NRU :: Browsing by Author "Muzira Mukisa, Ivan"

Browsing by Author "Muzira Mukisa, Ivan"

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Adopting traditional fermented foods as carriers for probiotics: The case of Obushera and Lactobacillus rhamnosus yoba
(Nutrition & Food Science, 2019) Muzira Mukisa, Ivan; Byakika, Stellah; Meeme, Rehema; Wacoo, Alex Paul; Sybesma, Wilbert
Traditional fermented products can be adopted as probiotic carriers. This study was aimed at evaluating the potential of using Obushera, a traditional sorghum beverage from Uganda, as a carrier for Lactobacillus rhamnosus yoba. Design/methodology/approach – Probiotic Obushera was produced by fermenting sorghum malt with Lb. rhamnosus yoba 2012 and Streptococcus thermophilus C106 at 30 °C and at room temperature (21°C-25 °C) for 24 h. Acidity, pH, total soluble solids and microbial counts were monitored. Consumer acceptability and purchase index of probiotic Obushera were compared to four commercial non-probiotic brands. Shelf stability of probiotic Obushera was determined by monitoring changes in pH, acidity, soluble solids, microbial counts and consumer acceptability during refrigerated storage. Findings – Lactobacillus rhamnosus yoba 2012 multiplied and lowered the pH of Obushera from 5.3 to < 4.0 (p < 0.0001) whilst increasing acidity from 0.21 to 0.46 per cent (p < 0.0001) in 9 h at 30 °C. Consumer acceptability varied with Obushera brand (p < 0.0001). The overall acceptability score of probiotic Obushera (score of 6.4 = like slightly) was similar to that of the two most acceptable commercial brands (scores of 5.8 and 6.6). Acidity, pH and Lb. rhamnosus counts of probiotic Obushera varied within 0.6 per cent –1.05 per cent (p < 0.0001), 3.3–3.4 (p < 0.0001), and 8.2-9.2 log cfu/ml (p < 0.0001), respectively during two months of storage. The overall acceptability of probiotic Obushera (scores of 6.9-7.8) did not change significantly during storage (p = 0.185). Practical Implications – Traditional fermented foods such as Obushera can be adopted as carriers of probiotic microorganisms. Originality/value – Use of commercial probiotic strains in traditional fermented foods is a novel approach that can be adopted to improve safety of traditional fermentations and health of consumers.
Antimicrobial Activity of Lactic Acid Bacteria Starters against Acid Tolerant, Antibiotic Resistant, and Potentially Virulent E. coli Isolated from a Fermented Sorghum-Millet Beverage
(International Journal of Microbiology, 2019) Byakika, Stellah; Muzira Mukisa, Ivan; Mugabi, Robert; Muyanja, Charles
Bacterial contamination of fermented foods is a serious global food safety challenge that requires effective control strategies. -is study characterized presumptive E. coli isolated from Obushera, a traditional fermented cereal beverage from Uganda. -ereafter, the antimicrobial effect of lactic acid bacteria (LAB) previously isolated from Obushera, against the E. coli, was examined. -e presumptive E. coli was incubated in brain heart infusion broth (pH � 3.6) at 25°C for 48 h. -e most acid-stable strains were clustered using (GTG)5 rep-PCR fingerprinting and identified using 16S rRNA sequencing. E. coli was screened for Shiga toxins (Stx 1 and Stx 2) and Intimin (eae) virulence genes as well as antibiotic resistance. -e spot-on-the-lawn method was used to evaluate antimicrobial activity. Eighteen isolates were acid stable and are identified as E. coli, Shigella, and Lysinibacillus. -e Stx 2 gene and antibiotic resistance were detected in some E. coli isolates. -e LAB were antagonistic against the E. coli. Lactic acid bacteria from traditional fermented foods can be applied in food processing to inhibit pathogens. Obushera lactic acid bacteria could be used to improve the safety of fermented foods.
