10 results on '"Ralf Greiner"'
Search Results
2. The effect of exogenous phytase supplementation on nutrient digestibility, ruminal fermentation and phosphorous bioavailability in Rambouillet sheep
- Author
-
Ralf Greiner, Daniel Menezes-Blackburn, Abdelfattah Zm Salem, Mona M.M.Y. Elghandour, German Buendía, and L.H. Vallejo
- Subjects
chemistry.chemical_classification ,Nutrition and Dietetics ,Phosphorus ,0402 animal and dairy science ,chemistry.chemical_element ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Bioavailability ,Excretion ,Neutral Detergent Fiber ,Blood serum ,Animal science ,chemistry ,040103 agronomy & agriculture ,Propionate ,0401 agriculture, forestry, and fisheries ,Dry matter ,Phytase ,Agronomy and Crop Science ,Food Science ,Biotechnology - Abstract
The effect of phytase supplementation with respect to a high sorghum grain diet on sheep voluntary feed intake, apparent nutrient digestibility, ruminal fermentation, phosphorus (P) excretion and blood serum P concentration was evaluated.; Results: Phytase supplementation significantly decreased fecal P excretion (P = 0.003), resulting in a 26% decrease in relation to the phytase free diet. Dry matter intake, nutrient digestibility, ruminal butyrate and serum P were not (P > 0.10) affected by the phytase level. Neutral detergent digestibility showed a tendency to increase linearly (P = 0.10) with increasing phytase levels. Ruminal pH was lower for phytase supplemented sheep, with a significant decrease (P = 0.007) at 9 h post feeding, whereas ruminal ammonia-N at 3 h post feeding was lower (P = 0.004) for the phytase treatment groups, resulting in a decreasing linear response (P = 0.001) with an increasing phytase dose. Duodenal pH was significantly reduced at 6 h post feeding. Propionate tended (P = 0.051) to be increased linearly as the phytase supplementation level increased.; Conclusion: Exogenous phytase supplementation of high sorghum grain diets significantly decreased fecal P excretion in Rambouillet rams. Phytase supplementation appears to affect neutral detergent fiber digestibility, duodenal and ruminal pH, ammonia and propionate. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.
- Published
- 2018
3. A novel purple acid phytase from an earthworm cast bacterium
- Author
-
Ralf Greiner, Reza Ghorbani Nasrabadi, Ahad Yamchi, and Elham Nourzadeh Roshan
- Subjects
0301 basic medicine ,chemistry.chemical_classification ,Nutrition and Dietetics ,biology ,030106 microbiology ,Ion chromatography ,Tartrate ,biology.organism_classification ,Dephosphorylation ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Enzyme ,chemistry ,Biochemistry ,Chelation ,Phytase ,Vanadate ,Agronomy and Crop Science ,Bacteria ,Food Science ,Biotechnology - Abstract
Phytases are a diverse group of enzymes initiating the dephosphorylation of phytate. Phytate is considered as an anti-nutritional compound because of its capability to chelate nutrients such as Fe2+ , Zn2+ , Mg2+ , and Ca2+ . In this study, several bacterial isolates obtained from earthworm casts were evaluated for their phytate degrading capability. Enzymatic properties and the sequence of the corresponding phytase-encoding gene of the selected isolate were determined.; Results: The phytase exhibited its highest activity at pH 4.0 and was stable from pH 3 up to pH 9. The temperature optimum was determined to be 65 °C. The strongest inhibitors of enzymatic activity were identified as vanadate, Cu2+ , and Zn2+ . High-performance ion chromatography analysis of enzymatic phytate dephosphorylation revealed that the first dephosphorylation product was d/l-myo-inositol(1,2,3,4,5)pentakisphosphate.; Conclusion: Owing to its enzymatic properties, such as tolerance to tartrate and the presence of the consensus motifs PDTVY, GNHE, DLG, VLFH, and GHDH, this phytase could be classified as a purple acid phytase. To the best of our knowledge, this is the first report describing a bacterial purple acid phytase. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
- Published
- 2018
4. Recent advances inγ-aminobutyric acid (GABA) properties in pulses: an overview
- Author
-
Nooshin Nikmaram, Mohamed Koubaa, Shahin Roohinejad, Ralf Greiner, B.N. Dar, Stuart K. Johnson, and Francisco J. Barba
- Subjects
0301 basic medicine ,2. Zero hunger ,chemistry.chemical_classification ,030109 nutrition & dietetics ,Nutrition and Dietetics ,Decarboxylation ,Glutamate decarboxylase ,04 agricultural and veterinary sciences ,Biology ,040401 food science ,Aminobutyric acid ,3. Good health ,Amino acid ,Lactic acid ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Enzyme ,chemistry ,Phytochemical ,Biochemistry ,Fermentation ,Agronomy and Crop Science ,Food Science ,Biotechnology - Abstract
Beans, peas, and lentils are all types of pulses that are extensively used as foods around the world due to their beneficial effects on human health including their low glycaemic index, cholesterol lowering effects, ability to decrease the risk of heart diseases and their protective effects against some cancers. These health benefits are a result of their components such as bioactive proteins, dietary fibre, slowly digested starches, minerals and vitamins, and bioactive compounds. Among these bioactive compounds, γ-aminobutyric acid (GABA), a non-proteinogenic amino acid with numerous reported health benefits (e.g. anti-diabetic and hypotensive effects, depression and anxiety reduction) is of particular interest. GABA is primarily synthesised in plant tissues by the decarboxylation of l-glutamic acid in the presence of glutamate decarboxylase (GAD). It is widely reported that during various processes including enzymatic treatment, gaseous treatment (e.g. with carbon dioxide), and fermentation (with lactic acid bacteria), GABA content increases in the plant matrix. The objective of this review paper is to highlight the current state of knowledge on the occurrence of GABA in pulses with special focus on mechanisms by which GABA levels are increased and the analytical extraction and estimation methods for this bioactive phytochemical. © 2017 Society of Chemical Industry.
