Quality changes

Field, S. W. and Swift, K. G. 1996 Effecting a Quality Change an engineering approach. London Arnold. 

With regard to choice and consumption of food, all human sensory perceptions are involved. Among them, vision is the most important one for selecting food and appreciating its quality. Color is an intrinsic property of food. A color change of food often is caused by a quality change. Consumers are attracted by the color of a food product. This imphes three main consequences for food producers ... 

Maharaj, V. and Sankat, C.K., Quality changes in dehydrated dasheen leaves effects of blanching pre-treatments and drying conditions. Food Res. bit., 29, 563, 1996. 

Knowledge of the actual gas composition in packs allows the assessment of quality and integrity of the final food packages, the efficiency of packaging processes, and aids in the identification or anticipated quality changes of the food product within the pack2,5. 

Gil MI, Aguayo E and Kader AA. 2006. Quality changes and nutrient retention in fresh-cut versus whole fruits during storage. J Agric Food Chem 54(12) 4284-4296. 

Gorny J, Hess-Pierce B, Cifuentes R and Kader A. 2002. Quality changes in fresh-cut pear slices as affected by controlled atmospheres and chemical preservatives. Postharvest Biol Technol 24 271-278. 

Chemical and physicochemical characteristics, conditions and processes are crucial for any biological system. A chemical basis also defines the conditions for the microbiologically initiated quality changes of wastewater under transport in sewers. Equilibrium and process-related aspects are important. 

Hvitved-Jacobsen, T., J. Vollertsen, andN. Tanaka (1999), Wastewater quality changes during transport in sewers — An integrated aerobic and anaerobic model concept for carbon and sulfur microbial transformations, Water Sci. Tech., 39(2), 242-249. 

It is important to notice that the empirical expressions (5.11) and (5.12) are simple, and, contrary to the DO mass balance in Equation (5.9) — as a part of the conceptual description of sewer processes — do not include a dynamic description of the wastewater quality changes taking place in a sewer. However, the simple DO mass balance expressed in Equation (5.10) may give useful information, as shown in Example 5.3. Generally, it is important that both simple and more complicated models exist. A model most appropriate to use will always depend on the actual objective and the information available. 

Aesoey, A., M. Storfjell, L. Mellgren, H. Helness, G. Thorvaldsen, H. Oedegaard, and G. Bentzen (1997), A comparison of biofilm growth and water quality changes in sewers with anoxic and anaerobic (septic) conditions, Water Sci. Tech., 36(1), 303—310. 

The results from this study support what has been dealt with throughout the text and especially focused on in Chapter 5 the concept s ability to predict wastewater quality changes in a sewer. The example shows that the corresponding process model can be used to simulate the average dry-weather performance of the sewer and serve as a tool for process design and management. The sewer, with its relation to the subsequent treatment plant, is generally... 

FIGURE 7.12. Results for validation of the conceptual sewer process model for prediction of wastewater quality changes. Measured and simulated absolute values and changes of COD fractions for 29 dry-weather events are compared for wastewater transport in a 5.2 km gravity sewer line from Dronninglund to Asaa. 

The hydraulic performance of sewer pipes can be described at different levels. In the case of nonstationary, nonuniform flow, the Saint Venant Equations should be applied. However, under dry-weather conditions, the Manning Equation is an adequate description of the wastewater flow in a gravity sewer pipe when considering the prediction of wastewater quality changes under transport. There are no grounds for using advanced hydraulic models because of the uncertainties in the prediction of the microbial transformations of the wastewater. 

The result of the aerobic scenario in terms of quality changes of the wastewater in the intercepting sewer is shown in Table 8.2. The in-sewer treatment is assessed by the changes that take place in the easily biodegradable substrates (readily biodegradable and fast hydrolyzable substrates) and in the... 

Chen, C.R., Ramaswamy, H.S., and Alii, 1.2001. Prediction of quality changes during osmoconvective drying of blueberries using neural network models for process optimisation. Dry. Technol. 19, 507-523. 

The technical functionality of chemical prodncts is the crucial product quality in B2B markets. Here especially trouble-free operating cycles and the minimisation of warranty risks play a decisive role. Enviromnental and health-related product qualities can only become significant for the market in places where the technical functionality is ensured and also sensitised customers or employees are available or where companies take action to secnre against scandals and create an image. The additional qualities become relevant especially on demand-dominated, dynamic markets with short product cycles and differentiated quality production. However, on stable mass markets with Fordist structures even minimum price increases or quality changes may prevent innovations or at least delay them for a long time. 

Water quality changes in reservoirs (primary production, sedimentation, organic matter decomposition, oxygen consumption)... 

Piet GJ, Zoeteman BC. 1980. Organic water quality changes during sand bank and dune filtration of surface waters in the Netherlands. J Amer Water Works Assoc 72 400-404. 

The concept of entropy-enthalpy compensation resulting in the critical conditions of enthalpic interactions and the molar mass independent sample retention turned out useful also for the understanding several other coupled methods of polymer HPLC. It is accepted [195,196] that the polymer species tend to elute at the critical conditions also when either eluent strength or quality change within the HPLC system in the course of the HPLC experiment that is in the continuous and local gradient methods (Sections 16.5.3, 16.5.4, and 16.5.6). Irrespective of the problems and limitations of LC CC, its concept belongs to the important breakthroughs in polymer HPLC. 

Maiti PK, Goddard IE WA. Solvent quality changes the structure of G8 PAMAM dendrimer, a disagreement with some experimental interpretations. J Phys Chem B 2006 110 25628-25632. 

Downey, G. (2002). Quality changes in frozen and thawed, cooked pureed vegetables containing hydrocolloids, gums and dairy powders. Int. J. Food Sci. TechnoL, 37, 869-877. 

Van Loey, A., Fransis, A., Hendrickx, M., Maesmans, G., Tobback, P. (1995). Kinetics of quality changes of green peas and white beans during thermal processing. J. Food Eng., 24, 361-377. 

Spoilage Ageing and unsuitable storage conditions can lead to quality changes of raw materials or products up to the complete spoilage of the product. 

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