Traditional sour dough bread (Difo Dabbo) making: I. Effects on phytic acid destruction

Abstract: The quantitative changes of phytate during the preparation of the traditional sour dough bread (Difo dabbo) and yeast-raised bread were investigated. Raw materials chosen for investigation were flour of high extraction, soy-fortified wheat flour (Dubbie flour), and white flour. The content of phytic acid was determined in all components (raw materials), intermediate products (doughs), and bread. It was found that pH was the most important factor in reducing phytic acid content. The most marked phytate reduction of 96%-100% occurred in bread made with soy-fortified wheat and white flour sour doughs. Reduction of phytate content in bread made from wholemeal wheat flour sour dough was relatively low. The phytate content in yeast-raised bread was reduced at most to 39% of the initial amount. The study results showed that it should be possible to bake traditional sour dough bread (Difo dabbo) from wholemeals with a low phytic acid content by using the sour dough procedure. Such traditional sour dough bread with very low levels of phytate may be a good source of iron, calcium, and zinc since phytate is known to interfere with the absorption of these minerals. [Ethiop. J. Health Dev. 1998;12(3):167-173

Forms and contents of oxalate and calcium in some vegetables in Ethiopia

Abstract: Contents and forms of oxalate and calcium in some vegetables of Ethiopia were determined. On the average, the total oxalate content of spinach, swiss-chard and beet root were 9794,7554 and 222 mg/100g on dry weight basis, respectively. The other vegetables studied however , contained low level of oxalate. Two fractions of oxalate were isolated- a fraction soluble in boiling water and an associated (nsoluble residue which was predominantly in the form of calcium oxalate. The water-soluble oxalates of vegetables studied account for over 50% of the total oxalate. Most of the calcium in the vegetables was in the form .of calcium oxalate whirh is unlikely to be available to the body. Since the intake of vegetables cannot be discouraged, it is worthwhile to improve the nutritional value of these vegetables by reducing the water-soluble oxalates as it accounts for over 50% of the total oxalate content. [Ethiop. J. Health Dev. 1995;9(1):13-18

Survey of Aflatoxin Contamination in Ethiopia

No abstract - Available on PD

THE EFFECT OF SOAKING TIME AND SOAKING SOLUTION ON THE NUTRITIONAL QUALITY OF GRASS PEA SEEDS

ABSTRACT: The effect of soaking time and soaking solution on the nutritional quality of grass pea seeds were studied. The soaking solutions used were:plain water (pH 7.3); ImM HCl (pH 3.0); ImM NaOH solution (pH 11.0) and 0.1% (w/v) wood ash solution (pH 12.0). Mature whole grass pea seeds soaked for 72 hr in the four soak media that were used resulted in total solids loss of 1.3, 1.2, 5.2 and 6.2 percent, respectively. Total protein content increased by 11 and 13 percent, respectively for seeds soaked for 72 hr in plain water and ImM HCl. In contrast, a total protein loss of 12 and 16 percent, respectively was noted in seeds soaked for 72 hr in ImM NaOH solution and 0.1% wood ash solution. The soaking process resulted in the loss of non protein nitrogen, total soluble sugars and reducing sugars. Soaking also influenced the ash and crude fibre contents of the seeds. The pH of the soaking solutions were also altered in accordance to the soaking process. However 'kikn' showed significantly lower nutrient retention values compared to the whole seeds mainly due to the higher loss of solids during soaking. [Ethiop. J. Health Dev. 1993;7(2):79-83

Traditional Sour Dough Bread (Difo Dabbo) Making: II. effects on the HCL-extractability of minerals

Abstract: Traditional sour dough bread (Difo dabbo) was prepared from wholemeal wheat flour, soy-fortified wheat flour (Dubbie flour) and white flour. Yeast-raised bread was prepared from Dubbie flour by the straight-dough process. Sour dough fermentation of bread significantly reduced phytic acid content and increased the HCl-extarctability of calcium, iron, zinc and phosphorus. The extractability increased with an increase in the period of fermentation. Higher extractability of the minerals was obtained in white flour sour dough bread. Wholemeal wheat flour sour dough bread exhibited relatively lower extractability of the minerals compared to the other two sour dough breads. Significantly (p<0.05) lower values for HCl-extractability of minerals were observed in bread prepared by the straight dough process. The sour dough fermentation is an effective method for improving HCl-extractability and possibly the bioavailability of minerals which helps to prevent and ameliorate mineral deficiencies and improving the nutritional status of people consuming such food. Ethiop. J. Health Dev. 1998;12(3):175-181

