Hagberg falling number and the nutritional value of wheat in broiler chicken diets

1. Three experiments were performed to study the effect of Hagberg falling number in wheat on performance, nutrient digestibility and AMEN in broilers. In two experiments, one hard and one soft wheat variety were used to study the interaction between falling number and hardness of wheat with regard to nutritional value. In these experiments, wheat batches with high falling number when harvested under dry conditions were used in broiler diets. 2. Wheat with reduced falling numbers (high, medium and low) was obtained by controlled germination. In the third experiment, wheat with reduced falling numbers were obtained by delayed harvesting times. 3. In each experiment, a total of 4 cereal batches with different falling numbers from each wheat variety were used to produce corresponding experimental diets with wheat as the major ingredient. Each diet was fed to broiler chickens ad libitum from d 1 to d 17 of age. 4. There was no consistent effect of falling number on performance. Low falling number did not improve feed utilisation or AMEN compared to the original wheat, despite a higher AMEN associated with higher starch digestibility. This phenomenon was not observed after reduction of falling number by delayed harvesting. Apparently, natural reduction of falling number resulted in enhanced degradation of arabinoxylans compared to controlled germination.     

The Leaching Behaviour and Balances of Nitrogen and Other Elements under Spring Wheat in Lysimeter Experiment 1985–92

Abstract

In a lysimeter study it was found that moderate rates of ammonium nitrate increased utilization percentages in spring wheat, and the leaching was 10% or less of added N. Over-optimal rates reduced utilization percentages and increased leaching to almost 50% of the highest doses. Late split application of calcium nitrate increased the percentage of N in grain. Furthermore, leaching of N was not reduced, but occurred somewhat later in the fall and winter seasons. Leaching of Cl^? was more rapid and that of SO₄ ^2- was delayed relative to the leaching of NO₃ ^?. Rather large negative N balances were obtained, also after over-optimal application rates, and total N content of the soil was reduced. Compared with the N₀ treatment, differences in soil N residues amounted to 15–25% of added N in seven years. Gaseous losses had apparently taken place both from the added N and from soil N according to the total-N analysis.     

Temperature variations during grain filling obtained in growth tunnel experiments and its influence on protein content,polymer build-up and gluten viscoelastic properties in wheat

The aim of this study was to investigate effects of temperature during grain filling on gluten quality characteristics at a lower to moderate temperature range. Experiments with two wheat varieties grown in field covered by polypropylene tunnels during grain filling were performed in two seasons. Mean day temperature differences achieved within the tunnel were approximately 2–2.5 °C from the open to the closed end. There were significant effects of temperature on grain maturity time, thousand grain weight and protein content. The resistance to stretching of the gluten doughs increased with the increasing day temperatures. This was reflected in the proportion of unextractable polymeric proteins (UPP). The results suggest that increases in temperature within this temperature range affect the polymerization of polymeric proteins, giving higher molecular weights, and hence increased Rmax and stronger gluten. The two varieties differed in their response to temperature. In addition, there were seasonal variations in gluten functionality that may be associated with fluctuations in day temperatures between the seasons.     

Effect of temperature variation during grain filling on wheat gluten resistance

The objective was to investigate effects of natural variation in temperature during grain filling on wheat (Triticum aestivum L) gluten quality. Seventeen field trials with four different varieties were conducted during the years 2005–2008. Temperature records were obtained from automatic weather stations located near the field trial sites. The period from heading to yellow ripeness was divided into 20 sub-phases of equal thermal time units, and a last sub-phase comprising the seven days after yellow ripeness. Partial Least Squares Regression was used to relate the temperature records of the different sub-phases to gluten quality analysed by the Kieffer Extensibility test and the SDS sedimentation test.     

Barley carbohydrate composition varies with genetic and abiotic factors

Abstract

Changes in chemical quality arising from genetic composition of different barley varieties as well as non-genetic factors were investigated by comparing samples from different seasons and locations. The samples (15), consisting of different varieties originating from Norway and Canada, were analysed for polysaccharide composition as well as total protein content. The results revealed differences in chemical parameters between the hulled and hull-less varieties, especially in carbohydrate composition. Also, variations within the types were found, which indicated that factors other than the presence or lack of hull may also influence the carbohydrate composition. As expected, varieties grown at the same location in both seasons had a lesser variation in their grain composition between the growing periods than varieties grown at different locations. Changing the growth location from Canada to Norway also gave an increase in starch and insoluble fibre, but decreased the amount of β-glucan, protein and soluble fibre. Promising varieties for the food industry are samples with an atypical starch characteristic without hull, due to higher levels of the proposed health-beneficial components. Also, the commercial Norwegian variety, Olve, had an advantageous grain composition and is a promising variety for food uses.     

