The Effect of Oat Fibre Powder Particle Size on the Physical Properties of Wheat Bread Rolls

M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) 45

View metadata, citationISSN and 1330-9862 similar papers at core.ac.uk original scientiﬁ c paperbrought to you by CORE doi: 10.17113/ft b.54.01.16.4177

Marcin Kurek*, Jarosław Wyrwisz, Monika Piwińska and Agnieszka Wierzbicka Division of Engineering in Nutrition, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences, PL-02-776 Warsaw, Poland Received: March 18, 2015 Accepted: October 23, 2015

Summary In response to the growing interest of modern society in functional food products, this study att empts to develop a bakery product with high dietary fi bre content added in the form of an oat fi bre powder. Oat fi bre powder with particle sizes of 75 μm (OFP1) and 150 μm (OFP2) was used, substituting 4, 8, 12, 16 and 20 % of the fl our. The physical properties of the dough and the fi nal bakery products were then measured. Results indicated that dough with added fi bre had higher elasticity than the control group. The storage modulus values of dough with OFP1 most closely approximated those of the control group. The addition of OFP1 did not aff ect signifi cantly the colour compared to the other samples. In- creasing the proportion of oat fi bre powder resulted in increased fi rmness, which was most prominent in wheat bread rolls with oat fi bre powder of smaller particle sizes. The addition of oat fi bre powder with smaller particles resulted in a product with the rheological and colour parameters that more closely resembled control sample.

Key words: dietary ﬁ bre, oat ﬁ bre, bread, particle size

Introduction dance with European Food Safety Authority (EFSA) health claims and European Union Commission Regula- The contemporary consumption model, character- tion No 432/2012 of 16 May 2012 (8,9), which established a ized by high ingestion of products rich in sugar and fat, list of permitt ed health claims for foods, apart from those yet low in vitamins, minerals, and dietary fi bre, is respon- referring to the reduction of disease risk and to children’s sible for many diseases of affl uence, such as diabetes, development and health. This health claim states that asthma, coronary heart disease and obesity (1). Mean- ‘oats increase the faecal bulk’ when a product has a high while, general consumption of bread products decreases level of dietary fi bre. This means more than 6 g of dietary as the society’s gross domestic product increases (2). How- fi bre in each 100 g of product, therefore complying with ever, in developed countries there is also a demand for a European Union Commission Regulation (EU) No 1047/ greater variety of bread with oat, bran, seeds, etc. (3). In 2012 of 8 November 2012 amending Regulation (EC) No such cases, the most probable solution is to fortify white 1924/2006 (9) regarding the list of nutrition claims. The bread products with dietary fi bre that has many functions addition of dietary fi bre to the bread matrix can lead con- (e.g. caloric reduction, available carbohydrate reduction, sumers to conclude that a product is healthy. This study moisture control, anticaking properties, textural modifi - was conducted to investigate whether that common belief cation and structural enhancement) (4,5). has merit. Dietary fi bre is an essential component in nutrition Principally, dietary fi bre is comprised of a non-carbo- and health (6,7). Thus, the present study will explore the hydrate component called lignin and non-cellulosic poly- addition of oat fi bre in wheat roll production in accor- saccharides, such as pectin substances and hemicellulos-