Development of a tempe-related food using kocho and grass pea as substrate

Abstract: Tempe was prepared by co-fermenting different proportions of kocho flour with grass pea using the traditional inoculum, Usar. The nutritive quality of tempe prepared from kocho-grass pea (20:80; 25:75; 30:70; 40:60; 50:50) was determined. The protein crude fibre and ash content increased significantly, while carbohydrates decreased slightly. The fat content of tempe made from all the kocho-grass pea combinations decreased by about one third. Soluble and reducing sugars increased by 2.6- and 2.9-, 4.8- and 9.5- and 7- and 10-fold, respectively, in 30:70, 40:60 and 50:50 kocho-grass pea combinations. Free amino acids and non-protein nitrogen similarly increased 8.5- and 24-, 23- and 7.5- and 6.5 and 20-fold, respectively, whereas minerals remained unaffected in 20:80, 25:75 and 30:70 kocho-grass pea combinations. Fermentation also significantly decreased the phytic acid and trypsin inhibitors but, increased tannin contents of the tempe. Co-fermentation of kocho-grass pea combinations into tempe greatly improved the nutrient of kocho in terms of protein, fat and ash contents. The tempe could be used for supplementary feeding. A fermentation scheme was therefore, developed for the production of an enriched product in which 40% to 80% grass pea was fermented with kocho flour for 48 hr. [Ethiop. J. Health Dev. 1997;11(1):67-73

Natural fermentation of Enset (Ensete ventricosum) for the production of Kocho

Abstract: Biochemical changes of fermenting enset were studied. After seven weeks fermentation, total protein, ash and total carbohydrates decreased by 15%, 16% and 34%, respectively. Significant (p<0.05) reduction in iron (15%), phosphorus (29%), calcium (51%), starch (23%), soluble sugars (93%), reducing-sugars (84%) and available carbohydrates (51%) were recorded. Free amino acids and non-protein nitrogen increased by 6- and 1.6-fold, respecively. The pH of the fermented mash fell from an initial value of 5.7 to 3.8 with a concomitant sharp rise in titratable acidity resulting in accumulation of organic acids. The predominant organic acids were lactic, iso-valeric and n-butyric acids followed by n-valeric and acetic acids. Other volatile fatty acids and ethanol were formed in lesser quantities. Fermentation of enset also resulted in significant reductions in tannins and trypsin inhibitors whereas oxalic acid remained unaffected. [Ethiop. J. Health Dev. 1997;11(1):75-81

Nutritional and antinutritional characteristics of Anchote (Coccinia abyssinica)

Abstract: The whole and peeled samples of anchote (Coccinia abyssinica) were analyzed for their nutrient and antinutrient contents. The protein, starch, total sugars, reducing sugars, vit-A, and vitB contents were higher in peeled anchote than in whole anchote samples. The phosphorous, potassium, sodium, calcium, magnesium, iron, zinc and copper contents of whole and peeled anchote were determined and peeling of anchote reduced the contents of calcium, potassium, phosphorous, iron and magnesium by 5%, 8%, 16%, 16%, and 19%, respectively. The phytic acid, oxalic acid and tannin contents of whole anchote were higher than those which were peeled by 20%, 22% and 29.6%, respectively. There were no detectable trypsin inhibitor activity in both samples of anchote. Oxalic acid in both anchote samples exists as insoluble oxalate and no water soluble oxalate was detected. As it is observed from the analysis made, anchote contained good nutrient composition with a good supplements of vitamins and minerals. Its antinutritional contents are probably of little nutritional significance and they may be still minimized or destroyed during cooking processes. [Ethiop. J. Health Dev. 1997;11(2):163-168

Effect of processing methods on the trypsin inhibitor, tannins, phytic acid and ODAP contents of grass pea seeds

Abstract: Grass pea seeds were given different treatments including cooking boiling, autoclaving, dry heating and fermentation into tempeh. Changes in the levels of the antinutritional factors due to the treatments were estimated. Dry heat treatment completely eliminated phytic acid and greatly reduced tannins, trypsin inhibitor activity and ODAP (100%,64%,87.4% and 75%, respectively). Cooking reduced tannins (74%), trypsin inhibitory activity (81 %) and ODAP (77%) while phytic acid was less affected (59.4%). Autoclaving had the most pronounced lowering effect on trypsin inhibitor activity (91 %), whereas other anti-nutritional factors were less affected. Boiling also decreased the trypsin inhibitor activity by 89.3%. Preprocessing of grass pea for tempeh fermentation and fermentation into tempeh significantly removed large portions of the antinutritional factors in grass pea. [Ethiop. J. Health Dev. 1995;9(2):97-103

Effect of natural fermentation on nutritional and antinutritional factors of tef (Eragrostis tef)

Abstract: Tef flour mixed with water in a 1:1.6 (w/v) ratio was allowed to ferment at 220 C for 96 hrs by the action of endogenous microflora in the batter. After 96 hrs total protein content in tef dough decreased by 12% whereas the NPN, free amino acids, free amino acid nitrogen, soluble protein and fat acidity increased 7.4-, 7.0-, 6.6-, 7.7- and 10.7- fold, respectively. Fermentation also resulted in significant drop in pH and sharp rise in titratable acidity of the 96 hrs fermented dough. Iron, phosphorus and calcium decreased by 43%, 35% and 41%, respectively, in the dough fermented for 96 hrs. Phytic acid, tannins and trypsin inhibitor contents were reduced by 72%, 55% and 69%, respectively. In ersho, the liquid portion drained off from the fermented dough, total protein, NPN, free amino acids, iron, calcium and phosphorus increased significantly whereas total and reducing sugars decreased during the two days of fermentation. The pH of ersho dropped slightly but the titratable acidity increased by 35%. These results could provide useful indices for the improved evaluation of tef fermentation. [Ethiop. J. Health Dev. 1997;11(1):61-66