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Reprinted from Journal of Food Science. G. N. BOOKWAL TER and C. L. MEHL TRETTER © 1976 by Institute of Food Technologists. USDA Northern Regional Research Laboratory, ARS, Peoria, IL 61604 _ Purchased by U.S. Dept. of Agriculture for Official Use.

DOUGH CONDITIONERS FOR 12% SOY-FORTIFIED BREAD MIXES

ABSTRACT ------We undertook to prepare fatty esters of polyethoxylated Dough conditioners in wa.xy solid and fluid forms were prepared by (1) and polypropoxy1ated propylene glycol and of glycerol glyco­ reactions of starch or lactose with glycerol or propylene glycol; (2) sides derived from starch and lactose, investigate methodology alkoxylation of polyol glycosides with ethylene oxide or its mixture for incorporating these experimental dough conditioners into a with propylene oxide; and (3) transesterification with methyl esters of dry mix with wheat and soy flour, and to evaluate their dough­ oleic, stearic or palmitic acid or triglyceride mixtures. Dry mixes of conditioning action in bread containing wheat flour fortified these experimental dough conditioners were prepared by chilling and with 12% soy flour. grinding the waxy conditioners to powder form and blending with de­ fatted soy flour. Grinding of the waxy products was facilitated by MATERIALS & METHODS incorporation of up to 10% fully hydrogenated soybean oil flakes (HSF). Fluid conditioners were added directly and blended with soy Experimental dough conditioners flour. When tested at the 0.5% level in 12% soy-fortified wheat bread, Glycosides of glycerol and propylene glycol were prepared from functional properties were the same whether the experimental dough starch (Otey et aL, 1968) and from lactose (Mehltretter and Wilham, conditioners were added to the bread formula either by dissolving in 1973). From starch, the reaction products were mixtures of polyol water or as a dry mix with the soy flour and wheat flour. Baking results glucosides and higher oligomeric polyol glycosides. From lactose, the were not affected by the incorporation of up to 10% HSF with the reaction products were polyol glucosides and polyol galactosides. The waxy products. The 12% soy-fortified bread containing waxy or fluid mixtures were alkoxylated with ethylene oxide or with mixtures of dough conditioner had substantially improved loaf volume, grain and ethylene oxide and propylene oxide and transesterified with methyl crumb color when compared to control bread with no conditioner. esters of oleic, stearic and palmitic acids and by triglyceride mixtures FDA approval of these new dough conditioners for food use has not yet (Crisco®, Proctor and Gamble Co.). The conceptual structure of one of been obtained. the possible products from a random mixture is illustrated in Figure 1. This stearic acid ester of polyetlwxylated glycerol a:-D-glucoside was prepared by the sequential reactions of starch with glycerol, ethylene INTRODUCTION oxide and methyl stearate. The nine preparations (A to I) for this study are shown in Table 1. The variables in these compositions are: starch or WHEAT FLOURS can be fortified with soybean flours to im­ lactose starting materials, glycerol or propylene glycol, levels of ethyl­ prove their nutritive value (Pomeranz, 1966). Defatted soy ene oxide or its mixtures with propylene oxide, methyl esters of various flour contains about 52% protein and 3.6% lysine, an essential fatty acids and triglycerides. All final products were either waxy solid amino acid. Wheat flour intended for breadmaking contains or fluid forms. These experimental dough conditioners do not have about 12% protein and 0.38% lysine. When wheat flour is FDA approval for food use. fortified with 12% soy flour, the levels of protein and lysine are about 16.8% and 0.76%, respectively (Tsen, 1974). Fortification of bread wheat flour with soy flour can cause undesirable effects on dough properties and bread quality (Tsen et al., 1971 a). Most noticeable in finished bread prod­ ucts are: darker crumb color, more open and coarser grain and Methyl Palmitate reduced loaf volu.me. Several fatty acid