AACC method

Approved Methods of the AACC, Methods 22-lOA and 56-81B, American Association of Cereal Chemists, St. Paul., Minn., 1983. 

Exact details of the method can be found in the total dietary fibre determination procedure AOAC Method 991.43 and AACC Method 32-07 (AOAC, 1995 AACC, 2000). 

The phosphorus content can be determined by wet oxidation of the starch with sulfuric (or nitric) acid and hydrogen peroxide followed by colorimetric estimation of the phosphomolybdate complex. A detailed procedure for gravimetric determination can be found in AACC method 40-57 (AACC, 2000). However, large sample sizes (2-5 g) are required in this method. 

Protein dispersibility index Dry product is dispersed in water by blending, then centrifuged at 880 x g for I0 min Protein dispersibility index (%) = (% water-dispersible prolein/% total protein) x 100 Advantages Tested in a collaborative study and found to be reproducible between laboratories. Disadvantages Limited to soy products protein is determined by Kjeldahl analysis, which can be a lengthy procedure. AOCS Method B a 10-65 (AOCS, 1999) AACC Method 46-24 (AACC, 2000)... 

The Megazyme procedure requires the company s Total Starch Assay Kit, which contains most of the necessary enzymes and chemicals. This procedure was approved by the American Association of Cereal Chemists (AACC Method 76-13 AACC, 1976) and the Association of Official Analytical Chemists (AOAC Method 996.11) following an extensive collaborative AACC/AOAC interlaboratory evaluation (McCleary et al., 1997b). The procedure is simpler than a previously reported method (AACC, Method 76-12). The procedure by Holm et al. (1986) described in the Alternate Protocol uses enzymes and chemicals purchased individually. 

McCleary, B.V., Gibson, T.S., and Mugford, D.C. 1997a. Collaborative evaluation of a simplified assay for total starch in cereal products (AACC Method 76-13). Cereal Foods World 42 476-480. 

TABLE 1. Fatty Acid Composition (%) of Vegetabie Oiis Used in Studies of Lubricant Basestocks (Gas Chromatography Anaiysis, AACC Method 58-18, 1993). 

Electronic moisture meters usually operate on a dielectric principle and/or kernel surface conductance with compensation for sample temperature and density. Thus, electronic moisture meters measure electrical properties that are calibrated to oven moisture measurements. The typical air-oven reference methods used for whole soybeans are the AOCS Method Ac 2-41, ASABE Standard S352.2, and AACC Method 44-15a. 

The AACC Method 44-15a (1999) is applicable to soybeans but has an air oven method that uses 15 g of unground soybeans in a tared moisture dish. Then they are heated at 103 1°C for 72 h. Replicate determinations should check within 0.2% moisture. This whole soybean method is the same as the ASABE Standard S352.2 (2006). 

AACC. Method 44-15a Moisture—Air-oven methods. American Society of Cereal Chemists St. Paul, MN, 1999. 

AACC Method 74-09 Measurement of Bread Firmness by Universal Testing Machine. 

There have been a number of reports in the literature of the measurement of ash content of flour by NIR, and most instrument manufacturers offer this application. There is compiete agreement among experts that ash cannot be measured directly by NIR, and therefore indirect measurement has been proposed via cellulose (61) or oil and particle size (25, 66). Experience in commercial mills has shown that ash calibrations are matrix sensitive and frequent recalibration is required as the grist is changed. AACC Method 08-21 is based on the Perten Instruments 86 Ash Series instruments, based on patented wavelengths that measm-e color (50). 

AACC Method 76-30A, falling number (AACC 56-81 A) or viscoamylograph... 

Method 28-20). In order to detect internal insect infestation, grains are viewed with x-rays (AACC Method 28-21) or broken kernels are treated with 60% isopropyl alcohol and heptane. Insects, fragments, and exoskeletons are separated by filtration on a cloth and viewed and quantified in a microscope (AACC Method 28-22). 

Quadrumat Junior or Senior Brabender Mills, Chopin Wheat Roller Mill, Buhler Wheat Roller Mill (AACC Method 26-20)... 

Color meters (Hunter Lab, Agtron [AACC Method 14-30] and others)... 

NIRA, Goldfisch, or Soxhlet apparatus (AACC Method 30-25)... 

AACC Method 76-11, Falling Number (AACC 56-81A) or Viscoamylograph... 

Hand Washing Method (AACC 38-10) or Glutomatic, AACC (AACC Method 38-11)... 

The efficiency of the various milling procedures is usually determined by the analysis of moisture, ash, fat, and color of refined products. The most common way to determine milling efficiency is by the quantification of ash (AACC Methods 08-03 and 08-12), because the degree of refining is inversely related to the mineral content. This is because bran contains 20 times more ash than the endosperm. Ash is determined gravimetrically after burning or incinerating a sample at temperatures of 600°C. There are other less accurate methods that can predict ash content. The most popular used today is the NIRA. 

The fat (AACC method 30-10) and fiber (AACC method 32-10) analyses are also used for the same purposes as ash determination. However, these methods are less common because they are more complicated to perform. Crude fiber is quantified after acid and alkaline hydrolyses, while fat is gravimetrically determined after extraction with solvents (usually petroleum ether). 

The color of refined wheat flour (AACC Method 14-30) or semolina is generally performed in an Agtion colorimeter operating in the green mode (546 nm). The sample (20 g) is mixed with 25 mL distilled water for 2 min in order to enhance color formation. Next, the slurry is read in the colorimeter that was previously calibrated with disc standards 0, 63, 85, and 100. Similar assays (AACC Methods 14-21 and 14-22) are also used to measure pasta and noodle color. The NIRA can be also calibrated to determine color. 

For durum wheats, the rapid quautitatiou of caroteues is performed using a spectrophotometer or colorimeter (AACC Method 14-50). The yellow pigmentation can be quantified by overnight extraction in aqueous n-butauol followed by measurement of absorbance at 435.8 nm (Dexter and Matsuo 1978). More frequently, the color of semolina is judged visually or with refractive light colorimeters (Allen et al. 1989, Symons and Dexter 1991). 

Muffle furnace (AACC Method 08-01) NlRAorKjeldhal methods (AACC 46-10,46-12 or 46-13) Color meters (Hunto Lab, Agtron and others)... 

The Zeleny (Zeleny 1947), sedimentation, and microsedimentation tests (AACC Methods 56-60,56-61A and 56-63) are based on a 5 min sedimentation volume of a fixed flour-water slurry stained with bromophenol and a weak acidic acetic-isopropanol solution (Figure 15.4). Samples containing high gluten yield higher sedimentation values. The values are also adjusted according to protein content. 

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