Application of refrigerated and frozen sorghum malt slurries in preservation of starter cultures of traditional fermented cereal-based beverages - a case of Obushera from Uganda
(Research Square, 2020) Muzira Mukisa, Ivan; Serwanga, Arnold; Byakika, Stellah
Industrial production of traditional fermented beverages in developing countries is limited by lack of commercial starter cultures. Saccharomyces (S.) cerevisiae MNC 21Y and Lactobacillus (L.) plantarum MNC 21 were identi􀂦ed as starter cultures for a Ugandan cereal beverage, Obushera. However, they are commercially unavailable due to lack of affordable appropriate propagating and preservation methods. In this study the starters were propagated in sorghum malt slurries (30 °C for 24 h) and stored at 5 °C and − 18 °C for 90 days. Viability and fermentation ability of the cultures was monitored. Results Viability was higher for starters stored at 5 °C (S. cerevisiae: 6 log cfu/g and L. plantarum: 7–9 log cfu/g during 90 days) than those at -18 °C (S. cerevisiae: 2 cfu/g and L. plantarum: 4 log cfu/g after 30 days). Refrigerated starters acidi􀂦ed Obushera (pH ≤ 4.5) faster (10–20 h) than frozen ones (18–24 h). Refrigerating the starters in sorghum malt slurries preserves them for at least three months. This provides an affordable option for starter commercialization and industrial production of traditional fermented foods.
An Audit into the Nature of Operations of Agro-processing Micro, Small and Medium Enterprises (MSMEs) in Uganda
(Journal of Food Industry, 2021) Kigozi, Julia; Baidhe, Emmanuel; Muzira Mukisa, Ivan; Muyanja, Charles; Namubiru, Leatitiah; Katarikawe, Brenda
The agro-processing Micro, Small, and Medium-Sized Enterprises (MSMEs) form an integral part of the manufacturing sector in Uganda. To effectively facilitate product certification among MSMEs, there is a need to fully understand the nature of their operations so that appropriate interventions can be put in place. This study assessed the status quo of operations at selected MSMEs in Uganda. A semi-structured paper-based questionnaire was administered to the owners, managers, or supervisors of 40 selected agro-processing MSMEs enrolled under the project “Empowerment of the Agro-Processing Industry to meet the Quantity and Quality Standards for the Local and Export Market”, a programme enhancing the practical skills of students at Makerere University dubbed the “EAPI Project.” The seven-section questionnaire consisted of both quantitative and qualitative questions focusing on (i) product optimization, (ii) raw material verification and storage, (iii) good manufacturing practices, (iv) measuring and testing equipment, (v) product assessment, presentation, and storage, (vi) waste and pest management, and (vii) infrastructure and energy utilization. The results indicated that only 23.7% of agro-processing MSMEs clearly understood the standards. Packaging was the most optimized parameter (74.4%), followed by texture and sensory properties (59% and 51.1%, respectively). About 74% of the agro-processing MSMEs were compliant in declaring the raw materials on the product label. Maintenance of valid medical certificates, routine inspection of personnel, and provision of protective gear ranked low, with a score of 1 out of 10. Inadequate documentation was a cross-cutting issue for all operations, yet it was a driver for GMPs. There is a need to strengthen the understanding and practice of food processing standards from the Uganda National Bureau of Standards (UNBS), in the agro-processing MSMEs through continuous human and institutional-capacity development programs.
Characterizing Selected Sorghum Grain Varieties and Evaluating the Suitability of Their Malt Extracts for Cultivating Microbial Biomass
(International Journal of Food Science, 2021) Byakika, Stellah; Muzira Mukisa, Ivan; Byenkya Byaruhanga, Yusuf
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 (81:6 ± 0:0%) and crude fat (2:9 ± 0:1%). There was no significant difference (p > 0:05) in the ash contents (2:1 ± 0:0%). The total sugars, free amino nitrogen, condensed tannins, and pH of the malt extracts were 106-116 g/L, 70-78 mg/L, 0.1-0.6 mg/mL, and 5.5-5.7, respectively. The composition of the sorghum malt extracts suggests their potential for use in cultivating microbial biomass.
Comparison of the microbial composition of African fermented foods using amplicon sequencing
(Scientific reports, 2019) Diaz, Maria; Kellingray, Lee; Akinyemi, Nwanneka; Olaoluwa Adefiranye, Oyetayo; Houngbédji, Marcel; Kamya, Deus; Muzira Mukisa, Ivan; Obodai, Mary; Mayer, Melinda J.; Oguntoyinbo, Folarin A.; Narbad, Arjan
Fermented foods play a major role in the diet of people in Africa, where a wide variety of raw materials are fermented. Understanding the microbial populations of these products would help in the design of specific starter cultures to produce standardized and safer foods. In this study, the bacterial diversity of African fermented foods produced from several raw materials (cereals, milk, cassava, honey, palm sap, and locust beans) under different conditions (household, small commercial producers or laboratory) in 8 African countries was analysed by 16S rRNA gene amplicon sequencing during the Workshop “Analysis of the Microbiomes of Naturally Fermented Foods Training Course”. Results show that lactobacilli were less abundant in fermentations performed under laboratory conditions compared to artisanal or commercial fermentations. Excluding the samples produced under laboratory conditions, lactobacilli is one of the dominant groups in all the remaining samples. Genera within the order Lactobacillales dominated dairy, cereal and cassava fermentations. Genera within the order Lactobacillales, and genera Zymomonas and Bacillus were predominant in alcoholic beverages, whereas Bacillus and Lactobacillus were the dominant genera in the locust bean sample. The genus Zymomonas was reported for the first time in dairy, cereal, cassava and locust bean fermentations.
