ACACIA ATAXACANTHA (BARK): CHEMICAL COMPOSITION AND ANTIBACTERIAL ACTIVITY OF THE EXTRACTS

Objective: The present work aimed to investigate the phytochemical constituents and antibacterial activity of several extracts of Acacia ataxacantha bark on pathogenic microbes. Methods: The phytochemical study was performed using tube test and Thin layer chromatography methods. The growth inhibitory effect and the Minimum Inhibitory Concentration of hexane, dichloromethane, ethyl acetate, methanol and hydroalcolic extracts were determined using the microplate dilution method. Results: Phytochemical screening revealed the presence of alkaloid, tannins, lignan, triterpenoids, anthracene derivatives, flavonoids, saponins and coumarins at different level. The extracts exhibited different effect against the tested bacteria. The minimum inhibitory concentrations of extracts ranged from 325 µg/ml to 5 mg/ml. Ethyl acetate extract was more potent than other extracts with the MIC values of 325 µg/ml against S. aureus and 625 µg/ml against all other tested bacteria. Escherichia coli was resistant to all extracts. Conlusion: These findings suggest that the rich phytochemical content of Acacia ataxacantha and its good antibacterial activity may be responsible for its popular and wide traditional use

Bio-preservative activities of Lactobacillus plantarum strains in fermenting Casssava ‘fufu’

The growth of three pathogens, namely Escherichia coli, Staphylococcus aureus and Salmonella typhii were investigated in fermenting and non-fermenting cassava. The pH of the steeped cassava was also examined during fermentation. Antimicrobial effects of the Lactobacillus plantarum on the pathogens were also determined by agar diffusion method. All the pathogens were inhibited by L. plantarum strains with Staph. aureus having the highest inhibitory zone followed by E. coli and S. thyphii. However, in the fermenting cassava, the pathogens increased in population within the first 36 h of the process and decreased to complete extinction after the 96 h of fermentation. The L. plantarum exhibited high but varying degree of inhibition on the pathogens. The findings justify the bio-preservative roles of lactic acid bacteria in traditional cassava products.Key words: Bio-preservation, Lactobacillus plantarum, fermentation, cassava and pathogens

Activated Charcoal—A Potential Material in Glucoamylase Recovery

The potential of activated charcoal in the purification of fungal glucoamylase was investigated. Various concentrations of activated charcoal (1–4% w/v) were used to concentrate crude glucoamylase from Rhizopus oligosporus at different temperature values (30–50°C). Effects of pH (3.0–6.0) and contact time (0–60 min) on enzyme purification were also monitored. Activated charcoal (3% w/v) gave a 16-fold purification in a single-step purification at 50°C for 20 min and pH 5.5. The result of SDS-PAGE analysis of purified glucoamylase showed two major protein bands with corresponding molecular weight of 36 kDa and 50 kDa. The method is inexpensive, rapid, and simple which could facilitate downstream processing of industrial enzyme

Possibilities of sweet potato [Ipomoea batatas (L.) Lam] value chain upgrading as revealed by physico-chemical composition of ten elites landraces of Benin

Sweet potato is one of the most important food security promoted root crops in the world, especially in sub-Saharan Africa. Unfortunately, the crop is still neglected and underutilized in Benin Republic. To establish baseline data for its better utilization for upgrading its value chain, 10 selected local varieties (01 cream, 02 white, 03 yellow, and 04 orange flesh-colored) were compared for their macro-nutritional composition assessed using standard Association of Official Analytical Chemists (AOAC) procedures and spectrophotometry methods. The results indicate that sweet potato dry matter, protein, fiber, and ash content ranged from 46.11 to 25.9%, 4.09 to 1.97%, 1.81 to 3.00%, and 4.70 to 2.56%, respectively and orange flesh cultivars were found very rich. Pearson correlation analysis of variables revealed that dry mater content is positively correlated with carbohydrate and energy values, but negatively correlated with ash and fiber content, while starch content is strongly correlated with fiber content. Principal component analysis allowed us to classify the sweet potato varieties into 03 varietal groups among which Group 2 (05 varieties) exhibited rich fiber, ash, and protein contents and may be recommended for infant foods formulations. These results constitute important orientation for sweet potato processing chain organization in Benin and for the establishment of future nutrition and breeding programme.Key words: Benin, sweet potato, Ipomoea batatas, nutritional composition, orange flesh cultivar, value chain

