Food Sci. Technol. Res., ++ (+), +3ῌ,/, ,**/

Application of Polyglycerol Mono- to Improve Breadmaking

+῍῍ + , -῍ Yoshiro MIYAMOTO , Mitsuhiro SAKAMOTO , Tomoko MAEDA and Naofumi MORITA

+ Ako Laboratory, Research and Development Laboratory, Sakamoto Yakuhin Kogyo Co., Ltd., +-,/ῌ3- Kizu, Ako, Hyogo 012ῌ*+0/, Japan , Department of Life and Health Sciences, Hyogo University of Teacher Education, 3.,ῌ+ Shimokume, Yashiro, Hyogo 01-ῌ+.3., Japan - Laboratory of Food Chemistry, Division of Applied Biochemistry, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, +ῌ+ Gakuencho, Sakai, Osaka /33ῌ2/-+, Japan

Received July +-, ,**.; Accepted October ,1, ,**.

The e#ects of polyglycerol mono-fatty acid esters (PGMFEs) on dough properties and baking were investigated using six PGMFEs with saturated fatty acid moieties (octanoic, decanoic, lauric, myristic, palmitic, and stearic acids). The addition of the PGMFEs (*./ῌ w/w of flour) to dough significantly increased its resistance, retention of the generated gas, and the volume of bread compared to loaves baked with the addition of and the control. These e#ects increased with a decrease in the chain length of the fatty acid moiety of the PGMFEs. Microscopic observation of the fermented dough with the PGMFEs showed that the gluten matrix became thick and that most of the starch granules were su$ciently covered with the gluten matrix as compared with the control. Also, addition of the PGMFEs with palmitic or stearic acid moieties retarded firmness in bread like that of bread baked with monoglycerides. These results indicated that the addition of PGMFEs as dough-conditioners promoted gluten formation and retarded the firming of bread by acting as a softener.

Keywords: dough, breadmaking, dough-conditioner, softener, gluten, polyglycerol mono-fatty acid esters (PGMFEs)

Introduction volume (Chung and Tsen, +31/; Jacobsberg et al., +310). Polyglycerol mono fatty acid esters (PGMFEs), syn- On the other hand, the e#ect of emulsifiers on the softness thesized with polyglycerol and fatty acids, are bio-grade and shelf life of bread are mainly correlated with starch. emulsifiers that are safe and o#er multiple functional Emulsifier combines with amylose in starch molecules properties such as acid resistance, salt resistance, thermo- and prevents it from re-crystallizing. Consequently, the stability, savoriness, and superior O/W emulsion. The bread keeps its softness. PGMFEs are widely applied in the food industry and are The PGMFEs are generally utilized in breadmaking as often used as the aerating agents for cake (Nash and dough conditioners. The addition of PGMFEs contain- Knight, +301; Hemker, +32+), antimicrobial agents (Conley ing a lauric acid moiety increases the loaf volume of the and Kabara, +31-; Razavi-Rohani and Gri$ths, +33.), and bread more than those having stearic and oleic acid O/W emulsifiers for co#ee-whitener and mayonnaise moieties (Garti and Aserin, +32+). However, it has not yet (Miyamoto and Matsushita, +322) etc. The PGMFEs are been elucidated how PGMFEs influence the loaf volume also applied in baked products such as cookies (Kuragano of the bread. Furthermore, the e#ects of the PGMFEs as et al., ,***). the softeners for breadmaking have not yet been com- In general, emulsifiers are essential to the baking proc- pletely clarified. Recently, we reported that the PGMFEs ess and have been applied to baking for a long period. a#ected the a$nity of gluten and starch in the dough and The main functions of the emulsifiers are to act as a that this depended strongly on the fatty acid moieties of dough-conditioner and a softener of bread. The e#ec- the PGMFEs (Miyamoto et al., ,**,). These results sug- tiveness of emulsifiers as dough-conditioners mainly gest that the PGMFEs function as the dough conditioner depends on gluten, which improves the mechanical toler- and the softener. ance of wheat dough and loaf volume. Dough con- Thus, in this study, the authors describe the dough ditioners, such as sodium stearoyl ,-lactylate or diacetyl properties and bread qualities resulting from the addition tartaric acid of combine with gluten of PGMFEs to wheat flour. Particularly, we emphasized and the polar lipids in wheat flour. Consequently, the on the e#ect of chain length of fatty acids moieties in the gluten-matrix becomes thick, covers the starch granules PGMFEs on the properties of dough and bread. The and makes the dough expand, hence the increase in loaf usefulness of the PGMFEs (Fig. +) used in breadmaking was studied in comparison to that of monoglyceride. E-mail: [email protected] (N. Morita). 20 N. MORITA et al.