The Effect of Selected Chemical Preservatives and Starter Cultures on the Sensory Characteristics and Shelf Life of Rice Injera
(Journal of Bioprocessing & Biotechniques, 2018) Hassen, Yassin; Muzira Mukisa, Ivan; Kurabachew, Henok
Injera is yeast-risen flat bread with a unique, slightly spongy texture. It is a national staple in Ethiopia that is eaten daily in virtually every household. Rice injera has a very short life (2-3 days) at room temperature and essentially spoils due to mould growth. The use of weak organic acid as preservative is allowed in acidic foods, primarily as mould inhibitors. In this study, the effects of chemical preservatives: benzoic acid, sodium benzoate, and potassium sorbate and starter cultures (Lactobacillus plantarum+Saccharomyces cerevisiae) on the quality and shelf life of rice injera were investigated. Benzoic acid (0.1%), sodium benzoate (0.1%), potassium sorbate (0.2%) and a 1:1:1 blend of the three (0.2%) were added immediately before baking. Qualitative descriptive analysis (n=10) was used to describe the characteristics of the injera samples. A consumer acceptability panel (n=30) was used to determine the acceptability and shelf life of injera. The preservatives significantly (p<0.05) prolonged the shelf life of injera for up to 10 days with the combination of the three starters achieving the greatest effect. The findings of this study showed that the rice injera prepared with chemical preservatives (0.1 benzoic acid, 0.2% potassium sorbate, 0.1% sodium benzoate and 0.2% of the three preservatives retains maximum overall acceptability. Rice injera produced under controlled fermentation L. plantarum, and S. cerevisiae produce injera with better sensory quality than the traditional by using Irsho. Nine descriptors/attributes describing appearance, aroma/odor, taste, and texture were generated to characterize the sensory properties of rice injera. Softness, rollablity, fluffiness, eye size, whitness of top and bottom surfaces and slight sour taste are main characterstics descriptors of rice injera. Softness, fluffiness, spongness, slight sourness and eye size are attributes associated with quality of rice injera. Therefore, a starter combination of L. plantarum+S. cerevisiae together with 0.2% of the blend of the preservatives (0.1% benzoic acid+0.1% sodium sorbate+0.2% potassium sorbate) in 1:1:1 ratio preservatives can be used to produce acceptable injera with a shelf life of 10 days at room temperature.
Effect of sweet potato endogenous amylase activation on in vivo energy bioavailability and acceptability of soy-enriched orange-fleshed sweet potato complementary porridges
(Food Science & Nutrition, 2018) Birungi, Catherine; Nabubuya, Agnes; Muzira Mukisa, Ivan
Energy bioavailability can be influenced by food matrix factors and processing conditions or treatments. In this study, the effects of endogenous sweet potato amylase enzyme activation and slurry solids content of soy-enriched orange-fleshed sweet potato (OFSP) porridges on in vivo energy bioavailability (energy, weight gain, and feed efficiency ratio) and porridge acceptability were determined. Fifty-six weanling albino rats were randomly assigned to two blocks each having eight groups of seven rats. The rats were housed in individual cages in a well-ventilated animal house. The intervention block had rats fed on activated porridges (held at 75°C for 15 min), while rats in the control block were fed on nonactivated porridges (boiled at 90–95°C for 10 min). The rats were fed for 28 days on 50 ml of porridge per rat per day. The four groups per block were each fed on porridges with varying amounts of total solids content (10%, 15%, 20%, and 25%). Weight gain, energy bioavailability, and feed efficiency ratio were determined at the end of the feeding period. Consumer acceptability of activated and nonactivated porridges at 25% solids content was determined using a nontrained human panel (n = 40). Activation of amylases did not significantly (p > .05) affect the bioavailable energy, cumulative weight gain, and feed efficiency of the rats. Increasing slurry solids content of activated and nonactivated porridges significantly (p < .05) increased feed efficiency ratio (−14.6 ± 11.7 to 102.3 ± 2.3), weight gain (−1.4 to 5.6 g ± 1.9 g), and bioavailable energy (702.8 ± 16.2 to 1242.8 ± 12.2 kcal). Activation of amylases reduced porridge viscosity but did not significantly influence the overall acceptability. This work demonstrates the opportunity of utilizing sweet potato amylases to facilitate the preparation of complementary porridges with appropriate viscosity and increased energy density.
