National Food Technology Research Center

Kanye Botswana, Botswana

National Food Technology Research Center

Kanye Botswana, Botswana
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Tembwe I.,University of Botswana | Ngila J.C.,University of KwaZulu - Natal | Kgarebe B.,National Food Technology Research Center | Darkwa J.,University of Johannesburg | Iwuoha E.,University of the Western Cape
Electrochimica Acta | Year: 2010

Nickel catecholate complexes, bis(diphenylphosphino)ethanenickelcatecholate [(dppe)NiO2C6H34-R1] R1 = CH3 (1), C(CH3)3 (2), H (3) and F (4)] were studied using CV and SWV techniques between -1.5 and +1.5 V at 50 mV s-1 in cathodic and anodic sweeps. Glassy carbon electrode was used with 0.1 M tetrabutylammonium tetrafluroborate (TBATFB) in CH2Cl2. Complexes 1-4 before addition of SO2, showed approximately reversible behaviour (ipa/ipc ≈ 1 and ΔE ≈ 77-88 mV); oxidation peaks observed between +313 and +524 mV, reduction peaks between +225 and +436 mV, depending on the substituent on the ligand. Detection limit 0.01 ppm, linear range 0.01-20 ppm, sensitivity 0.02 ppm/mV (with SWV) were obtained. The complexes 1 and 2 could be used as voltammetric sensors while complexes 3 and 4 would be suitable as amperometric sensors, for monitoring industrial SO2 emissions. © 2009 Elsevier Ltd. All rights reserved.

Jackson M.D.,University of the West Indies | Motswagole B.S.,National Food Technology Research Center | Kwape L.D.,National Food Technology Research Center | Kobue-Lekalake R.I.,Botswana College of Agriculture | And 4 more authors.
Public Health Nutrition | Year: 2013

Objective To evaluate the validity and reproducibility of a 122-item interviewer-administered quantitative FFQ developed to determine food and nutrient intakes of adults in Botswana. Design Relative validity of the FFQ was evaluated by comparing nutrient and food group intakes against four non-consecutive 24 h recalls administered over 12 months. The FFQ was repeated after 1 year to assess reproducibility. Setting Kanye, Botswana. Subjects Seventy-nine adults aged 18-75 years. Results Spearman correlation coefficients for the validity of energy-adjusted nutrients ranged from 0·42 (carbohydrate) to 0·49 (protein) for macronutrients and from 0·23 (Fe) to 0·44 (PUFA) for micronutrients. Exact agreement of quartile distribution for nutrients between the FFQ and recalls ranged from 27 % to 72 %. Weighted kappa values were lowest for retinol (0·13), Fe (0·22) and β-carotene (0·25) and ranged from 0·33 (SFA) to 0·59 (folate) for other nutrients (energy, carbohydrate, protein, fat, Ca and vitamin E). Spearman correlation coefficients between the recalls and FFQ for food groups ranged from 0·18 (dark green leafy and yellow vegetables) to 0·58 (poultry). Reproducibility correlation coefficients (energy-adjusted) varied between 0·39 for retinol and 0·66 for vitamin E, with most values falling between 0·50 and 0·60. Conclusions The FFQ had good relative validity for estimating habitual food group and nutrient intakes, but was poor for some micronutrients (Fe, retinol and β-carotene) and foods (fruits and dark green leafy vegetables). Copyright © 2012 University of the West Indies.