Table +. List of polyglycerol mono-fatty acid esters.

Fig. +. Structure of monoglyceride or polyglycerol mono- fatty acid ester. Rῌfatty acid moiety. nῌ* : monoglyceride, nῌ+ or more : polyglycerol mono-fatty acid ester.

Materials and Methods Materials Polyglycerol mono fatty acid esters (PGMFEs) were synthesized as follows. The poly- the Ladies Mixer KN-,** (Taisho Denki Co., Ltd., Osaka). used was POLYGLYCERIN ῒ1/* (polyglycerol- The optimum amount of water for each dough was deter- +*: hydroxyl value 23* mg KOH/g; Sakamoto Yakuhin mined from the water absorption ratio by the farinograph Kogyo Co., Ltd., Osaka). The polyglycerol and commer- mixing at /** Brabender Unit (B.U.). After mixing, the cially available fatty acids; octanoic (+*G-C2), decanoic (+* dough was divided into 0 pieces (-/ g/piece) and placed G-C+*), lauric (+*G-C+,), myristic (+*G-C+.), palmitic (+* into glass bottles (designed by Atto Co. Ltd.). Then the G-C+0), and stearic (+*G-C+2)(32ῌ pure, NOF Co., Ltd., bottles were set to stand in a water bath at -*ῑ and the Tokyo) were made to concentrations of + M each, and dough were fermented for +2* min. The volumes of total reacted with *.+ῌ of sodium hydroxide for . hat,,*ῌ and liberated gas were recorded by a computer program ,.*ῑ under nitrogen gas flow at atmospheric pressure. (Ferment digital recorder system version -.*, Atto Co. The reactions were stopped when the acid value of the Ltd.). However, the percentage of liberated gas from products became smaller than +.*. The list of the fermented dough was calculated by: PGMFEs used for the following experiments are shown in Leaked gasῐῌmL of total gas῎mL of leaked-out gas῍ Table +. The monoglyceride (glycerol monostearate: ῌῌmL of total gas῍῏+** Eq. (+) commercial grade, Riken Vitamin Co., Ltd., Tokyo) was used as a reference emulsifier. In all experiments, the Scanning electron microscopic observation The dough PGMFEs and the monoglyceride (*./ῌ of flour weight) sample was prepared by the same procedure described for were suspended in distilled water at //ῑ before use. The gas generation. A +* g dough sample was then subjected hard type wheat flour, Cameria, was obtained from to fermentation for -* min in a cabinet at a constant Nisshin Flour Milling Co., Ltd. (Kobe). temperature of -*ῑ and relative humidity of 2/ῌ. The Wheat dough properties Farinograph data (arrival, fermented dough sample was observed using a scanning development, and stability times) of the dough made from electron microscope (SEM) (Hitachi Model S-2**, Tokyo, wheat flour added with PGMFEs were obtained using a Japan), as reported previously (Morita et al., +330). farinograph (Brabendar, Germany) with a /* g stainless Bread baking The breadmaking formula and proce- steel bowl according to the AACC method (/.ῌ,+, +33.). dures were carried out using a slight modification of Mixing was done at the standard speed of 0- rpm at -*ῑ. AACC methods (optimized straight-dough method +*ῌ+* Extensograph data (resistance, extensibility, and area) of B, +33/; sponge-dough method +*ῌ++, +33/). For the the dough was obtained using a Brabender extensograph optimized straight-dough method, -** g of wheat flour, ../ based on the AACC method (/.ῌ+*, +33.). The pasting g of sodium chloride, +2 g of sucrose, -.0 g of dry baker’s curves of wheat flour containing the PGMFEs and yeast, +./ g of PGMFE and the appropriate amount of changes in the apparent viscosity of the aqueous wheat water were mixed for +/ min using a Ladies Mixer (KN- flour suspension were determined as described previously ,**). The mixed dough was subjected to an initial fer- (Maeda and Morita, ,**,). The slurry of 0* g of wheat mentation for 3* min in a cabinet at -*ῑ and a relative flour, *.- g of PGMFE, and ./* ml of distilled water were humidity of 2/ῌ. During fermentation, one punching heated from -*ῑ to 3-ῑ at a rate of +./ῑ/min. After was performed after 0* min, before the dough was divided keeping at 3-ῑ for +/ min, the paste was cooled to -*ῑ at into - pieces (+-* g/piece), rounded and molded using a the same rate of +./ῑ/min. Finally, the paste was kept at mechanical molder SM-,-* (Baker’s Production Co., Ltd., -*Cfor+/ min. Osaka), and placed in a baking pan. The dough was Gas production from the dough during fermentation subjected to a final proof of -- min in a cabinet main- Gas generation of the dough during fermentation was tained -2ῑ with a relative humidity of 3*ῌ before baking determined using a fermograph (Atto Co. Ltd., Osaka). at ,**ῑ for ,* min. One hundred and fifty grams of wheat flour, ,.,/ gof The formula and procedure for the sponge-dough sodium chloride, 3.* g of sucrose, +.2 g of dry baker’s yeast method were as follows: +2* g of wheat flour, -.0 gofdry (J.T. Foods Co., Ltd., Shizuoka), *./ g of PGMFE and the baker’s yeast, +./ g of PGMFE, and the appropriate optimum amount of water were mixed for +* min using amount of water were mixed for . min. The mixed Application of Polyglycerol Mono-Fatty Acid Esters to Improve Breadmaking 21