______*Corresponding author: Phone: +48 22 590 37 014; E-mail: [email protected] 46 M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) es. The structural components are found mainly in the Particle size distribution cell wall of plants (7). Dietary fi bre is primarily a constitu- Fibre particle size distribution was determined using ent of plant foods and includes materials that have di- Morphologi® G3SE (Malvern Instruments Ltd, Malvern, verse morphological and chemical structure. UK) equipped with a sample dispersion unit for dry sam- Basically, the process involved in the production of ples and a wet cell for hydrated samples. Size distribution bread is a highly complex one that entails a range of pa- was calculated as the relative volume of particles in size rameters that must be regulated. According to Almeida et bands presented as size distribution curves (Malvern Mi- al. (10), rheological measurements are used in the predic- cro soft ware v. 5.40, Malvern Instruments Ltd.). Particle tion of both the behaviour of wheat dough during bread size distribution parameters included the largest particle production and of the fi nal product quality. Despite the size (d(v,0.9)), mean particle volume (d(v,0.5)), smallest parti- fact that there are diff erent sources of dietary fi bre, Al- cle size (d(v,0.1)), Sauter mean diameter (d(3,2)), and mean meida et al. (10) argue that the dietary fi bre used in bread particle diameter (d(4,3)). Water-holding capacity of the fi - production aff ects both processing and fi nal product bre was determined as follows: 10 g of dietary fi bre was quality. soaked in 100 mL of distilled water and left overnight. Baking is the most important step in the bread pro- Then the bulk was fi ltered through a Büchner funnel and duction that transforms the raw dough to the bread using the water-holding capacity was calculated as the diff er- the heating. During baking, the mass loss is observed due ence between the amount of water used in the soaking to the loss of water that was incorporated into the dough process and the amount remaining in the bulk aft er fi ltra- during mixing. As already documented, dietary fi bre may tion. have a negative eff ect on the fi nal bread quality, leading to reduced volume of the bakery product, i.e. loaf volume Bread preparation (11,12). Components of the bread dough included (in %): The addition of large amounts of fi bre to bread re- fl our or fl our partly replaced with dietary fi bre 92, sults in a change in the bread physical properties, such as pressed yeasts 4, salt 2, sugar 1 and vegetable fat 1. Flour increased crumb fi rmness, crumb darkening, or changes was replaced by dietary fi bre at 4, 8, 12, 16 and 20 % of the in taste (13). These negative eff ects can be reduced by fl our wet mass. The water content was calculated based using an appropriate proportion of soluble to insoluble on the water-holding capacity of the dietary fi bre, and it fi bre fractions (14), and the addition of enzymes such as was: 58, 61, 64, 67, 70 and 72 % when the fl our was re- hemicellulose and pentosans (15). Reducing fi bre powder placed with 0, 4, 8, 12, 16 and 20 % of dietary fi bre, respec- particle size increases water-holding capacity by increasing tively. The obtained dough had a vis cosity of up to 500 the surface area. In the bread production, this is extreme- Brabender Units (BU) measured with rheometer Rotovis- ly important, because water is involved in the processes co RT20 (Haake, Vreden, Germany). All components, of starch gelatinization, protein denaturation, for mation apart from fat, were mixed with a spiral mixer (TRQ–42; of fl avour characteristics and it also signifi cantly aff ects RM Gastro, Ustron, Poland) at 100 rpm for 4 min. Aft er colour (14,15). the addition of oil, the dough was mixed for 6 min at 250 The aim of the study is to investigate the eff ects of the rpm, left to rest for 15 min, and then divided into 60-gram addition of oat dietary fi bre powder of two particle sizes rolls. The divided rolls rested for 15 min at room temper- on the physicochemical properties of wheat bread rolls ature, and were then put into the proofi ng chamber for 60 during storage and to provide recommendations on the min (35 °C, 80 % relative humidity) to double in volume. extent to which it is advisable to fortify wheat bread rolls Bread rolls were then baked at 210 °C for 15 min in a con- with oat fi bre. vection oven (CPE 110; Kuppersbuch, Gelsenkirchen, Germany). Aft er cooling, the bread was packaged into pa- per bags and stored for 3, 24 and 48 h at 20 °C. Materials and Methods Rheology Materials Rheological measurements were conducted with a Commercial wheat fl our was provided by a local sup- Rotovisco RT20 rheometer (Haake). The rheological ex- plier (Mlyny Zbozowe Zabczynscy, Łaskarzew, Poland). It amination was done using standard dough preparation, contained (in %): protein 10.62, ash 0.52, gluten 28.14 and but without yeast to avoid the infl uence of fermentation moisture 14.23. The composition of the fl our was mea- on the results. The creep and recovery test was followed sured with near-infrared spectroscopy (NIRFlex N-500; by a fi ve-minute period of relaxation. Next, the