USDA/ARS - Western Wheat Quality Laboratory
E-202 Food Science & Human Nutrition Facility East
P.O. Box 646394, Washington State University
Pullman, WA 99164-6394
Voice: 509.335.4062
Facsimile: 509.335.8573

METHODS

Alkaline Noodle Making
Formula contains 100 g flour, 0.5 g Na2CO3, 2 g NaCl and 34 g water (14% constant flour moisture basis) with dough sheet and noodles prepared with an Otake Laboratory Noodle Machine. Water may be adjusted for a nursery to more closely achieve optimum water absorption. Color measurements are made using a Minolta Chroma Meter set to the L* a* b* color system.

Alkaline Noodle Brightness Reading (L0ANC) & (L24ANC) L* reading from the Minolta Chroma meter at 0 hr and 24 hr.

Alkaline Noodle Red - Green Reading (A0ANC) & (A24ANC)a* reading from the Minolta Chroma meter at 0 hr and 24 hr.

Alkaline Noodle Yellow - Blue Reading (B0ANC) & (B24ANC) b* reading from the Minolta Chroma meter at 0 hr and 24 hr.

Alkaline Flour Color(PKCOLOR): An alkaline Pekar slick is prepared by pressing flour to a smooth surface, immersing in a 3.0% w/v alkaline solution consisting of 50 % K2CO3 and 50% Na2CO3 for 2 minutes. The sample rests at a room temperature of 77 for 4 hours before visual observation and scoring. Flours were scored by the following: S = satisfactory, Q = questionable, and U = unsatisfactory. Desirable flour color ranges from bright white through creamy yellow to bright yellow. Any dullness, brown, or greenish casts are unacceptable. Alkaline flour color is scored only on SWW, HWW, SWS and HWS flours which have a minimum RVA viscosity of 150 and a minimum NIR wheat hardness (UWHRD) value of 40.

Alkaline Water Retention Capacity (AWRC)
The percent increase in weight of 5 g of flour due to absorption of water from 25 ml of 0.1 N NaHCO3 solution after centrifugation. AACC Method 56-10 modified with use of round bottom polypropylene tubes and 5:1 solution to flour ratio (1),(17).
Bread Baking
An optimum absorption, optimum mixing, 90 minute fermentation straight dough method using 100 g flour, 1.8% dry yeast, 1.5% salt, 6% sugar, 0.3% malt extract, 4% dry milk solids, 75 ppm ascorbic acid, and 3% partially hydrogenated shortening with mono-and di-glycerides (Crisco) AACC Method 10-10B (1),(3),(4),(5),(6),(9).

Bake Water Absorption (BABS): The amount of water required to make a dough of proper consistency for bread baking when mixed to optimum conditions as judged by an experienced baker using the baking method described above (3).

Mixing Time (MTIME): Time in minutes required to mix the flour and the other bread dough constituents to the optimum condition as judged by an experienced baker(4).

Loaf Volume (LVOL): Volume of bread loaf, measured by canola seed displacement (cc).

Bread Crumb Grain (BCRGR): Subjective judgement of crumb grain quality as judged by an experienced baker.

Buhler Milling
Samples of some advanced nurseries are milled on a Buhler MLU-202 pneumatic laboratory mill (Figure 1). The samples are tempered to a predetermined moisture content ranging from 14.0% to 16.0%, depending on the hardness and known flour-bolting properties. The harder wheats require more water. Thus, the grain is conditioned so that the most rapid and complete separation of endosperm can be made. The temper solution contains a wetting agent (0.1% Aerosol OT) to hasten moisture penetration. The wheat is allowed to temper for 16-24 hours before milling to permit uniform distribution of the moisture. An additional 0.5% water is added 15-20 minutes prior to milling. The first and second break and first and second reduction streams predict long patent flour yield. All six flour streams are then combined to make a straight-grade white flour by sifting on a 120 stainless steel wire screen and thoroughly blending.

Flour Yield (FYELD): The percentage by weight of the total products recovered as straight-grade white flour.

Break Flour Yield (BFYELD): The percentage by weight of the total products recovered as flour off the break rolls.

