Tropicultura (Jan 2005)
Screening des microorganismes à potentialités fermentaires pour le manioc
Abstract
Screening for Properties of some Strains of Lactobacilli with Potentials Applications as Starter Culture for cassava fermentation. The present study is focussed on the nutritional importance of consumed leafy vegetables in Bini- Dang situated in the Adamawa savannah in Ngaoundere (Cameroon). Firstly, inquiries are held on some ethnonutritional data on the usage and consumption of leafy vegetables. Secondly, physicochemical analyses have been carried out on some nutrient and antinutrient contents of eight most consumed leafy vegetables recorded. They are: Thalinum triangulare, Momordica charantia, Moringa oleifera, Hibiscus cannabinus, H. sabdariffa, Cerathotheca sesamoïdes, Corchorus olithorus and Vigna unguiculata. Results obtained show that: the locality of Bini- Dang has an ethnic diversity with about 103 families composed of 19 ethnic groups, giving a total of 621 persons (adults and children) interrogated. Twentyfour leafy vegetables of different species are consumed. Among these vegetables, 66.66% are cultivated, 33.33% are picked from nature. The results based on statistical analyses of nutrients and antinutrients (P≤ 0.05) showed that these leafy vegetables were high in levels of carbohydrates 43.35 0.03% (C. olithorus) to 50.16 0.01% (H. sabdariffa) dry weight (DW) and average levels of proteins ranged from 18.39 0.01% DW (H. sabdariffa) to 26.48 0.01% DW (V. unguiculata). Total ashes are also important with contents between 8% (M. oleifera) and 14% (T. triangulare). Iron, the most representative mineral was found to be between 3.81 0.12% for M. oleifera and 10.13 0.36% for M. charantia. It was the only mineral found in high quantity. Vitamin C was also found to be high in V. unguiculata and T. triangulare more than 4% and the levels of pigments and antinutrents were low in all the vegetables analysed. The fibre levels were between 10.63 0.18% DW for M. charantia and 15.40 0.13% DW for H. sabdariffa. These leafy vegetables studied were found to have high nutritional potential. About hundred strains of microorganisms were isolated, from sun-dried cassava chips and characterised with the scope of identifying strains, which could be further use as starter culture for cassava retting. Of all the isolates, 80% were amylase producers; 66.66%, linamarase producers; 26.6%, pectinemethylesterase; 3.33%, pectate lyase and 26.6%, pectin lyase producers. From all of these strains, 65% were thermobacteria, 35% streptobacteria and 10% of betabacteria. Due to their interesting enzymatic profiles for cassava fermentation, these microorganisms could be identified as appropriate for the development of a starter culture for cassava fermentation.
