Comparison of beer quality attributes between beers brewed with 100% barley malt and 100% barley raw material

BACKGROUND: Brewing with 100% barley using the Ondea^® Pro exogenous brewing enzyme product was compared to brewing with 100% barley. The use of barley, rather than malt, in the brewing process and the consequences for selected beer quality attributes (foam formation, colloidal stability and filterability, sensory differences, protein content and composition) was considered. RESULTS: The quality attributes of barley, malt, kettle‐full‐wort, cold wort, unfiltered beer and filtered beer were assessed. A particular focus was given to monitoring changes in the barley protein composition during the brewing process and how the exogenous OndeaPro^® enzymes influenced wort protein composition. All analyses were based on standard brewing methods described in ASBC, EBC or MEBAK. To monitor the protein changes two‐dimensional polyacrylamide gel electrophoresis was used. CONCLUSION: It was shown that by brewing beer with 100% barley and an appropriate addition of exogenous Ondea^® Pro enzymes it was possible to efficiently brew beer of a satisfactory quality. The production of beers brewed with 100% barley resulted in good process efficiency (lautering and filtration) and to a final product whose sensory quality was described as light, with little body and mouthfeel, very good foam stability and similar organoleptic qualities compared to conventional malt beer. In spite of the sensory evaluation differences could still be seen in protein content and composition. Copyright © 2011 Society of Chemical Industry     

Influence of process parameters on scale reduction with H2

Abstract

A new pickling method that reduces the metal oxide on steel strip using H₂ has been studied through an extensive campaign of experimental tests. The process, referred to as 'acid free pickling', is environmentally friendly and does not use acid. It is most suitable for application to hot rolled low carbon steel strip. Experimental studies are in progress to validate the application of hydrogen on different metals.     

Modelling novel coal based direct reduction process

Abstract

The present paper develops a one-dimensional model of a novel coal based iron ore direct reduction process. In this process, a mixture of iron ore, coal fines and small amount of binder is made into pellets and these are placed in a bed. Air is forced upward through the pellet bed and provides oxygen for the volatiles and part of the coal in the pellets to be burnt. Initially the pellet bed is heated from the top. As the temperature of the top level of pellets increases, they start to evolve pyrolytic matter which is ignited and, as a consequence, the pellets at lower levels in the bed are heated. In this way, a flame propagates downward through the bed. The iron ore reacts with the gases evolved from the coal (including volatiles) and carbon in the coal and undergoes reduction. The model presented in the article simulates the processes occurring in the solid and gaseous phases. In the solid phase, it uses a novel porous medium model consisting of porous pellets in a porous bed with two associated porosities. The model includes equations for energy balance, reactions of iron oxide with carbon monoxide and hydrogen, coal pyrolysis and reactions between the gas components in the voids. The model shows that a rapidly increasing temperature front can travel downward through the bed if the air is supplied for long enough. The predictions of the modelling are discussed and compared with observations obtained from an experimental rig.     

Application of sessile drop technique (SDT) for study of reduction of FeO in slags: reduction by solid carbon as well as solute carbon

Abstract

With growing importance of smelting reduction processes, experimental research to understand reduction of FeO in molten slag and the foaming behaviour associated therein have assumed greater relevance. In a previous paper, experimental data on reduction of FeO in molten slag in a 30 kW capacity induction furnace have been reported. The present study used around 250 g slag in each experiment was concerned with influence of FeO concentration in molten slag and temperature on foaming and kinetics. The present paper describes a study on the same system carried out using the sessile drop technique (SDT) which, although it uses very small (～25 mg) sample size, is extremely versatile. Moreover, SDT allows one to actually see the reaction occur. An attempt has been made to correlate kinetic data obtained using the present set-up with the data where much larger sample sizes were used. Both solid carbon and solute carbon have been employed in reduction studies.     

Reaction rate and product morphology in carbon composite iron ore pellets with and without Portland cement

Abstract

The aim of this work is to study the reaction rate and the morphology of intermediate reaction products during iron ore reduction when iron ore and carbonaceous materials are agglomerated together with or without Portland cement. The reaction was performed at high temperatures, and used small size samples in order to minimise heat transfer constraints. Coke breeze and pure graphite were the carbonaceous materials employed. Portland cement was applied as a binder, and pellet diameters were in the range 5·6–6·5 mm. The experimental technique involved the measurement of the pellet weight loss, as well as the interruption of the reaction at different stages, in order to submit the partially reduced pellet to scanning electron microscopy. The experimental temperature was in the range 1423–1623 K, and the total reaction time varied from 240 to 1200 s. It was observed that above 1523 K the formation of liquid slag occurred inside the pellets, which partially dissolved iron oxides. The apparent activation energies obtained were 255 kJ mol^–1 for coke breeze containing pellets, and 230 kJ mol^–1 for those pellets containing graphite. It was possible to avoid heat transfer control of the reaction rate up to 1523 K by employing small composite pellets.     

Estimation of liquidus temperatures for steels using thermodynamic approach

Abstract

Alternative schemes for the prediction of liquidus temperatures have been tested against a large compilation of experimental measurements for steels ranging from low carbon to stainless steels. The best agreement overall was obtained with thermodynamic solutions using the IDS (model of interdendritic solidification) database, although certain empirical equations from the literature were adequate for low alloyed steels. Version L of the commercial ThermoCalc thermodynamics package was outperformed for some steel types by the empirical equations, prompting a reassessment of the Fe–Cr–Ni, Fe–Cr–Si, and Fe–Ni–Si systems used in the IDS database. Additionally, regression equations were determined from several thousand predictions computed by the IDS thermodynamic approach, and these performed almost as well as the proper thermodynamic approach at a fraction of the central processing unit time, also outperforming the earlier approaches.     