derivatives reportedly ~ or Glycerol Ethylene Oxide Methyl Stearate improve the baking characteristics of bread made with soy­ Starch or or or + + Mixtures with + or fortified wheat flour. The addition to wheat flour of natural Propylene Methyl Oleate lactose Glycol Propylene Oxide glycolipids (Pomeranz et aI., 1969a, b) from wheat or quaking or grass or of sucrose esters permitted fortifying with up to 16% Triglycerides soy flour without a substantial loss in the bread's physical properties. The addition of sodium stearoyl-2-lactylate (SSL) ~ to wheat flour fortified with as much as 12% soy flour also Starch Ethy.'ene", Methyl maintained high-quality bre;::-d characteristics (Tsen and Hoo­ OXide 10 ver, 1971 b). The 12% level of soy fortification of wheat flour II containing SSL was found by previous workers (Tsen et aI., CH zOICH zCHz-O I, OCICH Zlt6 CH 3 1971 a) to be the maximum level to maintain acceptable physi­ 1----0 cal quality characteristics. This work resulted in the develop­ ment of a 12% soy-fortified bread flour which is used in ex­ OICHzCHzOl,H port programs (USDA, 1972). I HIOCHz-CHzl,-O O-CHz-C-CHz-OICHzCHz OI,H Bean et a1. (1973) tested mono- and di-fatty esters of poly­ I ethoxylated and po1ypropoxy1ated propylene glycol and of H glycerol glycosides prepared from starch as improvers for O-ICHzCHzOI,H wheat flour fortified with 6% soy flour. The fatty esters were added to the bread formula by dissolving them in dough water. Fig. 1-Possible combinations of reactants that can produce experi­ The products tested showed promise for improving loaf vol­ mental dough conditioners. Conceptual structure of stearic acid ume and grain characteristics of soy-fortified bread. All the ester of polyethoxylated glycerol ex-D-glucoside prepared by the se­ dough conditioners were in fluid or waxy solid forms which quential reactions of starch with glycerol, ethylene oxide and were not conveniently added to baking formulas. methyl stearate.

Volume 41 (1976)-JOURNAL OF FOOD SCIENCE-67 68-JOURNAL OF FOOD SCIENCE- Volume 41 (1976)

Dry mixes Bread baking tests The physical state of the experimental dough conditioners (Table 1) Baking results of 12% soy-fortified bread flour with and required methodology to facilitate their incorporation in fully formu­ without experimental dough conditioner types A through H lated dry mLxtures of wheat and soy flours. In export programs (USDA, are compiled in Table 2. These results demonstrate the effec- 1972), a dry prepared mix is required. The waxy materials were heated to 65° C and cast into 1/4 in. x 1/8 in. ribbons which after hardening were cut to 1/4 in. x 1/4 in. x 1/8 in. pieces. These pieces were chilled to -12°C and ground (-20 U.S. Standard mesh) in a similarly chilled impeller mill. The chilled powder was immediately blended with de­ Table 1-Composition of experimental dough conditioners fatted soy flour. One dough conditioner hardened by the addition of 5 and 10% fully hydrogenated soybean oil flakes was reduced to pow­ Moles/mole dered form by this procedure. The fluid dough conditioners were Dough glycoside heated to 65° C and added directly to defatted soy flour in small drop­ conditioner Physical lets accompanied by mLxing in a Hobart mLxer. This step was followed type Eoa poa Glycoside state by screening (-14 U.S. Standard mesh) and remixing. The defatted soy flour-dough conditioner blends were then in a form suitable for prepar­ A 8.0 3.8 GGb Monooleate LC ing.a dry mLxture of wheat flour, soy flour and dough conditioner. B 5.0 0 GG Monostearate W Baking formula and procedure C 5.0 0 PGG Monostearate W GG Fatty ester, mixedd The experimental dough conditioners were evaluated in bread bak­ D 5.0 0 L ing tests at the 12% level of soy fortification. Comparisons were made E 8.2 0 GG Fatty ester, mixed L between dough conditioners (A to H), added to the bread formula F 5.0 0 GL Monopalmitate W either in dry mix form with the soy flour and wheat flour or with the G 2.5 0 GL Monopalmitate W dough water. Baking tests were made according to the procedure speci­ H 4.0 0 PGL Monopalmitate W fied for soy-fortified bread flour used