examined Buchi, Flawil, Switzerland). dough was subjected to the creep test with a constant The oat fi bre powder (provided by Micro Inc., War- shear stress of 50 Pa for 60 s, allowing the sample to re- saw, Poland) had 80 % dietary fi bre (78 % insoluble frac- cover for 180 s aft er the removal of the load. The forced tion and 2 % of soluble fractions). Two particle sizes were oscillation test was conducted in the plate-plate geometry used in the study: d(v,0.9)=75 μm (OFP1) and d(v,0.9)=150 μm with a 2-mm gap. The parameters were chosen aft er a set (OFP2) as provided by the manufacturer. The chemical of measurements had been performed to determine the composition of the dietary fi bre (provided by the manu- viscoelastic region. The frequency of oscillation was 1 Hz, facturer) was (in %): protein 4, available carbohydrates shear stress 600 Pa, angle rotation sensor 2°, and tempera- 3.2, fat 1.8 and ash 2.5. ture of the measurement 15 °C. Measurements were per- M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) 47 formed in triplicate and the measured parameters were: analyzed using ImageJ soft ware, v. 1.44 (National Insti- G’ (storage modulus, in Pa), G” (loss modulus, in Pa) and tute of Health, Bethesda, MD, USA). Aft er selection of the γ (deformation). central image of the crumb and determining the area, the image was converted into an 8-bit image to obtain a black Specifi c volume and moisture and white threshold followed by binary segmentation. The results are presented as a percentage of pore area in The volume and moisture content of baked bread the total area. The measured parameter was the mean cell rolls during storage were determined according to the area, expressed in mm2; this was calculated by dividing rapeseed displacement method (16). Each roll was the total area of cells by the total number of cells. weighed and the volume was measured 3, 24 and 48 h af- ter baking. The specifi c volume was reported in cm3 per g of the loaf. The moisture content of the roll samples was Total dietary fi bre determined by drying them overnight at 105 °C. Total dietary fi bre content in baked bread rolls was measured according to the AOAC method 2009.01-2009 Colour (17) modifi ed by the producer using the Fibretec™ 1023 system E (FOSS Inc., Eden Prairie, MN, USA). Colour determinations were carried out on bread crumbs using a CR-400 colourimeter (illuminant D65, measurement area ø=8mm, standard observers 2°; Konica Statistical analysis Minolta Inc., Tokyo, Japan), and the results were ex- The statistical calculations, including the analysis of pressed according to the CIELab colour space parameters: variance and Tukey’s test with signifi cance level at α=0.05, L (L=0 (black) and L=100 (white)), a (–a=greenness and and the Pearson’s correlation matrix, were performed using +a=redness), and b (–b=blueness and +b=yellowness). The STATISTICA v. 10 for Windows (StatSoft Inc., Tulsa, OK, parameters were measured 3, 24 and 48 h aft er baking. USA). Ten shots of the crumb and crust from three diff erent rolls were taken with the colourimeter. The changes in the roll crust colour were estimated according to the browning Results and Discussion index (BI) as follows: 100 (x-0.31) Particle size BI= /1/ 0.17 Table 1 presents the results of static automated image where analysis of the oat fi bre powder with water-holding ca- aL+1.75 pacity used for the wheat roll production. The particle x= /2/ sizes of dietary fi bre suggest that the whole mass of the 5.645La + 3.01 b two dietary fi bres was not homogenous because of a wide range of particle sizes from 14.7 to 132.5 μm of OFP1, and Firmness from 20.3 to 333.7 μm of OFP2. With regard to the water- Firmness was measured 3, 24 and 48 h aft er baking, -holding capacity of oat fi bre, diff erent outcomes were ob- using the universal testing machine Instron® 5965 (Instron tained compared to those achieved by two groups of re- Corp., Norwood, MA, USA) with a maximal load of 500 searchers (16,18) who concluded that decreasing particle N and 50 % penetration depth using a 40-mm diameter size leads to reduced hydration properties. The results probe. The test speed was 1.7 mm/s and the crumb cube confi rm the theory of Chau et al. (19) that a decrease in fi - size was 20 mm×20 mm×20 mm. The results were given as bre particle size results in a larger exposure of hydrophil- the maximum fi rmness in N. ic groups, which is connected with water absorption capacity. Porosity Porosity was estimated using image computer analy- Rheological properties sis. A loaf was cut into slices, each 2.5 cm thick. Photo- The creep and recovery test indicated that when the graphs of the slices were taken using a digital camera fl our is replaced with oat fi bre powder, the maximum de- (MicroPublisher 5.0 RTV; QImagining, Surrey BC, Cana- formation of OFP1 and OFP2 samples obtained aft er 60 s da) with illumination from lamps (Dulux L 36W/954, day- of the creep test was signifi cantly reduced (p≤0.05). The light; Osram, Munich, Germany) with the colour temper- results are shown in Figs. 1a and b. It is worth noting that ature 5400 K. Images were saved in TIFF format, then the values of deformation of the dough containing OFP1

