African Journal of Pure and Applied Chemistry最新文献

{"title":"Influence of duration and temperature of infusion on the heavy metal contents of some groups of tea in Nigeria","authors":"Wasiu Bolaji Tomori, Tolulope Oyelekan Oyewumi, Peter Enefola Omale","doi":"10.5897/ajpac2023.0903","DOIUrl":"https://doi.org/10.5897/ajpac2023.0903","url":null,"abstract":"Consumption of tea has been recommended not only for its taste and aroma but also for its medicinal importance, and these factors may contribute to public health concerns. The physicochemical characteristics of tea groups (green, black, and medicinal tea) were investigated using standard procedures. 2 g of each tea group and type were infused for 10 min at 60 and 80°C, and the extract was digested with a 2:1 mixture of HNO3 (65%) and H2O2 (30%) and then analyzed using Flame Atomic Absorption Spectrophotometry (FAAS) for Cd, Pb, Cu, Zn and Fe. The moisture content for green tea ranged from 6.75 to 7.50%, black tea from 5.50 to 8.50%, and medicinal/herbal tea from 7.50 to 13.25%, while the pH of the infusion at 60 and 80°C was found to be 7.0. The moisture content of medicinal tea was higher among the tea groups, as was their ash content, which was less than 8% for all groups and types of tea products. Furthermore, it was also found that the heavy metal content increases with an increase in infusion temperature for all similar brands of tea, except for some brands of medicinal tea. This may be due to plant species, soil conditions, and other environmental factors. There is no carcinogenic or noncarcinogenic health risk from elements in all tea brands and groups for both adults and children. However, there is a relative risk for children over adults, especially from Pb. Therefore, frequent consumption of all tea types and groups under investigation should be discouraged among children. Key words: Green tea, black tea, medicinal tea, infusion characteristics, health risk, Nigeria.&nbsp","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135976853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Major anthocyanin quantification, free radical scavenging properties and structural identification in Cymbopogon giganteus extracts","authors":"K. Bationo Remy, M. Dabire Constantin, Abdoulaye Yougoubo, Kabore Boukare, Sawadogo Ousseni, Koala Moumouni, Pale Eloi, H. Ch. Nebie Roger","doi":"10.5897/ajpac2023.0902","DOIUrl":"https://doi.org/10.5897/ajpac2023.0902","url":null,"abstract":"Anthocyanin-based colorants are highly appreciated by the food industry for their lower toxicity. However, in Burkina Faso, very little scientific information is available on potential sources of anthocyanins, despite significant progress in plant studies. This scientific report is the first to focus on anthocyanins of Cymbopogon giganteus from Burkina Faso and aims to valorize them for their use as an alternative to synthetic food colorants. The method using 2,2-diphenyl-1-picryhydrazyl (DPPH) reagent, the differential pH test, and Liquid Chromatography and High Performance Thin Layer Chromatography (LC and HPTLC) coupled to ultraviolet and mass spectrometry were used, respectively to determine free radical scavenging properties, anthocyanin content, and structure of anthocyanin compounds. Anthocyanin content evaluation showed values between 0.109 and 1.974 mg cyanidin equivalent per gram of extract. The free radical scavenging properties ranged from 305 to 446 µg/mL and we were able to identify in the high-content anthocyanin extracts, sixteen (16) anthocyanins compounds. Key words: Anthocyanins compounds, molecular characterization, mass spectrometry, LC-UV-MS/MS, free-radical properties.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136036624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of caffeine content of Nensebo coffee beans Southern Ethiopia, using ultra violet-visible (UV/V) is and high performance liquid chromatography (HPLC) methods in Ethiopia","authors":"Adane Legesse, Tadesse Abera, T. Tegene","doi":"10.5897/ajpac2021.0868","DOIUrl":"https://doi.org/10.5897/ajpac2021.0868","url":null,"abstract":"The main objective of the study was to determine caffeine content of coffee beans ( Coffee arabica ) collected from Nensebo district, West Arsi Zone, Oromia Region using ultra violet-visible and high performance liquid chromatography methods. The coffee beans were purchased from coffee supplying farmers’ cooperatives in Nensebo district (namely Tulu Gola, Habera, Refisa, Nensebo Chebi and Melka Dembi) and local coffee markets (in Hawassa and Shashemene). The coffee samples collected from the selected sites were mixed (homogenized). The same was done for coffee samples from coffee