Zvinowanda C.M.,Tshwane University of Technology | Okonkwo J.O.,Tshwane University of Technology | Agyei N.M.,University of Limpopo | van Staden M.,National Metrology Institute of South Africa | And 2 more authors.
American Journal of Biochemistry and Biotechnology | Year: 2010

Problem statement: Major adsorbent materials used in heavy metal ion removal from polluted aqueous streams are expensive and difficult to regenerate. In this study, the possibility of using Zea mays tassel, as an alternative low cost biosorbent material to remediate heavy metal pollution was investigated. Lead (II) was used because of its wide application in industrial products and well documented toxicity. Approach: Tassel was obtained from mature Zea mays cultivar R52 hybrid plants. The tassel was milled to a powder and was used to adsorb lead(II) ions from simulated solutions in batch experiments. The desorption of lead(II) was carried out using nitric acid and sodium citrate solutions. The adsorbent was characterized by FTIR, EDX and ESCA before and after application of lead(II) solutions. Results: For samples with concentrations of 100 mg L-1 Pb(II), 94-98% was adsorbed and 57-74 and 57-67% recoveries were achieved with 0.5-5 M nitric acid and 0.01-0.2 M sodium citrate as the stripping solutions, respectively. EDX spectrum of pure tassel indicated that group 1 and 2 metals were the major exchangeable ions present on its surface. ESCA analysis picked up small amounts of lead(II) in the form of Pb(OH)+ and Pb(NH)+ ions on the surface of tassel adsorbent exposed to Pb2+ ions and none on pure tassel sample. Functional groups such as -H, -NH2, -C = O and -COOH which are polar and are legends which are capable of binding heavy metals were identified by FTIR. Conclusion: The potential of Zea mays tassel to adsorb and recover heavy metals from aqueous solution was successfully demonstrated with Pb(II) sample solutions. The results obtained thus far demonstrated the possibility of using tassel powder in the removal as well as recovery of metals from aqueous solutions. © 2010 Science Publications.

Sun T.,Shanghai Institute of Technology | Jiang B.,Jiangnan University | Pan B.,China National Light Industry Council | Letsididi R.,National Food Technology Research Center
Journal of Food, Agriculture and Environment | Year: 2013

Cyclodextrin glucanotransferase (CGTase, EC 2. 4. 1. 19) had been used to transglycosylate rutin to increase its solubility and stability in water for food, cosmetic and pharmaceutical industry applications. However, this application was restricted by the availability of a CGTase-producing microbial strain, which has high efficiency in transglycosylation of rutin. Here, we reported a novel microbial strain SK13.002 producing CGTase with high efficiency in rutin transglycosylation. Based on cell morphological, biochem-physiological characteristics, this strain was identified as Bacillus sp. SK13.002. Phylogenetic analysis of 16S rDNA showed that SK13.002 16S rDNA shared 98.5% identity with 16S rDNA of Bacillus amyloliquefaciens NBRC 15535 and 97.5% identity with that of Bacillus vallismortis DSM11031. The CGTase produced by Bacillus sp. SK13.002 transglycosylated rutin more efficiently compared to CGTases isolated from other strains reported. Thus, Bacillus sp. SK13.002 could be a potential CGTase source for the transglycosylation of rutin and other food functional components.

Holse M.,Copenhagen University | Petersen M.A.,Copenhagen University | Maruatona G.N.,University of Pretoria | Maruatona G.N.,National Food Technology Research Center | Hansen A.,Copenhagen University
Food Chemistry | Year: 2012

Marama bean (Tylosema esculentum) is an underutilised legume indigenous to the Kalahari Desert region of southern Africa. The bean has high lipid content and hence is a potential source for production of edible oil. The headspace volatile composition of freshly pressed marama bean oil was explored and the oil was further studied during 7 months of storage under different light and temperature conditions. The oxidative stability of the oil was examined by measuring peroxide value, vitamin E content and FT-IR spectra. Additionally, the headspace volatile composition of the oil was investigated during storage by use of dynamic headspace GC-MS. The results showed that marama oil is highly stable and has good natural antioxidant properties; enzymatic lipid oxidation does not take place in marama oil. Light has a greater effect on the lipid oxidation than has temperature, and hence marama oil should preferably be stored in darkness and rather at 25°C than 35°C. Under these conditions, the marama oil has a shelf life of at least 7 months. © 2011 Elsevier Ltd. All rights reserved.