Table 1. The particle size and shape of dietary ﬁ bre powder with water-holding capacity (WHC) used for wheat roll production

d(3,2)/μm d(4,3)/μm d(v,0.1)/μm d(v,0.5)/μm d(v,0.9)/μm WHC/(mL/g) OFP1 (34.9±1.0)a (67.3±0.8)a (14.7±1.1)a (60.1±2.8)b (132.5±1.8)c (5.24±0.2)b OFP2 (53.3±1.1)b (141.2±2.5)b (20.3±1.8)ab (109.5±1.8)c (333.7±1.7)d (2.48±0.1)a

OFP1 and OFP2=oat fi bre powder with particle sizes of 75 and 150 μm, respectively. d(3,2)=Sauter mean diameter, d(4,3)=mean particle diameter, d(v,0.9)=the largest particle size, d(v,0.5)=mean particle volume, and d(v,0.1)=smallest particle size. Values with diff erent lett ers diff er signifi cantly (p≤0.05) 48 M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016)

a) 0 .007 The changes in the values of the storage modulus and w(oat fibre powder) %/ loss modulus demonstrate that wheat dough with oat ﬁ - 0 .006 0 12 bre is more elastic than viscous (Fig. 2). However, att en- 4 16 0 .005 8 20 tion should be paid to the fact that storage modulus values of the OFP1-containing dough were higher than of 0 .004 the OFP2-containing dough.

0 .003 9

Deformation/AU 0 .002 8 G’ for OFP2 7 0 .001 G’ for OFP1 6 G” for OFP2 0 ×k 5 0 50 100 150 200 250 4 G” for OFP1 t/s

' or3 ” / Pa GG 2 b) 0 .007 w(oat fibre powder) %/ 1 0 .006 0 12 0 4 16 048121620 0 .005 8 20 w(oat fibre powder)/%

0 .004 Fig. 2. Changes of storage (G’) and loss (G”) moduli of dough with 0, 4, 8, 12, 16 and 20 % of ﬂ our replaced with the oat ﬁ bre 0 .003 powder with particle sizes of 75 μm (OFP1) and 150 μm (OFP2)

Deformation/AU 0 .002

0 .001 Speciﬁ c volume and moisture content

0 The specifi c volume and moisture content of wheat 0 50 100 150 200 250 rolls with oat fi bre powder are shown in Table 2. The di- t/s etary fi bre of smaller particle sizes in wheat rolls in- Fig. 1. Results of the creep and recovery test of the dough with creased the specifi c volume of the fi nal product, but it was 0, 4, 8, 12, 16 and 20 % of fl our replaced with oat fi bre powder smaller than of the control. During storage, the loss of with particle sizes of: a) 75 μm (OFP1) and b) 150 μm (OFP2) volume was recorded, and the rolls with OFP1 lost from 6.1 to 6.7 % of volume aft er 48 h and those with OFP2 lost between 15.1 and 20.7 % of volume. Reduced loaf volume were higher than of that containing OFP2. The samples of may also be caused by gluten dilution and physicochemi- dough containing 4, 8, 12 and 16 % OFP1 recovered their primary form aft er removal of the load more eff ectively cal reactions among fi bre components, water and gluten than the dough containing OFP2, indicating higher elasti- (21). The moisture content is strongly correlated with the city of this dough. In the case of dough with the addition specifi c volume values. This means that the smaller parti- of 20 % of fi bre powder, this tendency was not observed, cles take up more water because of the larger surface area. which may indicate that the dough was oversaturated Moisture content is strongly correlated with the water up- with the fi bre powder. Fibre does not form a gluten struc- take during mixing of the dough (22). Dough with more ture, it creates a parallel viscoelastic system. This tenden- water-binding substances (such as fi bre) absorbs more cy conforms to the outcomes of studies by Ahmed et al. water, which can be bound during storage. The moisture (20), who observed that when the fi bre content increases, of OFP1-containing bread rolls was higher because the not only the maximum deformation values decrease, but smaller particle size and more hydrophilic groups from also elastic recovery is reduced. Dietary fi bre is highly hy- fi bre were prone to binding water (23). groscopic, and therefore it signifi cantly aff ects the rheological properties of dough. It is associated with higher water absorption while kneading, and the phenomenon Colour parameters of wheat rolls increases with an increase in the dietary fi bre content in Golden brown crust and creamy white bread crumbs dough (13). The rheological properties signifi cantly aff ect are the most important appealing factors that indicate the the fi nal quality of the product. The studies by Sabanis et quality of a bakery product to consumers (23). Table 2 al. (21) indicate that due to higher dough viscosity, small shows the browning indices of wheat roll crumbs. The air bubbles formed while kneading showed higher persis- rolls containing OFP1 had a lower browning index due to tance during baking. If viscosity is high, air bubbles may travel upwards during fermentation, but due to their in- the smaller particle size, which can bind more eff ectively creased amount, the crumbs exhibit bett er porosity. The into the starch-gluten matrix and do not infl uence the co- creep and recovery test is an eff ective way to demonstrate lour to the same degree as OFP2. It should be noted that physical properties of bakery products. Van Bockstaele et the higher the content of dietary fi bre, the browner the al. (22) observed that the creep and recovery test showed crust, as the colour change of the crust of the wheat rolls signifi cant correlations with protein content, Zeleny se- with high content of dietary fi bre was caused by oxida- dimentation value, farinograph water absorption, alveo- tion reaction and release of sugars, which participate in graph extensibility and bread volume. caramelization during baking (24). M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) 49

