Whole grain protein content

Models are constructed in analytics to describe the relationship between responses and factors. This is, for example, important for optimization of analytical methods on the basis of response surface methods (cf. Section 4.2). Models are also needed for cahbration of analytical methods. There, calibration of a single analyte in dependence on one or several wavelengths might be of interest. If, in the first example, the straight-line model would be adequate, for the second task of multiwavelength spectroscopy, multivariate approaches are needed. Calibrations in the case of unselective analytical methods must also be performed. These methods are termed simultaneous multicomponent analysis. In near-infrared (NIR) spectroscopy, the contents of water and protein in whole grain wheat are determined that way. 

Phytin content of whole seeds and protein bodies varies with species and cultivar. Examples of the chemical composition of the aleurone grains of rice and protein bodies (and isolated globoids) of cotton seed are shown in Table 2.7. Note, in particular, the higher phosphorus but lower protein content of the cereal aleurone grain in comparison with the dicot protein body. The concentration of the associated macronutrient elements can also be seen to differ. Qualitative as well as quantitative differences occur between the macronutrient compositions of different seeds, e.g. in C. maxima the globoid is rich in phosphate, potassium... 

Moisture is routinely measured concurrently with protein. Measurement may be made on ground wheat with two or three fixed filters (1940, 2230, and/or 2310 nm) or on whole grain as described above. Under ideal laboratory conditions, the standard deviation of differences between NIR and reference moisture values should be 0.25% or better. It is essential to record the NIR spectral data and determine the oven moisture contents of the calibration samples as close as possible in time, ideally on the same day. 

Reaction of protein with organic dyes has been utilized to estimate the protein eontent of cereal grains. These methods involve disruption of plant cell walls by ultrasound or homogenization, followed by dye-protein reaction, filtration, and color measurement [45]. None of these techniques adequately measures the total protein content of whole-plant material, for the most part, and so the problem of measuring total protein by a reference method that could be used by NIRS or other... 

The main sources of fibre in human diets are cereais and cereal products but all natural plant foods contain some. Because of their high water content vegetables and fruits have a much lower content than cereals, nuts, pulses and dried fruits. This can be seen from Table 10.8. The best source is bran which is produced during the refining of flour and makes up 10-16% of the whole wheat grain. Bran itself contains 40-50% of fibre as well as some starch, sugars, protein, fatty acids, minerals and vitamins. 

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