EFFECT OF FROST ON WHEAT AT PROGRESSIVE STAGES OF MATURITY: II. COMPOSITION AND BIOCHEMICAL PROPERTIES OF GRAIN AND FLOUR

1935 ◽  
Vol 13c (1) ◽  
pp. 1-31 ◽  
Author(s):  
A. G. McCalla ◽  
R. Newton

The increase in dry weight of wheat kernels after flowering accelerated slightly for 14 days, was steady for 10 days, then fell off gradually to zero in about 14 days more, when the kernels weighed 32 gm. per 1,000. At this stage they contained 58 to 60% dry matter, a critical point marking the practically complete cessation of chemical changes.The weight of nitrogen increased steadily to about 1 gm. per 1,000 kernels at the critical stage. Respiration losses of carbon, before and after harvest, appear to account largely for the changes in the percentage nitrogen in the kernels. The ratio of nitrogenous to non-nitrogenous material moved into the endosperm seems to have been nearly constant throughout the main developmental period.Ammonia nitrogen first increased to a maximum of 4.8 mg. per 1,000 kernels, then decreased to negligible proportions at the critical stage Salt-soluble nitrogen in fresh kernels decreased from an initial value of 75% of the total nitrogen to 22% at the critical stage, when a little more than one-third of it was non-protein. Drying the kernels before analysis changed the percentage composition, owing to respiration and synthesis, by an amount varying with rate and conditions of drying.Frost had no effect on the ash content of the kernels. Four degrees of frost (28° F.) had no effect on the per cent total, salt-soluble or non-protein nitrogen, but 8, 10 and 14 degrees, in cuttings before the critical stage, in both the gram and the flour milled from it reduced the per cent total nitrogen an effect ascribed to slowing up of respiration, and increased the per cent of the fractions, ascribed to checking of synthesisYields of washed gluten from the control samples were about the same at all stages, but physical properties did not attain maximum quality before the critical stage. Four degrees of frost did not affect yield, but reduced quality in cuttings before the critical stage. More severe frost reduced both yield and quality in immature samples, the effect of the heaviest frost on quality persisting to full maturityBoth reducing and invert sugar percentages declined m early stages of development. Frost did not affect invert sugar content, but 8, 10 and 14 degrees increased reducing sugars in flours from grain cut before the critical stage. This is ascribed partly to increased enzyme activity, as indicated by greater maltose production, and partly to slowing of respiration by frost injury. Gain in kernel weight by translocation after cutting took place in immature check samples but not in heavily frozen samples. Respiration losses in the stook were calculated to be about twice as great from the checks as from the heavily frozen samples.

1979 ◽  
Vol 6 (4) ◽  
pp. 449 ◽  
Author(s):  
GR Donovan

Eight wheat varieties which normally produce grain of different final percentage nitrogen content were grown under field and glasshouse conditions. The final percentage grain nitrogen of the field grown varieties ranked in the expected order; however, total nitrogen/grain, DNAIgrain, RNA/grain and non-protein nitrogen/grain during grain development differed between varieties. DNA/grain reached a maximum value in all varieties between 21 and 28 days post- anthesis, suggesting a longer period of cell division than previously reported. There was no apparent relationship between final percentage grain nitrogen and either DNA, total grain RNA or the concentration of grain amino acids during development. Heads from glasshouse grown wheat were detached at 8 days postanthesis and grown in liquid culture under conditions where the nitrogen concentration of the culture medium was varied. Fresh weight/grain, DNA/grain, RNA/grain and total grain nitrogen all increased with increasing nitrogen concentration in the culture medium, but grain dry weight remained constant at the different nitrogen concentrations. The changes in fresh weight/grain, DNA/grain and RNA/grain were not the same for all varieties. A possible relationship between total grain nitrogen and DNA/grain and RNA/grain during seed development exists for heads grown in culture for individual varieties. This apparent relationship for individual varieties cannot be used to explain intervarietal differences in total grain nitrogen because in some cases different varieties grown under identical culture conditions, although producing grain of equivalent total nitrogen, had widely differing levels of both DNA and RNA per grain.


