Studies about Obtaining Low Calorie and High Fiber Content Bakery Product Using Wheat Bran

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 Studies about Obtaining Low Calorie and High Fiber Content Bakery Product Using Wheat Bran Abstract M. Ognean 1*, Neli Darie 1 and Claudia Felicia Ognean 1 High fiber low calorie products have been useful in weight management diets significant steps in the prevention and treatment of overweight and obesity problems. We tried to obtain breads with increased levels of fiber which were produced by substituting wheat bran fractions for 10 or 20% of standard flours. The wheat bran fraction which was used as replacement for wheat flour was added in various forms: raw, fermented and washed in water after fermentation process. Effects of wheat bran on the dough properties and on the final product are described. The caloric values of wheat bran bread products were calculated. Product acceptability was judged by sensory evaluation. Keywords: low calorie, high fiber, bakery products, bread, wheat bran. I. Introduction Physiological properties of dietary fiber are associated with prevention of certain diseases. Dietary fiber is associated with weight control and act as natural barrier to excess energy intake. Fiber can prevent constipation by restoring normal bowel function. It helps to increase stool weight, produce softer and more bulky stool, and reduce gastrointestinal time (Schrijver et al., 1992). Gastrointestinal disorders (gallstone and appendicitis), biventricular diseases, diarrhea, irritable bowel syndrome and duodenal ulcer can be prevented or cured with high fiber diet. 1Faculty of Agricultural Sciences, Food Industry and Environmental Protection, 5-7, Ion RaŃiu Street, Sibiu, 550012, România, mihai.ognean@ulbsibiu.ro * To whom the correspondence should be addressed. 55

M. Ognean, Neli Darie and Claudia Felicia Ognean Fibers have protective effect against colonic cancer. Colonic bacteria can produce carcinogens either by metabolizing dietary substrates or from secretions produced in response to diet. Fecal bile acids were suggested as possible carcinogens. Prolonged transit time increases the degradation of bile acids to carcinogens (Jenkins et al., 1986). The bulking effect of fibers dilutes oncogenic potential of carcinogens by reducing their interactions in the intestinal mucosa and hence prevents colonic cancer. Dietary fibers in colon are metabolized or fermented to produce short chain fatty acids (acetic, propionic and butyric acid) and gases (hydrogen, carbon dioxide and methane). Butyrates have antitumor properties and propionates are implicated in lipid and glucose metabolism (Lanza and Butrum, 1986). The consumer awareness about the importance of fiber in diet increased the demand of high-fiber foods. Most of the research for use of fibrous material in bakery foods was focused on bread because it is a sensitive product in which the differences are easily noticeable. Fibers act as bulking agents and it serves to reduce the calorie content in food. The bulking nature and water retention properties of dietary fiber results in the formation of low calorie soft-type products that retains more moisture after baking and require lesser force to break than the control (Bullock et al., 1992; Dougherty et al., 1988). Numerous high fiber ingredients are available to the food industry and their functionality have been tested in various baked products as listed below (Table 1) Table 1. High-fiber ingredients available to the food industry, fiber content (g/100) and their functionality which have been tested in various baked products. Fiber Product Amount of fiber (g/100g) Reference source Biscuits Wheat bran 42.1 Breads Cellulose Variable, depends on source type (generally 96-98 for purified cellulose) Wheat bran 42.1 Oat hulls 79,2 Alphacellulose Brewers spent grain Hull-less barley fractions Rye flour Variable, depends on source type (generally 96-98 for purified cellulose) Variable, depends on source type 56 Leelavathi and Rao, 1993 Pomeranz al., 1977 et Volpe and Lehmann, 1977 Pretince and D Appolonia, 1977 42,1 Bhatty, 1986 dark: 12,8 medium: 4,5 light: 3 Khun and Grosch, 1989 Barley bran 16-24 Chaudhary and