markets (in Hawassa and Shashemene cities). The samples were roasted and ground using grinding machine. The resulting powders were boiled in distilled water and extracted with dichloromethane. The dichloromethane extracts were subjected to high performance liquid chromatoraphy and ultra violet-visible analyses. The data obtained from spectra the methods used in the study revealed that the caffeine content of the extract homogenized coffee beans of the selected sites in % (w/w) was found to be 1.03 ± 0.001 by high performance liquid chromatography and 1.17 ± 0.01 by ultra violet-visible analysis. Similarly, the caffeine content of Nensebo coffee samples purchased from coffee markets was found to be 1.14 ± 0.01 by high performance liquid chromatoraphy analysis. The findings showed that the caffeine contents of the coffee samples used in the study was within reported standards, and also relatively lower than reported caffeine contents of coffee beans growing in other parts of Ethiopia. Further studies are recommended to determine the levels of other chemicals constituents and minerals exist in the coffee beans in order to fully determine the properties (quality) of Nensebo coffee.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88436055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Filler characterization, mechanical properties, x-ray diffraction and crosslink density analysis of starch/natural rubber biopolymer composites","authors":"R. Uzoh, Ardo A. Buba, S. Osemeahon","doi":"10.5897/ajpac2018.0773","DOIUrl":"https://doi.org/10.5897/ajpac2018.0773","url":null,"abstract":"Starch fillers were extracted from three plant sources namely amora tuber, Tacca lentopeteloides; sweet potato, Ipomoea batatas; yam starch, Dioscorea rotundata and their particle size, pH, amylose, and amylopectin percentage decomposition determined accordingly. The starch was introduced into natural rubber in liquid phase (through gelatinization) by the latex compounding method and compounded according to standard method. The prepared starch/natural rubber composites was characterized by Instron Universal testing machine (UTM) for tensile mechanical properties. The composites was further characterized by x-ray diffraction and crosslink density analysis. The particle size determination showed that amora starch granules has the smallest particle size (156 × 47 μm) followed by yam starch (155 × 40 μm) and then sweet potato starch (153 × 46 μm) with the biggest particle size. The pH test also revealed that amora starch has a near neutral pH of 6.9, yam 6.8, and sweet potato 5.2 respectively. Amylose and amylopectin determination showed that yam starch has a higher percentage of amylose (29.68), followed by potato (22.34) and then amora starch with the lowest value (14.86) respectively. The tensile mechanical properties testing revealed that yam starch produced the best tensile mechanical properties followed by amora starch and then sweet potato starch. The structure, crystallinity/amorphous nature of the product composite was confirmed by x-ray diffraction, while the nature of crosslinking was confirmed by swelling test in toluene solvent using the Flory-Rehner approach. The increasing values of crosslink density in the starch/rubber composite is a clear evidence of good interfacial adhesion between the starch fillers and the rubber, hence good dispersion of starch fillers in the rubber. This research has rendered a workable strategy for enhancing interfacial interaction between a hydrophilic filler (Starch) and hydrophobic polymeric matrix (natural rubber) yielding moderately good tensile mechanical properties with prospects for the rubber processing industry. The studied fillers can partially replace carbon black as natural rubber fillers with reduced cost, no risk to human health and also an environment friendly approach .","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"398 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77725520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physicochemical and nutritional properties of Syzygium cumini (L.) skeels fruits grown in varied microclimates in Kenya","authors":"Chiteva Rose, Mmari Onyari John, W. Lydia, O. Vincent","doi":"10.5897/ajpac2022.0896","DOIUrl":"https://doi.org/10.5897/ajpac2022.0896","url":null,"abstract":"Wild fruits contribute significantly to food security, thus becoming an important global discussion. This study evaluated the physicochemical and nutritional properties of Syzygium cumini (L.) Skeels fruits from two microclimates in Kenya as essential contributors to the human diet. Analysis was done using standard methodologies including the use of inductively coupled plasma - optical emission spectrometer for elemental analysis and high-pressure liquid chromatography for the determination of Vitamin C. The T-test showed significant differences in the fruit breadth, pH, total ash, sodium, calcium, manganese, copper, and zinc. The Pearson correlation matrix showed a small positive association between total soluble solids and titratable acidity with altitude, a medium positive correlation with rainfall, and a strong positive correlation between sunshine and skin colour intensity. Larger fruits contained substantial amounts of protein and crude fiber with a significant increase in energy values in fruits with high crude fat and carbohydrates, all correlating positively with the microclimate conditions; altitude, and rainfall. This study exemplifies the potential of Syzygium cumini as an alternative feed supplement to strengthen food security. It provides information on the variation of the physicochemical and nutritional composition of the fruits with climatic conditions, for the industries to employ the best strategies in obtaining marketable products.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"2012 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86410766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nutritional, biochemical and phytochemical characterization of seeds and seed oil of pumpkins (Cucurbita maxima) grown in Malawi","authors":"E. C. C. Lesten, George Masamba Kingsley, Uluko Hankie","doi":"10.5897/ajpac2022.0891","DOIUrl":"https://doi.org/10.5897/ajpac2022.0891","url":null,"abstract":"P.O","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76245593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of proximate and physicochemical properties of crude palm oil from south-west and South-south Nigeria","authors":"Oladiran Raji Rafiu, Kesiye Inengite Azibaola, G. Jackson, Kayode Ajibesin Kola","doi":"10.5897/ajpac2022.0890","DOIUrl":"https://doi.org/10.5897/ajpac2022.0890","url":null,"abstract":"Crude palm oil is most worlds widely used oil, due to its nutritional and economic advantages. The proximate and physicochemical properties of fifty samples from local mills in Southern Nigeria were analyzed to determine their applicability as food and industrial usage applying standard procedures. The obtained results were: Moisture content (1.51 to 2.46%), ash content (0.30 to 0.50%), crude lipids (68.82 to76.77%), crude protein (2.44 to 3.25), carbohydrate (17.34 to 22.02%), energy value (697.80 to 716.04 Kcal/g), melting point (31.11 to 34.03°C), refractive index (1.465 to 1.469), specific gravity (0.8980 to 0.9140 g/mL), while viscosity ranged from 24.698 to 63.823 mPs. Others were saponification value (199.22 to 203.55 mg KOH/g), acid value (1.526 to 2.190 mg KOH/g), ester value (197.75 to 201.99 mg KOH/g), free fatty acid (0.719 to 1.090 mg KOH/g), peroxide value (3.186 to 5.450 mEq/g) and iodine value (45.57 to 50.60 Wij’s). The results showed good food and industrial applications except high moisture content which was above 0.29% recommended standard and may lead to short shelf life, therefore proper monitoring of local mills for effective standard operating procedures are required to reduce contamination which might have adverse health and economic effects.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"84 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77489143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dichlorodiphenyltrichloroethane (DDT) and its metabolites in house dust, soil and selected food crops from indoor residual sprayed areas of Apac and Oyam Districts, Uganda","authors":"Mukasa Paul, W. John, Namuyomba Proscovia, N. Emmanuel","doi":"10.5897/ajpac2022.0884","DOIUrl":"https://doi.org/10.5897/ajpac2022.0884","url":null,"abstract":"Dichlorodiphenyltrichloroethane (DDT) levels and its metabolites are reported in 75 soil and 75 vegetable samples from the vicinity of homesteads sprayed with DDT during indoor residual spraying (IRS) pilot exercise, carried out in 2008 in Apac and Oyam districts, Uganda as a measure to control malaria. The samples were randomly and conveniently collected in 2020 from selected villages of the districts, extracted using solid dispersion and multi-residue methods for soil and vegetable samples, respectively and analyzed using GC-ECD and GC-MS. DDT residues were detected in all samples collected. The ΣDDT (µg kg-1) in all indoor house dust, outdoor soil samples from villages of Apac and Oyam districts and control areas were 69.9±20.9 and 8.9±4.7, 113.4±22.6 and 15.4±4.3, and 1.13±0.27 and 1.8±0.9, respectively. ΣDDT were significantly higher (p < 0.05) in the study areas than the control areas. In vegetables, ∑DDT (µg kg -1 ) ranged between 1.7±0.3 and 8.3±4.0 and 2.3±0.4 and 11.4±7.5 in the study and control areas, respectively. Abelmoschus esculentus and Gynandropsis gynandra had the highest levels. The results suggest that IRS had an effect on DDT levels in the environment. However, ∑DDT in vegetables were significantly below (P < 0.05) the EU EMRL, thus, the results raise no concern regarding the potential health effects of DDT to the residents. Nevertheless, due to bioaccumulation effects of DDT, to control malaria, measures like Ecohealth rather than IRS of DDT should be embraced.