Humblot, Christèle (PhD)Baye, Kaleab (PhD)Tamene, Aynadis2019-09-192023-11-042019-09-192023-11-042018-06-02http://etd.aau.edu.et/handle/123456789/19132Folate is an essential nutrient in the diets of humans involved in vital functions of cell metabolism. It is currently one of the most actively studied vitamins. This is mainly due to its well established role in preventing neural tube defects in the developing foetus. The present study investigated the potential of using a cereal-based fermented food (injera), made from tef to increase the folate intake of vulnerable population groups. Tef flour (n=60), dough (n=60) and injera (n=60) were collected from the households of Addis (two household/sub-city). Total folate contents of tef flour, dough and injera was determined by microbiological assay using Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism to investigate the effect of processing on the total folate content. The contribution of tef injera consumption to the recommended nutrient intake (RNI) of folate was estimated for children and women of reproductive age. Numbering and isolation of potential folate producing LAB from fermented tef dough were conducted to study their folate production capability in culture media. Identification of folate producing LAB was done morphologically by gram’s staining and genotypically using sequencing of 16S rRNA coding genes. The bioavailability of folate produced by the selected best folate producing LAB strain (Lactobacillus plantarum P2R3FA) was evaluated using a rat depletion-repletion assay. L. plantarum P2R3FA isolated from tef dough and commercial Saccharomyces cerevisiae were tested alone or in combination for their ability to make injera with higher folate content. The folate production capability of L. plantarum P2R3FA has been also evaluated for three successive batch fermentations using back-slopping. The acceptability of folate-enhanced injera was estimated by 30 adult healthy volunteers, using a 9 point hedonic scale. The average folate content (dry weight basis) of tef flour was 58.7 μg/100 g and injera made by traditional process using ersho per fresh weight was 14.3 μg/100 g, which can contribute up to a maximum of 10 % to RNI of folate for children (1-3 years) and women of reproductive age. The effect of fermentation was variable as shown by folate retention, ranging from 60-148 %. Cooking led to folate losses (maximum of 52.8 %). The overall injera processing resulted in folate retention of 38-122 %. A total of 162 potential folate producing LAB were isolated, 19 of which were able to grow and produce folate on folate-free culture medium. Total folate production of the isolates ranged from 1 to 43 μg/L. Four high folate producing isolates were selected, and based on 16S rRNA sequencing all of them were members of the family Lactobacillaceae showing 98-100 % sequence identity to L. plantarum. The L. plantarum P2R3FA was able to restore normal blood folate status of folate-depleted rats. The least folate content was observed in injera fermented by traditional process using ersho. Though the folate content of injera made with S. cerevisiae was the highest and contributed 23 and 27 % to folate RNI of children and women of reproductive age respectively, it was the least accepted product by the potential consumers. Injera made with L. plantarum P2R3FA has also high amount of folate and contributed more than 15 % to the RNI. In addition, it was the most preferred product. The use of backsloping from the dough inoculated with L. plantarum P2R3FA was efficient since the folate content of injera was still very high and the acceptance by the potential consumers was very good.enBioavailabilityCerealDoughFermentationFolateInjeraLactic Acid BacteriaRatsTefThesis