Three types of wheat were submitted to two different milling procedures, giving rise to six flours which differed by some physico-chemical characteristics such as particle size, level of damaged starch and protein content. Differential scanning calorimetry was used for monitoring heat-induced structural changes in flour aqueous dispersions 80% water and in doughs 45% water. Differences between the thermal behaviour of the flour dispersions and doughs were explained mainly by differences in protein content. This result was confirmed after partial substitution of flour by gluten. Dynamic mechanical analysis performed at 20°C on the flour doughs indicated, as expected, a linear increase in the elastic modulus with increasing protein content. The results did not bring any evidence that, under these experimental conditions, starch damage might affect gluten hydration.
Authors:Rezső Schmidt, M. Barkóczy, P. Szakál, and et al.
Authors studied the effect of copper nutrition on the yield, kernel
weight and raw protein content of winter wheat. Copper was applied in the form
of copper tetramine hydroxide that was produced from a clean copper containing waste
originating from microelectronical industry. After suitable chemical
transformation this waste can be used as an excellent secondary raw material
for the preparation of copper fertilizer. The foliar application of copper
tetramine hydroxide complex at the phenological phase of tillering
significantly increased the yield, kernel weight and raw protein content of
winter wheat. The calculated copper doses that gave the maximum yield, raw
protein content and kernel weight were 1.04, 1.12 and 0.77 kg ha
Authors:R. Macêdo, O. de Moura, A. de Souza, and A. Macêdo
This work present comparative results on powder milk storage quality, obtained from analytical methods. Protein content was
determined conventional (Kjeldahl) and colorimetric with biuret reagent at 540 nm and integral quality by thermogravimetric
and biological methods. A method was developed for the protein separation of powder milk. Powder milk was submitted to degradation
processes at 45, 60 and 80°C for 20 days. The results indicated that protein content values were inconsistent if determinations
by Kjeldahl and colorimetric methods and biological tests were compared. There is evidence of thermal decomposition of powder
milk as detected by biological and thermogravimetric methods.
A set up forin vivo determination of nitrogen has been built. Phantoms containing different amounts of nitrogen have been measured as well as a volunteer in a pilot study. A total body protein content of 18.8 kg was calculated, to be compared with 17.0 kg estimated from potassium measurements.
The detection of characteristic gamma rays emitted promptly by elements after capture of neutrons is used as a means of radioanalytic analysis. Here it is shown that the method can be used for the measurement of the nitrogen (and therefore protein) content of small animals, those with mass around 3 kg.
The principal objective pursued in this study is to establish the base-line data on protein content and on the status of elemental
composition in human milk from Sudanese subjects. The protein content was derived by multiplying the nitrogen content by a
factor 6.25. The nitrogen was determined using a 14 MeV neutron generator. The median values for crude protein and the total
dry matter found in this study were 1.23% (volume) and 104 g/l, respectively. Some minor and trace elements of biological
significance namely, Cl, K, Ca, Mn, Fe, Cu, Zn, Cr, Co and Mo were determined using energy dispersive X-ray fluorescence spectrometry.
The results obtained show good compatibility with the data reported by the WHO on elemental composition of human milk from
different geographical regions.
Authors:T. Dessalegn, M. Labuschagne, and C. Deventer
The bread making quality of Ethiopian cultivars was studied using 18 quality traits at low and high protein environments. Significant variation was observed between genotypes with a broad range of milling, rheological and baking traits. Three different quality prediction models were constructed explaining 48% to 73% of the variation of mixing time and loaf volume, respectively. SDS-sedimentation alone accounted for 56% of the variation in loaf volume at the high protein environment. The variation of mixing time due to protein content alone was 37% at the low protein environment. SDS-sedimentation and mixograph mixing time were common in the three models. SDS-sedimentation, protein content and mixing time can be used as selection criteria in breeding programs where resources are limited. Hectoliter weight and grain weight also contributed to the variation of loaf volume and mixing time.
Authors:S. Peighambardoust, M. Ghamari, and S. Naghavi
Application of glutenin macro-polymer (GMP) gel analysis compared to conventional wheat quality indicators such as total protein content, Zeleny, and SDS sedimentation values was evaluated in quality classification of 13 Iranian wheat cultivars. The results showed no significant correlation between total protein content and breadmaking characteristics. Zeleny, SDS sedimentation and GMP tests showed significant correlation with loaf volume and bread height. GMP wet weight and small-strain deformation rheological characteristic of GMP-gel were correlated with large-strain deformation rheological properties of dough measured in Farinograph and bread quality (loaf volume and height). Significant (α < 0.01) correlation was found between rheological properties of the GMP gel and Farinograph characteristics of dough. Although GMP wet weight is regarded as a predictive measure for breadmaking quality of wheat, in the light of the results of this rather small sample set we did not find significant correlation between small-strain rheological properties of GMP-gel (storage modulus and tan δ) and breadmaking characteristics.