- Published
- 2017
5. Effects of natural blends of garlic and eucalypt essential oils on biogas production of four fibrous feeds at short-term of incubation in the ruminal anaerobic biosystem
- Author
-
Mona My, Elghandour, Mohamed Zm, Salem, Ralf, Greiner, and Abdelfattah Zm, Salem
- Subjects
Eucalyptus ,Rumen ,Plant Stems ,Animal Feed ,Zea mays ,Seeds ,Oils, Volatile ,Animals ,Plant Oils ,Cattle ,Digestion ,Food Additives ,Anaerobiosis ,Gases ,Garlic ,Sorghum - Abstract
The present study explored the effect of garlic and/or eucalypt oils on biogas production during in vitro ruminal fermentation of four agro industry byproducts. For this, 0-180 mg oil LGas production and nutrient degradability was oil type dependent. The oils enhanced (P 0.05) biogas and asymptotic biogas production for corn stalks and oat straw, although no effect was observed on asymptotic biogas production for sorghum straw and sugarcane bagasse. Addition of both oils decreased (P 0.05) fermentation pH for corn stalks, sorghum straw and oat straw and also increased (P 0.05) dry matter degradability for all four byproducts. Neutral detergent fibre degradability for all byproducts was higher (P 0.05) with garlic oil. Eucalypt oil, however, decreased (P 0.05) neutral detergent fibre degradability for sugarcane bagasse and corn stalks, although only weak effects were observed for sorghum and oat straws.With respect to ruminal biogas production, the addition of garlic oil showed better environmental effects than the addition of eucalypt oil and increasing oil concentrations resulted in enhanced fermentation characteristics. © 2018 Society of Chemical Industry.
- Published
- 2018
6. The effect of exogenous phytase supplementation on nutrient digestibility, ruminal fermentation and phosphorous bioavailability in Rambouillet sheep
- Author
-
Laura Haydee, Vallejo, German, Buendía, Mona Mmy, Elghandour, Daniel, Menezes-Blackburn, Ralf, Greiner, and Abdelfattah Zm, Salem
- Subjects
Dietary Fiber ,6-Phytase ,Feces ,Rumen ,Sheep ,Ammonia ,Dietary Supplements ,Fermentation ,Animals ,Biological Availability ,Phosphorus ,Animal Feed ,Sorghum - Abstract
The effect of phytase supplementation with respect to a high sorghum grain diet on sheep voluntary feed intake, apparent nutrient digestibility, ruminal fermentation, phosphorus (P) excretion and blood serum P concentration was evaluated.Phytase supplementation significantly decreased fecal P excretion (P = 0.003), resulting in a 26% decrease in relation to the phytase free diet. Dry matter intake, nutrient digestibility, ruminal butyrate and serum P were not (P0.10) affected by the phytase level. Neutral detergent digestibility showed a tendency to increase linearly (P = 0.10) with increasing phytase levels. Ruminal pH was lower for phytase supplemented sheep, with a significant decrease (P = 0.007) at 9 h post feeding, whereas ruminal ammonia-N at 3 h post feeding was lower (P = 0.004) for the phytase treatment groups, resulting in a decreasing linear response (P = 0.001) with an increasing phytase dose. Duodenal pH was significantly reduced at 6 h post feeding. Propionate tended (P = 0.051) to be increased linearly as the phytase supplementation level increased.Exogenous phytase supplementation of high sorghum grain diets significantly decreased fecal P excretion in Rambouillet rams. Phytase supplementation appears to affect neutral detergent fiber digestibility, duodenal and ruminal pH, ammonia and propionate. © 2018 Society of Chemical Industry.
