Protein determination, kernels

M. Manley, L. Van Zyl, B. G. Osborne. Using Fourier transform near infrared spectroscopy in determining kernel hardness, protein and moisture content of whole wheat flour. J Near Infrared Spectrosc 10 71—76, 2002. 

Knowledge of the amino acids developed slowly during the 19th century, since Mulder (200) and other pioneer workers devoted most of their efforts to the solution of other problems, particularly the elementary composition of proteins. As recently as 1890, Osborne (211) determined the elementary composition of oat-kernel proteins in the first of his now-classical investigations on vegetable proteins. 

The same shipment of raw, cooked and roasted glandless whole kernel cottonseed flours used in the FDA study was used to determine the protein efficiency ratio (PER) of each flour (8). The adjusted PER (Table II) of cooked (2.10) cottonseed was significantly higher than roasted (1.77) cottonseed. Protein retention efficiency (PRE) for roasted cottonseed (58.08) was lower than values for raw (60.54) and cooked (62.95) cottonseed. Relative protein values (RPV) indicated a utilization of 91, 91 and 96% of the protein in raw, roasted and cooked cottonseed, respectively. The multiplication of the (RPV) percentage utilization and the protein content of the cottonseed (Table I) results in the relative utilizable protein values (Table II). 

The reaction of the bisulfite ion with endosperm protein is completed in whole kernels in 6-10 hours.142,143 Both S02 and HS03 ions are capable of reducing disulfide bonds pH conditions inside the kernel probably determine which reaction predominates. The kernel pH of 3.6-4.0 reported by Wahl151 would favor HS03 as the reactant, but pH values can be closer to 4.0-4.5 in commercial steeps with a solubles level of 1-2% in the steep acid (unpublished data). 

Eight combinations (types 1-8, Table 10.12) of Wx-Al, Wx-Bl and Wx-Dl proteins are possible in common wheats.257 Near-isogenic lines of the eight types of wheats showed apparent amylose levels of 3% to 25%, as determined by the blue color of the amylose-iodine complex.266 The amylose level in wheat kernels increases positively with the level of waxy proteins.257,269 271 In the double nulls, the Wx-Al protein in type 5 wheat produces —3% less amylose than the Wx-Bl and Wx-Dl proteins (types 6 and 7, respectively). In the single nulls, compared to the wild type (type 1), absence of Wx-Bl (type 3) reduces the amylose content by —2% compared to —1% for the absence of either of the other two waxy proteins (types 2... 

Often, calibration of natural products and materials is a desirable goal. In these kinds of assays, it is usually not feasible to control the composition of calibration and validation standards. Some well-known examples include the determination of protein, starch, and moisture in whole-wheat kernels and the determination of gasoline octane number by NIR spectroscopy. In cases such as these, sets of randomly selected samples must be obtained and analyzed by reference methods. 

Hulling. Once the lint is removed, the hulls are separated from the seeds. Hulls that are allowed to remain with the kernels absorb oil during extraction and lower the quality of the meal produced by lowering the protein level. The hulls cannot be completely eliminated without a loss of kernel, so an acceptable level of hull retention must be determined, depending on the desired protein level of the final meal. 

Initial extraction of oil from oil fruit produces a cake of fruit skin, pulp, and kernel known as olive pomace or omjos. The value of this primary by-product of oil extraction depends on its oil and water contents, which are, in turn, determined by the method of oil extraction employed and the operating conditions. Pressure extraction yields a residue containing 4—5% oil, whereas classical presses leave 8-12% oil in the pomace (72). Pomace flours are used as animal feed due to their high content of protein, which is also of high quality. 

J. Baier, M.F. Richter, R.J. Cogdell, S. Oellerich, J. K5hler, Determination of the spectral diffusion kernel of a protein by single molecule spectroscopy. Phys. Rev. Lett. 100, 8108-1-4 (2008)... 

When soybeans are received at the crushing plant, they are sampled to analyze moisture, foreign matter, splits, and damaged-seed contents. Sometimes oil and protein contents are also determined (only test weight, total damaged kernels, heat-dam-... 

Aqueous solution (0.6 wt%) of a protein (ovalbumin, gelatin) and 0.2 g of PMS (Cp s = 10 wt%) or 0.02 g of nanosilica A-300 was mixed for 1 h and then centrifuged. The equilibrium concentration of protein in the liquid was determined by the Biuret method. A distribution function /(-AG) of Gibbs free energy (AG) of the protein adsorption was calculated using the kernel of the integral equation in the form of the Langmuir equation. 

Six varieties of okra were shown to have seed oil levels that ranged from 15.3 to 22%. The separated kernels contained 42-56% protein and a similar amount of oil (Telek and Martin, 1981). Rao et al. (1991) reported whole seeds and kernel contained 21% and 38.9% protein and 17.9% and 36.5% fat, respectively. A number of workers have determined the fatty acid composition of okra seed oil and the results are shown in Table 5.9. The three major fatty acids are linoleic, palmitic acid and oleic acid. 

Jart (1959) determined the fatty acid composition of olive kernels. The kernel oil appears to have a somewhat higher linoleic acid content and lower oleic content than the pulp oil (Table 7.8). In practice, the kernels are ground up with the pulp and the oil is expressed from the mixture of pulp and seed. The protein, oil and mineral contents of Egyptian and Jordanian olive oil cakes were investigated by Latief et aL (1976) and were found to be suitable for recovery of edible oil, protein pulp residue for cattle feed and mineral rich exhausted residue for use as fertilizer. 

H. Abe. et al. Non-destructive determination of protein content in a single kernel wheat and soybean by near infrared spectroscopy In Near-Infrared Spectroscopy The Future Waves Proceedings of the Seventh International Conference on Near-Infrared Spectroscopy, A.M.C. Davies, PhU Wifliams co-eds. NIR Publications, Chichester, UK, 1996, p. 457 61. 

W. Samer. Use of near-infrared reflectance measmement for the determination of protein and moistme content and kernel hardness in wheat (In German). Getreide Mehl Brot 32 272-276, 1978. 

The development of amylase activity in extracts of embryo-free and of GA3-treated, embryo-free maize kernels has been determined. The increase in amylase activity was accompanied by the appearance of several starch-degrading enzymes. Actinomycin D and cycloheximide prevented the amylolytic activity from developing. Other results indicated that the development of a-amylase activity in embryo-free maize kernels does not depend on gibberellic acid, but involves the de novo synthesis of protein. 

---