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"297 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87853235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Excess refractive indices and validation of mixing rules using binary mixture of methyl laurate + Pentan-2-ol at various temperatures (298.15, 303.15, 308.15, 313.15, and 318.15K)","authors":"R. Sunita, Sangwan Nisha, K. S. Rajesh","doi":"10.5897/ajpac2022.0888","DOIUrl":"https://doi.org/10.5897/ajpac2022.0888","url":null,"abstract":"Refractive index is a characteristic parameter of fluids with numerous industrial uses. The values of refractive indices of many pure liquids are known or can be found in the literature. However, when experimental values of the liquid mixtures are not available then refractive indices of binary mixtures and multi-component liquids are frequently assessed from the pure constituents using mixing rules. The refractive indices ( ) of binary mixture and pure liquids methyl laurate (M.L) and pentan -2-ol (P) over the entire mole fraction range at five temperatures (298.15, 303.15, 308.15, 313.15, and 318.15K) were measured using an Anton-Paar Abbemat 3200 refractometer and were tested with the traditional equations, viz Gladstone-Dale (G.D), Lorentz-Lorentz (L.L), Weiner-relation (W.R) and Heller-relation (H.R). The excess refractive indices ( ) were calculated using measured experimental refractive indices ( and ideal refractive indices. The values of excess refractive indices were found to be negative at low mole fractions and positive over the high mole fractions. The experimental data for binary mixture involving methyl laurate + Pentan-2-ol authenticate the mixing rules. binary mixture, mixing rules, methyl laurate.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84425974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of transport of glibenclamide drug across micro-pore supported model membrane using electro analytical methods","authors":"Kinati Terfa Geremew, Iqbal Alvi Naved, Sudhakar Sagaram","doi":"10.5897/ajpac2019.0800","DOIUrl":"https://doi.org/10.5897/ajpac2019.0800","url":null,"abstract":"Glibenclamide is a second generation sulfonyl urea compound used as an oral hypoglycemic or anti diabetic agent, a class of drug used to treat type-2 diabetes mellitus. The bilayer lipid membrane systems have been employed extensively as an experimental model of bio membranes. It is of major importance in medical research, particularly in the study of mechanism of a number of life saving therapeutic agents where a lipid bilayer is the primary site of interaction. The objective of this study was to investigate the transport of glibenclamide across micro-pore supported model bilayer lipid membrane. In this study, lipid bilayer membrane was prepared from L-alpha - phosphotidylcholine. Conductometric and potentiometric techniques were used to measure membrane conductance and membrane potential respectively as a function of concentration of the glibenclamide solution and temperature of the electrochemical cell maintained. The observed data were used to evaluate selectivity and activation parameters by making use of mathematical expressions derived on the basis of non-equilibrium and transition state theories. From membrane potential study, thermodynamically effective fixed charge density (ØX) and transport number of anions (t - ) obtained were 42.6 meq/lit and 0.76 respectively and membrane conductance of 0.1 molar glibenclamide drug solution at 37°C showed 26.11 + 0.01 (µs/cm), at this concentration and temperature values of activation parameters (Ea, ΔG*, Δ H*, -ΔS*) obtained were: 2516.47J/mole, 61605.71 J/mole,38.90J/mole and 206.60 J/k mole respectively. The observed and evaluated data indicated that selective membrane behavior was more pronounced in the dilute range and the drug molecules were diffused across the membrane passively. Hence it might be concluded that small amount of drug is more effective in getting the desired effect.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76710038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}