Table ,. Summary of farinograph data of wheat dough samples containing PGMFEs.

sponge was allowed to ferment for . h under the same conditions described above. After the first fermentation, +,* g of flour, 0.* g of sodium chloride, +/.* g of sucrose and the appropriate amount of water were mixed for +/ min. During mixing, the fermented sponge was added one- third each at +/, ,/,and-/ s. The mixed dough was then incubated for -* min in a cabinet maintained at -*῎ and a relative humidity of 2/ῌ. Subsequently, the dough was divided into - pieces (+-* g/piece), rounded and molded using the same mechanical mold, and placed in a baking pan. The dough was then subjected to a final proof for /* min in a cabinet at -/./῎ and a relative humidity of 3,ῌ, before baking at ,+2῎ for ,/ min. After baking, the bread was removed and immediately weighed, and the loaf volume was measured by the rapeseed displacement method. Measurement of firmness of bread during storage Staleness of bread was determined using a rheometer and data were processed as described previously (Morita et al., ,**,). A sample of bread (.ῌ.ῌ- cm-) was used with the plunger (,-cm diameter) was controlled at the compres- sion depth of 1 mm. Statistical analyses Data were analyzed independ- ently and at least in duplicate. Analysis of variance (ANOVA) was performed using Duncan’s multiple-range test to compare the means of each treatment; di#erences were considered significant at P῍*.*/.

Results and Discussion Dough properties The farinograph data of dough containing the PGMFEs during mixing are shown in , Table ,. The arrival time did not di#er markedly, but Fig. . Typical farinograms of dough sample containing PGMFE. development and stability times were shorter than those (A), Control ; (B), monoglyceride ; (C), +*G-C2. of the control. The stability time of dough increased as the chain length of the fatty acid moieties of the PGMFEs increased. The water absorption ratios of the PGMFEs the fatty acid moieties of the PGMFEs increased. Typi- (01.,ῌ02..ῌ) and monoglyceride (00.*ῌ) were not observed cal farinograms of dough containing +*G-C2 and mono- to di#er from that of the control (01.0ῌ). The water glyceride are shown in Fig. ,. absorption of the dough increased as the chain length of Table - shows the summary of some extensibility data 22 N. MORITA et al.

