Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread

Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread

LWT - Food Science and Technology xxx (2014) 1e6 Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.e...

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LWT - Food Science and Technology xxx (2014) 1e6

Contents lists available at ScienceDirect

LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt

Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread Pandurang Marpalle, Sachin K. Sonawane, Shalini Subhash Arya* Food Engineering and Technology Department, Institute of Chemical Technology, Nathalal Parikh Marg, Matunga (East), Mumbai, Maharashtra 400 019, India

a r t i c l e i n f o

a b s t r a c t

Article history: Received 31 January 2013 Received in revised form 26 March 2014 Accepted 4 April 2014 Available online xxx

The importance of polyunsaturated fatty acids (PUFA) in health and nutrition is well recognised. Flaxseed (Linum usitatissimum) has recently gained a lot of attention as functional food because of its unique nutrient profile. In the present work efforts were made to develop omega-3 enriched functional bread using raw and roasted ground flaxseed flour. Initially optimisation of each bread ingredient viz., salt, sugar, and shortening, GMS, yeast and water was carried out on the basis of sensory overall acceptability score. The standardised bread was incorporated with raw and roasted ground flaxseed (5, 10, and 15 g/ 100 g) flour. The effect of flaxseed incorporation on bread dough rheology parameters viz., dough stickiness and water absorption was studied. Increase in water absorption and dough stickiness was observed with increased flaxseed level. Further breads were evaluated for sensory parameters, colour and texture. The crumb softness increased with increase in flaxseed level. Bread was optimised at 10(g/ 100 g) flaxseed level based on sensory evaluation. Ó 2014 Elsevier Ltd. All rights reserved.

Keywords: PUFA Functional food ALA Rheology Flaxseed

1. Introduction Due to the increased awareness of consumers towards health; a demand for functional foods has risen dramatically. Flaxseed (Linum usitatissimum) is used as a potential source for functional food due to its unique nutrient profile. It is high in polyunsaturated fatty acids (73% of total fatty acids), moderate in monounsaturated fatty acids (18%), and low in saturated fatty acids (9%), linoleic acid constitutes is about 16% of total fatty acids, a-linolenic acid (ALA) about 57% (Morris, 2001; Oomah & Mazza, 1993). Evidences suggest that flaxseed dietary fibres suppresses postprandial lipaemia and appetite (Kristensen et al., 2013). Hence reduces the risk of cardiovascular diseases, causes reduction in bodyweight and fat accumulation (Park & Velasquez, 2012). Protection of our blood vessels from inflammatory damage is also provided by the lignans in flaxseeds (Dodin et al., 2008). Since flaxseed contains, three bioactive components dietary fibres, lignans and ALA, synergistically shows health benefits such as reduction in the risk of occurrence of breast cancer (Lowcock, Cotterchio, & Boucher, 2013), osteoporosis, diabetes (Wahba & Al-Zahrany, 2013), heart disease and menopausal symptoms (Thompson, 2003; Tzang et al., 2009).

* Corresponding author. E-mail addresses: [email protected], S. Arya).

[email protected]

(S.

According to the recent studies flaxseed consumption has also shown a decrease in postprandial glucose absorption, improvment in glucose tolerance and serum cholesterol levels (Hutchins, Cunnane, Domitrovich, Adams, & Bobowiec, 2013; Thakur, Mitra, Pal, & Rousseau, 2009). Thus, flaxseed can be incorporated into diet as ground flaxseed or flaxseed oil. Flaxseed incorporation in various bakery products such as cookies (Rodrigues et al., 2012), Chinese steamed bread (Hao & Beta, 2012), rice paper (Cameron & Hosseinian, 2013) has been studied. Flaxseed nutrients, particularly lignan, ALA and secoisolariciresinol diglucoside (SDG) have been found stable under normal processing, high temperature and storage conditions such as spaghetti fortified with ground flaxseed and flaxseedfortified macaroni (Chen, Ratnayake, & Cunnane, 1994; Hall, Manthey, Lee, & Niehaus, 2005; Manthey, Lee, & Hall, 2002). Research conducted by Muir and Westcott (2000) showed that the bread making process did not affect SDG stability. However, SDG recovery from the bread was only 73%e75% of the theoretical yield. Gluten formation during bread making could entrap the flaxseed and interfere with SDG recovery, which might lead to a low SDG yield. There is enough literature available on nutritional characterisation of flaxseed than its utilisation in processed foods (Marpalle, Sonawane, & Arya, 2014). Hence present work focuses on use of brown flaxseed flour as a functional ingredient in bread.

http://dx.doi.org/10.1016/j.lwt.2014.04.003 0023-6438/Ó 2014 Elsevier Ltd. All rights reserved.