- Published
- 2018
7. Effects of natural blends of garlic and eucalypt essential oils on biogas production of four fibrous feeds at short-term of incubation in the ruminal anaerobic biosystem
- Author
-
Mona MY Elghandour, Mohamed ZM Salem, Ralf Greiner, and Abdelfattah ZM Salem
- Subjects
Nutrition and Dietetics ,Agronomy and Crop Science ,Food Science ,Biotechnology - Published
- 2018
8. A novel purple acid phytase from an earthworm cast bacterium
- Author
-
Reza, Ghorbani Nasrabadi, Ralf, Greiner, Ahad, Yamchi, and Elham, Nourzadeh Roshan
- Subjects
6-Phytase ,Bacteria ,Bacterial Proteins ,Phytic Acid ,Enzyme Stability ,Animals ,Hydrogen-Ion Concentration ,Oligochaeta - Abstract
Phytases are a diverse group of enzymes initiating the dephosphorylation of phytate. Phytate is considered as an anti-nutritional compound because of its capability to chelate nutrients such as FeThe phytase exhibited its highest activity at pH 4.0 and was stable from pH 3 up to pH 9. The temperature optimum was determined to be 65 °C. The strongest inhibitors of enzymatic activity were identified as vanadate, CuOwing to its enzymatic properties, such as tolerance to tartrate and the presence of the consensus motifs PDTVY, GNHE, DLG, VLFH, and GHDH, this phytase could be classified as a purple acid phytase. To the best of our knowledge, this is the first report describing a bacterial purple acid phytase. © 2017 Society of Chemical Industry.
- Published
- 2017
9. Recent advances in γ-aminobutyric acid (GABA) properties in pulses: an overview
- Author
-
Nooshin, Nikmaram, B N, Dar, Shahin, Roohinejad, Mohamed, Koubaa, Francisco J, Barba, Ralf, Greiner, and Stuart K, Johnson
- Subjects
Plant Extracts ,Humans ,Fabaceae ,Nutritive Value ,gamma-Aminobutyric Acid - Abstract
Beans, peas, and lentils are all types of pulses that are extensively used as foods around the world due to their beneficial effects on human health including their low glycaemic index, cholesterol lowering effects, ability to decrease the risk of heart diseases and their protective effects against some cancers. These health benefits are a result of their components such as bioactive proteins, dietary fibre, slowly digested starches, minerals and vitamins, and bioactive compounds. Among these bioactive compounds, γ-aminobutyric acid (GABA), a non-proteinogenic amino acid with numerous reported health benefits (e.g. anti-diabetic and hypotensive effects, depression and anxiety reduction) is of particular interest. GABA is primarily synthesised in plant tissues by the decarboxylation of l-glutamic acid in the presence of glutamate decarboxylase (GAD). It is widely reported that during various processes including enzymatic treatment, gaseous treatment (e.g. with carbon dioxide), and fermentation (with lactic acid bacteria), GABA content increases in the plant matrix. The objective of this review paper is to highlight the current state of knowledge on the occurrence of GABA in pulses with special focus on mechanisms by which GABA levels are increased and the analytical extraction and estimation methods for this bioactive phytochemical. © 2017 Society of Chemical Industry.
- Published
- 2016
10. Purification and characterization of a phytate-degrading enzyme from germinated oat (Avena sativa)
- Author
-
Ralf Greiner and Marie Alminger
- Subjects
chemistry.chemical_classification ,Phytic acid ,Nutrition and Dietetics ,food.ingredient ,Phosphoric monoester hydrolases ,Molecular mass ,Biology ,chemistry.chemical_compound ,Hydrolysis ,Avena ,food ,Enzyme ,Biochemistry ,chemistry ,Phytase ,Enzyme kinetics ,Agronomy and Crop Science ,Food Science ,Biotechnology - Abstract
A phytate-degrading enzyme (myo-inositol hexakisphosphate phosphohydrolase) has been purified about 5,400-fold from germinated oat seedlings to apparent homogeneity. The molecular mass of the native monomeric enzyme was estimated to be about 67 kDa. Optimal pH for degradation of phytate was 5.0 and the optimal temperature 38 °C. Kinetic parameters for the hydrolysis of Na-phytate are KM 30 µM and kcat 356 s−1 at 35 °C and pH 5.0. The oat phytase exhibits a broad affinity for various phosphorylated compounds and hydrolyses phytate in a stepwise manner. The first hydrolysis product was identified as D/L-l(1,2,3,4,5) P5. © 1999 Society of Chemical Industry
- Published
- 1999
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.