Table -. Summary of extensograph data of wheat dough samples containing PGMFEs.

Fig. -. Typical extensograms of wheat dough sample containing PGMFE. (A), Control ; (B), monoglyceride ; (C), +*G-C2.

obtained from the extensograph test after +-/ min. The and the maximum and final viscosities were influenced by control dough had a resistance of /0* B.U., an extensibility the addition of PGMFEs. Addition of +*G-C2, +*G-C+*, of +22 mm, and an area of +., cm,. The resistance and and +*G-C+, (3*.-, 3*.0,and3+.*ῌ, respectively) resulted in area values for dough containing PGMFEs were signifi- lower temperature than the control (3,.-ῌ), and the tem- cantly greater than those of the control. Especially, +* perature decreased as the chain length of the fatty acid G-C2 showed the highest resistance and area values moieties of the PGMFEs decreased. In contrast, the addi- among all the additives (001 B.U. and +1- cm,, respective- tion of +*G-C+,, +*G-C+., +*G-C+0,and+*G-C+2 resulted in ly). The resistance and area values of the dough in- increasing maximum viscosity above that of the control, creased markedly with an increase in the chain length of and the viscosity increased as the chain length of the the fatty acid moieties of the PGMFEs. However, the fatty acid moieties of the PGMFEs increased. At the addition of the monoglyceride did not a#ect the ex- final viscosity, there was a lowering e#ect of the viscosity tensograph test. These results indicated that the addi- in all the PGMFEs. Therefore, the addition of PGMFEs tion of the PGMFEs strengthens the gluten matrix with lowered the maximum viscosity temperature and final the chain length of the fatty acid moiety being primarily viscosity, whereas the maximum viscosity increased . responsible. Typical extensograms of dough containing E#ects of PGMFEs on gas production The total +*G-C2 and monoglyceride are shown in Fig. -. amount of CO, gas generation and the ratio of the The changes in the apparent viscosity of the aqueous liberated gas from the dough containing the PGMFEs wheat flours containing PGMFEs measured by a Visco- after +2* min of fermentation using a fermograph are graph are shown in Table .. The gelatinization tempera- shown in Table /. The total volumes of CO, gas gene- ture of starch in the dough containing the PGMFEs (/3.2ῌ rated from the dough were almost fixed (+1...ῌ+11., ml) 0+.*ῌ) did not di#er markedly from that of the control without relating to the addition of the PGMFEs. Howev- (0*.*ῌ). However, the maximum viscosity temperature, er, the ratio of liberated gas was lowered remarkably by Application of Polyglycerol Mono-Fatty Acid Esters to Improve Breadmaking 23

Table .. Summary of viscograph data of wheat dough containing PGMFEs.

Table /. Total gas generation and ratio of leaked gas from dough containing PGMFEs.

the addition of the PGMFEs (+,..ῌ+0.3ῌ). This lowering matrix that covered most of starch granules contrary to e#ect decreased as the chain length of the fatty acid the addition of +*G-C+2. Therefore, the addition of the moiety of the PGMFEs decreased. Especially, the addi- PGMFEs resulted in a thick gluten matrix and the starch tion of +*G-C2 generated the lowest total CO, gas, which is granules were covered with gluten. This tendency lower than the control by about 3ῌ. Furthermore, the appeared more strongly as the chain length of the fatty addition of monoglyceride (,*.+ῌ) was almost similar to acid moiety of the PGMFEs decreased. These results the control (,+.,ῌ). These results indicated that the suggest that the addition of the PGMFEs prevents the PGMFEs have the ability to promote the retention of gas liberation of CO, gas from the dough during fermentation without inhibiting the enzyme activity of the yeast. by strongly combining to gluten and starch granules. SEM observations of fermented dough The SEM Baking results The results for the specific volume of results for dough containing +*G-C2 and +*G-C+2 after -* bread containing the PGMFEs baked using the optimized min of fermentation are shown in Fig. .. No distinct straight-dough and sponge-dough methods are shown in boundaries were observed between starch granules and Table 0. The addition of the PGMFEs remarkably in- gluten in the control (A). Addition of +*G-C+2 (C) caused creased the specific volume of bread made using both the starch granules to be covered with gluten, in addition methods (..01ῌ/.*, cm-/g; straight dough method, /.,2ῌ to the filamentous or fibrous portions of dough. Moreo- 0.-+ cm-/g; sponge dough method) as compared with the ver, addition of +*G-C2 (B) tended to form a thick gluten control (-.31 and /.+, cm-/g, respectively). Moreover, the 24 N. MORITA et al.

