- P O Box 7062 Kampala, Uganda
- +256772445113
Yusuf Byaruhanga
Makerere University, Food Technology and Nutrition, Faculty Member
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Research Interests: Geography and SHELF LIFE
African eggplant (Solanum anguivi Lam.) fruits reportedly exhibit antidiabetic properties, possibly due to the presence of bioactive compounds. This study aimed to assess the bioactive compounds content (BCC) and antioxidant activity (AA)... more
African eggplant (Solanum anguivi Lam.) fruits reportedly exhibit antidiabetic properties, possibly due to the presence of bioactive compounds. This study aimed to assess the bioactive compounds content (BCC) and antioxidant activity (AA) in the fruits of fourteen African eggplant accessions. The relationship between the fruit BCC and AA, and the plant (leaf, stem and fruit) morphological characteristics was determined. Morphological traits for the plant accessions were characterized based on existing Solanum species descriptors. Total phenolics, flavonoids, saponins, vitamin C and AA were determined by spectrophotometry, while total alkaloids were detected by gravimetry. HPLC was used for the quantification of phenolic compounds. Morphological characteristics, BCC and AA differed among the accessions. The fruit's accessions contained total phenolics (8.0-12.4 mg gallic acid equivalent/g dry weight (DW)), saponins (51.1-124.8 mg diosgenin equivalent/g DW), alkaloids (81.4-127.7 ...
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Previous studies have reported the presence of aflatoxins (AFB1, AFB2, AFG1 and AFG2), heavy metals (As, Cd and Pb) and organochlorine pesticide residues (OCPs) in rice sold in Uganda. However, the potential health effects associated with... more
Previous studies have reported the presence of aflatoxins (AFB1, AFB2, AFG1 and AFG2), heavy metals (As, Cd and Pb) and organochlorine pesticide residues (OCPs) in rice sold in Uganda. However, the potential health effects associated with consumption of rice have not been evaluated. The aim of this study was to evaluate the health risk of consuming rice sold in Uganda. A total of 45 packed and 30 open traded rice samples were randomly collected from retail outlets in the main rice trading areas of Uganda. Rice was analysed for AFB1, AFB2, AFG1 and AFG2, As, Cd, Pb and OCPs using AOAC standard methods. Dietary exposure of the consumers to contaminants was assessed using the estimated daily intake (EDI). The Hazard index (HI) and the incremental lifetime cancer risk (ILCR) were determined to define the non-carcinogenic and carcinogenic risk from contaminants, respectively. The potency of liver cancer cases in Uganda was 1.02E-5 and 1.05E-5 adults/year/100,000, and 6.50E-4 and 6.72E-5 ...
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Extrusion cooking is a modern high-temperature short-time (HTST) processing technology, which is becoming popular in certain industries because it offers several advantages over other types of cooking processes. The objective of this... more
Extrusion cooking is a modern high-temperature short-time (HTST) processing technology, which is becoming popular in certain industries because it offers several advantages over other types of cooking processes. The objective of this study was to evaluate the extrusion performance of sorghum (Sorghum bicolor) varieties commonly grown in Uganda. Four varieties of sorghum namely, Seso1, Epuripur, Seso3 and Eyera were extruded with and without defatted soy-flour. Physical-chemical properties of the extrudates including, lateral expansion, bulk density, hardness, water absorption index, water solubility index, as well as proximate composition were determined. The extrudates exhibited 240-300% lateral expansion and 0.067-0.095 g cm-3 bulk density. The water absorption index was 6.4-7.9 g g-1 compared to 1.9-2.3 g g-1 of the control; while the water solubility index was 6.5-13% compared to 3.4-5.0%% of the control. Extrusion of all the varieties reduced the peak and final viscosity of the...
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Drying processes including solar, oven, and refractance window were studied to determine their influence on the drying behavior of jackfruit slices and properties of resultant jackfruit powders. The loss of sample mass, converted to the... more
Drying processes including solar, oven, and refractance window were studied to determine their influence on the drying behavior of jackfruit slices and properties of resultant jackfruit powders. The loss of sample mass, converted to the ratio between the water content at time t and the initial water content (moisture ratio), was used as the experimental parameter for modelling drying processes. Fifteen thin layer drying models were fitted to the experimental data using nonlinear regression analysis. Based on the highest R 2 and lowest SEE values, the models that best fit the observed data were Modified Henderson and Pabis, Verma et al., and Hii et al. for RWD, oven, and solar drying, respectively. The effective moisture diffusivity coefficients were 5.11 × 10 − 9 , 3.28 × 10 − 10 , and 2.55 × 10 − 10 for RWD, oven and, solar drying, respectively. The solubility of freeze-dried jackfruit powder (75.7%) was not significantly different from the refractance window dried powder (73.2%) a...