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 Product Cakes and doughnuts Cookies Muffins Ready to eat cereals II. Experimental Fiber source Amount of fiber (g/100g) Reference flour Weber, 1990 Waxy hullless barley 1992 Berglund et al., 17-18 Potato pulp 1,6 Nebensy, 1995 Barley Newman et al., variable shorts 1998 Wheat Ognean and 85-90 fiber Darie 2006 Powdered Variable, depends on source type Ang and cellulose (generally 96-98 for purified cellulose) Miller, 1991 Wheat bran 42,4 Vratanina and Zabik, 1980 Oat fibers 85-90 Dougherty et al., 1988 High fiber wheat flour variable Ranhotra et al., Powdered Variable, depends on source type cellulose (generally 96-98 for purified cellulose) Bullock et al., Soy fiber 75 Oat bran 22 Hudson et al., Rice bran 21,7 1992 Potato Arora and 2,5 peels Camire, 1994 Barley Newmann et fiber variable al., 1998 fractions Barley 17,3 Berglund et al., 1994 Commercial white wheat flour and wheat bran were used for baking (Cibin Mill, Sibiu, Romania). The optimum conditions for bran fermentations were determined by preliminary experiments. Bran (100 g) was mixed with 350 g of water and the dry microorganisms (1.25 g of bread making yeast) in a large beaker. The beaker was then covered with aluminum foil and incubated in temperature cabinet. The conditions for the fermentations were 1.25% yeast, 20 hr, and 28 C Fermentation has been put into practice to improve the nutritional properties of wheat bran. Fermentation improved the availability of B group vitamins, provides optimum ph conditions for enzymatic degradation of phytate, and leads to a general 57

M. Ognean, Neli Darie and Claudia Felicia Ognean improvement of taste and aroma in the final products. During wheat bran fermentation several volatile compounds are formed, which contribute to a complex blend of flavors in the products (Blandino et al., 2003). The presence of aromas representative of diacetyl, acetic acid and butyric acid make fermented wheat bran based products more appetizing. The washing in water of the fermented wheat bran method was used for the enzymatic systems removing and also for lowering the acidity of the fermented bran. Data of the wheat flour, wheat bran and yeast are given in Table 2. Table 2. Data used on raw material. Raw material Characteristics Wheat flour (WF) - commercial wheat flour (Cibin Mill) - wet gluten: 28.9% - the deformation index: 6 mm - humidity: 13.7% - falling number: 265 - ash: 0.645% - Flour-graph absorption: 60.5% - dough development time: 2 min - mixing tolerance index: 80 BU - stability: 12 min - degree of softening: 80 BU Wheat bran raw - humidity:12.4% (WBR) - acidity: 2.6 Wheat bran fermented - humidity: 69% (WBF) - acidity: 6.8 Wheat bran washed in - humidity: 68% water after - acidity: 3.2 fermentation (WBFW) Compressed yeast - commercial type The baking formulas are given in Table 3. The maximum wheat bran quantity which can be added as replacement for wheat flour was determined by previous research. The samples where the wheat bran fraction which was used as replacement for wheat flour was 25% or even more, had very strong taste of bran and the final product appearance was unacceptable especially for the samples with fermented wheat bran. Loaves of bread were backed by a straight dough baking procedure with a 450 grams weighing. Dough was mixed in a Marché Siemens mixer. Kneading the dough was performed till a soft consistency was reached for all samples. The temperature of the dough removed from the mixer was 30 0 C. Then the dough was scaled, rounded and placed in the cylindrical baking pans for fermentation. The fermentation time was variable according to dough features. The fermentation and the final fermentation temperature was 30 0 C. The loaves of bread were baked at 220 0 C without steam for 35 minutes. 58

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 The volume of the cooled loaves was determinate by a millet seed displacement using a loaf volume meter (Fornet). Table 3. The baking formulas. Raw material Control 10 % 20 % 10 % 20 % 10% 20% sample WBR WBR WBF WBF WBFW WBFW Wheat flour (g) 100 90 80 90 80 90 80 Wheat bran, raw (g) - 10 20 - - - - Wheat bran fermented (g) - - - 10 20 - - Wheat bran washed in water after fermentation - - - - - 10 20 (g) Compressed yeast (g) 3 3 3 3 3 3 3 Salt (g) 1 1 1 1 1 1 1 Ascorbic acid (mg) 10 10 10 10 10 10 10 Water (ml) added up to the same consistency of the bread dough 54 58 68 43 30 39 23 Laboratory acceptance panels were used to give an indication of consumer acceptance of the products under study. Panelists (30 students from bread making laboratory discipline) were presented the test samples in individual panel booths under normal (daylight) illumination. They evaluated each product, including a control (plain wheat) sample, for quality attributes: taste, flavor, crust color, texture, mastication, crumb color, crumb porosity, general appearance, slicing, humidity, crumb elasticity and density. Acceptability of each quality attribute was rated with a score from 1 (lowest) to 10 (highest). Overall acceptability of each sample was rated on a verbal nine-point hedonic scale, and these ratings were converted to numerical scores where 1 = dislike extremely and 9 = like extremely. Products were considered acceptable if their scores for overall acceptability were above 5 (neither like nor dislike). 59