1962 ◽  
Vol 59 (3) ◽  
pp. 387-392 ◽  
Author(s):  
T. Z. Nowakowski

Italian rye-grass given ammonium sulphate or sodium nitrate at 56 or 112 lb. N/acre was analysed for total nitrogen, soluble nitrogen (non-protein-nitrogen) and soluble carbohydrates.Ten days after applying fertilizer the differences in total-N between the grass receiving 56 and grass receiving 112 lb. N/acre were very small. Total-N in grass decreased with growth, but the effect of the rate of nitrogen on total-N increased. At first the grass given sodium nitrate contained more soluble nitrogen than grass given ammonium sulphate, the difference being greater at 56 lb. N/acre; soluble nitrogen decreased with increasing growth. Ten days after applying fertilizer, the nitrate-N content of grass was very high (ranging from 0·1 to 0·9% in the D.M.) and it gradually decreased. At both levels of nitrogen application, grass given sodium nitrate contained much more nitrate-N than grass given ammonium sulphate. Forty days after applying nitrogen the nitrate-N contents of grass which received 56 and 112 1b. N/acre as ammonium sulphate were 0·039 and 0·222% of the dry matter, respectively; the grass supplied with sodium nitrate gave values of 0·082 and 0·438%.Total soluble carbohydrates in the grass were small early in growth and gradually increased. Nitrogen dressings had little effect on the content of soluble sugars (glucose + fructose + sucrose) but greatly decreased the fructosan. The pattern of changes in the total soluble carbohydrate content followed that in fructosan content. Early in growth, the total soluble carbohydrate/crude protein ratio was very small in grass from all treatments except the ‘control’. This ratio increased with growth and at the last sampling was 2·13 in grass receiving no nitrogen, and in grass supplied with 56 and 112 lb. N/acre as ammonium sulphate it was 1·44 and 0·72 respectively; the corresponding figures for grass receiving sodium nitrate were 1·13 and 0·66. The total soluble carbohydrate carbon/soluble nitrogen ratio in grass with no nitrogen was 18 at the first sampling and it increased gradually, reaching 70 at the last sampling. This ratio was considerably less with all nitrogen treatments than with ‘control’. The values obtained with 112 lb. N/acre were less than those obtained with 561b./acre, irrespective of the form of nitrogen used.The relationship between the soluble carbohydrate carbon content and the soluble nitrogen in grass is illustrated graphically and discussed.


1996 ◽  
Vol 2 (5) ◽  
pp. 335-339 ◽  
Author(s):  
F.C. Ibáñez ◽  
A.I. Ordóñez ◽  
M.S. Vicente ◽  
M.I. Torres ◽  
Y. Barcina

Idiazábal cheeses were made employing brining times of 12 h (batch A) and 36 h (batch B). Proteolytic changes in both batches were examined over 270 d of ripening; proteolysis was low in both batches, but lower in batch B than in batch A. Electrophoretic analysis revealed incom plete breakdown of αs and β-caseins at the end of the ripening period, particularly in batch B. The proportion of soluble nitrogen as a percentage of total nitrogen was 17.55% in batch B and 19.48% in batch A, while the proportion of non-protein nitrogen was 11.78% in batch B and 15.16% in batch A. The proportion of non-protein nitrogen as a percentage of soluble nitrogen was 67.17% in batch B and 77.88% in batch A. The free amino acids, the smallest non-protein nitrogen frac tion, attained values of 1203 mg/100 g of dry matter in batch B and 1902 mg/100 g of dry matter in batch A. After 60 d of ripening, the main free amino acids were glutamic acid, valine, leucine, lysine, and phenylalanine in both batches, although levels were higher in the batch with the shorter brining time. There was no clear trend in the non-protein-forming amino acids with either ripening time or brining time.


1955 ◽  
Vol 8 (2) ◽  
pp. 137 ◽  
Author(s):  
HS Mckee ◽  
RN Robertson ◽  
JB Lee

Pea fruits from two crops were sampled at different times from flowering. Changes in the fresh weight, dry weight, starch, soluble carbohydrate, protein nitrogen, and soluble nitrogen in both seeds and hulls were followed in two seasons and related Jo the changes in cell volume in the seeds. In one season respiration rates and phosphate, pectin, and ascorbic acid contents were also investigated. The seeds gained more carbohydrate and nitrogen than was lost by the hulls. Starch and protein were synthesized rapidly by the seeds. The increase in starch content in the seeds was followed by a decrease in soluble carbohydrate content, after which the seed ceased to accumulate water. These metabolic changes are discussed in the light of recent biochemical knowledge, and in relation to more detailed biochemical investigations in progress.