Effects of Feed Moisture Content, Soybean Ratio and Barrel Temperature on Physical and Functional Properties of Extruded Maize-Soybean Flour Blends
(Tanzania Journal of Science, 2022) Mugabi, Robert; Byakika, Stellah; Muzira Mukisa, Ivan
The effects moisture content, temperature and soybean ratio on expanded product characteristics of extruded maize-soybean blends were studied. Response surface methodology was used to study the effects of extrusion conditions on extrudate properties taking barrel temperature (BT), feed moisture content (FM) and soybean flour ratio (SR) as factors. Expansion ratio (ER), water absorption index (WAI), water solubility index (WSI), hardness and colour (b* - (+) yellowness) of the extrudates were determined. BT and FM had significant effects on ER (p < 0.05). At low FM levels, ER increased with BT. It was observed that both FM and BT significantly affected WAI and WSI. WAI increased as FM increased. Increasing FM to 20% resulted in a decrease in WSI, beyond which an increase was observed. Hardness increased significantly as feed moisture content increased. High SR content significantly increased the extrudate hardness. FM had no significant effect on colour. Colour increased as the SR and BT increased. Significant regression models explained the effects of SR, FM, and BT on all response variables. All of the response variables' R2, were higher than 0.89.
Food Safety Knowledge, Attitudes and Practices of Food Handlers along the Rice Value Chain of Uganda
(Journal of Food Industry, 2022) Namubiru, Leatitiah; Male, Denis; Muzira Mukisa, Ivan; Byenkya Byaruhanga, Yusuf
Food handlers play a critical role in controlling food contamination from “farm to fork”. Therefore, inadequate knowledge, poor attitudes and improper practices by food handlers pose a serious challenge to food safety. The aim of this study was to assess the knowledge, attitudes, and practices (KAP) of food handlers along the rice value chain of Uganda with the view of understanding factors that influence contamination of rice with aflatoxins, heavy metals and pesticides. A cross-sectional study, using a structured questionnaire through face-to-face interviews with 252 respondents was conducted in Butaleja, Gulu, Hoima, Kampala, Mutukula, Mbale and Mbarara districts. Categorical data was expressed as frequencies and percentages. The unique predictors of the KAP of rice handlers were defined using multivariate linear regression analysis. About 221 (87.7%) food handlers knew about the occurrence and causes of aflatoxins contamination in rice. Changes in colour (81.7%) and a musty smell (82.9%) were perceived to indicate the presence of aflatoxins. The main preand post-harvest aflatoxin preventative practices identified were growing resistant rice varieties (82.9%) and proper drying (79.8%). Food handlers were generally not knowledgeable (73.4%) about heavy metal contamination in rice. All food handlers used pesticides; however, 68.3% had never received formal training in pesticide use. Majority (86.1%) of food handlers were aware of the harmful effects of pesticides but on the contrary, this did not significantly change their practices towards safe pesticide use. At multivariate level, education was the unique predictor for aflatoxins and heavy metal contamination. Pesticide contamination was mainly influenced by district of residence. Therefore, appropriate educational programs organized to train food handlers can promote food safety in the rice value chain of Uganda. Interventions by regulatory agencies to strengthen enforcement of laws related to contaminants through regular surveillance at the farm and retail outlets are necessary to ensure compliance by food handlers.