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003

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P. Marpalle et al. / LWT - Food Science and Technology xxx (2014) 1e6

2. Materials and methods Refined wheat flour and gluten were gifted by General Mills India, Mumbai, India. Branded whole wheat flour (Aashirwad Atta, ITC Foods), shortening (Godrej), table salt (Tata salt), GMS, sugar, active dry yeast (Blue Bird Foods) and brown flaxseed were obtained from local market of Mumbai India. All other chemicals used for the analysis were of analytical grade. 2.1. Chemical analysis Proximate analysis of flaxseed, whole wheat flour and refined wheat flour and bread viz: moisture content, ash content, protein content, fat content, were carried out by AOAC (1990). Dry gluten was determined by AOAC (1995) methods; carbohydrate was calculated by difference. Damaged starch content was determined by the method of AACC (1992) by hydrolysing the damaged starch granules to maltosaccharides by controlled treatment with purified fungal aamylase. The fungal a-amylase treatment was designed to give complete solubilisation of damaged granules with minimum breakdown of undamaged granules. The degree of hydrolysis was measured using non-specific reducing sugar method using ferricyanide titration. Where, the damaged starch was determined based on amount of potassium ferrincyanide was reduced to potassium ferrocyanide by the reducing sugar in the filtrate i.e. maltose. 2.2. Preparation of flaxseed flour Flaxseed was roasted on pan about 80e90  C for 10 min. Flaxseed flour was prepared using laboratory grinder having 0.5 mm particle size.

acceptability. Different types of sample were coded with specific code and then panelists were instructed to evaluate the samples for sensory attributes as mentioned above. Meanwhile water was provided to the panelists to cleanse their palates in between every samples. The average scores indicated in the table (rounded to the nearest whole number) were based on a single evaluation of each of the 10 individuals. Ten trained panelists evaluated the bread for each parameter as: 9 e extremely like, 8 e like very much, 7 e like moderately, 6 e like slightly, 5 e Neither like nor dislike, 4 e dislike slightly, 3 e dislike moderately, 2 e dislike very much, 1 e extremely dislike. 2.5. Colour analysis Colour of bread crust, crumb of bread and dough colour were analysed by Hunter Lab Colorimeter, model DP-9000 D25 A (Hunter associates laboratory, Reston, VA, USA). The colorimeter was calibrated using a standard white and black plate. Here colour values L, a, b were measured. The dimension L indicate lightness, with 100 for white, 0 for black; a indicate redness when positive and greenness when negative, b indicate yellowness when positive and blueness when negative. 2.6. Dough stickiness Dough for bread making was prepared by straight dough method with thorough mixing and kneading of all ingredients and addition of required amount of water. The prepared dough was evaluated using The Stable Micro Systems CheneHoseney Dough Stickiness Rig test, using accessories such as 25 mm perspex cylinder probe (P/25P), 50 kg load cell and SMS/CheneHoseney Dough Stickiness Cell (A/DSC) (Hoseney & Smewig, 1999). 2.7. Bread firmness

2.3. Preparation and standardization of bread Bread was prepared by straight dough method (Amendola & Rees, 2002). Initially all the ingredients were weighed, mixed into white wheat flour and kneaded uniformly by adding water to form finished bread dough. Dough was kept for bulk fermentation for about 1 h at 30  C and 80% relative humidity (RH) followed by scaling, intermediate proving, moulding and second proving (for about 1e1.25 h). Finally baking was carried out at 220  C for 20e 25 min in baking oven. After baking bread samples were removed from pan and allowed to cool at room temperature. The standardization of ingredients of bread was carried out based on sensory evaluation using 9 point hedonic scale with 10 numbers of trained panelist. During standardization of each ingredient, salt was varied from 1, 1.5, 2(g/100 g), yeast was varied as 2, 2.5, 3(g/100 g), GMS was varied as 0.5, 1, 1.5(g/100 g), sugar was varied as 4, 5, 6(g/100 g), and shortening was varied as 1.5, 2, and 2.5(g/100 g). Water level was varied as 55, 57 and 60(g/100 g) for refined wheat flour and 60, 65 and 70(g/100 g) for whole wheat flour.

Firmness of bread was determined using AACC method No.7409 standard method (AACC, 1995). using The Stable Micro Systems texture analyser TA-XT2i equipped with 50 kg load cell in compression mode with a 36 mm diameter cylindrical probe. The texture analyser was set at a pre and post test speed of 1 mm/s and 1.7 mm/s respectively. 2.8. Bread quality characteristics Loaf weight and volume of bread samples were measured on 1 h after removal from the oven. Loaf volume was determined by the rapeseed displacement method. Specific volume was calculated by dividing loaf volume by loaf weight (Koca & Anil, 2007). 2.9. Statistical analysis The data were subjected to analysis of variance (ANOVA test) using SPSS for windows. Means were separated by Fisher’s protected least significant difference (LSD). The significant level was established at p  0.05.

