Influence of Cephalaria Syriaca Addition on Physical and Sensorial Properties of Wheat Bran Bread

Abstract

The effect of different Cephalaria syriaca products (CSP) (whole Cephalaria syriaca flour (WCSF) and defatted Cephalaria syriaca flour (DCSF)) on the final quality of bran breads was investigated. Five levels of Cephalaria syriaca products (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were used in this study. Results of this study showed that addition of CSP (WCSF and DCSF) to wheat bran bread had significant positive impact on bread specific volumes, crumb firmness and bread sensory characteristics, although addition levels (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) were very low. In general, specific volume, yield of volume, and some sensory characteristics of the bran bread increased when the addition levels of WCSF and DCSF increased, except for the level of 1.51 g/100 g bread CSP addition, in which a slight decrease was observed. Bran breads containing WCSF had significantly higher loaf specific volume, softness of breadcrumb and sensory characteristics than those of breads containing DCSF at all addition levels. Especially, the addition of 1.17 g WCSF significantly improved the quality of bran breads. This study indicates that these two CSP can be used as additives in bran bread production in order to improve the quality of bread.

Keywords:

• Cephalaria syriaca
• Wheat bran bread
• Bread quality
• Crumb softness

INTRODUCTION

Bran bread is produced by the addition of bran from different sources such as wheat, rye, oat and barley in different amounts. The bran layer of grains is the richest sources of fibre. Numerous epidemiological and experimental studies have suggested that the consumption of dietary fibre can decrease the risk of colon cancer.[1] A fibre-rich diet is lower in energy density, often has a lower fat content, is less in volume, and is richer in micronutrients, all of which have beneficial health effects. In this sense, bran bread or brown bread is an important staple food in many countries.[2–6]

The breadmaking quality of wheat flour and unique functional properties of wheat dough is generally associated with the quality and quantity of gluten proteins.[7] The nonendosperm components (germ, bran and epicarp hairs) of wheat caryopsis are known to be responsible for producing the low specific volume and dense crumb structure of brown bread. The weakening effect of bran layer on wheat flour dough is the result of a dilution of the gluten structure by the added bran. Besides, bran plays a prominent role in disrupting the gluten protein matrix. This results in lower loaf volume and subsequently has a negative effect on other quality attributes, such as crumb grain and tenderness.[8,9] For this reason, bran bread manufactured by the addition of bran to white flour has a poor consumption quality than white pan bread.

The chemical and physical effects of bran on baking quality have been studied extensively.[10–12] A large number of optional ingredients such as shortening, emulsifiers, oxidants and gluten are included in bran bread formulation to improve its shelf life and organoleptic properties. Cephalaria syriaca, an annual weed in wheat fields, is similar to a wheat grain in size and shape; and it is traditionally used to improve the rheological properties of dough by farmers living in some part of Turkey.[13] However, any study has not been carried out on the effect of Cephalaria syriaca on the quality of wheat bran bread, and there is no information on the effect of Cephalaria syriaca on the quality of wheat bran bread. The objectives of this research were to study the effects of Cephalaria syriaca products (CSP) such as whole Cephalaria syriaca flour (WCSF) and defatted Cephalaria syriaca flour (DCSF) on the quality of bran bread made of wheat flour (85%) and wheat bran (15%) (w/w).

MATERIALS AND METHODS

Materials

Commercial aestivum wheat flour, procured from the local market, was used for this study. Fine wheat bran was purchased from a commercial flourmill (BİRLİK A.Ş. Erzurum, Turkey). Wheat flour characteristics were as follows; protein: 11.51 g/100 g flour, wet gluten: 28.51 g/100 g flour, Zeleny sedimentation volume: 25.30 ml, falling number: 750 s, ash: 0.61 g/100 g flour, (flour moisture: 14 g/100 g flour). Cephalaria syriaca seeds were obtained from a seed merchant in Erzurum, Turkey. Common salt, pressed baker's yeast were obtained from the local market.

The following Cephalaria syriaca products were used in bran bread formulation: Whole Cephalaria syriaca flour (WCSF) and defatted Cephalaria syriaca flour (DCSF). Grains were milled in a Brabender waltz mill (Duisburg, Germany) with a sieve aperture of 1 mm diameter to produce WCSF. WCSF was freeze-dried with a freeze-dryer (Hetosicc, CD 2.5, Heto Co., Denmark) and extracted in a Soxhlet extractor with petroleum ether (60–80 °C for 12 h) to produce defatted flour (DCSF). Wheat flour (85%) plus wheat bran (15%) used in production of bran bread was partially added with these CSP at levels of 0.16, 0.50, 0.84, 1.17 and 1.51 g/100 g bread.