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Four types of Obushera, a fermented millet or sorghum beverage: Ekitiribita, Obuteire, Obutoko and Enturire were analyzed for their physico-chemical properties, sugars, organic acids and volatile compounds during fermentation. Standard... more
Four types of Obushera, a fermented millet or sorghum beverage: Ekitiribita, Obuteire, Obutoko and Enturire were analyzed for their physico-chemical properties, sugars, organic acids and volatile compounds during fermentation. Standard chemical methods were used to determine the physico-chemical properties of Obushera. The organic acids, carbohydrates, glucose, fructose and maltose were analyzed by highperformance liquid chromatography. The pH of all Obushera varied between 4.00±0.10 and 4.42±0.11 after 4 days of fermentation. The pH of Obuteire, Obutoko and Enturire dropped below 4.5 within one day of fermentation. Acidity ranged between 0.13% (Ekitiribita) to 1.33% (Enturire) after 4 days of fermentation. Dry matter decreased and varied between 5.4 and 22% after 4 days of fermentation. Fermentation resulted into a 20–40% reduction of dry matter in Obutoko, Obuteire and Enturire. Enturire had the highest dry matter content and decreased from 22% to 13%. Fermentation resulted in an ...
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Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder of glucose homeostasis associated with a status of insulin resistance, impaired insulin signaling, β-cell dysfunction, impaired glucose and lipid metabolism, sub-clinical... more
Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder of glucose homeostasis associated with a status of insulin resistance, impaired insulin signaling, β-cell dysfunction, impaired glucose and lipid metabolism, sub-clinical inflammation, and increased oxidative stress. Consuming fruits and vegetables rich in phytochemicals with potential antidiabetic effects may prevent T2DM and/or support a conservative T2DM treatment while being safer and more affordable for people from low-income countries. Solanum anguivi Lam. fruits (SALF) have been suggested to exhibit antidiabetic properties, potentially due to the presence of various phytochemicals, including saponins, phenolics, alkaloids, ascorbic acid, and flavonoids. For the saponin fraction, antidiabetic effects have already been reported. However, it remains unclear whether this is also true for the other phytochemicals present in SALF. This review article covers information on glucose homeostasis, T2DM pathogenesis, and als...
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Food control defines activities, along the food supply chain, that provide consumer protection and ensure that all foods provided for human consumption are wholesome, conform to safety and quality requirements, and are accurately labelled... more
Food control defines activities, along the food supply chain, that provide consumer protection and ensure that all foods provided for human consumption are wholesome, conform to safety and quality requirements, and are accurately labelled as prescribed by law. This review analysed the capacity and performance of the existing food control system in Uganda, with specific focus on the rice value chain. This study targeted food safety laws, regulations and agreements to which Uganda is signatory for gaps in, and opportunities for improvement of food control along the rice value chain. The operational components of a food control system including inspection, testing, certification, enforcement, and surveillance controls along the rice value chain were investigated. The analysis established there is a significant threat to food safety due to outdated laws, uncoordinated regulatory framework, overlapping mandates, limited testing capacity, inadequate human resource, limited awareness of co...
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Abstract: Edible films can be produced from kafirin but the diverse food product requirements necessitate modification of the films. To modify their functional properties, kafirin films were cast, with and without plasticizer, from... more
Abstract: Edible films can be produced from kafirin but the diverse food product requirements necessitate modification of the films. To modify their functional properties, kafirin films were cast, with and without plasticizer, from glacial acetic acid (GAA) and aqueous ethanol (AE), then heated using microwave energy. A power of 80W for 2min caused an approximately two- and fourfold increase in the tensile strength of non-plasticized and plasticized films, respectively. Film glass transition temperature increased by about 15%. Film biodegradability was slowed. However, only the digestibility of the non-plasticized films cast from AE heated for the longest time (4min) was decreased, by about 25%; while that of the other films was not affected. GAA cast films had higher digestibility than AE cast ones, possibly as a result of acid-mediated deamidation of kafirin. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis indicated heat-induced kafirin oligomers. Scanning electron micro...