Influence of EAPI Skills Training Course on the Knowledge, Attitude, and Practice of Undergraduate University Students: A Case of the EAPI Program, Uganda
(International Journal of Learning and Development, 2021) Kigozi, Julia; Baidhe, Emmanuel; Muzira Mukisa, Ivan; Muyanja, Charles; Namubiru, Leatitiah; Katarikawe, Brenda
Upon employment, fresh graduates have been widely criticized for their underperformance due to their lack of relevant practical skills. Furthermore, students need training that allows them to blend knowledge with the practice in the workspace. This study assessed the influence of an ‘Empowerment of the Agro-processing Industry (EAPI)' skills training for the agro-processing industry, on the knowledge, attitude, and practice among students in the School of Food Technology Nutrition and Bio-Engineering (SFTNB), Makerere University. Students were trained in 8 modules including; food process and value-chain management, food product optimization, national and international standards of food products, application of good management practices (GMP) and hygienic food processing, quality control in food production processes, waste management, infrastructure development to meet quality & production capacity in food production facilities and food product marketing & preparation for export markets. A semi-structured questionnaire with a descriptive, scale and thematic analysis was used to evaluate the impact of the training. The reliability of the responses of the questionnaires was tested using Cronbach’s alpha and they showed high reliability; yielding values that ranged between 0.88 and 0.97. Results showed a statistically significant difference (p < 0.05) in knowledge, attitude and practice for product optimization, adequate processing facility, standardization, certification, and export marketing. Cronbach’s alpha values ranged between 0.88 and 0.97 for all stated variables indicating that the scales were sound and reliable. Therefore, the inclusion of similar study material into the current curriculum would help improve and enrich the curriculum thereby producing well-prepared students for the food processing industry in Uganda.
Influence of Fieldwork on the Preparedness of Food Technology and Bioengineering students for the Job Market: A Case study of EAPI Student Skills Enhancement Program
(Business and Management Research, 2021) Kigozi, Julia; Baidhe, Emmanuel; Muzira Mukisa, Ivan; Muyanja, Charles; Namubiru, Leatitiah; Katarikawe, Brenda
This study aimed at evaluating the influence of fieldwork on the professional and personal skills among Food Technology and Bioengineering (FTB) students of Makerere University. The data was obtained from 40 respondents from three FTB programs (Food Science and Technology, Human Nutrition, and Agricultural Engineering). A semi-structured electronic questionnaire was used to collect the data. The questionnaire comprised of Part 1: Student biography, Part II: Participation in the EAPI student skills enhancement program, Part III: Professional skills, and Part IV: Personal growth. Part I and II consisted of closed-ended questions while Part III and Part IV were evaluated on a 5-point Likert scale (1- Strongly disagree and 5 – Strongly Agree). Descriptive analysis was used to evaluate the student demographic information and participation in the student enhancement program. The reliability of the Likert scale for professional development and personal growth was determined using the Cronbach’s alpha index. The study results indicated that 60% (n=40) of the respondents better understood their career goals through fieldwork, 83% (n=40) increased their skills and knowledge in performing particular tasks, 55% (n=40) changed their attitude and feelings about self and others, while 75% (n=40) had the opportunity to apply theoretical concepts to the actual work environment. Fieldwork stimulated the FTB students’ interest in the field of food processing, mindset change especially concerning job creation, conduct, and prospects. The study findings explain the need to adjust the mode of knowledge delivery and dispensation at the Higher Education Institutions to reduce the rate of unemployment and improve the employability of students.
Influence of food safety knowledge, attitudes and practices of processors on microbiological quality of commercially produced traditional fermented cereal beverages, a case of Obushera in Kampala
(Food Control, 2019) Byakika, Stellah; Muzira Mukisa, Ivan; Byenkya Byaruhanga, Yusuf; Male, Denis; Muyanja, Charles
Traditionally, fermented foods were only consumed in regions of their origins but owing to increasing demand, some are finding their way into foreign markets. The challenge though, is the generally uncontrolled nature of the fermentations which raises safety concerns. This paper highlights the food safety challenges associated with traditional fermented foods with a special focus on commercially produced and packaged Obushera, a Ugandan traditional fermented cereal beverage. Microbial counts, titratable acidity (TA) and pH of Obushera samples (n=59) were determined. Food safety knowledge, attitudes and practices (KAP) of processors (n=47) were also evaluated. About 50% of samples did not conform to safety requirements. Obushera had 0.0–7.3 log cfu/mL total and thermo-tolerant coliforms, 0.0–6.2 log cfu/mL E. coli and 0.0–8.1 log cfu/mL Staphylococcus spp. Flour samples had 3.7–7.3 log cfu/g total coliforms, 3.2–7.1 log cfu/g thermo-tolerant coliforms, 1.0–4.9 log cfu/g E. coli and 2.4–7.3 log cfu/g Staphylococcus spp. Salmonella spp was not detected. Obushera (56 out of 59 samples) with pH≤4.0 and TA=0.1–3.1% had coliforms and Staphylococcus spp above the recommended minimum values. Scores showed that processors had fairly good knowledge (63.0 ± 2.3%) and attitudes (52.2 ± 3.0%) but poor practices (38.7 ± 2.4%). There was no correlation between the KAP and product quality. Therefore, processors should adopt better processing technologies that enhance food safety. There is also need for enforcement and regulation of food safety by concerned authorities. Trainings for processors should aim at positively changing their attitudes and causing them to adopt appropriate practices.
