Food quality, measurement

Ultrasound is one of the more dynamic areas of food quality measurement, as indicated by the rapid rate at which commercial ultrasound instrumentation is entering the market (Mulet et al., 1999 Povey, 2001 Povey and Higgs, 2001). Many reviews of the literature on the subject have also appeared recently (Povey, 1997a Kress-Rogers, 2001). This dynamism is the result of two decades of developmental work (Povey and Wilkinson,... 

It is claimed that commercially-available ultrasound equipment can measure the following quality parameters of dairy products levels of solids, solids non-fat (SNF), protein, water and fat solid fat content (SFC), colloidal stability, gelation point, adulteration with oil, particle size, particle size distribution, oil composition, protein denaturation and fat oxidation. This incomplete list represents an impressive contribution towards the solution of food quality measurement although the present authors are slightly skeptical regarding some of these claims. In this review only those applications will be addressed which are regarded as robust. 

D. R. Massie. A high-intensity spectrophotometer interfaced with a computer for food quality measurement. In Quality Detection in Foods. J. J. Gaffney, ed. SL Joseph, MI American Society of Agricultural Engineers. 1 12-15,1976. 

The successful and profitable control of frozen food quality requires workable standards of product quality and condition and suitable methods for determining the degree of product conformance with standards. The frozen fruit and vegetable industry has developed rapidly during the past 20 years and serious concentration upon the development of adequate standards and objective methods for quality measurement is necessary. Such standards and methods should be placed on a uniform basis the country over and given official and legal status. 

Quality control is intended to monitor and evaluate the performances of both food and human processes that contribute to food quality. The basic principle of this function is the control circle that involves (1) the taking of a process sample by the analysis or measuring unit, (2) determining whether process results meet set tolerances or limits, (3) judging the character and level of any discrepancy, and (4) application of corrective action to adjust the system to an acceptable level (Figure 7.1.1). A distinction is made between measuring and analysis, whereby the first involves direct measurements (e.g., pH, temperature) and the second involves taking samples, sample preparation, and actual analysis. ... 

Established in 1894, AOAC International is an independent association of scientists and organizations in the public and private sectors devoted to promoting methods validation and quality measurements in the analytical sciences. AOAC has a mission to ensure the development, testing, validation, and publication of reliable chemical and biological methods of analysis for foods, drugs, feed-stuffs, fertilizers, pesticides, water, forensic materials and other substances affecting public health and safety and the environment. 

Low Resolution Nuclear Magnetic Resonance (LR-NMR) systems are routinely used for food quality assurance in laboratory settings [25]. NMR based techniques are standardized and approved by the American Oil Chemist s Society (AOCS) (AOCSd 16b-93, AOCS AK 4-95), the International Union of Pure and Applied Chemistry (IUPAC) (solid fat content, IUPAC Norm 2.150) and the International Standards Organization (ISO) (oil seeds, ISO Dis/10565, ISO CD 10632). In addition to these standardized tests, low resolution NMR is used to measure moisture content, oil content and the state (solid or liquid) of fats in food. Table 4.7.1 summarizes common food products that are analyzed by low-resolution NMR for component concentration. 

Lambing K. (1992). Biophoton measurement as a supplement to the conventional consideration of food quality , in Popp F.A., Li K.H., Gu Q. Recent Advances in Biophoton Research and its Applications, Technology Center Kaiserslautern, International Institute of Biophysics, Germany, World Scientific. 

Effect-based critical limits for soils and ground water have been derived or are under development in various countries for multiple purposes (Radojevic and Bashkin, 1999). These criteria can be used to assess the environmental quality of a site or area, to set priorities in control measures and to derive emission reduction goals. Most of the values are derived from comparable starting points such as protecting terrestrial population, water supply, food quality, and finally, animal and human health. 

As we proceed with discussing the various system properties and measurement methods that can be used to investigate water and solids mobility, it is important to keep in mind the influence the complexity of food systems, such as in the ice cream example just discussed, can have on our ability to measure, interpret, understand, and predict food quality, stability, and safety. 