Effect of frying treatments on texture and colour parameters of deep fat fried yellow fleshed cassava chips

Effects of frying treatments on texture (hardness) and colour parameters (L, a, b, Delta) during deep fat frying of yellowfleshed cassava root slices (TMS 01/1371) were investigated. Slices (dimension of 40mm × 25mm × 3 mm) were divided into three portions and subjected to vacuum frying (fresh slices) and atmospheric frying (fresh and predried slices) and equivalent thermal driving forces (ETDF) of 60∘C, 70∘C, and 80∘C were maintained during frying. The quality attributes investigated were best preserved in vacuum fried chips. The overall colour change in chips fried under vacuum conditions at 118∘C and 8 min was the least (21.20) compared to fresh and atmospherically predried ones (16.69 and 14.81, resp.). A sharp reduction in the breaking force was obtained for all frying treatments after 8 min and this effect was the least in vacuum fried chips. First-order kinetics modeled the changes in quality attributes for all the temperatures investigated. Rate constants k (min−1) obtained for vacuum frying were almost equal to that of atmospheric frying while activation energies for hardness and colour change were 53.30 and 467.11 KJ/mol, respectively. Quality attributes studied were best preserved during vacuum frying

Adsorption isotherms and thermodynamics properties of water yam flour

Adsorption isotherms of water yam flour were determined by static gravimetric method of saturated salt solutions in the range of water activities between 0.11 and 0.96 and at temperatures of 25, 35 and 45 °C. The experimental sorption data was fitted to five models: Guggenheim-Anderson-De Boer (GAB), Peleg, Iglesias-Chirife, Exponential and Oswin and the differential enthalpy and entropies were determined. Equilibrium moisture contents decreased with increase in temperature at all the water activities studied. Peleg model gave the best fit for the sorption isotherm of water yam flour. Monolayer moisture content values estimated from the GAB-model were found to decrease with increases in temperature. The differential enthalpy and entropy decreased with increases in moisture content. The isokinetic temperature was 371.32 K and the compensation theory was satisfied

Awareness of Cassava Peel Utilization Forms among Cassava Processors in Rural Communities of Southwest, Nigeria

Significant quantities of generated peels are been thrown on dumping sites in southwest, Nigeria thereby constituting a source of environmental pollution. This study assessed the awareness of cassava peel utilization forms among cassava processors in rural communities of southwest, Nigeria. Interview guide was used to elicit information from 200 cassava processors through a multistage sampling technique. Data were analyzed with both descriptive and inferential statistics. Result revealed that majority of the cassava processors were women (76.5%), married (75.0%), and members of cassava processing associations (89.5%) with 73.0% having at least primary education. The mean age and cassava processing experience were 53.01 and 22.76 years respectively. About 23.0% of the processed cassava tubers constituted peels. The study also revealed that 50% of the cassava processors discarded peels as waste, 26% sold generated peels while 24% fed the peels to their livestock. Also 93.5% of the cassava processors were not aware of any cassava peel utilization technology. Chi-square analysis revealed that significant association existed between existing practice on cassava peel utilization (χ2=17.341, p<0.05) and cassava processors’ awareness of cassava peel utilization forms. The study concluded that substantial quantity of peel been generated is discarded as waste due to lack of awareness of cassava peel utilization technologies in the study areas. The study therefore recommended that improved technologies on the utilization of cassava peel should be popularized through result demonstration among cassava processors in southwest, Nigeria

How Reliable is the Cuprates System to Recent Technology?