in export programs (USDA, I 6.6 0 PGL Monopalmitate W 1972). The bread formula is as follows: a EO = ethylene oxide; PO = propylene oxide. % g b GG = glycerol glycoside from starch; PGG = propyleneglycol glycoside from starch; GL = glycerol glycoside from lactose; PGL Wheat flour 88 200 = propyleneglycol glycoside from lactose. Soy flo ur, defatted, lightly toasted 12 CL = liquid; W = waxy solid (at ambient temperatures). Dough conditionera 0.5 b 1 d Mixed = mixed esters (transesterified with Crisco®, Proctor and Yeast, compressed 2.5 b 5 Gamble Co.). Salt 2.0b 4 Sugar 4.0b 8 Water (containing 10 ppm KBr) 68.0b 136 a Premixed with soy flour or water. Table 2-Effeet of experimental dough conditioners on the baking b Percent of wheat-soy flour. quality of 12% soy-fortified bread

The bread wheat flour contained 11.3% protein, 0.71% ash an~ Dough Vol 12.7% moisture. The dough scaling weight was 150g; this amount conditioners increase yielded a pup loaf weighing about 125g after baking. Each batch pro­ and their Grain Loaf (% over Baking duced two pup loaves. Each of the experimental dough conditioners premixes with score Crumb vol b nonfat quality and controls containing no fat were tested by this procedure. The ex­ soy flour (15 max) colora (cc) control) rankingC perimental bread was evaluated for grain score and crumb color accord­ ing to standard laboratory practice (Bookwalter et aI., 1971). Bread Ad (SF)e 12 95 6031mnf 26 2 volume was measured by standard AACC (1962) procedures. A (W)g 12 95 630 klmn 31 Chemical analyses were made following standard procedures B (SF) 12 95 630 klmn 31 2 (AACC, 1962). Analysis of variance (Snedecor and Cochran, 1968) and B (W) 12 95 635 jkl 32 Duncan's (1955) multiple-range test were used to examine results. Sta­ B + 5% HFh (SF) 12 95 665jk 38 tistical significance is at the 5% probability-of-error level wherever the (SF) term "significant" appears in this paper. B + 10% HF 12 95 632 kim 32 C (SF) 12 95 642 jkl 34 C (W) 12 95 637 jkl 33 RESULTS & DISCUSSION D (SF) 12 95 585 n 22 3 D (W) 11.5 95 587 mn 22 Dry mix preparation E (SF) 12.5 95 632 kim 32 2 Experimental fluid and waxy solid dough conditioners A E (W) 12.5 95 637 jkl 33 through H (Table 1) were satisfactorily blended into dry mix F (SF) 12 95 625 klmn 30 2 form by the methods described. Waxy sample I was too soft to F (W) 12 95 627 klmn 30 grind as evidenced by sticking in the impeller mill and plugging G (SF) 12.5 95.5 600lmn 25 2 the screen. The waxy samples required more processing steps G (W) 12 95 600lmn 25 and controlled conditions than did the fluid samples. Waxy H (SF) 12.5 95 665jk 38 sample B produced a drier, less sticky powder after grinding H (W) 12.5 95.5 680 j 42 when 5 or 10% fully hydrogenated soybean oil flakes were None 10 92 475 p 4 incorporated. Waxy samples C and G produced the driest None 10 92 487 p powders after grinding. These results indicate that preparation None 10 92 480p of dough conditioners in dry mix form is facilitated by in­ creased hardness of the waxy samples or by the use of fluid a 100 = white; ~5 = creamy samples. Increased hardness may be achieved by varying the b Average of two c 1 = best types and amounts of components during preparation or by d Experimental dough conditioner type A through H (Table 1) the addition of fully hydrogenated soybean oil flakes. Using e (SF) = dough conditioners premixed with soy flour, then preblended available equipment, a commercial scale process for incorpo­ with dry ingred ients. f Coded means (j to p) with no letter in common differ significantly rating the experimental fluid dough conditioners in a soy­ (5% level) wheat mix could be readily achieved. Additional process de­ g (W) = dough conditioners dissolved in dough water. velopment would be required for scaling up the waxy type. h HF = fully hardened soybean oil flakes. DOUGH CONDITIONERS IN SOY BREAD MIXES-69

