Degradation of phytate in composite wheat/cassava/sorghum bread by activation of intrinsic cereal phytase

The objective of this study was to degrade the phytic acid content in composite wheat/cassava/ sorghum bread by activating intrinsic cereal phytases during the baking process. The aim was to reach a phytate:iron molar ratio <1 to achieve an enhanced iron absorption in humans. Means to activate the phytase included dough preparation at different pH values and temperature as well as pre-soaking of the sorghum flour before baking. The phytic acid and mineral content was measured by high-performance ion chromatography. In the composite bread without pH adjustment of the dough, the phytate content was 1.58 μmol/g. After adjustment of the dough pH to 4.3, the phytate content in the composite bread decreased to 0.86 μmol/g. Soaking of the sorghum flour at 22\ub0C for 3 h at pH 4.3 before baking, further decreased the phytate content to 0.58 μmol/g. Increasing the soaking temperature to 37\ub0C and addition of 10% wheat flour resulted in a phytate content of 0.14 μmol/g in the composite bread, that is a reduction by 97% of the initial phytate content. The phytate:iron molar ratio was then 0.70 and the phytate:zinc molar ratio was 1.1 that is expected to have a positive effect on the absorption of both minerals in humans

Effect of Hydrocolloids and Emulsifiers on Baking Quality of Composite Cassava-Maize-Wheat Breads

Cassava is widely available worldwide but bread quality is impaired when cassava is used in the bread formulation. To overcome this problem, different improvers were tested in the preparation of composite cassava-maize-wheat (CMW) breads. Emulsifiers, diacetyl tartic acid ester of monoglycerides (DATEM), sodium stearoyl-2-lactylate (SSL), and lecithin (LC); and hydrocolloids, carboxymethylcellulose (CMC) and high-methylated pectin (HM pectin) were added during dough preparation of the composite flours (cassava-maize-wheat, 40 : 10 : 50). Each emulsifier was tested in combination with the hydrocolloids at levels of 0.1, 0.3, and 0.5% while hydrocolloids were used at a level of 3%. Bread quality attributes such as specific loaf volume, crust colour, crumb moisture, and firmness were measured. The specific volume of the fresh breads significantly improved with the addition of hydrocolloids (7.5 and 13%) and in combination with emulsifiers (from 7.9 to 27%) compared with bread produced without improvers. A significant improvement of brownness index and firmness of the composite flours breads was achieved with the addition of hydrocolloids and emulsifiers. The results show that emulsifiers and hydrocolloids can significantly improve the baking quality of CMW breads and thereby enhance the potential for using locally produced flours in bread baking

Phytate degradation in composite wheat/cassava/sorghum bread: Effects of preincubation of Pichia kudriavzevii TY13 and presence of yeast extract.

Diet based on whole cereal flours is associated with a high prevalence of iron deficiency anemia and zinc deficiency in low/middle-income countries. Such flours contain high content of phytate that chelates minerals such as iron and zinc, making them unavailable for absorption by humans. To improve the mineral absorption, a phytate:iron molar ratio <1 and a phytate:zinc molar ratio <5 is needed to be achieved. This study aimed to improve the phytate degradation in composite wheatcassava-whole sorghum flour bread by adding a phytase releasing yeast Pichia kudriavzevii TY13 in baking, preincubated or not, with addition of yeast extract. The phytate and mineral contents were measured by high-performance ion chromatography. Addition of P. kudriavzevii TY13 to the composite flour dough and fermentation for 2 h at room temperature resulted in a 98% phytate degradation.However, the same phytate reduction in the composite bread was achieved after 1 h fermentation at room temperature with addition of preincubated P. kudriavzevii TY13 plus yeast extract. Increasing the fermentation temperature to 30\ub0C, the phytate content was equally low after fermentation for 1 h with P. kudriavzevii TY13 (preincubated or not) plus yeast extract. In conclusion, a faster reduction of phytate in composite bread was obtained by increasing the fermentation temperature, and addition of P. kudriavzevii TY13 (preincubated or not) with added yeast extract. The phytate to iron molar ratio wasthen 0.2 and the phytate to zinc molar ratio 0.6, which strongly indicates an improved bioavailability of both minerals from such a bread

Enhancing the retention of β-carotene and vitamin C in dried mango using alternative blanching processes.

The effects of microwave (MW) dry blanching of mango in comparison with conventional waterblanching and blanching in closed plastic bags prior to hot air drying (70\ub0C) were evaluated on theretention of vitamin C and β-carotene and on the activity of polyphenol oxidase (PPO) and ascorbic acidoxidase (AAO) enzymes. Blanching conditions for MW and water blanching were 2 min at 90\ub0C hightemperature and short time (HTST) or for 10 min at 70\ub0C low temperature and low time (LTLT). PPO wascompletely inactivated by the blanching treatments, while low AAO activity remained. High retentions(~100%) of vitamin C were found in dried mango after blanching treatments HTST with MW andblanching in closed plastic bags, while lower retention was observed after LTLT with MW (81.8 \ub1 4.5%),and conventional water blanching 86.7 \ub1 2.6% (HTST) and 78.6 \ub1 2.5% (LTLT). Blanching resulted inpartial oxidation of L-AA into dehydroascorbic acid (DHAA). Lower retention of all-trans-β-carotene wasobtained in MW and HTST water blanched dried mango (82 to 90%) compared with LTLT water blancheddried mango (~100%). In all dried blanched mango samples the levels of 13-cis-β-carotene isomerincreased. A slight darkening of colour was observed only in conventional blanched mango samples