Maruatona G.N.,University of Pretoria | Maruatona G.N.,National Food Technology Research Center | Duodu K.G.,University of Pretoria | Minnaar A.,University of Pretoria
Food Chemistry | Year: 2010

Marama bean is a protein-rich, underutilised, drought-tolerant legume in sub-Saharan Africa. Its utilisation may be increased through value addition into protein-rich flours. Defatted flour from unheated and dry-heated (150 °C/20 min) whole marama beans (UMF and HMF) were analysed for physicochemical and protein-based functional properties. Heating significantly increased in vitro protein digestibility of marama bean flour. Of functional importance are the high levels of tyrosine present in marama bean flours. Heating significantly reduced protein solubility and emulsifying capacity of marama bean flours whilst water absorption capacity was improved. Foaming capacity was not affected by heating. UMF could be useful in food systems requiring high emulsifying capacity, but would not be suitable for applications requiring high water absorption and foaming capacity. Due to its high protein contents, marama bean flour could be used to increase the protein quality of cereal-based foods to help alleviate protein-energy nutrition in the region. © 2010 Elsevier Ltd. All rights reserved.

Mokhawa G.,National Food Technology Research Center | Kerapeletswe-Kruger C.K.,National Food Technology Research Center | Ezeogu L.I.,National Food Technology Research Center | Ezeogu L.I.,University of Nigeria
Journal of Cereal Science | Year: 2013

Proteolysis is vital to the generation of amino acids and short peptides during malting. The qualitative and quantitative effects of malting on proteolytic digestion were investigated for 11 Botswana sorghum cultivars. Protein hydrolysis was influenced by sorghum grain cultivar. All protein fractions were degraded, although the extents of their digestion appeared cultivar-dependent. The most significant changes in total and free kafirins occurred among the HMW aggregates while the 45kDa dimer appeared the most recalcitrant. Free kafirin monomers were digested in variety-defined manner; α-kafirin faded the most (ca. 82%) in Phofu, but appeared least digested (≤10%) in Lekgeberwa; β-kafirin faded the most in Phofu and Segaolane (90-94%) but only 46% in Lekgeberwa. Overall, α-kafirin appeared the least digested of the free monomers. The proportion of free kafirin accounted for by the 45kDa and monomeric kafirins increased in all malts (except Lars Vyt and Mafia), probably due to protein depolymerisation. Grain variety significantly influenced (p < 0.001) malt FAN levels. Mean FAN values were highest in Segaolane (225mg/100g) followed by Sefofu, Town and BSH-1, but lowest in Mafia (96.9mg/100g). Results indicate wide variability in the proteolytic malting digestibility of the eleven sorghum cultivars. © 2013 Elsevier Ltd.

Motswagole B.S.,National Food Technology Research Center | Mongwaketse T.C.,National Food Technology Research Center | Mokotedi M.,National Food Technology Research Center | Kobue-Lekalake R.I.,National Food Technology Research Center | And 4 more authors.
Annals of Nutrition and Metabolism | Year: 2013

Background: Micronutrient deficiencies are common and compound the effects of human immunodeficiency virus (HIV) infection in Africa. Nutritional interventions, particularly vitamin A supplementation, may improve immune functioning and delay disease progression. Aim: To investigate the effect of fortified sorghum meal provided for 12 months on the immune status of adults with HIV. Methods: HIV-infected men and women were enrolled in a double-blind randomized placebo-controlled trial in Kanye, Botswana, to receive either sorghum meal fortified with micronutrients including vitamin A (n = 67) or control (n = 65). Serum retinol, iron, zinc, albumin, CD4 cell count and HIV viral load were assessed at baseline and every 3 months. Results: Baseline serum retinol levels were 1.6 μmol/l in both groups and no significant difference was observed at the end of the intervention (control group: 1.5 μmol/l; experimental group: 1.6 μmol/l). In addition, there was no significant difference in the mean (Q1, Q3) CD4 cell count; 348 (220, 456) cells/mm 3 for the control group versus 338 (228, 426) cells/mm3 in the experimental group after intervention. Conclusion: In this study, fortified sorghum meal did not influence serum retinol, CD4 cell count and HIV viral load. Future intervention studies should carefully consider the composition and dosing of food supplements needed to improve immune status and delay disease progression. Copyright © 2013 S. Karger AG, Basel.