tiveness of the experimental dough conditioners in improving Bean, M.M., Mehltretter, C.L., William, C.A. and McGuire, T.A. 1970. Fatty esters of polyalkoxylated polyol glycosides as bread additives. the baking characteristics of 12% soy-fortified bread. Paired Food Prod. Develop. 7: 30. comparisons are shown for experimental dough conditioners Bookwalter, G.N., Mustakas, G.C., Kwolek, W.F., McGhee, J.E. and premixed with soy flour (SF) and samples added with the Albrecht, W.J. 1971. FUll-fat soy flour extrusion cooked: Properties and food uses. J. Food Sci 36: 5. dough water (W). There were substantial differences in baking Duncan, D.B. 1955. Multiple range and multiple F tests. Biometrics 2: quality between bread made with and without 0.5% dough 1. Mehltretter, C.L. and William, C.A. 1973. Ethoxylated glycerol and conditioner. Grain scores were about two points lower, color propylene glycol glycoside palmitates from lactose. J. Am. Oil values were three shades darker and loaf volume was signifi­ Chern. Soc. 50: 425. cantly lower in bread made with no dough conditioner. Vol­ Otey, F.R., Mehltretter, C.L. and Rist, C.E. 1968. Starch-derived polyol glycosides. Properties and potential applications. Cereal Sci Today ume increase of the bread made with dough conditioners 13: 199. ranged from 20-42% over the nonfat control. The least signifi­ Pomeranz, Y. 1966. Soy flour in breadmaking. Baker's Dig. 40(3): 44. cant difference for comparing two mean loaf volume values in Pomeranz, Y., Shogren, M.D. and Finney, K.F. 1969a. Improving breadmaking properties with glycolipids. 1. Improving soy products Table 2 is 42.6 cc. There was no significant difference in with sucroesters. Cereal Chern. 46: 503. baking quality between experimental conditioners added as a Pomeranz, Y., Shogren, M.D. and Finney, K.F. 1969b. Improving breadmaking properties with glycolipids. 2. Improving various dry mix with (SF) or with (W). These results are indicative of protein·enriched products. Cereal Chern. 46: 512. no change in baking potential when the waxy or fluid dough Snedecor, G.W. and Cochran, W.G. 1968. "Statistical Methods," 6th ed. conditioners are converted to a dry mix form. Iowa State College Press, Ames. Tsen, C.C. 1974. Fatty acid derivatives and glycolipids in high·protein The baking quality of waxy sample B was not changed bakery products. J. Am. Oil Chern. Soc. 51: 81. when as much as 10% fully hardened soybean oil flakes were Tsen, C.C., Hoover, W.J. and Phillips, D. 1971a High·protein breads. Use of sodium stearoyI·2-lactylate and calcium stearoyl-2·lactylate incorporated. This result suggests that hard fat may be added in their production. Baker's Dig. 45(2): 20. to a waxy sample to improve milling properties without af­ Tsen, C.C. and Hoover, W.J. 1971b. The shortening-sparing effect of sodium stearoyl·2-lactylate and calcium stearoyl-2-lactylate in bread fecting baking quality. In an overall baking quality ranking baking. Baker's Dig. 45(3): 38. (Table 2), experimental dough conditioners C and H rated best USDA, 1972. Soy-fortified bread flour for use in export programs. while sample D rated lowest. This result may be related to the Announcement WF-9, September 27, 1972. Agricultural Stabili· zation and Conservation Service. ASCS Commodity Office, 6400 use of propylene glycol in preparation of samples C and Hand France Avenue, South, Minneapolis, Minn. 55435. glycerol in sample D or to the presence of monoglycerides and Ms received 4/25/75; revised 8/30/75; accepted 9/3/75. mixed esters in sample D. This work demonstrates that glycosides prepared from starch or lactose are very effective dough conditioners in 12% soy-fortified bread. High functionality is indicated when added to a bread formula with either the dough water or as a premix with the soy and wheat flours. Presented at the 35th Annual Meeting of the Institute of Food Technologists, Chicago, IlL, June 8-12, 1975. Dr. W.F. Kwolek, Biometrician, USDA North Central Region, ARS, REFERENCES stationed at the Northern Laboratory, provided statistical evaluations. The mention of firm names or trade products does not imply that AACC. 1962. "Cereal Laboratory Methods," 7th ed., Rev. 1971. they are endorsed or recommended by the U.S. Dept. of Agriculture American Association of Cereal Chemists, St. Paul, MN 55121. over other firms or similar products not mentioned.