Functional propertiesas solubility, water and oil adsorption, emulsifying capacity. emulsion activity and stabilityof protein isolates from faba beans, soybeans and sunflower seed depending on the isolation process were determined.Proteins isolated under mild conditions, it means by precipitation using dialysis or dilution of salt extracts with water, show the highest solubility, characterized by a sharp minimum of solubility at a rather narrow range of pH. An incubation of the precipitated proteins at low pH (pH 2) results in a decrease of the solubility on the alcaline and acidic part of the solubility profile.On the contrary to the decreased solubility, the proteins denatured by acid show an increased water adsorption capacity. Depending on the kind of protein and the conditions of preparation these values can reach the manifold ones of the control. Smaller increases of oil adsorption in acid-denatured proteins were found, too.The emulsion activity and stability were not or only slightly influenced, but the emulsifying capacity was strongly decreased by the denaturation procedure. The emulsifying capacity was influenced by the solubility of the protein, but a strong correlation does not exist.The high water adsorption of Promine D can be reached by the other plant proteins after denaturation. The sunflower protein showed the highest emulsifying capacity.Increasing the pH from the isoelectric range to 7 improves all studied functional properties.'
Over a period of 5 weeks an experiment was performed with 192 one-day-old Cobb 500 cockerels, which were randomly divided into two experimental groups of 12 cages (replicates) of 8 birds each. The objective of the experiment was to estimate whether the supplementation of a barleybased diet with β-glucanase influences the performance and gastrointestinal ecosystems of broiler chickens in terms of ileal viscosity and pH as well as the concentration of short-chain fatty acids (SCFA) and lactic acid in different segments of the gastrointestinal tract. In the period from day 15 to day 35, dietary enzyme supplementation significantly improved FCR values (1.90 vs 1.85). Body weight gains, liver and caeca weights were not affected by β-glucanase inclusion. Enzyme supplementation decreased ileal viscosity (P≤0.05) and affected SCFA concentrations in the crop and caeca. In digesta from different gastrointestinal segments, lactic acid was detected at the highest levels in the ileum, followed by the crop, gizzard and caeca. The total concentration of SCFAs was found to be highest in the caeca, followed by the ileum, crop, and gizzard. In the crop, the concentrations of acetate, and in the caeca, those of propionate as well as of total SCFA, increased following dietary enzyme supplementation. In none of the examined gastrointestinal segments was the pH value affected (P≤0.05) by enzyme supplementation.
Pea flour with a protein content (N x 6,25) of 25% was subjected to an extraction by 10% NaCI. The changes of the meal particles during the extraction were studied by electron microscopy. 89 % of the nitrogen sdbstances were extracted, 14% of which are albumins.The nitrogen solubility curve of the meal has a minimum of 18 % solubility at pH 4-5.The proteins in the NaCl extract were fractionated using dialysis (separation of globulins and albumins) and preparative gel chromatography (separation of the 11 S and 7 S globulins). The 1 1 S and 7 S globulins were homogenous in gel chromatography and ultracentrifugation. Their sedimentation coefficients go2 were I1,9 S and 6,4 S , respectively. They differ significantly in the gel electrophoresis.The amino acid composition of the isolated globulins shows a relatively high content of glutamin and aspartic acid as well as arginine and a lack of sulphur containing amino acids which are limiting. EAA indices of 69, 63, 62, 32 and 78 were calculated for pea flour, the raw globulin fraction, the 11 S and 7 S fraction, and the albumine fraction, respectively. Therefore for preserving the nutritive value of the pea material preparation processes are to be applied which exclude the loss of albumins during the protein isolation. IntroductionIn recent years, due to protein shortage, interest in pea seeds as a potential protein raw material has grown.The major protein fraction of pea seeds are globulins which constitute 80-90 per cent of all proteins [I]. Like other leguminous globulins the pea globulins consist mainly of two proteins, the legumine-like 11 S protein and the vicilin-like 7 S protein [2, 31. A minor fraction, consisting mainly of low-molecular weight proteins, manifests its affiliation to albumins by its solubility in water. These protein fractions differ in their amino acid composition. The globulins as typical storage proteins contain a considerable quantity of acidic amino acids in the amidated form (glutamic acid -glutamine, aspartic acid -asparagine) and arginine. On the other hand they are (especially vicilin) short of sulphur-containing amino acids and tryptophane [3].The amino acid composition of pea albumins is more advantageous from the nutrition point of view due to a high content of essential amino acids, sulphur containing amino acids included [4, 51.It was the aim of this work to isolate the main protein fractions from pea flour using a combined salt extraction -gel filtration -technique and to study their chemical and physico-chemical properties, it means the amino acid composition and the behaviour in ultracentrifugation and gel electrophoresis. G WI AZDA/SCHWENKE/RUTKOWSKl Material and methods Raw materialThe raw material under investigation was flour (0 i 0,15 mm) obtained from shelled commercial peas (Pisurn satzvum L.), Victoria type. Protein isolation proceduresProtein preparations for comparative purposes were obtained by the -method of incomplete isolation according to OBERG [6] under the conditions described by GWIAZDA et al.[7], with products...
A characteristic feature of cruciferous oilseeds is a high level of sulfur compounds as sulfur‐containing amino acids and glucosinolates which determine the nutritional value of rapeseed meal and affect processing factors in oil mills. During rapeseed processing, products of glucosinolate splitting are liberated and attack metal and, as a result, a specific sulfur corrosion of oil mill equipment develops. The most exposed are cooker, toaster and transporters of wet meal. The results of industrial investigation of sulfur corrosion are described and the sensitivity to corrosion of several construction steels during rapeseed processing is considered. A high content of sulfur‐containing compounds in starting oil significantly depressed the nickel catalyst activity and influenced the kinetics of rapeseed oil hydrogenation. Removal of these compounds by refining and its influence on the rate of oil hydrogenation are discussed.
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