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Purpose: Transformation of pumpkin flesh and seeds into dry flours increases their shelf stability and versatility. This study sought to optimise drying conditions for production of flour with high nutritional and nutraceutical value from... more
Purpose: Transformation of pumpkin flesh and seeds into dry flours increases their shelf stability and versatility. This study sought to optimise drying conditions for production of flour with high nutritional and nutraceutical value from flesh and seeds of C. pepo L var. fastigata using Response Surface Methodology, I optimal design. Research Method: Pumpkin flesh and seeds were dried following temperature time combinations got using I optimal design. All dry samples were tested for ascorbic acid, total carotenoids, total antioxidant capacity and starch digestibility. Seeds were also tested for in vitro protein digestibility, trypsin inhibitor activity, alpha tocopherol, beta tocopherol, and alpha tocotrienol. Findings: The predicted optimum drying conditions for production of C. pepo L var. fastigata flour with maximum nutritional quality and bioactivity were 57°C; 6.9 hours for flesh and 60°C; 3.15 hours for seeds. The most influential model terms were temperature for resistant s...
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Research Interests: Engineering, Chemistry, Microwave, Energy, Medicine, and 14 moreFilm, FTIR, Raman, Agricultural, CHEMICAL SCIENCES, Secondary Structure, Protein Secondary Structure, Agricultural and Food Chemistry, Microwave-Energy, American Chemical Society, Polyphenol, Infrared Spectrometry, SDS PAGE, and Disulfide bond
Amylolytic lactic acid bacteria (ALAB) can potentially replace malt in reducing the viscosity of starchy porridges. However, the drawback of using ALAB is their low and delayed amylolytic activity. This necessitates searching for... more
Amylolytic lactic acid bacteria (ALAB) can potentially replace malt in reducing the viscosity of starchy porridges. However, the drawback of using ALAB is their low and delayed amylolytic activity. This necessitates searching for efficient ALAB and strategies to improve their amylolytic activity. Two ALAB, Lactobacillus plantarum MNC 21 and Lactococcus lactis MNC 24, isolated from Obushera , were used to ferment starches in MRS broth: sorghum, millet, sweet potato, and commercial soluble starch. The amylolytic activity of MNC 21 was comparable to that of the ALAB collection strain Lb. plantarum A6, while that of MNC 24 was extremely low. MNC 21, MNC 24, and their coculture were compared to A6 and sorghum malt for ability to ferment and reduce the viscosity of sorghum porridge (11.6% dry matter). ALAB and the coculture lowered the pH from 6.2 to <4.5 within 12 h, while malt as a carrier of wild starter took about 20 h. Coculturing increased lactic acid yield by 46% and 76.8% compa...
Research Interests: Chemistry, Food Science, Rheology, Biology, Medicine, and 15 moreMultidisciplinary, Humans, Sorghum, Applied Environmental Microbiology, Viscosity, Newborn Infant, Fermentation, Analysis of Variance, Time Factors, Lactobacillus Plantarum, Base Sequence, Lactic Acid, Lactococcus lactis, Molecular Sequence Data, and Infant food
Microbial biomass is cultivated for different technological applications including food processing, medicine, waste management, and research. The conventional growth media used are generally expensive thus necessitating the development of... more
Microbial biomass is cultivated for different technological applications including food processing, medicine, waste management, and research. The conventional growth media used are generally expensive thus necessitating the development of more affordable alternatives. In this study, four sorghum grain varieties, SESO 1, SESO 3, Epuripur, and Eyera, and their malt extracts were characterized which is aimed at determining their suitability for growing microbial biomass. The varieties had kernel length, kernel width, kernel thickness, and thousand kernel weigh equivalent to 3.8-4.3 mm, 3.2-4.5 mm, 2.4-2.8 mm, and 12.4-20.2 g, respectively. SESO 1 and Epuripur had corneous endosperm textures whereas those of SESO 3 and Eyera were intermediate and floury, respectively. Varieties had germinative energies > 90% and total defects < 8%. SESO 3 had the highest (p < 0.05) crude protein (10.8 ± 0.3%) and dietary fiber (22.5 ± 0.4%) whereas Epuripur had the highest (p < 0.05) starch ...