Table 2. The speciﬁ c volume (ν), moisture content, and browning index of wheat rolls with oat ﬁ bre powder

t/h Composite w(oat ﬁ bre) 3 24 48 3 24 48 3 24 48 bread % ν/(cm3/g) Moisture content/% Browning index Control 0 6.4g 6.0h 5.9f 47.8a 47.5a 47.2a 50.4a 50.4a 50.5a 4 5.8f 5.5f 5.4e 50.6bc 49.6b 48.8ab 53.3b 52.7b 53.0b 8 5.4e 5.1e 5.0d 50.8bc 49.8ab 49.0ab 56.0d 55.9d 55.1bc OFP1 12 4.8c 4.6cd 4.5cd 51.2c 50.2c 49.0b 57.3e 57.4e 56.8bc 16 4.3b 4.1b 4.0c 51.3c 50.7c 50.2c 59.3f 58.3f 58.8d 20 4.0ab 3.8ab 3.7ab 51.8c 51.6d 51.5e 60.5g 60.5g 61.4e 4 5.4e 5.2e 5.0a 48.9ab 48.4ab 47.76a 54.1c 53.2c 53.0b 8 5.0bc 4.8d 4.7cd 49.8b 48.9ab 48.5ab 56.4d 55.6d 55.4bc OFP2 12 4.5a 4.3c 4.2c 51.7d 51.2d 50.78cd 58.1e 58.2e 57.9c 16 4.1ab 4.0b 3.8b 51.7d 51.3d 50.88d 60.6g 59.8f 59.4d 20 3.6a 3.5a 3.4a 51.5cd 51.2d 50.74cd 62.4h 60.5ef 59.8d

OFP1 and OFP2=oat fi bre powder with particle sizes of 75 and 150 μm, respectively. Values with diff erent lett ers in superscript diff er signifi cantly (p≤0.05)

It was demonstrated that while storing OFP1- and cate that smaller sizes of dietary fi bre added to bakery OFP2-containing samples, a signifi cant change in light- products result in fewer diff erences compared to the con- ness occurred, but it was not observed in the control sam- trol sample. However, it is worth noting that the reduced ple. OFP1 and OFP2 samples did not diff er in terms of lightness of bakery products may be a result of water redness (a) values during storage; however, they were sta- binding to the fi bre, creating the environment for reac- tistically signifi cantly diff erent in terms of yellowness (b). tions between sugars and amino acids (25). The colour of bakery products with added dietary fi bre changes as a result of a caramelization and the Maillard Firmness parameters reaction. That is true only if we want to explain the colour Firmness was measured during storage of wheat rolls of the surface of bakery products directly exposed to high in order to determine the eff ects of the addition of oat fi - temperatures. In the case of bread crumb, such high tem- bre powder on staling (Fig. 3). Staling is one of the most peratures are not reached. Therefore, it is reasonable to important changes that aff ect bakery products during perform measurements only for crumbs, the colour of storage, and it has a signifi cant eff ect on the aroma and which directly correlates with ingredients used in the fi rmness, perceived by consumers as quality indicators. dough production (9). Results obtained in this study indi- Staling can be described as increased fi rmness of bakery

a) b)