Sekwati-Monang B.,University of Alberta | Sekwati-Monang B.,National Food Technology Research Center | Valcheva R.,University of Alberta | Ganzle M.G.,University of Alberta
International Journal of Food Microbiology | Year: 2012

The choice of the cereal substrate determines sourdough microbiota, however, the substrate-associated ecological factors for this phenomenon have not been elucidated. This study investigated the competitiveness of Lactobacillus sanfranciscensis LTH 2590, a wheat sourdough isolate, and four isolates from sorghum sourdoughs (ting), Lactobacillus casei FUA3166, Lactobacillus harbinensis FUA3199, Lactobacillus parabuchneri FUA3169, and Lactobacillus coryniformis FUA3307, in sorghum sourdoughs, sorghum sourdoughs supplemented with maltose, or wheat sourdoughs. Fermentations were characterised by determination of cell counts, pH, and quantification of metabolites. Maltose was the main carbon source in wheat sourdoughs whereas glucose was the major carbon source in sorghum. L. coryniformis and L. parabuchneri produced 1,3- and 1,2-propanediol from glycerol and lactate, respectively, metabolites that were previously not observed in sourdough. To determine the competitiveness of strains, wheat and sorghum slurries were inoculated with equal cells counts of L. sanfranciscensis, L. parabuchneri, and L. casei fermented at 28. °C or 34. °C and propagated by back-slopping every 24. h. Lactobacilli in sourdough were quantified by plating and species-specific quantitative PCR (qPCR). Generally, sorghum and wheat sourdoughs inoculated with isolates from ting gave no appreciable differences in the metabolites produced during the fermentation process. L. sanfranciscensis grew in wheat but not in sorghum sourdoughs, or sorghum sourdoughs supplemented with 2% maltose, 1% tryptone, 0.1% l-cysteine and 2% sucrose. Furthermore, L.sanfranciscensis decreased progressively during propagation of sorghum sourdoughs but ting isolates were overgrown by L. sanfranciscensis after three propagations in wheat sourdoughs independent of the incubation temperature. The anti-microbial activity of four different types of sorghum extracts was tested against L. sanfranciscensis, L. parabuchneri, and L. casei to correlate the resistance to phenolic compounds to growth in wheat or sorghum sourdoughs. L. sanfranciscensis was inhibited by phenolic extracts from sorghum flours whereas ting isolates were resistant. In conclusion, microbiota of sorghum sourdough differ from wheat and rye because sorghum contains active concentrations of antimicrobial phenolic compounds, and offers glucose as major carbon source. © 2012 Elsevier B.V.

Mosele M.M.,Copenhagen University | Mosele M.M.,National Food Technology Research Center | Hansen A.S.,Copenhagen University | Hansen M.,Copenhagen University | And 2 more authors.
Food Chemistry | Year: 2011

Marama bean (Tylosema esculentum) is a wild-growing legume adapted to semi-arid conditions in southern Africa. Both immature and mature seeds are used as food by locals and marama bean has potential as a crop plant. Physicochemical and histochemical methods were used to study the accumulation of nutrients and their localisation in immature and mature seeds. The immature seeds had a high content of moisture (67%) and protein (21%), and a low content of lipid (1.5%). At maturity, proteins formed spherical bodies that were embedded in a droplet lipid matrix. The mature seeds are exceptional as they have a high content of protein (32%) and lipid (40%) and no starch. Staining of polysaccharides indicated increases of pectin and cellulose during maturation, parallel with the general increase of cell wall thickness; however, lignin was absent. The content and distribution of protein, lipid and carbohydrates in immature and mature marama beans make this underutilised nutritive legume a prospective crop plant and interesting for food processing applications. © 2011 Elsevier Ltd. All rights reserved.

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