Research Interests: Food Science and Sorghum
The performance of a hammer mill fabricated in Uganda was evaluated and the optimal performance conditions were determined. The evaluation was done with screen hole diameters (S) of 1.5, 2.0, and 3.0 mm, hammer tip speeds (H) of 68.12,... more
The performance of a hammer mill fabricated in Uganda was evaluated and the optimal performance conditions were determined. The evaluation was done with screen hole diameters (S) of 1.5, 2.0, and 3.0 mm, hammer tip speeds (H) of 68.12, 81.81, 102.17 m s and hammer thicknesses (T) of 4.0, 5.0, and 6.0 mm for determination of energy consumption and geometric mean diameter (GMD) using a modified central composite design (CCD) split-plot experimental design. Screen hole diameter and hammer thickness had significant effects on energy consumption (p<0.05). S and H had a significant effect on GMD but T did not have a significant effect on GMD. S and H had significant effects on both GMD and energy consumption. Quadratic effect of T, interaction effects of TH and HS also had significant effects on energy consumption. The hammer mill was most efficient with a hammer thickness of 5 mm, hammer tip speed of 83.57 m s and screen hole diameter of 2.16 mm, both for energy consumption and flour ...
... Effect of pre-icing duration on quality deterioration of iced Nile perch (Lates niloticus). C. Karungi , YB Byaruhanga and JH Muyonga Corresponding Author Contact Information , E-mail The Corresponding Author. ... (9th ed ed.),,... more
... Effect of pre-icing duration on quality deterioration of iced Nile perch (Lates niloticus). C. Karungi , YB Byaruhanga and JH Muyonga Corresponding Author Contact Information , E-mail The Corresponding Author. ... (9th ed ed.),, Longman Scientific and Technical, London (1991). ...
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Cultivation of lactic acid bacteria cultures is vital for research and commercial production of fermented foods. However, the conventional growth media used are generally costly. Malt extracts from four sorghum varieties (SESO 1, SESO 3,... more
Cultivation of lactic acid bacteria cultures is vital for research and commercial production of fermented foods. However, the conventional growth media used are generally costly. Malt extracts from four sorghum varieties (SESO 1, SESO 3, Epuripur, and Eyera) were evaluated as alternative low-cost growth media for Lactobacillus plantarum MNC 21. Saccharified sorghum malt extracts were inoculated with 4 log cfu/mL MNC 21 and incubated at 30°C for 24 h. MRS broth was the reference medium. Microbial counts, pH, titratable acidity (TA), free amino nitrogen (FAN), and total sugars were measured. Maximum microbial counts in the extracts and MRS broth were 9 and 10 log cfu/mL, respectively. Maximum growth rate in the extracts was 0.7–0.9 log cfu/mL/h and 0.8 log cfu/mL/h in MRS broth. The final pH of the extracts was 3.5–3.6, with an overall increase in TA of 1.2% in Epuripur and 0.2% in other varieties. Final pH and TA of MRS broth were 4.1 and 1.3%, respectively. Total sugars dropped by 9...
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The purpose of this study was to establish the probiotic potential of lactic acid bacteria (LAB) starter cultures, Lb. plantarum MNC 21, L. lactis MNC 24, and W. confusa MNC 20, isolated from a traditionally fermented sorghum-millet... more
The purpose of this study was to establish the probiotic potential of lactic acid bacteria (LAB) starter cultures, Lb. plantarum MNC 21, L. lactis MNC 24, and W. confusa MNC 20, isolated from a traditionally fermented sorghum-millet beverage from Uganda. The cultures were examined for tolerance to acid and bile salts, bile salt hydrolase (BSH) activity, antibiotic susceptibility, biogenic amine production, mucin degradation, hydrophobicity, auto-aggregation, adherence to the ileum, coaggregation, and antimicrobial properties against selected pathogenic species. Lb. rhamnosus yoba 2012, a known probiotic, was the reference. The isolates were tolerant to acid (pH = 3) and bile (1%). W. confusa MNC 20 and Lb. plantarum MNC 21 exhibited medium BSH activity (11–15 mm diameter of hydrolysis zone) while L. lactis and Lb. rhamnosus yoba 2012 exhibited low BSH activity (<10 mm diameter of hydrolysis zone). All isolates lacked mucolytic activity. Lb. plantarum MNC 21 and W. confusa MNC 20 ...
