Alveograph Algorithms to Predict Functional Properties of Wheat in Bread and Cookie Baking '

Cereal Chem. 66(2):81-86 A total of 73 wheat samples (23 soft white winter, 20 soft white spring, 15 plus protein. In hard wheats, loaf volume was predicted (r= 0.950; SE= 49 club, seven hard red winter, six hard red spring, and two hard white winter) cm) using alveograph L plus protein. Specific volume (an index of protein were milled and analyzed for gross composition and flour texture (by quality) could be predicted in hard wheats (r= 0.946; SE= 3.1 cm /% near-infrared reflectance spectroscopy). The wheat flours were baked into protein) using alveograph P, W, and hardness. In soft wheats, specific cookies and bread and evaluated on an alveograph. A multivariable model volume was predicted (r = 0.855; SE = 6.56 cm 3 /% protein) using produced the highest correlation coefficient using combinations of protein, alveograph L and W plus hardness. The equations were verified using hardness, and alveograph values P, L, and W to predict loaf volume, wheat flours with known gross composition and end-use parameters. specific volume, and cookie diameter. Cookie diameter was predicted from Cookie diameter in soft wheat flour was predicted with r = 0.934 and an P and protein (r 0.797; standard error [SE] = 0.14 cm). Loaf volume was average residual of 0.06 cm. Loaf volume was predicted in hard wheat predicted (r= 0.914; SE= 68 cm ) in soft wheats using alveograph L and W flours with r = 0.939 and an average residual of 33 cm . Since the early studies of Chopin (1927), the alveograph has been used mainly to evaluate breadmaking quality of wheat flours (Bennett and Coppock 1956, Bloksma 1957, Chen and D'Appolonia 1985, Chopin 1927, Dubois 1984, Khattak et al 1974, Marcelle 1955). Some studies were conducted on the use of the alveograph in determination of cookie-making quality (Grebaut 1984, Rasper et al 1986) with rather limited success. Rasper et al (1986) suggested that the failure to relate alveogram indexes to cookie-baking performance reflects the limited sensitivity of the latter rather than the inadequacy of the rheological test to respond to quality differences in tested wheats. In studies of breadmaking quality of U.S. and Canadian (as in European) wheats, the main emphasis has been on the W value (Bloksma 1957, Faridi and Rasper 1987). It is of interest that Shogren et al (1963a,b) pointed to the low L values of U. S. hard red winter wheat flours. Chen and D'Appolonia (1985) reported that all three alveograph values (P, L, and JW) were highly correlated with extensigraph values. However, only the P value was correlated (negatively) with flour protein, wet gluten, and loaf volume. The objective of this study was to determine whether alveograph values alone or in combination with other parameters (such as protein content and hardness), could be used to develop algorithms to predict breadand cookie-making properties of Pacific Northwest wheats. The results were also used to determine whether there were differences in alveograph parameters between winter and spring wheats. Determination of appropriate end-use properties of wheat flours should be considered both for differentiation between low-protein soft and high-protein hard wheats and for fine differentiation among samples within each class. While the hard wheats are not likely to be used in production of cookies and cakes, soft and relatively high-protein wheats are used widely in bread production. Consequently, our statistical evaluation encompassed testing hard and soft wheats in breadmaking and soft wheats only in cookiemaking. College of Agriculture and Home Economics Research Center, Washington State University, Pullman. USDA, ARS Western Wheat Quality Laboratory, Pullman, WA, and Dept. of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-4004. Mention of firm names or trade products does not constitute endorsement by the U.S. Department of Agriculture over others not mentioned. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Association of Cereal Chemists, Inc., 1989. MATERIALS AND METHODS Samples of commonly grown wheat varieties and advanced experimental selections were obtained for this study from two locations (Pullman and Lind, WA) from the 1984 crop year. Included in this study set were 23 soft white winter (SWW), 20 soft white spring (SWS), 15 club, seven hard red winter (HRW), six hard red spring (HRS), and two hard white winter (HWW) wheats for a total of 73. These wheats were milled to approximately 72% extraction on a Buhler pneumatic mill. The resulting flours were analyzed for moisture, ash, and protein (methods 46-12,44-16, and 8-01, respectively; AACC 1983). The hardness value was a number derived by near-infrared reflectance, arbitrarily scaled using one wavelength (1,680 nm) from a Technicon IA 400 (Bruinsma and Rubenthaler 1978). The scale of hardness ranged from zero to 129.0, with hard wheat flours averaging 95.5 and soft wheat flours averaging 32.5 (Table I). A cookie diameter algorithm verification set was composed of six commercial SWW, club, and SRW wheats from the United States and France. Each was evaluated as mentioned above. A loaf volume algorithm verification set was composed of five plant breeders' HRW samples from the 1979 crop year grown in Kansas and 13 plant breeders' HRW and HRS samples from the 1987 crop year grown in the Pacific Northwest. Each was evaluated in accordance with the above procedures. Since hard and soft flours generally perform well in only some of a wide range of potential end-use products, the sample set was separated into two parts according to their marketing classes (hards and softs). The soft white (SWW and SWS) and club wheat flours were baked into cookies using the micro baking test method (AACC method 10-52). The result of the cookie test is expressed as the average diameter (cm) of one cookie. All wheats, regardless of class, were baked into 100-g loaves using the optimized straight-dough breadmaking method (AACC 10-lOB). The resulting loaf volume (cm ) was measured by a volume displacement method. The specific volume of the loaf was calculated as: Specific volume= (loaf volume 400)/protein (14% mb) The 400 cm base offset represents the volume of loaf produced if all the protein components of the flour are removed or if no functional protein is present (Hoseney 1986). Because the base loaf volume due to nonprotein fractions is removed, specific volume expresses the volume (cm) of bread expected to be produced for each percent increase in protein. Specific volume is an indicator of protein quality (Rubenthaler and Pomeranz 1987). The flours were tested on a Chopin MA 82 alveograph. A 2.5% sodium chloride solution was used to hydrate a 250-g sample of each flour to the level specified by AACC method 54-30 (129.4 ml Vol. 66, No. 2, 1989 81 at 14% moisture). Mixing at 240 C totaled 8 min including a 1-min scrapedown period after the first minute of mixing. Five dough pieces were produced from each sample and allowed to rest for 20 min at 25°C. At the end of the resting period, each sample was inserted into the alveograph. A bubble was blown and the resulting air pressure profile was recorded on a recording manometer. Each chart was analyzed for several factors: P, the maximum overpressure needed to blow the dough bubble; L, the average TABLE I Summary of Variable Parameters of Wheat Flours Variable Minimum Maximum Mean SD