2015 ◽  
Vol 27 (1) ◽  
pp. 105-114 ◽  
Author(s):  
R. Kubiczek ◽  
M. Rakowska

Total and soluble nitrogen, protein and non-protein -nitrogen was determined as well as the amino acid composition of the caryopses of ten rye varieties including three bred in Poland and cultivated on a commercial scale: 'Dańkowskie Złote', 'Dańkowskie Selekcyjne' and 'Borkowskie Tetra'. and seven foreign varieties characterized by a high total protein content (11.9-16.4% in dry weight). In the varieties examined the amount of protein nitrogen increased in the same degree as did the content of total nitrogen. The amino acids limiting the nutritive value of the protein in rye caryopses were mostly lysine and methionine, and in the varieties with high protein content tryptophan. The low-protein varieties had a relatively higher content of lysine, sulphur amino acids, tryptophan and other amino acids (as % of protein) than the high protein ones, but their absolute amino acid content (as % of dry weight) was lower.


1938 ◽  
Vol 16c (9) ◽  
pp. 377-390 ◽  
Author(s):  
J. Ansel Anderson ◽  
C. Alan Ayre

Determinations of total nitrogen and nitrogen fractions were made on 144 samples of barley representing 12 varieties grown at each of 12 widely separated experimental stations in Canada.A highly significant positive correlation between alcohol-soluble protein nitrogen and total nitrogen was found both within and between varieties. No correlation between total nitrogen and other nitrogen fractions was found between varieties; but significant positive correlations were found within varieties, that for insoluble protein nitrogen being considerably higher than those for total salt-soluble nitrogen, salt-soluble protein nitrogen, and non-protein nitrogen. With increasing total nitrogen, the proportion in salt-soluble form decreases, that in alcohol-soluble form increases, and that in insoluble form remains relatively constant. The results thus offer further support for Bishop's "Protein regularity principle".Mean varietal differences were found with respect to each nitrogen fraction, but elucidation of differences in nitrogen distribution patterns was complicated by the effect of varietal differences in total nitrogen content. Statistical analyses demonstrated the validity of eliminating this effect by adjusting varietal means for fractions to values corresponding to equal total nitrogen contents. When this was done it was found: that the three two-rowed varieties (Charlottetown 80, Hannchen, and Victory) were higher in alcohol-soluble protein nitrogen and lower in insoluble protein nitrogen than any of the six-rowed varieties; and that the four smooth-awned six-rowed varieties (Nobarb, Regal, Velvet, and Wisconsin 38) were lower in total salt-soluble nitrogen and higher in insoluble nitrogen than any of the rough-awned six-rowed varieties (O.A.C. 21, Mensury, Ott. 60, Olli, Peatland, and Pontiac). Owing to the variation between varieties within classes, and the small number of varieties studied, the average differences between the three classes are not statistically significant. Nevertheless, since by comparison with the rough-awned six-rowed varieties, the two-rowed varieties yield higher malt extracts, and the four smooth-awned varieties yield lower malt extracts and are lower in enzymatic activity, the indications of a possible relation between nitrogen distribution and malting quality are interesting.


1941 ◽  
Vol 19c (7) ◽  
pp. 234-250 ◽  
Author(s):  
H. R. Sallans ◽  
W. O. S. Meredith ◽  
J. A. Anderson

Inter- and intravarietal relations between malt extract and barley properties (extract, starch, total nitrogen, 1000-kernel weight, salt-soluble nitrogen, saccharifying activity, cellulose-lignin residue, and steeping time) have been investigated by developing prediction equations for malt extract.The most useful single factors for intervarietal prediction are barley extract, starch, and cellulose-lignin residue, in the order given. The inclusion of salt-soluble nitrogen and steeping time, as additional independent variables, with barley extract or starch, results in a significant improvement in the level of prediction. The most accurate equation was: malt extract = 1.1 + 0. 93 barley extract + 7.44 salt-soluble nitrogen − 0.035 steeping time. This equation serves to indicate the relative extract yield of varieties grown at the same station, the standard error being ± 0.8%. The constant, 1.1, varies from station to station; hence, although this average value gives relative extract yields, the constant must be evaluated for specific environments if absolute extract yields are required.The most useful single factors for intravarietal prediction are barley extract, starch, and total nitrogen. Statistical analysis showed that only barley extract and total nitrogen could be effectively combined for prediction purposes. The equation is: malt extract = A + 0. 58 barley extract − 2.4 total nitrogen, standard error ± 0.6%. The factor A is dependent on variety but the data suggest that for Canadian malting varieties this constant has a value of about 35.7.Attempts to develop a generalized equation applicable to all samples, irrespective of varieties and the environment in which they were produced, proved unsuccessful. This is apparently due to significant differences between the inter- and intravarietal partial regression coefficients for the properties studied.