M. Ognean, Neli Darie and Claudia Felicia Ognean III. Results and Discussions Pictures of the outcome breads are shown in pictures from Figure 1. Fig. 1. The comparative appearance of the control sample bread (no.1 no bran added) compared to bread samples with different kinds of bran added as follows: no. 2 10 % wheat bran raw; no. 3 20 % wheat bran raw; no. 4 10 % Wheat bran fermented; no. 5 20 % Wheat bran fermented; no. 6 10 % Wheat bran washed in water after fermentation; no. 7 20 % Wheat bran washed in water after fermentation. In figure 2 it can be seen the crumb s comparative appearance of the control sample compared to samples with different kinds of bran added 60

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 1 2 3 1 4 5 1 6 7 Fig. 2. The crumb s comparative appearance of the control sample bread (no.1 no bran added) compared to breads samples with different kind of bran added as follows: no. 2 10 % wheat bran raw; no. 3 20 % wheat bran raw; no. 4 10 % Wheat bran fermented; no. 5 20 % Wheat bran fermented; no. 6 10 % Wheat bran washed in water after fermentation; no. 7 20 % Wheat bran washed in water after fermentation. The results of bread sensorial evaluation are given in Table 4. As it can be seen by sensorial evaluation of bread samples (see Table 4) and as it can be expected the replacing of the wheat flour with the wheat bran fraction in any forms (raw, fermented or fermented and washed in water after fermentation process) altered the physical and sensory properties of the sample. These effects depend greatly on the type of bran chosen and its addition levels. 61

M. Ognean, Neli Darie and Claudia Felicia Ognean As it can be seen breads containing 10 % crude bran fraction was considered by 30 consumer panelists as more than acceptable for all specific quality characteristics and overall acceptability. Despite overall score > 6.11 for bread containing 20% crude bran fraction consumer panelists judged crumb color and crumb porosity quality items as unacceptable. Those quality items received score < 5 for all bread samples with 20% different kinds of bran added. Bread containing 20% fermented bran fraction was judged as being at the limit of acceptability (overall score = 5.06). For many quality items it received score < 5 (see Table 4). The lowest overall score were received for the samples with fermented bran. Despite the fact that the fermentation process has been put into practice to improve the nutritional properties of wheat bran, the same process also produced great increment of the medium acidity. Therefore the sample which was obtained by replacing wheat flour with fermented wheat bran was sourer than the others. Especially the sample with 20% fermented bran used by replacing wheat flour had this deficiency. Table 4. Sensorial bread evaluation. Quality items Control 10 % 20 % 10 % 20 % 10% 20% sample WBR WBR WBF WBF WBFW WBFW Taste 9.10 7.81 6.23 6.50 3.84 7.25 4.86 Flavor 8.14 7.23 5.31 6.12 4.02 6.92 9.98 Crust color 7.90 8.50 7.46 7.56 6.23 6.91 5.68 Texture 8.52 8.01 6.52 7.23 5.87 7.86 6.12 Mastication 8.42 8.14 6.52 7.65 5.52 7.78 6.15 Crumb color 9.05 5.51 3.54 5.45 3.25 5.46 3.48 Crumb porosity 8.50 7.12 4.89 6.65 3.89 6.74 4.20 General appearance 9.40 8.21 5.61 7.32 4.18 7.23 4.17 Slicing 9.11 8.42 6.51 8.23 6.45 8.21 6.57 Humidity 9.62 9.15 7.86 8.56 6.56 8.54 6.65 Crumb elasticity 9.08 8.50 6.35 7.89 6.02 8.06 6.12 Density 9.06 8.35 6.54 8.08 4.84 8.12 5.01 Overall score 8.83 7.91 6.11 7.27 5.06 7.42 5.75 Not only was the taste altered by replacing wheat flour with fermented bran. The rheologycal dough properties also were altered. After 1 hour of fermentation the dough became more plastic, sticky and the gases retention was greatly reduced. We think that this fact is caused by the acidity. The proteolytic enzymes released by the microorganisms which fermented the wheat bran also had a synergic effect with that of the acidity. The intention of the washing process of the fermented bran was to reduce the acidity and to dilute the concentration of the enzymes in the mixture. This is the reason for the better quality of the outcome breads which were obtained with wheat bran washed in 62

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 water after fermentation. Though these products had lowest quality compared with that of the samples which were obtained with crude bran. Table 5. The reduction of the caloric value for the outcome breads. Bread Fiber content Caloric value humidity Sample kcal/100g % g/100g bread bread Percentage reduction of the caloric value (%) Control sample 46.5 2.07 221 10 % WBR 47.7 4.26 204 7.7 20 % WBR 51.3 6.00 180 18.6 10 % WBF 48.9 3.50 200 9.5 20 % WBF 50.5 4.43 183 17.2 10% WBFW 47.6 2.59 205 7.2 20% WBFW 48.2 4.63 191 13.6 250 Caloric content (kcal / 100 g of crumb) 200 150 100 50 0 0% 10% 20% Percent of bran substituting the wheat flour Wheat bran raw Fermented wheat bran Wheat bran washed in water after fermentation Fig. 3. The caloric content of the samples obtained by replacing the wheat flour with different kinds of wheat bran compared to that of the control sample. The more bran added by replacing the wheat flour, the lower the quality of the outcome bread. The crumb became denser and more humid. The porosity of the crumb 63