Influence of growth temperature on content, viscosity and relative molecular weight of water-soluble β-glucans in barley (Hordeum vulgare L.)

β-Glucan content and viscosity of water-soluble β-glucans have a considerable impact on the digestion of barley. Eight different 2-row barley (Hordeum vulgare L.) cultivars were grown in controlled environment chambers at five different temperatures until maturity. The samples were pearled, milled and analysed for their content of total, insoluble and soluble β-glucan. The water-soluble fraction was extracted at 37 °C, subjected to amylase treatment and freeze-dried. Water-soluble crude β-glucans were solubilised in distilled water, analysed for viscosity and their purity was checked by nuclear magnetic resonance. Molecular weights were profiled by size exclusion chromatography with RI detection. The content of total β-glucan varied from 4.0% to 7.4%, and was significantly affected by the growth temperature. An interaction between cultivar and growth temperature was observed for the total β-glucan content. The extractability was significantly affected by growth temperature, as there was recorded an increasing amount of water-soluble β-glucan with increasing growth temperature. Both the viscosity and the molecular weight of the water-soluble β-glucans increased with the growth temperature.     

Effects of Cultivar and Temperature During Grain Filling on Wheat Protein Content,Composition, and Dough Mixing Properties

Three wheat cultivars, Bastian, Polkka, and Tjalve, were grown in growth chambers at 9, 12, 15, 18, and 21°C during grain filling in 1994, 1995, and 1996. The wheat samples were analyzed for protein content and sodium dodecyl sulfate (SDS) sedimentation volume. The mixing properties of sifted flours were determined by mixograph, and the flour protein composition was determined by size-exclusion fast protein liquid chromatography (SE-FPLC). The protein content, sedimentation volume, and mixogram parameters were affected by the temperature during grain filling. The protein content increased as the temperature increased. The sedimentation volumes and the mixograph data showed temperature effects that could not be explained by variation in protein content. The proportion of the polymeric flour proteins increased with increasing temperature. Positive correlations were found between the proportion of polymeric proteins and SDS sedimentation volume and, within each year, between the proportion of polymeric proteins and mixograph peak time. Negative correlations were found between the proportion of low molecular weight flour proteins (proportion of fraction IV) and sedimentation volume. The differences in these quality parameters among cultivars exceeded the effect of temperature during grain filling.     

Investigating environmental factors that cause extreme gluten quality deficiency in winter wheat (Triticum aestivum L.)

Unstable breadmaking quality of wheat due to environmental influence has been a problem for Norwegian milling industries. Large variation in gluten quality was observed from field trials with Norwegian winter wheat conducted in several locations between 2005 and 2013. Moreover, extremely poor gluten quality was observed in several locations in the 2007 and 2011 season, and indicated almost complete loss of breadmaking quality. To investigate the environmental factors which cause extremely weak gluten, gluten proteins were characterized in samples selected within the 2011 season. The results revealed that the proportion of large glutenin polymers decreased in wheat samples with extremely weak gluten. Moreover, re-polymerization of large glutenin polymers, which normally occur during the resting period of a dough, did not take place in gluten prepared from these samples. Incubation of total proteins extracted from these samples in an in vitro system showed a drastic degradation of gluten proteins indicating protease activities. The origin of the proteases remains unclear; however, exogenous proteases derived from Fusarium spp. seem to play a key role for protein degradation, and thus causing severe quality deficiency. A genotypic difference was found between the two cultivars and one of them had higher resistance against the factors influencing gluten quality in negative way.     

Combined nitrogen and sulphur fertilisation and its effect on wheat quality and protein composition measured by SE-FPLC and proteomics

Soil sulphur deficiency, which is increasingly prevalent in Western Europe, lowers wheat yields, and also affects the gluten quality of the flour. Differences in S availability may change the proportion of S-poor to S-rich gliadins and glutenin subunits. This may cause unpredictable and unwanted variations in wheat quality. The combined effects of nitrogen (N) and sulphur (S) fertilisers and split application of S and N on wheat gluten quality and composition were investigated. The results revealed effects of S fertilisation on dough quality. At high N fertilisation levels significant responses to S fertilisation were found which emphasised the need for precision application of S in intensive wheat production systems. Protein fractionation by SE-FPLC showed that quality differences were associated with changing proportions of high M_r polymeric proteins. Changes in protein composition of salt soluble proteins were also confirmed by proteomics. Glyceraldehyde-3-phosphate dehydrogenase and one of the serpin protein spots increased at high N, combined with the lower S level. The enzymes also increased in samples with increased S fertilisation combined with low N, but was not changed at higher N levels. Furthermore, at high N the serpin protein spot, and also a 27 K protein and one unidentified protein spot decreased with increasing S.