Bread Crumb Amylograph Studies . I . Effects of Storage Time , Shortening , Flour Lipids , and Surfactants '

Cereal Chem. 69(5):495-501 Sodium stearoyl lactylate, sucrose monopalmitate, diacetyl tartaric acid the height of the plateau before the viscosity onset. The plateau was esters of monoand diglycerides, monoglycerides, and petroleum etherformed by progressive lowering of the initial viscosity, presumably caused extracted flour lipids were added to a bread formula at the 0.5% level by amylopectin retrogradation in bread crumb over the storage time. to make breads with and without shortening. Bread crumb compressibility Amylograph readings of bread crumb were significantly correlated with was measured after one, two, and five days of storage at room temperature, crumb firmness. Storage days, loaf volume, and cooling-end or holdingand the crumbs were then used for amylograph studies. Compressibility end viscosity in the crumb amylogram were included in the best-fitting increased with storage length and decreased with crumb moisture content regression equations of crumb firmness. The relation of amylograph readand loaf volume. Amylograph readings of breads made with different ings to crumb compressibility was attributed to effects of lipid materials additives were significantly different. Storage time of the bread did not on both amylograph readings and crumb compressibility. significantly affect the crumb amylogram readings except, in some breads, The amylograph was first utilized by Yasunaga et al (1968) to study the pasting characteristics of bread crumb. The effects of storage times of bread on crumb amylograms have been investigated by several workers (Yasunaga et al 1968, D'Appolonia and MacArthur 1974, Kim and D'Appolonia 1977, Morad and D'Appolonia 1980, Kai 1985). They reported possible relationships between crumb amylogram readings and bread storage, but they did not obtain sufficient data to draw conclusions. The effects of shortening and certain surfactants on crumb amylograms were also studied to a limited extent, and further work seems necessary. Bread crumb samples have been prepared for amylograph tests in two ways. D'Appolonia and co-workers (D'Appolonia and MacArthur 1974, Kim and D'Appolonia 1977, Morad and D'Appolonia 1980) used a lyophilizing-and-grinding method. Bread crumb was freeze-dried, ground, and then agitated in a Waring Blendor in water before the amylograph test. Since freezedrying may exert an extraneous effect on bread crumb, this method may mask the effect of storage time. Yasunaga et al (1968) and Kai (1985) soaked bread crumb in distilled water for 1 hr and dispersed the crumb to a smooth slurry, but they did not report the procedure for measurement of the crumb moisture content before the amylograph tests. The solids concentration in the amylograph should be maintained at the same level for comparison. The two-stage AACC method 44-15A (AACC 1983) for moisture content measurement in bread takes one day and is thus unsuited for use with the amylograph test at different storage periods. A rapid method for moisture content measurement in bread crumb needs to be developed. Therefore, this study was designed to develop and validate a rapid method for moisture measurement in bread crumb and to investigate the effects of storage time, shortening, flour lipids (FL), and surfactants on bread crumb amylograms and the relationships of bread crumb amylogram readings with crumb firmness. 'Contribution 90-95-J, from the Kansas Agricultural Experiment Station, Manhattan, KS 66502. Cooperative investigation between the U.S. Department of Agriculture, Agricultural Research Service and the Kansas Agricultural Experiment Station. Presented in part at the 1986 Annual Meeting of the American Association of Cereal Chemists, Toronto, Canada. Mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned. 2 Graduate research assistant and professor, respectively, Department of Grain Science and Industry, Kansas State University, Manhattan 66506. 3 Supervisory research chemist, U.S. Grain Marketing Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Manhattan, KS 66502. 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., 1992. The amylograms of bread crumb had some unique features that were usually not observed in starch or flour amylograms. A companion report, part two of this study, will address the cause of those unique properties. MATERIALS AND METHODS Materials The flour was a commercial bread flour of 10.6% protein (14% mb) obtained from Archer Daniels Midland Co., Abilene, KS. The yeast used was Fermipan Instant Yeast from Gist-Brocades N.V., Holland. The unemulsified shortening, Bakeall (Bunge Edible Oil Corp., Kankakee, IL) was made from meat fats and vegetable oils. The surfactants used included sodium stearoyl lactylate (SSL) (100% over U.S. 20 mesh, m.p. 45-48°C, acid value 60-80, ester number 150-160, lactic acid 31-34%) and saturated distilled monoglycerides (MG) (90% over U.S. 60 mesh, m.p. 57-64°C, a-monoglyceride 90%, free glycerine 1%, iodine value 25-30) obtained from BREDDO Inc., Kansas City, KS; powdered diacetyl tartaric acid esters of monoand diglycerides (DATEM) (V 35 922, E-472e, containing 20% tricalciumphosphate) and sucrose monopalmitate (SMP) (DK Ester F-140, HLB 14, Dai-Ichi Kogyo Seiyaku, Japan) purchased from Chemische Fabrik Gruenau, Illertissen/Bayern, Germany. The surfactants were added directly to other baking ingredients and thoroughly blended before mixing. Flour Lipid Extraction and Fractionation Flour lipids were extracted from the flour with petroleum ether using the Soxhlet apparatus over a 24-hr period. The composition of the extract was examined by fractionation using silicic acid column chromatography and thin-layer chromatography (Chung et al 1977). The petroleum ether-extracted FL were blended with flour in a mortar and pestle and used as an additive in the bread