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This study aimed at understanding peel and flesh characteristics of Cucurbita maxima Duchesne subsp maxima, Cucurbita pepo L var. fastigata and Cucurbita moschata Decne pumpkin varieties and how the fruit characteristics relate to its... more
This study aimed at understanding peel and flesh characteristics of Cucurbita maxima Duchesne subsp maxima, Cucurbita pepo L var. fastigata and Cucurbita moschata Decne pumpkin varieties and how the fruit characteristics relate to its postharvest stability. Mature fruits were stored at ambient conditions (28oC and 78% Relative humidity) for eight months. Cell microscopic structure, intercellular space size, sugars, starch, cellulose, hemicellulose, lignin, degree of esterification of pectin, polygalacturonase activity, and cumulative moisture lost were determined monthly. Sucrose, starch, cellulose and hemicellulose content and degree of esterification of pectin of different varieties decreased with storage. Glucose and fructose content increased to a maximum and then reduced. Polygalacturonase activity and lignin generally increased with storage time. Size of intercellular spaces, and cumulative moisture lost from both flesh and peel increased with storage. Sucrose breakdown was ke...
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ILRI works with partners worldwide to help poor people keep their farm animals alive and productive, increase and sustain their livestock and farm productivity, and find profitable markets for their animal products. ILRI's... more
ILRI works with partners worldwide to help poor people keep their farm animals alive and productive, increase and sustain their livestock and farm productivity, and find profitable markets for their animal products. ILRI's headquarters are in Nairobi, Kenya; we have a principal campus in Addis Ababa, Ethiopia, and 14 offices in other regions of Africa and Asia. ILRI is part of the Consultative Group on International Agricultural Research (www.cgiar.org), which works to reduce hunger, poverty and environmental degradation in developing countries by generating and sharing relevant agricultural knowledge, technologies and policies. © 2011 International Livestock Research Institute (ILRI) This publication is copyrighted by the International Livestock Research Institute (ILRI). It is licensed for use under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. To view this license, visit http://creativecommons. org/licenses/by-nc-sa/3.0/. Unless otherwise no...
Summary Mycotoxins in food are of growing health importance due to their association with a number of human and animal diseases. In humans, mycotoxins have been associated with neural tube defects, oesophageal and liver cancer.... more
Summary Mycotoxins in food are of growing health importance due to their association with a number of human and animal diseases. In humans, mycotoxins have been associated with neural tube defects, oesophageal and liver cancer. Additionally, mycotoxins affect productivity and trade with in the affected communities. The incidence and extent of mycotoxins in sorghum and millet is not well established. The conditions in tropical agricultural zones, which are the main production areas of sorghum and millet, favour the growth of moulds. Some species of the moulds Fusarium and Aspergillus found growing on millet and sorghum are known to produce mycotoxins. There are few reports of mycotoxin presence in millet and sorghum and the extent to which these toxins are produced in these grains is not well established. This paper explores the incidence, extent and health risk of mycotoxins in millet and sorghum.
Four types of Obushera, a fermented millet or sorghum beverage: Ekitiribita, Obuteire, Obutoko and Enturire were analyzed for their physico-chemical properties, sugars, organic acids and volatile compounds during fermentation. Standard... more
Four types of Obushera, a fermented millet or sorghum beverage: Ekitiribita, Obuteire, Obutoko and Enturire were analyzed for their physico-chemical properties, sugars, organic acids and volatile compounds during fermentation. Standard chemical methods were used to determine the physico-chemical properties of Obushera. The organic acids, carbohydrates, glucose, fructose and maltose were analyzed by high-performance liquid chromatography. The pH of all Obushera varied between 4.00±0.10 and 4.42±0.11 after 4 days of fermentation. The pH of Obuteire, Obutoko and Enturire dropped below 4.5 within one day of fermentation. Acidity ranged between 0.13% (Ekitiribita) to 1.33% (Enturire) after 4 days of fermentation. Dry matter decreased and varied between 5.4 and 22% after 4 days of fermentation. Fermentation resulted into a 20–40% reduction of dry matter in Obutoko, Obuteire and Enturire. Enturire had the highest dry matter content and decreased from 22% to 13%. Fermentation resulted in an...
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In spite of intervention efforts, in Uganda, as in other developing countries, high levels of anaemia among pregnant women continue. Anaemia among women of reproductive age (15-49 years) is a matter of national concern. This study was... more
In spite of intervention efforts, in Uganda, as in other developing countries, high levels of anaemia among pregnant women continue. Anaemia among women of reproductive age (15-49 years) is a matter of national concern. This study was carried out to assess determinants of anaemia in Kiboga district. This was a single cross-sectional, descriptive survey. The anaemia status of the pregnant women was determined by measuring their haemoglobin levels. Possible determinant factors including socio-economic characteristics, knowledge, attitudes, practices and food intake were assessed using a structured questionnaire. Results showed that the prevalence of anaemia among pregnant women in Kiboga district was high enough (63.1%) to be described as a severe public health problem. The uptake and utilisation of the public-health intervention package to combat anaemia in pregnancy was low, with iron/folic acid supplementation at 13.2%, use of intermittent preventive treatment of malaria 45.4%, and...