Fig. .. Scanning electron micrographs of dough samples fermented for -* min containing *./ῌ PGMFEs. (A), control ; (B), +*G-C2 ; (C), +*G-C+2.

Table 0. E#ects of PGMFEs on the specific volume of bread made by straight or sponge-dough method.

addition of the PGMFEs increased the specific volume of previous study (Miyamoto et al., ,**,), the free lipid of the bread relative to the addition of monoglyceride except for dough increased during mixing and was associated with +*G-C+2 in the sponge-dough method. The specific the shorter chain lengths of the fatty acid in the PGMFEs. volume of bread to which PGMFE of +*G-C2 had been In general, the PGMFEs are more likely to form an a- added was +,0ῌ of the control using the optimized crystalline gel in aqueous solution than a monoglyceride straight-dough method, whereas it was +,-ῌ using the (Lauridsen, +310; Hemker, +32+). The tendency to form sponge-dough method. Consequently, the addition of gels increases as the chain lengths of the fatty acid moiety PGMFEs increased the specific volume of bread, in a way of the PGMFEs decrease. It is thus quite possible for that was inversely proportional to the chain length of the these short chain fatty acid moiety PGMFEs to become fatty acid moieties in the PGMFEs. uniformly distributed in the dough during the mixing Bread staleness The e#ects of the PGMFEs on the process, and because the amount of binding in gluten firmness of bread during storage at ,/ῌ are shown in Fig. increases instead of to the lipid. Namely, the formation /. The addition of PGMFEs softened the bread compared of the gluten matrix is promoted with the PGMFEs to the control. The bread with +*G-C+2 PGMFEs was the having short fatty acid chain, and the amounts of gas softest, and its firmness was equivalent to that of the retention increases in the dough. Conversely, it is bread containing monoglyceride. This result indicated thought that the amount of PGMFEs having long fatty that PGMFEs prevent retrogradation of the bread as well acid chain bonding to gluten is relatively low at the as the monoglyceride. dough stage as well as the addition of the monoglyceride The addition of the PGMFEs to wheat flour improved (Inoue et al., +33/). Therefore, these PGMFEs combine the loaf volume and retarded retrogradation of bread. with the starch during baking and maintain the softness The loaf volume of bread made from wheat flour with of the bread. Accordingly, we conclude that the added PGMFEs was larger than that made using mono- PGMFEs are considerably good dough-conditioners and glycerides, but retardation of firmness was relatively sim- bread softeners. ilar. The e#ect of the fatty acid moiety in the PGMFEs on loaf volume of bread was similar to that observed for Conclusion bread made with monoglyceride (Riisom et al., +32.). In a The e#ects of PGMFEs on dough properties and the Application of Polyglycerol Mono-Fatty Acid Esters to Improve Breadmaking 25