Firmness/N Firmness/N

w w (oat fibre powder)/% (oat fibre powder)/%

t(storage)/h t(storage)/h

Fig. 3. Changes of fi rmness of wheat rolls during storage depending on the fl our replacement with 0, 4, 8, 12, 16 and 20 % oat fi bre powder with particle sizes of: a) 75 μm (OFP1) and b) 150 μm (OFP2) 50 M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) products over time caused by retrogradation of amylose Total dietary fi bre and amylopectin. For that reason, increasing interest has Fig. 5 shows the total dietary fi bre content of the test- been devoted to producing complex compounds with ed rolls. An interesting tendency is that bakery products amylopectin and amylose with substances belonging to a with OFP1 contained more fi bre than bakery products dietary fi bre group in order to inhibit retrogradation (26). Fig. 3 shows changes of crumb fi rmness of wheat rolls af- with OFP2. This is associated with the fact that smaller fi - ter the addition of the fi bre powder. It can be seen that bre particles have larger surface, and consequently, their the addition of dietary fi bre resulted in increased fi rm- water-binding capacity is higher, and water is released ness 3 h aft er baking, which is statistically more signifi - faster during baking and storage. Therefore, a lower mass cant (p≤0.05) in samples with the OFP1 than in those con- is obtained, and there is a relative increase in the fi bre taining OFP2. Firmness increased signifi cantly with the content in bread rolls (32). length of storage, especially of the samples containing 16 and 20 % OFP1, which is associated with a high amount 16 of insoluble fi bre in the used fi bre powder (27). Both lack 14 of fi rmness and volume are aff ected by the content of hy- OFP1 )% 12 drocolloids in fi bre powder. When bread with high mass OFP2 fraction of dietary fi bre is heated, hydrocolloids with 10 8 strong bonds are formed, and these bonds cannot be bro- g ken by enzymes in fl our due to their low amount (27). 6 f d e Smaller changes in the fi rmness value were observed in 4 c c cd the fi bre with larger particles than in the fi bre with small- w(total dietary fibre / b b 2 ab er particles. However, in this study, it was determined a a 0 that the addition of both OFP1 and OFP2 increased the 048121620 fi rmness of bakery products. A correlation analysis de- w(oat fibre powder)/% monstrated a signifi cant positive correlation between fi rmness and the storage modulus G’ (R=0.77) and loss modu- Fig. 5. The total dietary fi bre content in wheat bread rolls with lus G” (R=0.78). Strong correlations between rheological 0, 4, 8, 12, 16 and 20 % of fl our replaced with oat fi bre powder with particle sizes of 75 μm (OFP1) and 150 μm (OFP2). Values parameters and texture indicate that fi rmness depends on with diff erent lett ers diff er signifi cantly (p≤0.05) the storage modulus. The fact that fi rmness increases with increased fi bre content may be due to the increased water-holding capacity of the fi bre. Therefore, chemical Conclusion reactions can occur more easily, aff ecting the physical parameters (28). Fibre micronization may also be associated There are only few scientifi c reports focused on the with the destruction of the aleurone layer of cells during use of oat fi bre as an additive to bakery products. This grinding. As a result, enzymes, glutathione or phytates study has demonstrated that reducing the particle size of are released and they may impair gluten formation due to fi bre powder aff ects the characteristics of bakery prod- chemical reactions (29). ucts. Because of greater granulation of bakery products, it is possible to obtain dough with bett er rheological prop- Porosity of baked wheat rolls erties and colour parameters than when using products without the addition of fi bre. The problem of increased Visual characteristics of crumbs, such as mean cell fi rmness of bakery products accompanying the addition area, are among the elements that constitute the quality of of fi bre may be associated with the high water-binding ca- the fi nal product (30). As can be seen in Fig. 4 only the pacity of dietary fi bre. It is therefore necessary to prepare average size of bread crumb pores was altered by the ad- a formula that optimises the amount of water. dition of dietary fi bre. The crumbs containing OFP1 had less porous structure, which could be explained by lower viscosity of the dough caused by dietary fi bre, resulting Acknowledgements in lower carbon dioxide formation during fermentation This study was supported by Project no POIG.01. (31). 03.01-14-041/12 ‘Bioproducts’, innovative technologies of pro-health bakery products and pasta with reduced ca- 60 loric value, co-fi nanced by the European Regional Devel- opment Fund under the Innovative Economy Operational 50 Programme 2007–2013. 40 30 OFP1 y=–70.433x+55.823; R²=0.8872 20 References Porosity/% OFP2 y=–65.533x+53.636; R²=0.7582 10 1. Melanson KJ, Angelopoulos TJ, Nguyen VT, Martini M, Zuk- ley L, Lowndes J, et al. Consumption of whole-grain cereals 0 048121620during weight loss: eff ects on dietary quality, dietary fi ber, w(oat fibre powder)/% magnesium, vitamin B6, and obesity. J Am Diet Assoc. 2006; 106:1380–8. Fig. 4. The porosity of wheat bread rolls with 0, 4, 8, 12, 16 and htt p://dx.doi.org/10.1016/j.jada.2006.06.003 20 % of fl our replaced with oat fi bre powder with particle sizes 2. Quilez J, Salas-Salvado J. Salt in bread in Europe: potential of 75 μm (OFP1) and 150 μm (OFP2), expressed as percentage benefi ts of reduction. Nutr Rev. 2012;70:666–78. of whole area of bread slice htt p://dx.doi.org/10.1111/j.1753-4887.2012.00540.x M. KUREK et al.: Wheat Bread Rolls with Oat Fibre, Food Technol. Biotechnol. 54 (1) 45–51 (2016) 51