M. Ognean, Neli Darie and Claudia Felicia Ognean became worse with the increasing of the amount of bran which was used for wheat replacing (see Figure 2). The samples with 20% wheat flour replaced by different kinds of bran are humid. Concerning the appearance of the outcome bread it can be seen that the best appearance of the crumb had the sample with 10% wheat flour replaced by crude wheat bran. The samples which were obtained by replacing the wheat flour with the fermented wheat bran had the worse appearance. The caloric values of the breads were calculated (see Table 5). A reduction for the caloric value was obtained for each sample which had wheat bran added. The more wheat bran added the more water bonded and the lower the caloric value for the outcome product. This reduction of the caloric content is due both to the lower caloric value of the bran compared to that of the flour and to the water binding capacity of the wheat bran. So these samples had greater water and lowest dry matter contents. 6 Total fiber content (g / 100 g of crumb) 5 4 3 2 1 0 20% 10% 0% Percent of bran substituting the wheat flour Wheat bran raw Fermented wheat bran Wheat bran washed in water after fermentation Fig. 4. The fiber content of the samples obtained by replacing the wheat flour with Figure different 4 kinds The fiber of wheat content bran of compared the samples to that obtained of the control by replacing sample. the wheat flour with different kind of wheat bran compared to that of the All control the samples which were obtained by replacing an amount of wheat flour with different kinds of bran had a greater water content compared to that of the control sample. The greatest water content was for the samples with 20% crude bran. Though, the reduction of the caloric content is not as high as expected. For the sample with 10% bran, the reduction of the caloric content was between 7.2% and 9.5% 64

Acta Universitatis Cibiniensis Seria F Chemia 9(2006-1):55-66 (see Table 5). The samples with 20% bran added had a greater reduction of the caloric content. In this case the reduction was between 13.6% and 18.6%. The fiber content of the samples obtained by replacing the wheat flour with different kinds of wheat bran compared to that of the control sample can be seen in Figure 4. As it can be seen in figure 4 the fiber content increased but not much. For the samples which were obtained by replacing 10% of the wheat fiber with bran, the fiber content increased between 2.07% and 4.26%. In the best case, the replacing of wheat flour with 20% of bran, the fiber content increased up to 6%. The best improvement of the fiber content was for the samples obtained with crude bran. IV. Conclusions Ultimately our study team concluded that the formulation by replacing an amount of wheat flour with wheat bran in intention to obtain high fiber and low calorie bread is not the best way to achieve these goals. The reasons are that the sample with 20% bran had an increase of only 6% fiber content and just 18.6% reduction of the caloric value. Also this sample had very low sensorial features. So the breads with bran are not a good source of fiber as expected. The reduction of the caloric content is remarkable only if the replacing of the wheat flour with the wheat bran is greater than 15%. But at this level of replacing the sensorial acceptability of the outcome bread decreases very much and becomes almost unacceptable (see Table 4). Bread with low caloric value and high caloric content will be possible to obtain by replacing various amount of flour with other products with greater water binding capacity and lower caloric value and greater fiber content. Even in this case there is a limit for replacing formula. This limit is set by the three-dimensional properties of the gluten network. The added substances interact in different ways with the gluten and in many cases affect in a negative manner the structure of the gluten network. These are the reasons for the limitations in the process of replacing the flour. V. References 1. Ang, J. F., and Miller, W. B., Cereal Foods World, 1991, 36:558-464. 2. Berglund, P. T., Fastnaught, C. E., and Holm, E. T., Cereal Foods World, 1992, 37:707-714. 3. Berglund, P. T., Fastnaught, C. E., and Holm, E. T., Cereal Chem, 1994, 71:91-95. 4. Bhatty, R. S., Cereal Chem, 1986, 63:31-35 5. Bhatty, R. S., Cereal Chem., 1999, 76:589-599. 6. Blandino, A., Food Research International, 2003, 36: 527-543; 7. Bullock. L. M., Handel, A. P., Segall, S., and Wasserman. P. A., Food Technology, 1992, 46:83-86. 8. Chaudhary, V. K., and Weber, F. E., Cereal Foods World, 1990, 35:560-562. 65

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