Oat Bran Fermentation by Rye Sourdough
ABSTRACT Cereal Chem. 79(3):345-348 Hydration of oat bran including fermentation by rye sourdough was studied. Three types of oat bran suspensions were prepared (a control, one with whole meal rye flour added, and one with rye starter added). The suspensions were incubated for 1, 2, 3 and 4 hr. β-Glucan content and solubilities of protein and β-glucan were analyzed. Viscosity of the super- natants of oat bran suspensions was determined. Neither the rye sour- dough nor the rye flour alone had a significant effect on the total β- glucan content of oat bran suspensions. However, the addition of rye, either as whole meal rye flour or as sourdough starter, markedly increased the solubility of β-glucan and proteins and simultaneously decreased the viscosity of the water-soluble fraction of oat bran suspension. This sug- gests that a hydrolysis of β-glucan had occurred that could change the rheological properties of oat bran in baking and the physiological potential of oat bran in nutrition. Bread rich in oat bran is a potential daily source of soluble fiber which in oat bran is mainly (1→3)(1→4)-β-D-glucan, referred to as β-glucan. However, when using bran in baking, the rigid fiber particles of bran disturb the formation of the gluten-protein matrix (Gan et al 1989). To reduce this disturbing effect, the bran particles can be softened by hydration, thus enabling enzymatic function. Oat bran itself should be enzymatically inactive because of the kiln- drying treatment performed in the milling process. Nevertheless, hy- drating might risk activating micro-organisms and hydrolysis of β- glucan. In baking, micro-organisms such as bacilli and molds can be controlled by lowering the pH level (adding acids or by lactic acid fermentation). In oat bran baking, lactic acid fermentation would prevent harmful microbial growth and would also provide flavor to the bread. Sourdough starter could be used in oat bran hydration, especially in countries where sour rye bread is pro- duced and bakeries keep their own rye sourdough starter on hand. However, the rye sourdough starter also contains enzymes such as the endogenous hydrolytic enzymes of rye flour. These could affect the properties of the oat polysaccharides and protein. In rye baking, rye flour components in the sourdough undergo considerable change involving swelling, solubilization, and partial hydrolysis, and the breakdown products have an important role as flavor compo- nents. The aim of this study was twofold: 1) to determine the effect of oat bran fermentation by rye starter on the soluble β-glucan and protein contents in oat bran suspensions and on the viscosity prop- erties of the solubles; and 2) to evaluate the potential for β-glucan hydrolysis by the rye flour and by rye sourdough. MATERIALS AND METHODS Commercial oat bran (Melia Ltd, Raisio) was used in this study. The oat bran was ground with a laboratory pin-mill KT-30 (Koneteol- lisuus Oy, Helsinki). The particle size distribution was obtained by sieving the milled oat bran (50 g) through sieves (1.6, 1, 0.71, 0.4, 0.2) for 10 min on a laboratory Bühler-Miag sieve (Braunschweig 1977). Most of the oat bran particles (85%) were retained on apertures of 1.6 to 0.4 mm. Amounts retained by sieves 1.0, 0.71, and 0.4 were 27.4, 26.8, and 30.5%, respectively. Only 1% of oat bran particles were >1.6 mm. The remaining two fractions retained by the 0.2-mm sieve and passed through the sieve were 8.5 and 6.7%, respectively.
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ABSTRACT: Despite the lack of international agreement regarding the definition and classification of fiber, there is established evidence on the role of dietary fibers in obesity and metabolic syndrome. Beta glucan (β-glucan) is a soluble fiber readily available from oat and barley grains that has been gaining interest due to its multiple functional and bioactive properties. Its beneficial role in insulin resistance, dyslipidemia, hypertension, and obesity is being continuously documented. The fermentability of β-glucans and their ability to form highly viscous solutions in the human gut may constitute the basis of their health benefits. Consequently, the applicability of β-glucan as a food ingredient is being widely considered with the dual purposes of increasing the fiber content of food products and enhancing their health properties. Therefore, this paper explores the role of β-glucans in the prevention and treatment of characteristics of the metabolic syndrome, their underlying mechanisms of action, and their potential in food applications.Journal of nutrition and metabolism 01/2012; 2012:851362.
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ABSTRACT: A tension stiffening model is presented which enables the calculation of average tensile stresses in concrete, after yielding of reinforcement, in reinforced concrete elements subjected to uniaxial tension, shear or flexure. To determine the average tensile stress–strain relationship for concrete, a crack analysis approach is employed taking into account the bond mechanism between concrete and deformed reinforcing bars, and numerical analyses are conducted to determine the tensile behavior of reinforced concrete members including post-yield response. Analytical parametric studies are conducted to determine the influence of various parameters including concrete compressive strength and reinforcement yield strength, ultimate strength, hardening stress, and hardening strain. Analysis results obtained from the proposed model, when compared to experimental results for uniaxial members, indicate good agreement for structural behavior after yielding of reinforcement. The proposed model makes it possible to accurately calculate reinforcement stresses at crack locations and, thus, average strain conditions which result in rupture of reinforcement. This leads to more realistic predictions of the uniaxial, flexural, and shear ductility of reinforced concrete members.Engineering Structures - ENG STRUCT. 01/2011; 33(5):1723-1733.
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ABSTRACT: Organizations are required to comply with changes in legislation and policy. Yet the implementation of new legislation is often expensive, can have long lead times and is prone to failure. The existing situation significantly constrains policy-making. To improve this, policy makers and policy executors are searching for ways to achieve higher levels of flexibility and agility in their business process management systems. Flexibility is the ability to react to changes and agility is the speed in responding to variety and change. Both flexibility and agility are multi-dimensional concepts. This paper presents principles for creating flexibility and agility when implementing new or revised policies into business processes. These principles include: 1) defining and using business services, 2) integrating and orchestrating business services through the use of events, 3) separating process, knowledge and resources and 4) implementing policy in an integrated manner. Business services are components encapsulating business functions and having clear responsibilities and accountabilities. The case study shows that these forms of flexibility and agility can help to implement policies more quickly and cost effectively. An organization's resources and level of flexibility and agility determines what laws can be implemented within a certain time. The improvement of flexibility and agility requires innovations on all levels: infrastructure, business process and organization. The level of flexibility and agility should always be measured by a combination of measures. We make plea for instruments assessing the impact of policies on organizations prior to implementation.Government Information Quarterly 01/2012; 29(Supplement 1):S61-S71. · 1.42 Impact Factor