Baking Procedure

The wheat bran bread formula consisted of wheat flour (1000 g), fine wheat bran (15%, flour basis), compressed yeast (3.0%, flour basis), salt (1.5%, flour basis), and water (up to optimum absorption). The mix (wheat flour plus bran) used in wheat bran bread production was added by Cephalaria syriaca products (CSP) at levels of 0.16, 0.50, 0.84, 1.17 and 1.51 g/100 g bread. Bran breads without CSP were used as control. All ingredients were poured into a mixer (Stephan Um-5, Stephan, Germany) and mixed for 3 min by applying low speed (1500 rpm). The resulting dough was rested for 10 min, divided (160 g), kneaded, and then rested again (10 min); dough was sheeted and rolled, proofed in a fermentation cabinet (at 30°C and 80% relative humidity for 70 min), and baked (220°C for 25 min) according to the method of Haros et al.[14] Properties of bran bread produced from composite flour were determined.

Analytic Procedures

Mass and volume were measured 1 h after removal of bread loaves from the oven. Wheat bran bread specific volume was determined the rape seed displacement method[15] and volume yields were calculated by relating the bread volume to 100 g of flour with a moisture content of 14% (w/w).[16] Color intensity of bran breads was determined using the Minolta Colorimeter CR-200 (Minolta Camera Co., Osaka, Japan).[17]

Instrumental Textural Properties

The wheat bran breads were wrapped up into polyethylene bags and stored at 20 ± 1°C for one week. Bread firmness throughout 7 days storage at room temperature was objectively measured according to a modified version of AACC method 7409[18] with a texture analyzer (TA-XTplus, Stable Micro Systems, Godalming, Surrey, UK) equipped with a cylindrical probe (P/25) using a 30 kg load cell. Bread was cut into one-inch thick slices. Tests were carried out after 1, 2, 3, 4, 5, 6, and 7 days in the central part of the slice. Sample was compressed by 40% at speed rate 1.7 mm/s. The firmness was defined as the force (in grams) required compressing the sample by 40% of its original width.

Sensory Analysis

Finished breads were allowed to cool for 1–2 h at room temperature and then were evaluated using a nine-point hedonic scale as recommended by Land and Shepherd,[19] where 9 = like extremely; 5 = neither like nor dislike; and 1 = dislike extremely. Before sensory testing, loaves were sliced into 2.5-cm thick slices. The end slices were discarded and 4 × 4 cm squared pieces were prepared from each slice and immediately placed in plastic boxes. Each box was given a three-digit code number. Sensory evaluation was performed by 20 untrained panelists (10 males and 10 females) who were graduate students and staff members of the Department of Food Engineering, Atatürk University. Panelists were chosen using the following criteria: ages between 20 and 55, non-smokers, without reported cases of food allergies, who consume wheat bran bread. The panelists had some experience on sensory evaluation. The tests were performed in an isolated room with good illumination and natural ventilation. Panelists were served a set of five-treated samples of WCSF along with a control sample (not containing CSP) and then they were served a set of five-treated samples of DCSF along with a control sample. The panel members were asked to evaluate each loaf for grain, colour and texture of crumb, aroma, taste and overall acceptance and instructed to rinse their mouth with water after each bread sample evaluation.

Statistical Analysis

All the experiments were carried out in triplicate and in two different trials. SPSS 10.0 software for Windows (SPSS for Windows Release 10.01. Chicago, IL, USA, SPSS Inc.) was used to perform statistical analyses. Differences in wheat bran bread because of addition of CSP (WCSF and DCSF) were tested for significance using analysis of variance (ANOVA) techniques. Duncan's new multiple range test were used when the ANOVA indicated significant difference in mean values. A level of significance of P < 0.05 is used throughout the analysis. All data are presented as the mean ± SE.

RESULTS AND DISCUSSION

Wheat bran breads produced with the addition of WCSF and DCSF at different levels (1.16, 0.50, 0.84, 1.17 and 1.51 g/100 g bread) are shown in Fig. 1. Specific volume and yield of volume of the bran bread significantly (P < 0.05) increased with increasing WCSF addition levels from 0 to 1.17 g compared to the control, and slightly decreased at the 1.51 g WCSF addition level compared to other addition levels (Table 1). While WCSF and DCSF showed similar effects on specific volume of bran bread at levels of 0.16 and 0.50 g, the increase in specific volume of bran breads made from WCSF was higher than that of DCSF at levels of 0.84, 1.17 and 1.51 g. Breads made with 1.17 g WCSF had the highest specific volume (3.18 ml g⁻¹) and yield of volume (420.9%).