Audio acoustic plant condition monitoring of spiral bevel gearbox

Abstract

Plant condition monitoring (PCM) is widely used by a variety of industries as part of a condition based maintenance programme. This replaces the previous ‘schedule’ based maintenance programme, in which individual components of a machine are replaced at specified intervals. With PCM the condition of the individual components is monitored, and they are only replaced when their performance is deemed unsatisfactory. PCM techniques are often capital and/or labour intensive, and their use limited to critical machines only. The objective of the present research is to develop a system comprised of microphones and accelerometers which is able to screen industrial environments, such as the hot rolling mill at Corus's Port Talbot plant, for machine faults. The system would use the minimum number of transducers to remotely screen the maximum number of machines, but is not required to provide detailed diagnostic information. To date, an omnidirectional microphone has been used successfully to detect badly damaged gear teeth. The method does not require the use of a soundproof enclosure to filter out background noise. A finite element analysis model of the test rig has been created to determine the eigenfrequencies and eigenmodes of the test rig and to improve the understanding of the vibration behaviour of the faults.     

Ejection of steel and slag droplets from gas stirred steel melts

Abstract

Liquid ejections from gas stirred melts can be classified into small film and jet droplets caused by bubble bursting and larger splashes resulting from gas channels formed at higher exiting gas velocities. In view of the conditions in ladle metallurgy, experimental investigations were carried out at moderate to low gas flowrates in an arc heated, bottom stirred 150 kg steel melting furnace and an 80 L water tank. Droplets were collected at different heights above the melt level, while gas flowrates, viscosities, surface tensions, and slag layer thickness were varied. The number of steel droplets collected decreased greatly with height (in the range 30-110 mm) and with size (in the range 0·1-1·8 mm). Calculations showed that the entrainment of droplets is strongly influenced by the velocity of upward flowing gases. While at low flowrates typical for secondary metallurgy (0·1 m s ^-1), only droplets <50 μm will be entrained, BOF (basic oxygen furnace) typical flowrates (20-50 m s ^-1) will cause particles up to 500 μm to be carried into the dust removal systems. Higher surface tensions resulted in increased droplet ejection, while higher viscosities led to a decreasing quantity of ejected melt. Slag layers led to a decrease in the ejection of steel droplets and to an increase in ejected slag but they did not completely stop steel ejection, because gas bubbles appear to entrain steel drops when they rise through the slag layer. Bubble bursting in a pure slag system caused large but few slag droplets due to the high viscosity of the slag as compared to the steel melt.     

Effect of Actinidin on the Protein Solubility, Water Holding Capacity, Texture, Electrophoretic Pattern of Beef, and on the Quality Attributes of a Sausage Product

ABSTRACT:  The objective of this study was to study the effect of actinidin, a sulfhydryl protease from kiwi fruit, on the protein solubility (nitrogen solubility index [NSI]), water holding capacity (WHC), texture, and SDS–PAGE pattern of beef and to evaluate the effect of pretreatment of beef with actinidin on the quality attributes of a sausage product. Actinidin was partially purified by precipitation with ammonium sulfate, followed by DEAE-Sephadex column chromatography. Actinidin significantly ( P < 0.05) increased NSI and WHC of beef; the highest NSI and WHC (approximately 20% and 8% increase, respectively) was observed when beef was incubated with 0.9 unit enzyme/g beef. Texture analysis indicated increased tenderization (10% decrease in shear force) when slices of cattle beef were treated with actinidin at 37 °C for 2 h. SDS–PAGE results indicated appearance of several low molecular weight bands (<10 kDa) after treating beef with different levels of actinidin for 30 or 60 min. Slight changes in protein band in the range of 100 to 120 kDa and 13 to 25 kDa were also observed. Use of actinidin-tenderized beef significantly improved emulsion stability, texture, and organoleptic properties of the sausage product.     

Modification in physical properties of rice gel by microbial transglutaminase

BACKGROUND: Microbial transglutaminase (MTGase) may catalyse the cross‐linking between a peptide‐bound glutaminyl residue and an ε‐amino group of lysine residue in protein. MTGase has been used to modify many food proteins for improving the physical properties of products. However, its effect on the physical properties of rice products has not been investigated before. The present study aimed to investigate the effect of MTGase, as an additive in rice flour, on the rheological, textural and thermal properties of rice gel. RESULTS: Both the elastic and the viscous moduli of rice gel were increased as a result of the addition of MTGase to rice flour. The addition of MTGase at 0.01–0.3 U mg^?1 increased textural parameters (hardness and gumminess) and rheological properties. Differential scanning calorimetry also showed that MTGase treatment decreased the enthalpy change in gelation. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) confirmed that rice proteins were polymerised through the MTGase reaction. CONCLUSION: The present study proved that the cross‐linking of protein molecules in rice flour by the action of MTGase may improve the physical properties of rice gel. The addition of MTGase in rice flour in an adequate amount is essential for achieving appropriate physical properties of the product. Copyright © 2008 Society of Chemical Industry