Milling Time: The time required in minutes to mill a 2-kg sample with the Buhler experimental mill and obtain a normal separation of bran, shorts, and flour. Time is dependent on adjustments made by an experienced miller after visually observing the milling properties.

Milling Score (MSCOR): Calculated as follows:

MSCOR = 100 - [(80 - flour yield) + 50 (flour ash - .30)

+ 0.48 (milling time - 12.5) + 0.5 (65 - per cent long patent)

+ 0.5 (16 - first tempering moisture)]

Cibacron Blue (DSI)
Units: DU/g (dextrinizing units/g). Directly measures alpha-amylase activity through the liberation of Cibacron blue dye covalently linked to a beta-limit dextran substrate.
Cookie Baking
The micro method employs 40 g flour at 25% absorption, 60% sugar, 30% emulsified shortening, 3% dry skim milk, 2.06% NaHCO3, 0.68% NH4Cl, 0.26% NaCL, and 0.24% emulsifier (distilled mono- and di-glycerides). AACC Method 10-52 modified (1),(7).

Cookie Diameter (CODI): The average diameter, of one cookie (cm).

Top grain score (TGS): A visual evaluation score describing the top grain of the sugar snap cookie. Range of 0 to 10, with 10 being the best.

Falling Number (FN)
Determined by AACC Method 56-81B (1).
Farinograph
The Farinograph is equipped with a 50-g bowl and the Constant Flour Weight procedure (14% moisture basis) is employed. AACC Method 54-21A (1).

Farinograph Absorption (FABS): The amount of water required to center the highest portion of the Farinograph curve on the 500 Brabender unit (BU) line.

Farinograph Mixing Peak Time (FPEAK): The time interval, in minutes, from the first addition of water until the curve reaches its maximum height.

Farinograph Stability Time (FSTAB): The number of minutes the top of the curve remains above the 500 unit line when the highest portion (peak) is centered on the 500 unit line.

Farinograph Mixing Tolerance Index (MTI): The difference in Brabender Units (BU) from the top of the curve at peak mixing time to the top of the curve five minutes after the peak mixing time.

Flour Ash (FASH)
The percentage ash from a 4-g sample of flour ignited and heated for 15 hours at 550 in a muffle furnace. AACC Method 08-01 (1).
Flour Moisture (FMIST)
The reference test uses 2 g of flour heated in an aluminum dish in a forced-draft oven for 20 min at 130, allowed to cool and weighed (OVENFMIST). AACC modified Method 44-16 (1). The NIR spectrometer (Technicon 450) (NIRFMIST) is used as the routine moisture measure and is adjusted with the OVENFMIST to obtain FMIST.
Flour Swelling Volume (FSV)
The flour swelling volume reported in mL/g. Using 0.45g flour on a dry weight basis, 12.5 mL water is added and the mixture is well dispersed. The samples are placed in a hot water bath at 92.5, and are continuously inverted for thirty minutes. A rapid cooling in a ice water bath followed by 5 minutes in 25 water is used to bring the samples to room temperature. Then the samples are centrifuged at 1,000g for 15 minutes. The height of the gel is read in mm and reported in mL/g using the following conversion formula. ((mm*1.52)-0.30mL)/0.45g.
Japanese Sponge Cake Baking
Formula contains 100 g flour, 100 g sugar, 100 g fresh egg, 40 g water (14).

Cake Volume (CAVOL): Volume displacement of sponge cake, measured with canola seeds (cc).

Sponge Cake Score (SCSOR): Additive score of texture, volume, external factors and crumb grain (open-ended). The standard flour produces a cake with a score equal to 80.

Micro Milling
Grain samples (5-10 g), generally from early generation lines are equilibrated to 13% (soft) or 14% (hard) moisture content. They are milled on the micro mill, where four samples can be milled simultaneously. The micro mill consists of two pairs of corrugated rolls and double sifters with 38 and 135 mesh stainless steel screens. The bran over the 38 mesh screens is evaluated for milling properties by visual examination for the degree of bran clean up. The throughs of the 135 mesh screen is the equivalent to break flour. This is available for small scale predictive tests, such as SDS-sedimentation, Flour Swelling Volume, etc. A schematic of the micro mill is shown in Figure 3. (2),(13)