1978 ◽  
Vol 50 (2) ◽  
pp. 137-146
Author(s):  
Terttu Ettala ◽  
Matti Kreula ◽  
Hilkka Tähtinen

The effect of sulphur deficiency and sulphur fertilisation on the nitrogen compounds of plants was studied, using timothy as the test species. The samples were obtained from 4 field trials performed in northern Finland. The nitrogen and sulphur treatments in each of these trials were as follows: a) N O, S O, b) N 48, S O, c) N 48, S 34, d) N 96, S O and e) N 96, S 68 kg/ha. Nitrogen was applied as NPK compound fertiliser and sulphur in the form of gypsum. In trials 1and 2 sulphur given in addition to nitrogen increased the yield considerably. The contents of soluble-, protein-, a-amino-, ammonium- and nitrate-nitrogen, as well as the free and peptide- and protein-bound amino acids were determined in the harvested timothy. Nitrogen fertilisation did not have any noticeable effect on the protein-nitrogen content of sulphur-deficient plants, but sulphur fertilisation increased it by an average of 26 % (trial 2). The proportion of soluble nitrogen of the total nitrogen in trials 1 and 2 averaged 50 % with N-fertilisation and 37 % with N+S fertilisation. Sulphur fertilisation decreased the contents of a-amino-, ammonium- and nitrate-nitrogen, and also their proportions of the total nitrogen. In those trials (3 and 4) in which sulphur fertilisation did not increase the yield, the proportion of soluble nitrogen of the total nitrogen was an average of 33 % with all treatments. In sulphur-deficient timothy the content of asparagine and aspartic acid totalled 60 % of the content of free amino acids, and their nitrogen formed about 17% of the total plant nitrogen. The corresponding figures with sulphur fertilisation were 39 % and 3.5 %, and in those trials where there was no sulphur deficiency (trials 3 and 4) on average 27 % and 2.5 %, irrespective of fertilisation. The proportion of soluble nitrogen of the total nitrogen of timothy was closely correlated (r = 0.79***) to the N/S ratio, as was the proportion of asparagine plus aspartic acid of the total free amino acids (r = 0.91***).


1969 ◽  
Vol 22 (6) ◽  
pp. 1321 ◽  
Author(s):  
JF Turner

The enzymes UDPG pyrophosphorylase and ADPG pyrophosphorylase were assayed during the growth of wheat grains. Changes in fresh weight, dry weight, water, sucrose, reducing sugars, starch, total nitrogen, protein nitrogen, and soluble nitrogen were followed simultaneously. Throughout development the activity of UDPG pyrophosphorylase per grain was much greater than the activity of ADPG pyrophosphorylase. Both enzymes increased in activity during the phase of starch synthesis and a sharp rise in ADPG pyrophosphorylase was associated with the onset of rapid starch formation. ADPG pyrophosphorylase activity decreased to a very low level when starch formation in the grain ceased. UDPG pyrophosphorylase activity also decreased at this time. Although the participation of UDPG is not excluded, it is suggested that the main substrate for starch synthesis in the wheat grain is ADPG. A mechanism for the synthesis of starch from sucrose is proposed.


1956 ◽  
Vol 34 (4) ◽  
pp. 601-619 ◽  
Author(s):  
D. J. Samborski ◽  
Michael Shaw

The first leaves of resistant (var. Khapli) and susceptible (var. Little Club) species of wheat were heavily inoculated with P. graminis (Race 15B). The effect of the frequency of the pustules on their size and on the leaves is described. The oxygen consumption, total dry weight, total nitrogen, and sugar contents of leaf disks were measured at frequent intervals after inoculation. At infections of Little Club massive increases in dry weight occurred in 10 to 15 days, but the percentage total nitrogen remained close to that of healthy leaves. Oxygen consumption per unit dry weight or per unit of tissue nitrogen rose to from 2.5 to 3.0 times that for healthy tissue and then fell off again. The duration and degree of the rise were dependent on environmental conditions. At infections on Khapli, both dry weight and the percentage total nitrogen declined rapidly and the leaves turned yellow and died in about eight days, suggesting a rapid breakdown of protein. Oxygen consumption per unit dry weight or per unit of tissue nitrogen rose more rapidly, to from 2.0 to 2.5 times that of healthy tissue, and declined again sooner than at infections on Little Club. With both species, the 'accumulation' at infections of radioactive glucose, or its products, roughly paralleled the course of respiration. With leaves of Little Club, initially low in carbohydrate and having a low respiratory quotient, a marked rise in the respiratory quotient occurred at developing infections; little or no rise occurred with Khapli. The results of the sugar analyses suggested that the increase in respiration following infection was not initially dependent on an increase in the sugar content above that found in the healthy leaf. The significance of the results is discussed.


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