treatments using 0.3 mm diameter showed increase de-lignification compared with those for 0.6 and 1.2 mm diameters indicating pore diffusion limitation at larger particle sizes. Maximum degree of de-lignification of 62.2% was obtained at 50 oC and pH 11 using 0.3 mm particle diameter after 48 h treatment with 6% sodium hydroxide. Hence, the derived model predicts degree of delignification of bagasse using these agents with high accuracy.Key words: Sugarcane bagasse, De-lignification, Sodium hydroxide, Reaction mode

Characterization of ZrO2 - Al2O3 mixed oxides support prepared by urea hydrolysis

The characteristics of Al2O3 , ZrO2 and three binary mixtures of ZrO2 -Al2O3 were studied by determining their BET surface areas, micropore surface area, total pore volume, adsorption-desorption isotherms, the X-ray diffractogram, surface acidity and catalytic functionality for cumene cracking. The XRD results show that the incorporation of alumina into the zirconia from 50% and beyond renders it amorphous. Furthermore, the mixed oxide containing 50% alumina and 50% zirconia had the highest BET surface area of 199.9 m2/g whilst pure zirconia had the lowest BET surface area of 37.19 m2/g. The pores for all the mixed oxides were found to be monomodal and zirconia pores were more open. The results of the acidity measurements and cumene cracking functionality indicates that whilst pure zirconia has low total acidity, the incorporation of alumina increases its acidity through a synergistic effect. Keywords: ZrO2- Al2O3 , suppor

Temperature-programmed reduction and acidic properties of molybdenum supported on MgO–Al2O3 and their correlation with catalytic activity

Aseries of catalyst withMoloading from 2 to 14 wt.% on MgO–Al2O3 mixed oxide supportwas prepared by incipient wetness impregnation method. Pure MgO and Al2O3 were prepared by using Mg(NO3)2·6H2O and Al(NO3)3·9H2O salt solutions and urea as hydrolyzing agent. MgO–Al2O3 (1:1) mixed oxide was prepared by co-precipitation of appropriate quantities of magnesium nitrate and aluminum nitrate salts. BET surface area, pore volume, pore size distribution, TPR, acidity and acid strength distributions of catalysts and supports were measured. MgO–Al2O3 (1:1) mixed oxide showed a biomodal pore size distribution. LTOCand TPR results showthat an optimum8%Moon MgO–Al2O3 is sufficient to form MoO3 monolayer. TPR technique can also be used as a vital tool to determine the monolayer coverage. HDS activity has been correlated with LTOC. Introduction of basic MgO in the lattice of Al2O3 moderates the strong acidity in MgO–Al2O3. Impregnation of acidic MoO3 species further enhances the acidity favorable for HYC. Keywords: TPR; Acidity; Mixed oxides; Catalytic activit