Influence of Thermal Processing on Hydrolysis and Stability of Folate Poly-γ-glutamates in Broccoli (Brassica oleracea var. italica), Carrot (Daucus carota) and Tomato (Lycopersicon esculentum)
(Journal of agricultural and food chemistry, 2010) Wambui Munyaka, Ann; Verlinde, Philippe; Muzira Mukisa, Ivan; Oey, Indrawati; Van Loey, Ann; Hendrickx, Marc
The folate poly-γ-glutamate profile, their concentrations, and hydrolysis by endogenous γ-glutamyl hydrolase (GGH) were evaluated in broccoli, carrot and tomato. Further studies on the effect of time and temperature on folate poly-γ-glutamate hydrolysis and stability were carried out in broccoli since this vegetable showed the highest long-chain and total folate poly-γ-glutamate concentration. The evolution of L-ascorbic acid, total phenols and Trolox equivalent antioxidant capacity (TEAC) values was evaluated in parallel. Upon thermal inactivation of GGH prior to crushing, it was observed that broccoli, carrot and tomato contained poly-γ-glutamates with one to seven glutamate residues but differed in the predominant poly-γ-glutamates. Crushing of raw broccoli, carrot and tomato resulted in significant poly-γ-glutamate profile changes in broccoli and carrot (indicating GGH-catalyzed hydrolysis) but not in tomato. In this study, the actual crushing of raw broccoli matrix had a greater effect on folate poly-γ-glutamate hydrolysis than incubation conditions (0-30 min at 25-55 C). During treatments at 25-140 C, folate retention was higher at 80 and 100 C than at the other temperatures. A similar trend in thermal stability was observed for folates, vitamin C, total phenols and TEAC value, an indication that conditions that result in endogenous antioxidants degradation might also result in folate degradation.The folate poly-γ-glutamate profile, their concentrations, and hydrolysis by endogenous γ-glutamyl hydrolase (GGH) were evaluated in broccoli, carrot and tomato. Further studies on the effect of time and temperature on folate poly-γ-glutamate hydrolysis and stability were carried out in broccoli since this vegetable showed the highest long-chain and total folate poly-γ-glutamate concentration. The evolution of L-ascorbic acid, total phenols and Trolox equivalent antioxidant capacity (TEAC) values was evaluated in parallel. Upon thermal inactivation of GGH prior to crushing, it was observed that broccoli, carrot and tomato contained poly-γ-glutamates with one to seven glutamate residues but differed in the predominant poly-γ-glutamates. Crushing of raw broccoli, carrot and tomato resulted in significant poly-γ-glutamate profile changes in broccoli and carrot (indicating GGH-catalyzed hydrolysis) but not in tomato. In this study, the actual crushing of raw broccoli matrix had a greater effect on folate poly-γ-glutamate hydrolysis than incubation conditions (0-30 min at 25-55 C). During treatments at 25-140 C, folate retention was higher at 80 and 100 C than at the other temperatures. A similar trend in thermal stability was observed for folates, vitamin C, total phenols and TEAC value, an indication that conditions that result in endogenous antioxidants degradation might also result in folate degradation.
Lactic Acid Bacteria Antagonism of Acid-tolerant and Antibiotic-resistant Nonstaphylococcal Pathogenic Species Isolated from a Fermented Cereal Beverage using Baird-Parker Agar
(Journal of agricultural and food chemistry, 2010) Byakika, Stellah; Muzira Mukisa, Ivan; Muyanja, Charles
Fermented foods may contain acid-tolerant and antibiotic-resistant pathogenic microorganisms. Pathogens can be antagonized by lactic acid bacteria, resulting in improved microbiological safety. This study assessed the antagonistic effects of selected lactic acid bacteria against pathogenic bacteria isolated from a cereal fermented food. Materials and Methods: Eight presumptive staphylococci isolated from a commercially produced cereal fermented beverage on Baird-Parker agar supplemented with tellurite were identified using 16S rRNA sequencing. Acid resistance of the isolates was assessed using acidified media (brain heart infusion broth of pH 3.6 and 1.5% acidity) for 48 h followed by taking plate counts. Antibiotic resistance (19 antibiotics) was assessed using the disk diffusion assay. A spot-on-the-lawn method was used to assess antagonistic effects of Lactobacillus plantarum MNC 21, Lactococcus lactis MNC 24, Weissella confusa MNC 20 and Lactobacillus rhamnosus yoba 2012 against Lysinibacillus macroides, Bacillus subtilis, Enterococcus faecalis and Escherichia coli. Results: Presumptive staphylococci were identified as Lysinibacillus macroides (n = 1), Bacillus subtilis (n = 2), Enterococcus faecalis (n = 4) and Escherichia coli (n = 1). These isolates were acid-tolerant (from 6.3 ±0.9 log cfu/mL at 0 h to 3.6 ±0.9 log cfu/mL at 48 h), antibiotic-resistant (multiple antibiotic resistance index of 0.1–0.5) and their growth was inhibited by the lactic acid bacteria (inhibition zone diameters of 14–24 mm). Conclusions: The lactic acid bacteria cultures of MNC 20, MNC 21, MNC 24 and Lactobacillus rhamnosus yoba 2012 can be used in various food fermentations to inhibit growth of bacterial pathogens; thus, improving product safety.
