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16 Quality Evaluation of Cereals and Cereal Products Vladimir F. Rasper University of Guelph, Guelph, Ontario, Canada Charles E. Walker* BRIAustralia Ltd., North Ryde, New South Wales, Australia The quality of cereals and various cereal products is determined by a variety of characteristics that may be assigned different significance levels, depending upon the desired end product. These characteristics can be divided into chemical, enzymatic, and physical. Likewise, individual quality testing me
  1 16Quality Evaluation of Cereals and Cereal Products  Vladimir F. RasperUniversity of Guelph, Guelph, Ontario, CanadaCharles E. Walker * BRIAustralia Ltd., North Ryde, New South Wales, AustraliaThe quality of cereals and various cereal products is determined by a variety of characteristics that may be assigned differentsignificance levels, depending upon the desired end product. These characteristics can be divided into chemical, enzymatic, andphysical. Likewise, individual quality testing methodologies can be classified into those concerned with the chemical components of the tested material, assays for estimating enzymatic activity, and tests dealing with various physical or physicochemical properties.Procedures based on small-scale product preparation, e.g., laboratory milling and experimental baking tests, are also parts of themethodology. Tables 1 and 2 contain a list of the procedures most commonly employed as part of the Approved Methods of theAmerican Association of Cereal Chemists [1] or Standards of the International Association for Cereal Chemistry and Technology[1823]. The expected ranges of values measured by these procedures for different types of wheat flour are given in Tables 35.IChemical Tests  A Moisture  Moisture determination is an essential step in evaluating the quality of cereal grains and their products. The behavior of the grains inboth storage and milling depends to a great extent on their moisture content. Moisture content also influences the keeping quality of flour and bakery products. The knowledge of moisture content is required for comparing production data at a uniform level of drysolids and for compliance with government regulations. Similarly, since compositional percentages are inversely related to moisturecontent in the analyzed material, results of chemical analyses have to be reported on a fixed-moisture basis. In North America, it hasbecome a common practice to report the results on the 14% basis, whereas in Europe the dry solids basis is often preferred, and 12%is used in other countries for some products.There are many methods for testing moisture content, and their results may vary considerably. It is therefore important that all testsare made by the same method when the results are intended for the same purpose or different laboratories are involved. In reportingthe results, the method used should be indicated so that in comparing results of different methods, a proper correction factor can be  2 applied. * This work was co-authored by Dr. Walker while on leave from Kansas State University, Manhattan, Kansas.   Disclaimer: It is common practice in the Cereal Technology field to refer to equipment by manufacturer and/or by brand names. Where company nameshave been used in this article, it is for clarity and identification only. No endorsement of any particular company or its products in preference to othersimilarly suited equipment is implied.   TABLE 1 Some of the Most Commonly Used AACC Approved Methods and ICC Official Standards for Testing Grains andFlours   Tested property   Principle   AACC Methods a   ICC Standard b   Chemical constituent   Moisture   Oven-drying   44-15A   109/1   44-16   110/1   44-18   44-19   44-20   Dielectric meter   44-11   Vacuum drying   44-40   Distillation with toluene   44-51   Protein   Automated Kjel-Foss method   46-08   Automated colorimetric method   46-09   Improved Kjeldahl method   46-10   105/1   46-11   46-12   Micro-Kjeldahl method   46-13   Udy-dye method   46-14A   Biuret method   46-15   Combustion method   46-30   Gluten   Hand washing   38-10    3 Machine washing   38-11   137   Mineral matter (ash)   Incineration   08-01   104   08-02   08-03   Crude fiber   Chemical digestion   32-10   105/1   Dietary fiber (insoluble)   Enzymatic and chemical digestion   32-20   Crude fat   Solvent extraction   30-10 30-25   136   Fat acidity   Titration   02-01A   02-02A   02-03A   Starch   Enzymatic   76-11   128   Polarimetric   76-20   122   Starch damage   Enzymatic   76-30A   Enzymatic activity    -Amylase   Colorimetric   22-01   108   22-06   Nephelometric   22-07   Viscometric   Amylography   22-10   126   Falling number   56-81B   107   Pressuremetric   22-11   Volumetric   22-14   Chemical (incubation in situ)   22-15   22-16   Rapid Viscometric   22-08    4 61-02   Proteases   Chemical   22-60   22-61   Spectrophotometric   22-62   Colorimetric   22-63   46-11   46-12   (table continued on next page)   Continued    TABLE 1   Tested property   Principle   AACC Methods a   ICC Standard b   Physical properties   Farinography   Dough mixing   54-21   115   Mixography   Dough mixing   54-40   Extensigraphy   Dough stretching   54-10   114   Alveography   Dough stretching   54-30   121   Particle size   Centrifugation   50-10   Sedimentation   127   Physicochemical properties   Sedimentation value   Swelling and sedimentation   56-60   116   Oxidizing, bleaching, and maturing agents   Oxidizing agents   Chemical   48-02   Acetone peroxides   Chemical   48-05   Ascorbic acid   Chemical   86-10  
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