Impact of dietary iron intake on anaemia in Tanzanian schoolchildren

Objective. To investigate the nutritional relationship between dietary intake and prevalence of anaemia among Tanzanian schoolchildren. Methods. Dietary intakes of 101 schoolchildren aged 7 - 12 years were assessed using a pre-tested food frequency questionnaire. Haemoglobin (Hb), haematocrit, erythrocyte protoporphyrin (EP) and serum ferritin (SF) were used to determine their anaemia and iron status. Other socio-economic variables were collected using a profile questionnaire. Results. Significantly lower intake of iron was seen in 48% of schoolchildren with Hb 0.05). In stepwise multiple regression analysis, daily iron intake remained the most significant nutrient predicting for Hb status. There was a significant correlation between iron intake and serum ferritin (r = 0.233, p < 0.05). Conclusion. Iron intake in this Tanzanian community is inadequate for maintaining normal iron nutrition. The factors contributing to the inadequacy include consumption of foods with low iron bioavailability. Food-based intervention should be one of the important strategies for reducing the magnitude of the problem of anaemia in this community. South African Journal of Clinical Nutrition Vol.17(3) 2004: 94-10

Breech delivery at a University Hospital in Tanzania

Background There is a global increase in rates of Cesarean delivery (CD). A minor factor in this increase is a shift towards CD for breech presentation. The aim of this study was to analyze breech births by mode of delivery and investigate short-term fetal and maternal outcomes in a low-income setting. Methods The study design was cross-sectional and the setting was Muhimbili National Hospital (MNH), Dar-es-Salaam, Tanzania. Subjects were drawn from a clinical database (1999–2010) using the following inclusion criteria: breech presentation, birth weight ≥ 2,500 g, single pregnancy, fetal heart sound at admission, and absence of pregnancy-related complication as indication for CD. Of 2,765 mothers who had a breech delivery, 1,655 met the inclusion criteria. Analyses were stratified by mode of delivery, taking into account also other birth characteristics. The outcome measures were perinatal death (stillbirths + in-hospital neonatal deaths) and moderate asphyxia. Maternal outcomes, such as death, hemorrhage, and length of hospital stay, were also described. Results The CD rate for breech presentation increased from 28 % in 1999 to 78 % in 2010. Perinatal deaths were associated with vaginal delivery (VD) (adjusted odds ratio (aOR) 6.2; 95 % confidence interval (CI) 3.0–12.6) and referral (aOR 2.1; 95 % CI 1.1–3.9), but not with parity, birth weight, or delivery year. Overall perinatal mortality was 5.8 % and this did not decline, due to an increase in stillbirths among vaginal breech deliveries. Mothers with CD had more hemorrhage compared to those with VD. One mother died in association with CD, and one died in association with VD. Conclusion A breech VD, compared to a breech CD, in this setting was associated with adverse perinatal outcome. However, despite a significant increase in CD rate, no overall improvement was observed due to an increase in stillbirths among VD

Compact fiber-optic fluorosensor using a continuous-wave violet diode laser and an integrated spectrometer

A compact fluorosensor with a fiber-optic measurement probe was developed, employing a continuous-wave violet diode laser as an exciting source and an integrated digital spectrometer for the monitoring of fluorescence signatures. The system has the dimensions 22x13x8 cm(3), and features 5 nm spectral resolution and an excellent detectivity. Results from measurements on vegetation and human premalignant skin lesions are reported, illustrating the potential of the instrument. (C) 2000 American Institute of Physics. [S0034-6748(00)04508-1]

Analysis of spatial variability in hyperspectral imagery of the uterine cervix in vivo

The use of fluorescence and reflectance spectroscopy in the analysis of cervical histopathology is a growing field of research. The majority of this research is performed with point-like probes. Typically, clinicians select probe sites visually, collecting a handful of spectral samples. An exception to this methodology is the Hyperspectral Diagnostic Imaging (HSDI®) instrument developed by Science and Technology International. This non-invasive device collects contiguous hyperspectral images across the entire cervical portio. The high spatial and spectral resolution of the HSDI instruments make them uniquely well suited for addressing the issues of coupled spatial and spectral variability of tissues in vivo. Analysis of HSDI data indicates that tissue spectra vary from point to point, even within histopathologically homogeneous regions. This spectral variability exhibits both random and patterned components, implying that point monitoring may be susceptible to significant sources of noise and clutter inherent in the tissue. We have analyzed HSDI images from clinical CIN (cervical intraepithelial neoplasia) patients to quantify the spatial variability of fluorescence and reflectance spectra. This analysis shows the spatial structure of images to be fractal in nature, in both intensity and spectrum. These fractal tissue textures will limit the performance of any point-monitoring technology