Microbiological safety and physicochemical composition of Bongo, a traditional fermented milk product from Lyantonde district, Uganda
(Scientific African, 2020) Muzira Mukisa, Ivan; Ssendagala, George William; Byakika, Stellah
Traditional fermented dairy products, including Bongo, are an important emerging market owing to their nutritional benefits and probiotic potential. Production of Bongo is unstan- dardized, unregulated and may raise public safety concerns. Microbial counts and physic- ochemical parameters ( n = 30 Bongo samples), production protocol, and hygiene practices of processors ( n = 15) were evaluated. Over 93.3% of the products were contaminated with potentially pathogenic microbes including Enterobacteriaceae, coliforms, Sulphur reducing clostridia, Enterococcus spp. and Staphylococcus spp. About 40% of the samples had pH ≥4.0. Most processors had inadequate hygiene practices which compromised product safety. These results indicate the need for developing product specifications, training processors in good food safety practices and enforcing relevant regulations.
Nutritional Characteristics of Selected Insects in Uganda for Use as Alternative Protein Sources in Food and Feed
(Journal of Insect Science, 2019) Bbosa, Tom; Tamale Ndagire, Catherine; Muzira Mukisa, Ivan; Fiaboe, Komi K. M.; Nakimbugwe, Dorothy
Insects are potential ingredients for animal feed and human food. Their suitability may be influenced by species and nutritional value. This study was aimed at determining the nutritional profile of four insects: Dipterans; black soldier fly (Hermetia illucens Linnaeus) family stratiomyidae and blue calliphora flies (Calliphora vomitoria Linnaeus) family Calliphoridae; and orthopterans; crickets (Acheta domesticus Linnaeus) family Gryllidae and grasshoppers (Ruspolia nitidula Linnaeus) family Tettigoniidae to establish their potential as alternative protein sources for animals (fish and poultry) and humans. Gross energy, crude protein, crude fat, crude fiber, carbohydrates, and total ash were in the ranges of 2028.11–2551.61 kJ/100 g, 44.31–64.90, 0.61–46.29, 5.075–16.61, 3.43–12.27, and 3.23– 8.74 g/100 g, respectively. Hermetia illucens had the highest energy and ash content; C. vomitoria were highest in protein and fiber content, R. nitidula were highest in fat, whereas A. domesticus had the highest carbohydrate content. All insects had essential amino acids required for poultry, fish, and human nutrition. The arginine to lysine ratios of H. illucens, C. vomitoria, A. domesticus, and R. nitidula were 1.45, 1.06, 1.06, and 1.45, respectively. The fatty acids comprised of polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs). Palmitic acid (23.6– 38.8 g/100 g of total fat) was the most abundant SFA, exception R. nitidula with 14 g/100 g stearic acid. Linoleic acid (190–1,723 mg/100 g) and linolenic acid (650–1,903 mg/100 g) were the most abundant PUFAs. Only C. vomitoria had docosahexaenoic acid. The study indicates that the insects studied are rich in crude protein and other nutrients and can potentially be used for human and animal (fish and poultry) feeding.