Figure 1 Wheat bran breads containing different levels (g/100 g bread) of CSP (WCSF, DCSF). (Figure provided in color online.)

Table 1 Effect of Cephalaria syriaca products on specific volume and yield of volume of bran breads (mean ± SE) ^a

CSP	Addition Level (g/100 g bread)	Specific Vol. (ml g^−1)	Yield of Vol. (%)
WCSF	0 (C)	2.43±0.01e	329.8±0.98f
	0.16	2.77±0.01d	362.2±0.3e
	0.50	2.85±0.00c	400.6±1.2c
	0.84	3.04±0.00b	411.7±0.5b
	1.17	3.18±0.02a	420.9±0.8a
	1.51	2.80±0.00cd	376.0±0.6d
	GM	2.84 ± 0.01	383.5 ± 1.4
	P	**	**
DCSF	0 (C)	2.43±0.01c	329.8±0.9e
	0.16	2.78±0.02a	368.0±0.8bc
	0.50	2.81±0.02a	372.8±0.2a
	0.84	2.78±0.02a	370.2±0.7ab
	1.17	2.71±0.00a	365.8±0.2c
	1.51	2.58±0.00b	352.6±0.2d
	GM	2.68 ± 0.00	359.8 ± 0.6
	P	**	**
^aMeans with different letters in the same column are statistically different at (P < 0.05). CSP: Cephalaria Syriaca Product; WCSF: Whole Cephalaria Syriaca Flour; DCSF: Defatted Cephalaria Syriaca Flour; GM: Grand mean; P: Probability; ** < 0.01;PU: penetration unit; and C: Control group.
**P < 0.01; PU: penetration unit; and C: Control group.

Loaf volume and yield of volume are important quality indices of bread, determined by quality and quantity of the protein in the flour.[20–22] A good loaf volume is achieved if the gas bubbles within the fermented dough expand with minimal rupture during the proofing and baking. That is, the loaf volume shows the power of the dough to expand in the oven. This leads naturally to the conclusion that baking performance relates to the interplay between R _max (maximum resistance) and extensibility of dough, since both factors indirectly characterize the extent of the expansion that will occur during the expansion of the gas bubbles.[23] These results agree with our previous study[13] in which the effect of CSP on the rheological properties of wheat flour was investigated and the rheological properties of wheat flour added with CSP were considerably improved with regard to especially extensograph characteristics such as dough resistance, area (energy) and ratio number.

Although the firmness values of both control group and breads with CSP increased linearly during seven-day storage, the treated samples were found to be softer in all cases compared to control group (Fig. 2A, B). While the addition levels of CSP at the beginning of storage period (1 and 2 days) had little effect on firmness value of bran bread, but at later storage times, the effect of addition levels were more prominent. Bread staling is a complex process, and is generally defined as the increase in the crumb firmness or the decrease in the crumb softness and a parallel loss in product freshness. The most important change associated with staling of bread is the gradual increase in the firmness or decrease in the softness of crumb.[24,25,26,27] When staling effects of both control group and CSP (WCSF and DCSF) treated breads were compared for the crumb firmness, CSP significantly decreased bread firmness during storage (Fig. 2A, B). In general, the 1.17 g WCSF and DCSF addition level showed the best results in firmness of bread crumb during all storage period, which was in agreement with the increase of the specific volume. That is, CSP showed similar positive effects on both crumb firmness and loaf volume. The decrease in crumb firmness can be explained by the increase in loaf volume as well as the improvement in crumb characteristics. It is stated that the increased loaf volume is directly related to the decreased firmness values and this is due to an increased probe-to-crust distance as loaf volume increased.[28]

Figure 2 Effect of WCSF (A) and DCSF (B) on firmness value of bran breads. (Means with different letters in the same column are statistically different at [P < 0.05]).

Table 2 shows data of sensory evaluation of bran breads made from CSP (WCSF and DCSF). In general, all sensory traits and colour value of bran breads obtained from wheat-wheat bran composite flour added with DCSF were lower than those of WCSF. In addition, the effect of CSP addition level was evident on all the sensorial characteristics and colour values of bran bread (Table 2, Fig. 3).