The emergence of cuprates as a high Tc superconductor gave high hopes in the discovery of a room temperature superconductor. It is almost three decades and the highest critical temperature attained on the cuprates is about 135K. A brief overview was conducted on the progress made so far on the cuprates. A mathematical approach was used to design a formula which could determine the experimental results of critical temperature of versed cuprates superconductors. The result of our findings shows that the possibility of attaining the experimental room temperature cuprates superconductor seems very narrow. The study recommended an elaborate approach on the hybridization of cuprates for future research. Hence, there is possibility of having cuprates with wide engineering applicatio

Mineral and antinutrient content of high quality cassava-tigernut composite flour extruded snack

This study investigated the mineral and antinutrient composition of extruded snack produced from different blends of high quality cassava and tigernut flour. The extruded snacks were produced using a single-screw laboratory extruder at constant feed moisture (27%), screw speed (60 rpm) and barrel temperature (80C). It was observed that the extrudates had higher values for mineral composition (phosphorus, calcium, magnesium, potassium and iron) than the composite flour which showed that extrusion cooking improves the absorption of the minerals. The antinutrient (tannin, phytate, saponin, oxalate, alkaloids and total phenolic) contents of all the flour blends significantly (P < 0.05) increased with tigernut flour inclusion. Extrusion cooking resulted in significant (P < 0.05) reduction in the antinutrients of the extrudates. The study showed that extrusion cooking reduced the antinutritional factors thereby increasing the bioavailabilty of minerals. Also, the minerals were not affected by the extrusion cooking process probably because minerals are heat stable

Influence of synthesis approach on controlled microstructures and photocatalytic properties of ag/agbr-activated carbon composites on visible light degradation of tetracycline

The influence of the synthesis approach (thermal polyol and deposition–precipitation) regarding the dispersion of Ag/AgBr nanoparticles dispersed on activated carbon prepared from chemical impregnated pinecone (TP-AABR-ACK, and DP-AABR-ACK) was studied, to increase their photocatalytic efficiency on the degradation of tetracycline (TC). The physicochemical characterization evidenced the significance of the ACK catalyst promoter in enhancing controlled microstructures (morphologies and particle size distributions), synergistic interface interaction between AABR NPs and the carbonaceous support, and efficient photogenerated charge carriers separation within TPAABR- ACK, and DP-AABR-ACK composites. The results revealed 92% removal of TC within 180 min under the LED visible light irradiation, which was achieved using TP-AABR-ACK when compared to DP-AABR-ACK composite and other catalysts in this study. Such superior results achieved with TP-AABR-ACK composite were attributed to controlled morphologies, reduced particle size and agglomeration, improved absorptivity, and superior cooperative effect between the AABR and ACK catalyst promoter as evidenced from SEM, EDX, TEM, UV-DRS, and electrochemical characterizations, respectively. Furthermore, enhanced TOC removal and abundance of reactive superoxide anion generation were achieved with the TP-AABR-ACK composite in this study.Supplementary Materials: Figure S1: Thermogravimetric analysis of ACK, DP-AABR-ACK, and TP-AABR-ACK, Figure S2: Photocatalytic degradation efficiencies of (A) ciprofloxacin, and (B) rhodamine B as a function of irradiation time for (a) TP-AABR-ACK, (b) DP-AABR-ACK, (c) TPAABR, (d) DP-AABR and (e) photolysis, Figure S3: Reusability test AABR-ACK nanocomposites for the degradation of TC under LED visible light illumination, and (b) XRD patterns of the AABR-ACK nanocomposites prior, and then afterward test.The Sasol University Collaboration Program, National Research Foundation of South Africa, the Vaal University of Technology and the Built Environment and Information Technology Department, University of Pretoria.https://www.mdpi.com/journal/catalystsam2022Chemical Engineerin