Batch processing, quality monitoring

A further example of process quality monitoring and reactor batch profiling using NIRS comes with oleo-chemical and biodiesel production. An established use of FT-NIR analysis (AOCS Method Cd le 01) is the determination of the key vegetable oil processing parameters - iodine value (IV) and percentage trans fat content (%Trans) (Figure 5.38). 

C Undey, S Ertunc, and A Cinar. Online batch/fed-batch process performance monitoring, quality prediction, and variable contribution analysis for diagnosis. Ind. Engg. Chem. Research, 42 4645-4658, 2003. 

Despite the fact that the operating characteristic (OC) curve of the USP (905) test guarantees a significant portion of each batch will have poor quality before batch rejection is probable [42,43], companies have become comfortable with their odds. Process analytical monitoring tools such as NIR spectroscopy, which are capable of high-speed sampling in line, online, or at line, have been perceived as an additional burden on the rate of successful batch release. 

Concurrent validation is conducted under a protocol during the course of normal production. The first three production-scale batches must be monitored as comprehensively as possible. The evaluation of the results is used in establishing the acceptance criteria and specifications of subsequent in-process control and final product testing. Some form of concurrent validation, using statistical process control techniques (quality control charting), may be used throughout the product manufacturing life cycle. 

Traditional batch processing involves periodic monitoring of quality. A pill production line, for example, may be monitored by examining every 10 thousandth pill for integrity, coating, and stamp. If a given pill is found to be deficient, all pills produced in that batch of 10,000 would be recycled, discarded, or reexamined. The process can potentially add unnecessary expense to the production process and can lead to possible inappropriate release from quarantine (pills are stored until passed, creating possible human error in premature shipment). 

As described previously in the present publication, we have developed a batch process for producing isoelectric soluble soy protein hydrolysate (ISSPH) with a bland taste. From studies of the kinetics of the hydrolysis reaction, which takes place in this process, we have come to the conclusion that the reaction is adequately controlled by keeping pH constant and monitoring DH. Termination of the reaction at a preset value of DH ensures a reproducible, optimal organoleptic quality of the product. 

Batch processes are inherently dynamic and more difficult to monitor, control and optimise than steady state, continuous processes. Quality control of the product in a dynamic process is more difficult to achieve. Also, process safety is more difficult to achieve in a dynamic system than in continuous production. 

The term quality control is used differently around the world. In the Far East, particularly Japan, it refers to what the Western industrial nations call quality assurance (QA), which is discussed shortly. QC in the West refers to the process of monitoring the product to establish whether or not it conforms to specified requirements, for example to demonstrate that a manufactured batch of a chemical used as a pharmaceutical raw material meets all the requirements of the specification published in the British Pharmacopoeia. In fact, this is not true QC, other than to prevent the release and use of substandard product. It only assesses quality, after the process is complete, and this is both costly and of limited operational use. In the analytical laboratory, QC refers to the analyses conducted along with a batch of samples, the results of which are used to judge whether the analyses were made correctly. For this... 

The extent of process and quality control used in weldbonding (Chapter 8) must be based on the end use of the hardware being bonded. Methods in current use should be selected to fit a specific application. Consistent joint strength can be assured by evaluating cured weldbond tensile-shear specimens, cleaned with each batch of parts, for strength and bond quality. Consistent weld quality can be assured by hourly evaluation of uncured tensile shear and macro specimens for strength and weld quality. Even higher assurance can be obtained from the use of an in-process weld monitor that... 

At this point in the manufacturing sequence, a series of characterization procedures are usually inserted to check the slip quality and uniformity. They are standard in-process quality control checks to make sure that the slip is the same as the batches that preceded it into manufacture. The characteristics monitored are ... 

Details of the specific types of apparatus need not normally be given except for nonstandard processes. A flow chart of the manufacturing operation and the in-process controls (and acceptance limits) is required. Proposals for alternative processes will need to be supported by appropriate data to show that the finished products resulting from these are consistent with the finished product specification. Certain manufacturing operations such as mixing may require additional information on quality parameters monitored during production and prior to batch release. Appropriate quality parameters should be included in the finished product specification regardless of the outcome of validation studies (e.g., content uniformity for solid and semi-solid products). 

The lead time, for incorporation of enzymes as an adjunct in whatever form into commercial food processes, appears to be far longer than equivalent innovation lead times m non-food, or even pharmaceutical processes. The exception to this finding is that there are enzymes which play an important role in many analytical and quality control procedures in the food industry, without the use of which, for batch or continuous process monitoring, many product lines would not be possible. 

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