Fig. /. E#ects of PGMFEs on firmness of bread during storage for - days. : + day, : , days, : - days. A, control ; B, monoglyceride ; C, +*G-C2 ;D,+*G-C+* ;E,+*G-C+, ;F,+*G-C+. ; G, +*G-C+0 ;H,+*G-C+2. baking quality were investigated by using six PGMFEs 0., (in Japanese). with a saturated fatty acid moiety. We confirmed that Jacobsberg, F.R., Worman, S.L. and Daniels, N.W. (+310). Lipid the addition of PGMFEs significantly increased the gas binding in wheat-flour dough: the e#ect of DATEM emulsifier. retaining ability of fermented the dough and the loaf Journal of the Science of Food and Agriculture, ,1, +*0.ῌ+*1*. volume of the bread as compared with the monoglyceride. Kuragano, T., Ueda T., Kubo M. and Katsuta K. (,***). E#ect of Regarding the microscopic structure of the dough to polyglycerol fatty acid ester on the spread factor of cookie /+ .+ῌ.2 which PGMFEs had been added during fermentation, the products. Nippon Kaseigaku Kaishi, , (in Japanese). Krog, N. (+31+). Amylose complexing e#ect of food grade gluten matrix became thick and covered the starch gran- emulsifier. Starch, ,-, ,*0ῌ,+*. ules. Also, they were more enhanced with PGMFEs that Lauridsen, J.B. (+310). Food emulsifiers: Surface activity, edibili- have short saturated fatty acid chain. ty, manufacture, composition, and application. Journal of the American Oil Chemists Society, /-, .**ῌ.*1. References Maeda, T. and Morita, N., (,**,). Flour quality and pentosan American Association of Cereal Chemists. (+33.). Approved prepared by polishing wheat grain on breadmaking. Food Re- Methods of the AACC (3th ed.). Method /.ῌ,+, approved April search International, -0, 0*-ῌ0+*. +30+, revised October +33.; Method /.ῌ+*, approved April +30+, Miyamoto, A. and Matsushita, K. (+322). Properties of poly- revised October +33.. The association: St. Paul, MN. glycerol esters and their uses in the food industry. New Food American Association of Cereal Chemists. (+33/). Approved Industry, -*, +,ῌ+2 (in Japanese). Methods of the AACC (3th ed.). Method +*ῌ+*B, approved No- Miyamoto, Y., Sakamoto, M., Maeda, T. and Morita, N. (,**,). vember +33/; Method +*ῌ++, approved November +33/.The E#ects of polyglycerol mono-fatty acid esters on gluten and association: St. Paul, MN. starch in wheat flour dough. Nippon Shokuhin Kagaku Kogaku Chung, O.K. and Tsen, C.C. (+31/). Changes in lipid binding and Kaishi, .3, /-.ῌ/-3 (in Japanese). protein extractability during dough mixing in presence of Morita, N., Nakata, K., Hamauzu, Z. and Toyosawa, I. (+330). E#ect surfactants. Cereal Chemistry, /,, /.3ῌ/0*. of a-glucosyl rutin as improvers for wheat dough and Conley, A.A. and Kabara, J.J. (+31-). Antimicrobial action of breadmaking. Cereal Chemistry, 1-, 33ῌ+*.. esters of polyhydric . Antimicrobial Agents and Chemo- Morita, N., Maeda, T., Miyazaki, M., Yamamori, M., Miura, H. and therapy, ., /*+ῌ/*0. Ohtsuka I. (,**,). Dough and baking properties of high- De Stefanis, V.A., Ponte Jr., J.G., Chung, F.H. and Ruzza, N.A. amylose and waxy wheat flours. Cereal Chemistry, 13, .3+ῌ.3/. (+311). Binding of crumb softeners and dough strengtheners Nash, N.H. and Knight, G.S. (+301). Polyglycerol esters. Food Engi- during breadmaking. Cereal Chemistry, /., +-ῌ,.. neering, /, 13ῌ2,. Garti, N. and Aserin, A. (+32+). Evaluation of polyglycerol fatty Riisom, T., Krog, N. and Eriksen, J. (+32.). Amylose complexing acid esters in the baking of bread. Bakers Digest, //, +3ῌ,+. capacities of cis-andtrans-unsaturated monoglycerides in rela- Hemker, W. (+32+). Associative structure of polyglycerol esters in tion to their functionality in bread. Journal of Cereal Science, ,, food emulsions. Journal of the American Oil Chemists Society, +*/ῌ++2. /2, ++.ῌ++3. Razavi-Rohani, S.M. and Gri$ths, M.W. (+33.). The e#ect of mono Inoue, S., Tugita, K., Koike, S., Maruzeni, S. and Kamoi, I. (+33/). and polyglycerol laurate on spoilage and pathogenic bacteria E#ects of fatty acid species of monoglyceride on breadmaking associated with foods. Journal of Food Safety, +., +-+ῌ+/+. properties. Nippon Shokuhin Kagaku Kougaku Kaishi, .,, 0-.ῌ