Browsing by Author "Sybesma, Wilbert"
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Item 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, WilbertTraditional 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.Item Feasibility of A Novel On‐Site Detection Method for Aflatoxin in Maize Flour from Markets and Selected Households in Kampala, Uganda(Toxins, 2018) Wacoo, Alex Paul; Wendiro, Deborah; Nanyonga, Sarah; Hawumba, Joseph F.; Sybesma, Wilbert; Kort, RemcoIn sub-Saharan Africa, there is a high demand for affordable and accessible methods for on-site detection of aflatoxins for appropriate food safety management. In this study, we validated an electrochemical immunosensor device by the on-site detection of 60 maize flour samples from six markets and 72 samples from households in Kampala. The immunosensor was successfully validated with a linear range from 0.7 0.1 to 11 0.3 g/kg and limit of detection (LOD) of 0.7 g/kg. The maize flour samples from the markets had a mean total aflatoxin concentration of 7.6 2.3 g/kg with approximately 20% of the samples higher than 10 g/kg, which is the maximum acceptable level in East Africa. Further down the distribution chain, at the household level, approximately 45% of the total number contained total aflatoxin levels higher than the acceptable limit. The on-site detection method correlated well with the established laboratory-based HPLC and ELISA-detection methods for aflatoxin B1 with the correlation coefficients of 0.94 and 0.98, respectively. This study shows the feasibility of a novel on-site detection method and articulates the severity of aflatoxin contamination in Uganda.Item Probiotic Enrichment and Reduction of Aflatoxins in a Traditional African Maize-Based Fermented Food(Nutrients, 2019) Wacoo, Alex Paul; Muzira Mukisa, Ivan; Meeme, Rehema; Byakika, Stellah; Wendiro, Deborah; Sybesma, Wilbert; Kort, RemcoFermentation of food products can be used for the delivery of probiotic bacteria and means of food detoxification, provided that probiotics are able to grow, and toxins are reduced in raw materials with minimal effects on consumer acceptability. This study evaluated probiotic enrichment and detoxification of kwete, a commonly consumed traditional fermented cereal beverage in Uganda, by the use of starter culture with the probiotic Lactobacillus rhamnosus yoba 2012 and Streptococcus thermophilus C106. Probiotic kwete was produced by fermenting a suspension of ground maize grain at 30 C for a period of 24 h, leading to a decrease of the pH value to 4.0 and increase in titratable acidity of at least 0.2% (w/v). Probiotic kwete was acceptable to the consumers with a score of 6 on a 9-point hedonic scale. The products were stable over a month’s study period with a mean pH of 3.9, titratable acidity of 0.6% (w/v), and Lactobacillus rhamnosus counts >108 cfu g1. HPLC analysis of aflatoxins of the water-soluble fraction of kwete indicated that fermentation led to an over 1000-fold reduction of aflatoxins B1, B2, G1, and G2 spiked in the raw ingredients. In vitro fluorescence spectroscopy confirmed binding of aflatoxin B1 to Lactobacillus rhamnosus with an efficiency of 83.5%. This study shows that fermentation is a means to enrich with probiotics and reduce widely occurring aflatoxin contamination of maize products that are consumed as staple foods in sub-Saharan Africa.