Extraction and Enrichment of (1 F.3),(1-*4)-,f-D-Glucan from Barley and Oat Brans

Cereal Chem. 70(l):77-80 Soft white wheat flours from varied growing conditions were analyzed However, when the correction for protein content was not taken into for selected variables of gluten and components of flour lipid to identify account, total protein was shown to be negatively correlated with cookie those that are associated with baking quality as measured by cookie diameter. Among the components of flour lipid, polar lipid had the highest diameter and cake volume. Statistical analysis indicated that among the correlation with cake volume. These variables, therefore, appear to be gluten variables, yield of gluten and pentosan in gluten were the variables important in the end-use quality of soft white wheat. most associated with cookie diameter corrected for protein content. Soft wheat flours with low protein content are used for pastry products rather than for breadmaking, where hard wheat flour with higher protein content is used (Hoseney et al 1988). However, the protein content is not the only factor determining end-use properties. Protein quality can influence the baking properties of both hard wheat flour (Orth and Bushuk 1972) and soft white wheat flour (Kaldy and Rubenthaler 1987). An important factor in protein quality is the gluten characteristics of a dough. Gluten is formed by the interactions of the proteins, glutenin and gliadin, which also associate with lipid and pentosans during dough formation (D'Appolonia and Kim 1976, Hoseney 1986). A strong dough with an extensive gluten network is suitable for breadmaking (Pomeranz 1988). In contrast, a weak dough, without an extensive gluten network, is best for cookies and cakes (Gaines 1990). Consequently, flour quality is influenced by the nature of the gluten and its various components. However, very little is known about gluten and its components in soft white wheat flour, especially with reference to baking quality. Pentosans also have an influence on flour quality and dough formation (Yamazaki 1955, Shogren et al 1987). Native flour pentosans were found to have a negative effect on both cookie diameter and cake volume (Kaldy et al 1991). Some pentosans are part of the gluten matrix, but the exact nature of the association with the matrix is unknown. Also, the influence of the glutenassociated pentosans on baking quality of soft white wheat flour has not been established. Flour lipids also influence the baking quality of soft white wheat flour. Cookies baked from flours with the lipids removed had smaller diameters than those baked from unextracted flours (Cole 'Contribution 3879067 of the Lethbridge Research Station. 2 Agriculture Canada, Research Station, Lethbridge, Alberta T I J 4B 1. 3 Retired. 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., 1993. et al 1960). Studies on cake quality have also indicated that removal of lipids reduces cake volume (Seguchi and Matsuki 1977). As far as lipid fractions are concerned, nonpolar and polar lipids in spring wheat flour have been shown to have an influence on loaf volume (Bekes et al 1986). Both nonpolar and polar lipids were found to be necessary for the restoration of cookie spread in defatted flour from a cultivar of eastern soft white wheat (Kissell et al 1971). The purpose of this study was to examine gluten and lipid components in flours from soft white wheat grown under a broad range of conditions and to identify the gluten and lipid variables most associated with baking quality. MATERIALS AND METHODS Soft white wheat samples were collected from a broad range of growing environments in Alberta and Ontario, Canada, and in Washington State. Fifteen samples of soft white spring wheat were from a 500-km-wide region of Alberta. Ten samples were cv. Fielder, one was cv. Owens, one was cv. Dirkwin, and the remaining three samples were mixed (commercial) spring wheat cultivars, mainly Fielder and Owens. All were grown in 1984 except one Fielder sample, which was grown in 1983. Of khe five samples from Washington State, four were Fielder. One was grown in 1981, another in 1982, and two samples in 1983. The other sample was Owens, grown in 1984. Three of the five winter wheat samples from Ontario were the cultivar Fredrick, grown in 1982, 1983, and 1984. The two other samples were mixed (commercial) cultivars grown in 1984. All samples were milled on a Buhler pneumatic laboratory mill at the USDA Western Wheat Quality Laboratory, Pullman, WA, as described previously (Kaldy and Rubenthaler 1987). Cookie and cake baking, as well as some of the other tests, were also done at the Western Wheat Quality Laboratory as described previously (Kaldy and Rubenthaler 1987). The samples were stored under refrigeration. Some of the carbohydrates in flour were analyzed as previously described (Kaldy et al 1991). As reported previously (Kaldy and Rubenthaler 1987, Kaldy Vol. 70, No. 1, 1993 77