Aspects of processing

A great variety of products are made from cereals. However, to keep the topic focused, we will concentrate on only one type of product aerated or leavened breads. Bread from wheat has been studied more extensively than other wheat products or the processing of other cereals. Much of the basic science developed in this area can, however, serve as a basis for other areas of cereal processing. 

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The examples discussed in tliis chapter show a strong synergy between fundamental physical chemistry and device processing metliods. This is expected only to become richer as shrinking dimensions place ever more stringent demands on process reliability. Selecting key aspects of processes for fundamental study in simpler environments will not only enable finer control over processes, but also enable more sophisticated simulations tliat will reduce tire cost and time required for process optimization. 

This article discusses several aspects of processed meat products including (/) health and safety concerns (2) meat processing ingredients, procedures, and machinery (J) ha2ard analysis critical control point (4) fat reduction in meat products (5) sous-vide processing and (6) nutritional labeling. 

Another aspect of process improvement is color improvement. Eor example, use of phosphoric acid and formaldehyde on the dimer product is said to improve color (68). Other treatments, both on the raw materials and on the finished product, have also been used. Most of these are variations of standard fatty material color reduction techniques. 

Process Technology Considerations. Innumerable complex and interacting factors ultimately determine the success or failure of a given ethylene oxide process. Those aspects of process technology that are common to both the air- and oxygen-based systems are reviewed below, along with some of the primary differences. 

Thus, methods are now becoming available such that process systems can be designed to manufacture crystal products of desired chemical and physical properties and characteristics under optimal conditions. In this chapter, the essential features of methods for the analysis of particulate crystal formation and subsequent solid-liquid separation operations discussed in Chapters 3 and 4 will be recapitulated. The interaction between crystallization and downstream processing will be illustrated by practical examples and problems highlighted. Procedures for industrial crystallization process analysis, synthesis and optimization will then be considered and aspects of process simulation, control and sustainable manufacture reviewed. 

This model is unique in its description of what constitutes a management system, and its effort to address the planning, organizing, implementing, and control aspects of process safety management systems. 

The application of the science of human factors to eliminating error in all aspects of process design, management, operation, and maintenance is the focus of this work. Human error has been a major cause of almost all of the catastrophic accidents that have occurred in the chemical process industries (CPI). If one adopts the broad view of human error as being the result of a mismatch between human capabilities and process demands, then clearly management s role is critical in the following areas ... 

Nitric acid is one of the three major acids of the modem chemical industiy and has been known as a corrosive solvent for metals since alchemical times in the thirteenth centuiy. " " It is now invariably made by the catalytic oxidation of ammonia under conditions which promote the formation of NO rather than the thermodynamically more favoured products N2 or N2O (p. 423). The NO is then further oxidized to NO2 and the gases absorbed in water to yield a concentrated aqueous solution of the acid. The vast scale of production requires the optimization of all the reaction conditions and present-day operations are based on the intricate interaction of fundamental thermodynamics, modem catalyst technology, advanced reactor design, and chemical engineering aspects of process control (see Panel). Production in the USA alone now exceeds 7 million tonnes annually, of which the greater part is used to produce nitrates for fertilizers, explosives and other purposes (see Panel). 

Process validation should be extended to those steps determined to be critical to the quality and purity of the enantiopure drug. Establishing impurity profiles is an important aspect of process validation. One should consider chemical purity, enantiomeric excess by quantitative assays for impurity profiles, physical characteristics such as particle size, polymorphic forms, moisture and solvent content, and homogeneity. In principle, the SMB process validation should provide conclusive evidence that the levels of contaminants (chemical impurities, enantioenrichment of unwanted enantiomer) is reduced as processing proceeds during the purification process. 

On the other hand, it has also become clear that a materials-oriented synthesis of conjugated poly(phenylene)s cannot narrow its attention to properties of molecules only in solution, but has to include aspects of processing and supramolecu-lar ordering as well. The rigid-rod character of PPPs therefore suggests the use of chain stiffness as a structure-forming principle in the design of supramolecular motifs. 

There are some aspects of process design in which decisions are based primarily on past experience rather than on quantitative performance models. Problems of this type include the selection of constraction materials, the selection of appropriate models for evaluating the physical properties of homogeneous and heterogeneous mixtures of components, and the selection of safety systems. Advances in expert systems technology and information management will have a profound impact on expressing the solutions to these problems. 

Let us now give a brief synopsis of the themes advanced by each of the ten chapters. The five chapters of Volume 21 (Part 1) advance paradigms which are related to product and process design, while the five chapters of Volume 22 (Part II) focus on aspects of process operations. 

A final aspect of process analytical chemistry is the vulnerability of the sensitive detector components to the harsh conditions sometimes encountered in process sampling. It may be possible to physically separate sensitive components, especially the electronics, from the sampling site. Fiber optics... 

The detailed design and specification of the automatic control schemes for a large project is usually done by specialists. The basic theory underlying the design and specification of automatic control systems is covered in several texts Coughanowr (1991), Shinskey (1984) (1996) and Perry et al. (1997). The books by Murrill (1988) and Shinskey (1996) cover many of the more practical aspects of process control system design, and are recommended. 

Torrent, M., Sola, M., and Frenking, G. (2000). Chem. Rev. 100, 439. A 54-page high-level paper dealing with theoretical aspects of processes in which metal complexes function as catalysts. 

Another important aspect of process flow requirements is reflected in inventory policies. These often involve finite and dedicated storage, although frequent cases include shared tanks as well as zero-wait, non-intermediate and unlimited storage policies. Material transfer is often assumed to be instantaneous, but in some cases such as in pipeless plants delay is significant and must be accounted for. 

Heat and mass balance equations are used in all aspects of process modelling however, what is key to this model is an understanding of the electrolytic process behind the cell. For example, the model must be able to predict current efficiency and k-factor if it is to predict electricity consumption. Most of these electrolytic parameters are calculated using empirical relationships derived from experimental data both from test cells and the full-scale plant. Considering k-factor, this is primarily a function of brine strength and temperature. Figure 20.5 illustrates the experimentally derived function used in the model. 

Berthold, W. and J. Walter (1994). Protein purification aspects of processes for pharmaceutical products. Biologicals 22(2) 135-50. 

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