Mixogram
A 10-g instrument is used to characterize wheats as to market class and estimate mixing and baking properties of flours. To reduce the time and expense involved in reproducing the mixograms, a reference chart was developed to characterize each curve as to type ranging from very weak to exceptionally long and strong types. Instructions for the use of the chart and the chart itself is found in INTERPRETATION OF DATA. The descriptions of Mixograph Absorption (MABS)and Mixograph Type (MTYPE) also appear in INTERPRETATION OF DATA. AACC Method 54-40A (1),(8).
Modified Quadrumat Milling
The preliminary nurseries (250-500 g) are experimentally milled on a Quadrumat System as modified by Jeffers and Rubenthaler 10). The procedure is described in the 27th Annual Report, Oct. 1976 (Pgs. 1-14). Conversion of the data to give a predicted Buhler flour yield and milling score are done with the following linear equations:Figure 2

Predicted Buhler Milling Score

Soft Wheat (y = -21.60185 + 1.27367 x)

Hard Wheat (y = - 3.43818 + 1.0448 x)

where, y = Predicted Buhler flour yield

and x = Original Quadrumat flour yield

Modified Quadrumat Milling Short Flow
Wheat samples (approximately 40-100g size) are atmospherically conditioned (tempered) by placing the wheat (in envelopes) into a constant temperature and relative humidity chamber. Moisture content is raised to the desired level (13.0% - soft wheat and 14.5% - hard wheat). The conditioned wheat is ground only through the Quadrumat break rolls. The standard sifting schedule used in the Modified Quadrumat SR. milling procedure is followed. Break flour produced from hard wheat is usually 25 - 30% and from soft wheat about 45 - 50%. This amount of flour produced is generally sufficient for certain physio-chemical predictive tests that require little flour ie., mixogram, Rapid Visco Analyzer viscosity, Brookfield viscosity or AWRC.

Bran (%BRAN): The percentage of bran in the total products.

Break Flour Yield(%BFYELD): The percentage by weight of the total products recovered as flour off the break rolls.

Midds (%MIDDS): The percentage unground middling stock in the total products.

Potential Flour Yield (%PFYELD): The potential flour equal to break flour and unground middling stock.

Protein Quality (PROQ)
An assessment of the protein quality for bread baking. The loaf volume of experimental lines is compared to a historical regression that predicts loaf volume based on protein content. If loaf volume of the experimental line is 25 cc of the historical, then PROQ = 0. If loaf volume of the experimental differs from the predicted loaf volume by more than 25 cc, then a "+1" or "-1" is generated. This new parameter replaces the previous X-Y scatter plot of protein vs. loaf volume with the historical and nursery regression lines. Currently the regression is of the form y=ax+b, where loaf volume (y) = flour protein (x) times 65 (a, slope) plus 140 (b, intercept), or LVOL = FPROT(65) + 140.
Rapid Visco Analyzer (RVA)
A hot-pasting viscosity measured by the Rapid Visco Analyzer, using 3.5g of flour on a 14% moisture basis, in 25 mL water. The viscosity reported is the peak viscosity in RVA units (centipoise X 10). The temperature profile used to obtain the peak viscosity consists of 2 min at 60, then constant rate heating to 93 in 6 minutes with a final hold of 2 min at 93, for a total of 10 min. The RVA emulates the Brabender Amylograph. Foreign users have suggested that an Amylograph viscosity value (not analyzed here) of 500 Brabender Units (BU or AU) is a minimum value, and 1000 or greater is a desirable value for certain types of noodle quality. RVA and Amylograph peak viscosity values have a linear correlation of about 0.99. Therefore, minimum RVA values would be near 125 with values above 210 desirable.
Sample Preparation
Wheat or flour samples are logged into the WAS computer system and assigned a crop YEAR, NURSERY number, and a SAMPLE# number. All wheat samples are frozen at -20 for 2 days to kill insects, cleaned on a Carter dockage (Simon-Carter Co., Minneapolis, MN) tester if necessary, measured for test weight and then scoured in a Cyclone Grain Scourer (model 6, Forster and Son, Ada, OK) and sub-sampled for proximate analysis.
Single Kernel Analysis
300 kernels are individually analyzed using a Single Kernel Characterization System (SKCS) Model 4100 (Perten Instruments). The mean and standard deviation from the 300 kernel sample are reported for four parameters. They are hardness, size, moisture, and weight. The machine works by weighing (SKWT) each kernel prior to it being dropped between a rotor and crescent which crushes it. The crescent has a load cell attached which will sense the kernels size (SKSIZE), the force (SKHRD) needed to crush the kernel, and the moisture (SKMST) of each kernel. The rotor is ribbed to sweep the crushed kernel past the crescent preparing the machine for the next kernel. An algorithm using a 4-class histogram to categorize the class (SKCLASS) as hard, soft or mixed.
Test Weight (TWT)
Determined by AACC Method 55-10 (1).
Udon Noodle Making
Formula contains 300 g flour, 6.0 g NaCl, 96 g water (14% constant flour moisture basis) with dough sheet and noodles prepared with an Otake Laboratory Noodle Machine (14). Often, optimum water absorption is used as opposed to constant absorption. Color measurements are made with a Minolta Chroma Meter set to the L*a*b* color system.