3. Bautista-Castaño I, Serra-Majem L. Relationship between bread gy study. Eur Food Res Technol. 2006;223:333–40. consumption, body weight, and abdominal fat distribution: htt p://dx.doi.org/10.1007/s00217-005-0208-6 evidence from epidemiological studies. Nutr Rev. 2012;70: 19. Chau CF, Wen YL, Wang YT. Improvement of the functional- 218–33. ity of a potential fruit insoluble fi bre by micron technology. htt p://dx.doi.org/10.1111/j.1753-4887.2012.00454.x Int J Food Sci Technol. 2006;41:1054–60. 4. Angioloni A, Collar C. Gel, dough and fi bre enriched fresh htt p://dx.doi.org/10.1111/j.1365-2621.2006.01171.x breads: relationships between quality feats and staling kinet- 20. Ahmed, AR, Mohammed I, Senge B. Oscillation measure- ics. J Food Eng. 2009;91:526–32. ments and creep test of bread prepared from wheat-lupin htt p://dx.doi.org/10.1016/j.jfoodeng.2008.09.033 fl ours and wheat fl our-lupin fi bre dough’s blends. Ann 5. Gélinas P. Preventing constipation: a review of the laxative Transac Nord Rheol Soc. 2012;20:145–52. potential of food ingredients. Int J Food Sci Tech. 2013;48: 21. Sabanis D, Lebesi D, Tzia C. Eff ect of dietary fi bre enrich- 445–67. ment on selected properties of gluten-free bread. LWT – htt p://dx.doi.org/10.1111/j.1365-2621.2012.03207.x Food Sci Technol. 2009;42:1380–9. 6. Mora YN, Contreras JC, Aguilar CN, Meléndez P, Garza IDL, htt p://dx.doi.org/10.1016/j.lwt.2009.03.010 Rodríguez R. Chemical composition and functional proper- 22. Van Bockstaele F, De Leyn I, Eeckhout M, Dewett inck K. ties from diff erent sources of dietary fi bre. Am J Food and Rheological properties of wheat fl our dough and the rela- Nutr. 2013;1:27–33. tionship with bread volume. I. Creep-recovery measure- htt p://dx.doi.org/10.12691/ajfn-1-3-2 ments. Cereal Chem. J. 2008;85:753–61. 7. Klosterbuer A, Roughead ZF, Slavin J. Benefi ts of dietary fi - htt p://dx.doi.org/10.1094/CCHEM-85-6-0753 bre in clinical nutrition. Nutr Clin Pract. 2011;26:625–35. 23. Kurek M, Wyrwisz J, Piwińska M, Wierzbicka A. Applica- htt p://dx.doi.org/10.1177/0884533611416126 tion of response surface methodology in optimizing oat fi bre 8. Scientifi c opinion on the substantiation of a health claim re- particle size and fl our replacement in wheat bread rolls. lated to oat beta-glucan and lowering blood cholesterol and CyTA – J Food. 2016;14:18–26. reduced risk of (coronary) heart disease pursuant to Article htt p://dx.doi.org/10.1080/19476337.2015.1036309 14 of Regulation (EC) No 1924/2006. EFSA J. 010;8(12):1885. 24. Rosell, CM, Santos E, Collar C. Physico-chemical properties htt p://dx.doi.org/10.2903/j.efsa.2010.1885 of commercial fi bres from diff erent sources: a comparative 9. European Union Commission Regulation (EU) No 1047/2012 approach. Food Res Int. 2009;42:176–84. of 8 November 2012 amending Regulation (EC) No 1924/2006. htt p://dx.doi.org/10.1016/j.foodres.2008.10.003 Off J EU. 2012;L310:36–7. 25. Zhang LH, Xu HD, Li SF. Eff ects of micronization on proper- 10. Almeida EL, Chang YK, Steel CJ. Eff ect of adding diff erent ties of Chaenomeles sinensis (Thouin) Koehne fruit powder. dietary fi ber sources on farinographic parameters of wheat Innov Food Sci Emerg Technol. 