Table 2 Effect of Cephalaria syriaca products on sensory traits and colour values of bran breads (mean ± SE) ^{a b}

					Crumb colour
CSP	Addition level (g/100 g bread)	Crumb grain	Aroma	Taste	+a	+b
WCSF	0 (C)	4.0±0.0d	5.0±0.0d	5.0±0.0c	5.2±0.0	18.5±0.2ab
	0.16	5.3±0.1c	6.3±0.1bc	6.6±0.0b	5.6±0.0	18.7±0.1a
	0.50	6.0±0.0b	6.0±0.0c	6.5±0.0b	5.3±0.1	17.9±0.0bc
	0.84	6.5±0.0b	6.6±0.1b	7.0±0.0a	5.3±0.0	17.4±0.1c
	1.17	7.4±0.1a	7.1±0.0a	7.2±0.1a	5.1±0.0	17.7±0.0c
	1.51	6.3±0.2b	6.3±0.1bc	6.5±0.1b	5.4±0.0	17.8±0.1c
	GM	5.9 ± 0.0	6.3 ± 0.0	6.5 ± 0.0	5.3 ± 0.0	18.0 ± 0.0
	P	**	**	**		*
DCSF	0 (C)	4.0±0.0d	5.0±0.0c	5.0±0.0c	5.2±0.0ab	18.5±0.2a
	0.16	5.4±0.0c	6.5±0.0a	5.7±0.0b	5.5±0.1a	18.0±0.1ab
	0.50	6.3±0.1ab	5.8±0.0b	6.2±0.0a	4.9±0.0abc	17.4±0.0b
	0.84	6.4±0.1ab	6.2±0.2ab	5.7±0.1b	4.7±0.1bc	16.4±0.2c
	1.17	6.6±0.1a	6.1±0.0ab	6.6±0.1a	4.5±0.0c	16.4±0.0c
	1.51	6.1±0.0b	6.2±0.1ab	6.6±0.0a	4.6±0.0c	16.9±0.1c
	GM	5.8 ± 0.0	6.0 ± 0.0	5.9 ± 0.0	5.2 ± 0.0	17.4 ± 0.0
	P	**	**	**	*	**
^aMeans with different letters in the same column are statistically different at (P < 0.05). ^b Breads were evaluated using a 9 point hedonic scale where 9=like extremely, 5=neither like nor dislike and 1=dislike extremely. CSP: Cephalaria Syriaca Product; WCSF: Whole Cephalaria Syriaca Flour; DCSF: Defatted Cephalaria Syriaca Flou; +a: red; +b: yellow; GM: Grand mean; P: Probability ;*P < 0.05; **P < 0.01; and C: Control group.

Figure 3 Effect of WCSF and DCSF on crumb colour (A), L colour value (B), crumb texture (C), and overall acceptability (D) (L, lightness–darkness).

The addition of both WCSF and DCSF to bran bread affected positively its sensorial properties such as crumb grain, aroma, taste, crumb texture and overall acceptability as compared to the control group. Crumb grain, aroma, taste, crumb texture and overall acceptability scores of bran breads significantly increased as the CSP level increased up to 1.17 g/100 g bread. However, in general, CSP addition at the level of 1.51 (g/100 g bread) significantly decreased these scores as compared to the addition level of 1.17 (g/100 g bread). Crumb colour, L and +b value were negatively affected by the increase of addition levels of both WCSF and DCSF, which might be attributed to the darker colour of CSP than wheat flour. Colour values of WCSF and DCSF as follows: L, 65.66, a, +2.09, b, +19.01 and L, 87.07, a, −0.52, b, +8.96, respectively. Both crumb colour (sensorial characteristic) and crumb L value decreased as WCSF and DCSF addition levels increased, and DCSF darkened crumb colour of bran bread more than WCSF (Fig. 3A, B). The increases in DCSF and especially in WCSF levels up to about 1.17 g significantly improved the scores for crumb texture and general acceptability (Fig. 3C, D). The increase in scores for crumb texture and general acceptability was more pronounced in WCSF than DCSF. The maximum score (7.35) of general acceptability was obtained at the level of 1.17 g WCSF.

CONCLUSION

Results of this study showed that addition of CSP (WCSF and DCSF) to wheat bran bread had significant positive impact on bread specific volumes, crumb firmness and bread sensory quality except for bread crumb colour, although addition levels (0.16, 0.50, 0.84, 1.17, and 1.51 g/100 g bread) was very low. In general, specific volume, yield of volume, softness of bread crumb and some sensory characteristics of the bran bread significantly increased as the addition levels of WCSF and DCSF increased from 0 to 1.17 g. Bran breads containing WCSF had significantly higher loaf specific volume, bread crumb softness and sensory characteristics than those of breads containing DCSF at all addition levels. Especially, addition of 1.17 g WCSF and DCSF further improved the quality of bran breads. From the above results, it could be concluded that it is feasible to produce bran bread with good volume, crumb firmness and sensory characteristics from wheat-wheat bran composite flour when CSP is added into the system. It was determined that CSP improved the quality of bran bread but it was not clear how they accomplished this. For this reason, further studies are needed in this area.