Research Interests: Nursing, Adolescent, Pregnancy, Humans, Female, and 15 moreAnemia, Risk factors, Middle Aged, Questionnaires, Adult, Public health systems and services research, Pregnant Women, Risk Factors, Iron Deficiency Anemia, Cross Sectional Studies, Hemoglobins, Energy Intake, Health Services Accessibility, Pregnancy complications, and Residence Characteristics
This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and... more
This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometry at 450 nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (p<0.05. The fresh cowpea leaf b-carotene and vitamin C content was 140.9 and 164.3 mg / 100g DM respectively and decreased (p<0.05) with drying. Open sun drying method caused the greatest b-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved b-carotene and vitamin C retention by 15% and 7.5% respectively. The b-carot...
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ABSTRACT Maltedandun-maltedsorghum(Sorghumbicolor (L.) Moench)flourwasgammairradiatedwithadose of 10kGyandthenre-irradiatedwith25kGy.Theeffectsofirradiationonmicrobialdecontamination, amylaseactivity,fermentability(usinganamylolytic L.... more
ABSTRACT Maltedandun-maltedsorghum(Sorghumbicolor (L.) Moench)flourwasgammairradiatedwithadose of 10kGyandthenre-irradiatedwith25kGy.Theeffectsofirradiationonmicrobialdecontamination, amylaseactivity,fermentability(usinganamylolytic L. plantarum MNC21strain),starchgranule structureandviscosityweredetermined.Standardmethodswereusedduringdeterminations.The 10 kGydosehadnoeffectonmicrobialloadofun-maltedflourbutreducedthatofmaltedflourby3log cycles.Re-irradiationresultedincompletedecontamination.Irradiationofmaltcausedasignificant (po0.05) reductioninalphaandbetaamylaseactivity(22%and32%,respectively).Irradiationofun- malted flourincreasedtheratesofutilizationofglucoseandmaltoseby53%and100%,respectively, during fermentation.However,microbialgrowth,rateoflacticacidproduction,finallacticacid concentrationandpHwerenotaffected.Starchgranulesappearednormalexternallyevenafterre- irradiation,however,granulesrupturedanddissolvedeasilyafterhydrationandgelatinization. Productionofhighdrymatterdensityporridge(200gdrymatter/L)withaviscosityof3500cPwas achievedbyirradiationofun-maltedfloutat10kGy.Gammairradiationcanbeusedtodecontaminate floursandcouldbeutilizedtoproduceweaningporridgefromsorghum.
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Various extraction and drying conditions for the isolation of kafirin from dry-milled, whole grain sorghum have been investigated, with a view to optimizing extraction of the protein for commercial food coatings and packaging films. The... more
Various extraction and drying conditions for the isolation of kafirin from dry-milled, whole grain sorghum have been investigated, with a view to optimizing extraction of the protein for commercial food coatings and packaging films. The addition of sodium hydroxide to an aqueous ethanol extractant increased the yield and solubility of kafirin. Subsequent heat drying at 40 degrees C was shown to cause the kafirin to aggregate as indicated by an increase in intermolecular beta-sheets. Extraction of the flour using ethanol (70%, w/w) with 0.5% (w/w) sodium metabisulfite and 0.35% (w/w) sodium hydroxide at 70 degrees C followed by freeze-drying of the protein was found to produce a yield of 54% kafirin with good film-forming properties. The kafirin films were assessed for their sensory properties, tensile strength, strain, and water vapor permeability. Fourier transform infrared spectroscopy was used to study the secondary structure of the extracted kafirins. The best films were made with kafirin containing a large proportion of nativelike alpha-helical structures with little intermolecular beta-sheet content as indicated by the Fourier transform infrared reflectance peak intensity ratios associated with these secondary structures. The principal factor affecting the secondary structure of the protein appeared to be the temperature at which the protein was dried. Heat drying resulted in a greater proportion of intermolecular beta-sheets. Any industrial-scale extraction must therefore minimize protein aggregation and maximize native alpha-helical structures to achieve optimal film quality.