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Abstract  

Determination of protein content in food materials is usually done by analyzing the nitrogen amount by wet chemical Kjeldahl method. An improved accuracy accompanied by smaller analyzing intervals can be achieved using nondestructive neutron activation. Analyses have been performed using 14 MeV neutrons to determine the content of N and P in single wheat corns. Irradiation parameters have been optimized to prevent serious radiation damage in the grains. About 200 single corns have been investigated with total net weights ranging from 30 to 70 mg. The tested arrangement allows determination of nitrogen amount in a single corn down to 0.3 mg with an accuracy of better than 4%. Mean nitrogen concentrations in the range from 9 to 19% per corn have been detected.

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Winter wheat (Triticum aestivum L.) yield samples taken from a consecutive series of crop years representing drought, normal and moist conditions at the Nagygombos experimental site of the Szent István University have been evaluated. The impact of N topdressing and crop year conditions on the performance of protein and wet gluten content were studied.The results suggest that ascending levels of N topdressing, and increased number of applications had a beneficial effect on the protein content, as well as on wet gluten values. Crop year had a significant effect on quality manifestation. The drier the crop year, the better the recorded quality performance. The magnitude of changes was bigger in case of gluten than in that of protein values. There were minor differences between the two varieties examined, especially in their response patterns to nitrogen supply. Dough formation depends mainly on the gliadin/ glutenin ratio, but there is less information on the agronomic and climatic impacts that may cause alterations in that.

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The cotton bollworm (Helicoverpa armigera Hübner), which migrated in the Carpathian-basin from Mediterraneum in the last decades, is becoming an increasingly serious problem for maize producers in Hungary. In several regions the damage it causes has reached the threshold of economic loss, especially in the case of the sweet maize cultivation. The aim of the research was to determine the changing of ears weights and in-kernel accumulation and alteration in grain as a function of cotton bollworm mastication.Our investigation confirmed that there is an in-kernel and protein pattern change of maize grain by cotton bollworm. Our results proved the significant damaging of each part of ears by cotton bollworm masticating (the average weight loss of ears: 13.99%; the average weight loss of grains: 14.03%; the average weight loss of cobs: 13.74%), with the exception of the increasing of the grain-cob ratio. Our examinations did not prove the water loss — that is the “forced maturing” — caused by the damage. Decreasing of raw fat (control: 2.8%; part-damaged: 2.6%; damaged: 2.4%) and starch content (control: 53.1%; part-damaged: 46.6%; damaged: 44.7%) were registered as a function of injury. In contrast, the raw protein content was increased (control: 4.7%; part-damaged: 5.3%; damaged: 7.4%) by maize ear masticating. The most conspicuous effect on protein composition changing was proved by comparison of damaged grain samples by SDS PAGE. Increased amounts of 114, 50, 46 and 35 kDa molecular mass proteins were detected which explained the more than 50% elevation of raw protein content. The statistical analysis of molecular weights proved the protein realignment as a function of the pest injuries, too.

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The work was conducted to determine the practical applicability of size-exclusion high performance liquid chromatography in testing wheat bread-making quality and specify which of the peak characteristics, is the best indicator of wheat quality. The research was realized on 29 cultivars of different quality. The wheat quality was evaluated by protein content, content of wet gluten, gluten index, and farinograph rheological characteristics. All of the determined peak characteristics can be used as the indicators of wheat quality but the closest correlations with the quality parameters were found for the absolute peak areas and/or relative peak areas. The area of peak 1 was positively correlated with the dough stability (r = 0.50) and negatively correlated with the degree of dough softening (r = −0.49). The relative and absolute areas of the peak 2 were in positive correlation with sedimentation volume (r = 0.68; 0.68), farinograph water absorption (r = 0.50; 0.57) and protein content (r = 0.56; 0.57). The characteristics of peaks 3 and 4 were in the closest correlation with the investigated parameters of bread-making quality, the correlation coefficients related to the peaks 3 and 4 were nearly equal and reached values 0.58–0.77. The peak height can be used as a supplemental wheat quality indicator especially for determination of certain glutenin subunits. The area/height ratio or the contents of protein fractions are of the minor importance. Then the model predicting bread-making quality from peak characteristics was built. The values of coefficients of determination R2 were the highest for Zeleny sedimentation volume (0.83–0.97). The agreement between predicted and observed values increased when not single characteristics, but their combinations were considered.