Luck, W.A.P. 1981. Structures of water in aqueous systems. In Water Activity Influences on Food Quality (L.B. Rockland and G.F. Stewart, eds), pp. 407 134. Academic Press, New York. Ludescher, R.D., Shah, N.K., McCaul, C.P., and Simon, K.V. 2001. Beyond Tg Optical luminescence measurements of molecular mobility in amorphous solid foods. Food Hydro colloids 15, 331-339. Ludwig, R. 2001. Water From cluster to the bulk. Angewandte Chem. Int. Ed. 40, 1808-1827. Maclnnes, W.M. 1993. Dynamic mechanical thermal analysis of sucrose solutions. In The Glassy State in Foods (J.M.V. Blanshard and PJ. Lillford, eds), pp. 223-248. Nottingham Univ. Press, Loughborough, Leicestershire. 

The second aspect mentioned above considers the environmental impacts of farming systems on the produce from a more consumer-relevant point of view. Thus, the appropriate indicator to measure the impacts on the produce is food quality. 

In this study, the term food quality will be used in a very narrow sense. The term includes properties of food that can be directly measured by scientific methods. Of course, this is not an economic viewpoint on quality, as expressed in the quote " Quality is what the consumer thinks it is". The production process itself can be an important part of food quality for the consumer. A more environmentally sensitive production method might lead to higher food quality in the perception of the consumer while it does not change any measurable property of the food itself Thus, to avoid confusion, it is important to keep in mind that the narrow, scientific definition of quality is used here. 

Knowing the relationships between chemical and sensorial variables, objective methods can be obtained to evaluate the food quality. Juries of experts cannot be formed and used so easily as the measurement of chemical quantities can. Besides, the knowledge of these relationships will be able to retain, so to speak, sensorial evaluations and follow the evolution of taste over a long period, so that it may be foreseen as well. 

The research presented here describes how molecular processes can be measured and manipulated by a variety of new approaches to improve food quality. The development and formation of flavors in both plant and... 

Voisey, P. W. Instrumental Measurement of Food Texture, in "Rheology and Texture in Food Quality," J. M. de Man,... 

Strategies to measure the effects of production methods on food quality... 

Food quality is not a single property that can be measured by an easily defined and agreed... 

However, although these aspects are discussed as separate topics below, in line with the way scientific studies and regulatory issues are normally defined, most consumers still see them as parts of a holistic picture where the good intentions of the people involved in the food supply chain are the most important assurance for all aspects of food quality. In this context, stringent safety measures and sophisticated process control, which are the cornerstone of food quality assurance schemes in conventional supply chains, maybe seen by consumers at best as self-imposed restrictions that prove the sincerity of these good intentions, and at worst as unfair, unnecessary burdens introduced through lobbying from big profit business to support its suppression of small-scale or local producers. 

In terms of organic food quality, the question is then whether high, acutely toxic concentrations occur in the relevant plant foods and if so, what production factors are important to predict and preferably prevent this from happening, or if other measures can be used to alleviate the harmful effects. 

An important aspect of food processing, common with other processing industries, is yield of finished product from starting raw materials for any shift and for specific unit operations. Computer-integrated manufacturing can start with the measurement of material flows and build upon this information. Instrumentation for the on-line measurement of specific food qualities of importance lo the consumer such as Food flavor, aroma, texture, and microbial content arc under development. These quality factors... 

PER is a method to metabolize or determine the quality of protein in foods. Quality is measured by the amount of usable protein and the growth resulting from it through an animal assay. Formerly, this method was used as the standard method for all protein quality analysis. However, there is some question as to whether or not it is a valid measurement. This is because PER does not account for the differences in amino acid requirements between humans and rats (Seligson and Mackey, 1984), nor does PER account for the protein needed for cell maintenance. Therefore, PER results often overestimate the requirements for some amino acids and underestimate others. Specifically, PER tends to underestimate the protein quality of lysine-deficient proteins such as wheat gluten (Hackler, 1977). 

Bourne, M.C. 1976. Interpretation of force curves from instrumental texture measurements. In Rheology and Texture In Food Quality (J.M. deMan, RW. Voisey, V.F. Rasper, and D.W. Stanley, eds.) pp. 355-381. AVI Publishing Company, Westport, Conn. 

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