Nutritional composition, quality, and shelf stability of processed Ruspolia nitidula (edible grasshoppers)
(Food science & nutrition, 2017) Ssepuuya, Geoffrey; Muzira Mukisa, Ivan; Nakimbugwe, Dorothy
The nutritional and commercial potential of the edible grasshopper (Ruspolia nitidula, nsenene in Luganda), a delicacy in Uganda and many East African tribes, is limited by a short shelf life and unverified nutritional value. This research established that R. nitidula is nutritious with 36–40% protein, 41–43% fat, 2.5–3.2% carbohydrate, 2.6–3.9% ash, 11.0–14.5% dietary fiber, and 900– 2300 μg/100 g total carotenoids on a dry matter basis. Sautéing was the most preferred processing method resulting in grasshoppers with a notably better aroma and flavor. After 12 weeks of storage at room temperature, processed and vacuum packed, ready-to- eat grasshoppers maintained their edible quality with an acid value of 3.2 mg KOH/g, a total plate count of log 1.8 cfu/g, and an overall acceptability of 6.7–7.2 on a 9-point hedonic scale. Further research is required for extending the shelf stability beyond 12 weeks and characterizing the profile of major nutrients.
Potential application of lactic acid starters in the reduction of aflatoxin contamination in fermented sorghum-millet beverages
(International Journal of Food Contamination, 2019) Byakika, Stellah; Muzira Mukisa, Ivan; Paul Wacoo, Alex; Kort, Remco; Byenkya Byaruhanga, Yusuf; Muyanja, Charles
Aflatoxin contamination in traditionally fermented cereal-based beverages is a serious food safety challenge considering that commercialization of these products is rising. The challenge is aggravated by the fact that aflatoxin elimination from the food chain is almost impossible. This paper focuses on Obushera, a popular traditional spontaneously fermented sorghum – millet beverage from Uganda. Method: Mold and total aflatoxin levels in cereal flours and Obushera from different markets in Kampala were determined. Ability of lactic acid bacteria (LAB) starters from Obushera; Lb. plantarum MNC 21, W. confusa MNC 20 and L. lactis MNC 24 to bind aflatoxin B1 (AFB1) was evaluated against Lb. rhamnosus yoba 2012 as the reference strain. Results: Mold counts in sorghum, millet and Obushera ranged between 0.0–2.4 log cfu/g, 2.0–6.5 log cfu/g and 2.0–5.5 log cfu/g, respectively. None of the flours complied with food safety standards for molds (maximum = 4 log cfu/g) while 88.0% of Obushera did (standard = maximum 1.3 log cfu/g). Total aflatoxin levels in sorghum, millet and Obushera were 22.3 ± 21.2 ppb, 9.9 ± 10.0 ppb and 10.4 ± 6.1 ppb, respectively. LAB bound 19.3–69.4% of AFB1 in a 1000 ppb solution with binding efficiency in the order of Lb. rhamnosus yoba 2012 = Lb. plantarum MNC 21 > W. confusa MNC 20 = L. lactis MNC 24. The LAB-AFB1complex remained stable under a series of washes with physiological saline. Conclusion: This study indicates that LAB with aflatoxin binding properties can be exploited for controlled cereal fermentations to improve food safety.
Potential Benefits of the EAPI Agro-processing Skills Training Course on Micro, Small, and Medium Scale (MSMEs) Agro-processors in Uganda
(Journal of Food Industry, 2020) Kigozi, Julia; Baidhe, Emmanuel; Oluk, Isaac; Muzira Mukisa, Ivan; Muyanja, Charles; Namubiru, Leatitiah; Katarikawe, Brenda
Micro, Small, and Medium Scale Enterprises (MSMEs) in Uganda contribute significantly to socio-economic growth and development. Several training programs have been organized to upgrade the skills and competencies of personnel in these agro-processing enterprises but these often lack a wholistic approach. An Empowerment of the Agro-Processing Industry (EAPI) training was organised to include eight modules covering the key concepts necessary for an agro-processor. These included; food process and value-chain management, product optimization, national and international food standards, Good Management Practices (GMP) and hygienic food processing, quality control, waste management, infrastructure development for food production and food product marketing. This study assessed the potential benefits of the EAPI training on 40 agro-processors from 40 selected agro-processing facilities. Upon completion of a three-day skills development training, MSME practitioners were interviewed using a semi-structured questionnaire. Descriptive, scale, and thematic analysis were used in the study. The questionnaire used was reliable (Cronbach’s coefficient alpha for relevancy = 0.873). Agro-processors found all modules relevant with an average score ranging between 8.7 and 9.5 on a scale of 10. Increase in knowledge, and interaction between stakeholders were the most outstanding potential benefits of the training. Respondents anticipated improving their operations after the training. Provision of handouts, increasing the number of days for the training, and simplifying the language of delivery were some of the suggested improvements. The study suggests that trainings of this nature could improve operations at different agro-processing facilities.

Browsing by Author "Muzira Mukisa, Ivan"

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