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The gluten proteins of 15 winter wheat cultivars grown in eastern Croatia were studied for their contribution to the bread-making quality. Composition of high-molecular-weight glutenin subunits (HMW-GS) was analyzed by SDS-PAGE, while the quantity of gluten proteins was determined by combined extraction/RP-HPLC procedure. The results of the linear correlation analysis carried out on the particular gluten proteins and technological properties showed that the amount of total gluten content highly correlates with protein content. Among gluten proteins, the glutenins showed higher correlation with protein content, with pronounced influence of HMW-GS, than gliadins. Wet gluten content was significantly correlated to total gliadin quantity. Gluten index as gluten quality parameter was positively influenced by total glutenins and low-molecular-weight glutenin subunits (LMW-GS), and negatively, by the ratios of gliadin to glutenin (Gli/Glu), whereas the amount of gliadins was not important. Dough development time was strongly correlated with total gluten content, total glutenins and the Gli/Glu ratio. Dough mixing resistance was strongly affected by total glutenin content with pronounced influence of HMW-GS. Degree of dough softening is mainly negative influenced by total glutenins and ratio of Gli/Glu. Farinograph quality number as flour quality index was highly positively correlated with total glutenins, with emphasized influence of HMW-GS. The Gli/Glu ratio had the highest influence on dough maximum resistance. Dough extensibility showed moderate correlation with total gliadins. The results of the linear correlation indicated that loaves volumes were significantly influenced by total gluten proteins, HMW-GS and LMW-GS.

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63 70 Birch, C.J. and Long, K.E. (1990). Effect of nitrogen on the growth, yield and grain protein content of barley ( Hordeum vulgare ). Australian Journal of

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. Effect of nitrogen and pesticides on the yield and protein content of winter wheat. — Cereal Research Communications vol. 34 no. 1 509–512 pp. Kismányoky T. Effect of nitrogen and

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Összefoglalás

Debreceni Egyetem Agrár- és Műszaki Tudományok Centruma Látóképi Kísérleti Telepén, középkötött mészlepedékes csernozjom talajon, két eltérő évjáratban – aszályos (2007) és kedvező vízellátottságú (2008) években – korai, optimális és késői vetésidőben beállított kísérletben vizsgáltuk a kukorica terméshozamát, fehérje- és keményítőtartalmát. A kísérleti terület talajának pH értéke 6,6, Arany-féle kötöttsége 37. A talaj nitrogén és kálium ellátottsága jó, P-ellátottsága közepes. Az alapadatokhoz feno-, illetve fitometriai megfigyelések, talajtani vizsgálatok kapcsolódnak. A termés, fehérje- és keményítőtartalom adatok a tenyészidőcsoportban köztermesztésben szereplő 24 hibrid eredményei. A kiértékelést az SPSS for Windows 13.0 statisztikai programcsomaggal végeztük. A vetésidőnek mindkét évben jelentős, eltérő mértékű hatása volt a termésre. A tényezők (vetésidő, hibrid) közül 2007. évben a vetés idejének hatása volt a legjelentősebb, míg 2008. évben a hibrid hatása felülmúlta a vetésidő hatását. A száraz, aszályos évjáratban (2007. év) a termés az optimális vetésidőben volt szignifikánsan a legnagyobb (6,111 t/ha). A kedvező vízellátottságú évjáratban (2008. év) a korai vetéssel értük el a nagyobb terméseredményt (8,910 t/ha), az eltérő vetésidőpontok terméseredményei között azonban nem volt szignifikáns különbség. A hosszabb tenyészidejű hibridek szemtermése – mindkét évben – szignifikánsan nagyobb (P < 0,05) volt, mint a rövidebb tenyészidejűeké. Aszályos évjáratban (2007. év) a legnagyobb szemtermése a középérésű (FAO 400) (6,596 t/ha), míg a kedvező vízellátottságú évjáratban (2008. év) a késői (FAO 500) érésű hibrideknek (9,864 t/ha) volt. A kedvező évjáratban (2008) a nagy termésekben alacsonyabb fehérjetartalmat mértünk, mint a vízhiányos kisebb termésekben, 2007 évben. A kukoricaszem fehérjetartalma 2007 évben a késői vetésidőben (11,9 g × 100 g–1 sza.) volt a legnagyobb. A vetésidő 2008-ban szignifikánsan nem befolyásolta a fehérjetartalmat. Az igen korai (FAO 200) csoportba tartozó hibridek fehérjetartalma minden vetésidőben és mind két évben (P < 0,001) szignifikánsan nagyobb volt, mint a korai (FAO 300), középérésű (FAO 400) és késői (FAO 500) hibrideké. A fehérjetartalomban a legnagyobb különbség az aszályos évjáratban (2007) a korai és a késői vetésidő között volt. A jó vízellátottságú évjáratban (2008) a vetésidők hatására egyik FAO csoport fehérjetartalma sem változott szignifikánsan. A terméshozam és a fehérjetartalom között negatív összefüggés igazolódott, a nagy terméshozamú évben (2008) a fehérjetartalom kisebb, mint a gyengébb termésű évben (2007). A vetésidő mindkét évben szignifikánsan befolyásolta a kukoricaszem keményítőtartalmát (P < 0,001). Mind az aszályos mind a kedvező évjáratban a hibridek keményítőtartalma között (2007-ben P < 0,001, 2008-ban P < 0,05) jelentős különbség mutatkozott. 2007 évben a vetésidő × hibrid kölcsönhatás szignifikáns és a keményítőtartalom is magasabb volt. A száraz (2007) évben nagyobb keményítőtartalmat mértünk, mint a jó vízellátottságú (2008) évben. Ugyanakkor mindkét évben a késői vetésidőben mértük a legnagyobb keményítőtartalmat (74,4 g × 100 g–1 sza., 72,1 g × 100 g–1 sza.). A késői tenyészidejű (FAO 500) hibridek keményítőtartalma szignifikánsan nagyobb volt (P < 0,05), mint a rövidebb tenyészidejűeké. A felhasználás szempontjából fontos beltartalmi értékek csak kiváló genetikai háttérrel és termesztéstechnológiával (vetésidő) valósulhatnak meg.