Udon Noodle Brightness Reading (L0UNC) & (L24UNC) L* reading from the Minolta Chroma meter at 0hr and 24hr.

Udon Noodle Red - Green Reading (A0UNC) & (A24UNC) a* reading from the Minolta Chroma meter at 0hr and 24hr.

Udon Noodle Yellow - Blue Reading (B0UNC) & (B24UNC) b* reading from the Minolta Chroma meter at 0hr and 24 hr.

Noodle Yield(NYELD): Relative score assigned to WTIN (see below).

Noodle Score(NOSCOR): Additive score incorporating raw and cooked noodle color, yield and texture.

Noodle Weight Increase (WTIN): Percentage weight increase of cooked noodle relative to raw noodles.

Raw Noodle Color Score (RNCOL): The score subjectively assigned to raw noodles which were assessed visually. The standard control raw noodle is assigned a score of 16. Scores assigned to the experimental raw noodle can range from 1-20.

Cooked Noodle Color Score (CNCOL): The score subjectively assigned to cooked noodles which were assessed visually. The standard control raw noodle is assigned a score of 16. Scores assigned to the experimental cooked noodle can range from 1-20.

Cooked Noodle Texture Score (TEXTNO): The score assigned by a sensory panel which considers factors such as chewiness, firmness and/or softness, springiness, elasticity, and other bite characteristics. The standard control cooked noodle is assigned a score of 32. Scores assigned to the experimental cooked noodles can range from 1 to 40.

UDY Wheat Hardness (UWHRD)
A small sample is ground on the UDY Cyclone mill with a 0.5-mm screen, and analyzed in a NIR Spectrometer (Technicon IA 450) calibrated to standard FGIS NIR wheat grain hardness values. AACC Method 39-70A (1).
Viscosity (VISC)
Dial reading X 7.5 of a RVT Brookfield Synchro-Lectric Viscometer fitted with a modified No. 2 spindle at 50 R.P.M. using a suspension of 20 g of flour in 100 ml of water and 7 ml of 1 N lactic acid (12).
Wet Gluten
Expressed on a percentage weight basis. 25g flour is wetted and worked into dough, repeatedly washed with tap water until all starch is released then weighed. AACC Method 38-10.
Wheat Moisture (WMIST)
A small sample is ground on a Tecator Cemotec 1090 Sample Mill. The reference test uses 2 g of ground wheat heated in an aluminum dish in a forced-draft oven for 40 min at 130, allowed to cool and weighed. AACC modified Method 44-16 (1) (OVENWMIST). Generally, 10% or 3 samples (whichever is higher) are used per nursery to obtain the oven wheat moisture. The results are averaged and the mean is applied as the Wheat Moisture (WMIST), in the WAS system.
Wheat Protein (WPROT) and Flour Protein (FPROT)
Protein concentration is determined by NIR (NIRWPROT and NIRFPROT). Minor corrections are made based on the results from about 10% of the samples analyzed using the combustion method (Leco, model FP-428) (LECOFPROT and LECOWPROT). Wheat Protein: AACC Method 39-10. Flour Protein: AACC Method 39-11. Leco Protein: AACC Method 46-30 (1).