2009;10:633–7. htt p://dx.doi.org/10.1016/j.ifset.2009.05.010 fl our. Cereal Chem. 2010;87:566–73. htt p://dx.doi.org/10.1094/CCHEM-05-10-0063 26. Sivam AS, Sun-Waterhouse D, Waterhouse GIN, Quek SY, Perera CO. Physicochemical properties of bread dough and 11. Rubel IA, Pérez EE, Manrique GD, Genovese DB. Fibre en- fi nished bread with added pectin fi ber and phenolic antioxi- richment of wheat bread with Jerusalem artichoke inulin: ef- dants. J Food Sci. 2011;76:97–107. fect on dough rheology and bread quality. Food Struct. 2015; htt p://dx.doi.org/10.1111/j.1750-3841.2011.02086.x 3:21–9. htt p://dx.doi.org/10.1016/j.foostr.2014.11.001 27. Anil M. Using of hazelnut testa as a source of dietary fi ber in bread making. J Food Eng. 2007;80:61–7. 12. Khater ESG, Bahnasawy AH. Heat and mass balance for bak- htt p://dx.doi.org/10.1016/j.jfoodeng.2006.05.003 ing process. J Bioprocess Biotech. 2014;4:190190. htt p://dx.doi.org/10.4172/2155-9821.1000190 28. Ho LH, Abdul Aziza NA, Rajeev B, Azaharib B. Storage studies of bread prepared by incorporation of the banana 13. Gómez M, Ronda F, Blanco CA, Caballero PA, Apesteguía A. pseudo-stem fl our and the composite breads containing hy- Eff ect of dietary fi bre on dough rheology and bread quality. drocolloids. CyTA – J Food. 2014;12:141–9. Eur Food Res Technol. 2003;216:51–6. htt p://dx.doi.org/10.1080/19476337.2013.806597 htt p://dx.doi.org/10.1007/s00217-002-0632-9 29. Gelinas P, McKinnon C. Dietary fi bre and β-glucan in strong 14. Dhingra D, Mona M, Rajput H, Patil RT. Dietary fi bre in bread wheat cultivars: does it matt er? Int J Food Sci Tech. foods: a review. J Food Sci Technol. 2012;49:255–66. 2013;48:670–2. htt p://dx.doi.org/10.1007/s13197-011-0365-5 htt p://dx.doi.org/10.1111/j.1365-2621.2012.03216.x 15. Collar C, Santos E, Rosell CM. Assessment of the rheological 30. Yi J, Kerr WL. Combined eff ects of freezing rate, storage profi le of fi bre-enriched bread doughs by response surface temperature and time on bread dough and baking proper- methodology. J Food Eng. 2007;78:820–6. ties. LWT – Food Sci Technol. 2009;42:1474–83. htt p://dx.doi.org/10.1016/j.jfoodeng.2005.11.026 htt p://dx.doi.org/10.1016/j.lwt.2009.05.017 16. Laurikainen T, Härkönen H, Autio K, Poutanen, K. Eff ects of 31. Kurek M, Wyrwisz J, Piwińska M, Wierzbicka A. Infl uence enzymes in fi bre-enriched baking. J Sci Food Agric. 1998;76: of the wheat fl our extraction degree in the quality of bread 239–49. made with high proportions of β-glucan. Food Sci Technol, htt p://dx.doi.org/10.1002/(SICI)1097-0010(199802)76:2≤239: Campinas. 2015;35:273–8. :AID-JSFA942>3.0.CO;2-L htt p://dx.doi.org/10.1590/1678-457X.6537 17. AOAC Offi cial Method 2009.01-2009. Total dietary fi ber in 32. Pourfarzad A, Mahdavian-Mehr H, Sedaghat N. Coff ee sil- foods. Enzymatic-gravimetric- liquid chromatographic meth- verskin as a source of dietary fi bre in bread-making: optimi- od. Gaithersburg, MD, USA: AOAC International, 2009. zation of chemical treatment using response surface meth- 18. Rosell CM, Santos E, Collar C. Mixing properties of fi bre-en- odology. LWT – Food Sci Technol. 2013;50:599–606. riched wheat bread doughs: a response surface methodolo- htt p://dx.doi.org/10.1016/j.lwt.2012.08.001