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The total body composition of 4×10 female, 5-month-old New Zealand White rabbits was determined, using direct chemical analysis and computerised tomography (CT). Ten non-pregnant rabbits (control) and 3 × 10 pregnant rabbits at days 14, 21 and 28 of gestation, respectively, were included in the study. With the advancement of pregnancy, the body weight (BW) of does significantly (P < 0.05) increased (control: 3255 g, day 28: 3938 g), while the dry matter, DM (control: 43.02%, day 28: 40.94%), ether extract, EE (control: 20.15%, day 28: 18.13%), crude protein, CP (control: 20.15%, day 28: 18.13%), and energy concentration decreased (control: 12.41 MJ/kg BW, day 28: 11.81 MJ/kg BW). During pregnancy the protein content of uteri (control: 12.24%, day 28: 49.45% of DM) and the retained energy in the form of uterus with fetuses (day 14: 0.824 MJ, day 28: 2.189 MJ) increased, while the dry matter (control: 82.39%, day 28: 28.96%) and ether extract content (control: 86.05%, day 28: 45.92% of DM) of uteri decreased. With the advancement of pregnancy the dry matter (day 14: 39.70%, day 28: 18.65%) and crude protein (day 14: 75.74%; day 28: 63.63% of DM) content and the number of fetuses (day 14: 8.8; day 28: 6.4) decreased, while their fat concentration (day 14: 10.13%, day 28: 24.34% of DM) increased. According to the equations created from the CT pictures, body fat (R2 = 0.871) and energy (R2 = 0.926) content can be predicted with high accuracy. The accuracy of predicting body protein content is much lower (R2 = 0.356), which can be improved by introducing the body weight as a new dependent variable (R2 = 0.797). It can also be concluded that, in contrast to other animal species, rabbit fetuses show considerable development not only in the last trimester of gestation but already from the second half of pregnancy.

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Jolánkai, P. — Tóth, Z. — Kismányoki, T. (2006): Effect of nitrogen and pesticides on the yield and protein content of winter wheat. Cereal Research Communications, 34.1. 509–512. Kismányoki T

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