2.4. Sensory evaluation of bread 3. Results and discussion Sensory evaluation of bread was carried out using nine-point hedonic scale with 10 numbers of trained panelist who were healthy postgraduate students (M.Tech and Ph.D Research Scholars) of food technology between age group of 23e30 years without any medical disorder with a male : female ratio of 50% (Stone & Sidel, 2004). Sensory panelists were asked to rate and give score for different parameters such as crust colour, crumb grain, crumb texture, crumb colour, flavour/taste and overall

3.1. Proximate analysis of raw materials The proximate analysis of raw material in present study is given in the Table 1. From table it can be seen that flaxseed flour showed highest fat content (40.5) compared to whole wheat flour (2.36) and refined wheat flour (2.33). The protein content in refined wheat flour was about 10.37(g/100 g) where as in whole wheat

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003

P. Marpalle et al. / LWT - Food Science and Technology xxx (2014) 1e6 Table 1 Proximate analysis of whole, refined wheat flour and flaxseed flour.a Constituents (g/100 g)

Refined wheat flour

Moisture Ash Fat Protein Dry gluten Damaged starch Carbohydrate

9.27 0.67 2.33 10.37 9.26 9.53 77.36

a

Whole wheat flour

Flaxseed

Table 3 Effect of different levels of ingredients on sensory parameters of refined & whole wheat flour bread.a Ingredient

      

0.11 0.29 0.28 0.32 0.25 0.51 0.42

10.27 0.67 2.36 11.27 10.20 13.50 75.42

      

0.33 0.28 0.18 0.24 0.20 0.30 0.26

6.00  0.40 3.00  0.50 40.50  0.50 22.58  0.23 N/A N/A 27.91  0.55

Table 2 shows the changes in chemical composition of refined wheat flour bread supplemented with different levels of flaxseed. A positive increase in moisture content, fat and protein content of bread with increase in flaxseed level was observed. This could be due to the higher dietary fibres, fat and protein content in flaxseed. Total ash content was also increased linearly with increased level of flaxseed. 3.3. Standardization of bread In the standardized bread, ingredients were optimised at a level of salt 1(g/100 g); yeast 3(g/100 g); GMS 0.5(g/100 g); sugar 6(g/ 100 g); shortening 2.5(g/100 g) both for refined flour bread and whole wheat flour bread. Water level was optimised at 57(g/100 g) for refined flour bread and 65(g/100 g) for whole wheat flour bread. The data presented in Table 3 found statistically significant for overall acceptability scores for which ingredient level was optimised. 3.4. Effect of flaxseed level on sensory parameters of bread The effect of raw and roasted ground flaxseed flour on sensory attributes of bread made with refined and whole wheat flour is presented in Table 4. The presented data inferences that roasted ground flaxseed was more acceptable than raw ground flaxseed. In general ANOVA results indicated that there were significant differences (p < 0.05) among control, 5, 10 and 15(g/100 g) flaxseed levels. But for 15(g/100 g) flaxseed level taste and overall acceptability scores were below the level of acceptance, and thus received negative ratings. Hence 10(g/100 g) roasted ground flaxseed level was most acceptable among the presented data on sensory attributes. Hence bread sample made with 10(g/100 g) roasted ground

Table 2 Effect of RGF level on chemical composition of refined wheat flour bread.a Constituents (g/100 g)

Control

5(g/100 g) flaxseed

Moisture 38.46  0.41 39.20  Ash 0.83  0.28 1.33  Fat 2.13  0.23 3.16  Protein 10.55  0.09 12.01  Carbohydrate 48.01  0.31 44.38 

10(g/100 g) flaxseed

15(g/100 g) flaxseed

0.34 39.80  0.34 40.86  0.28 2.00  0.50 2.67  0.28 5.67  0.57 6.16  0.40 17.28  0.38 21.61  1.2 35.25  1.12 28.68 

0.30 0.28 0.28 0.34 0.61

a Note: All values are mean  SD of three determinations; RGF: roasted ground flaxseed.

Overall acceptability Refined wheat flour

Whole wheat flour

Market sample

8.3  0.94

8.0  0.66

Salt

1 1.5 2 2 2.5 3 0.5 1 1.5 4 5 6 1.5 2 2.5 RWF 55 57 60

7.4a 7.0a 6.1b 6.5a 7.3b 7.7c 7.6a 6.8b 6.6c 6.0a 6.5b 7.4c 6.6a 7.3b 7.9c

0.51 0.66 0.56 0.70 0.48 0.67 0.84 0.78 1.07 0.66 0.84 0.51 0.51 0.48 0.62

6.9a  0.56 6.1b  0.73 5.6c  0.84 5.9a  0.56 6.1b  0.87 6.7c  0.67 7.6a  0.84 6.8b  0.78 6.6c  1.07 5.3c  0.67 6.1b  1.10 6.7a0.67 5.7a  0.67 6.0b  1.05 7.0c  0.83

6.7a  0.82 7.7b  0.67 6.9c  0.56

6.2a  0.91 7.0b  1.05 5.8c  1.03

Yeast

GMS

3.2. Effect of roasted ground flaxseed level on chemical composition of refined wheat flour bread

(g/100 g)

Control

Note: All values are mean  SD of three determinations; N/A: Not Applicable.

flour it was about 11.27(g/100 g) and for flaxseed flour it was 22.58(g/100 g). Dry gluten in refined wheat flour and whole wheat flour was about 9.26 and 10.2(g/100 g) respectively.

3

Sugar

Shortening

Water

WWF 60 65 70

              

a Means in the same column followed by different letters differ significantly p  0.05; RWF: refined wheat flour, WWF whole wheat flour.

flaxseed and refined wheat flour was further used for physicochemical analysis of process and product. Our results are in accordance with Ramcharitar, Badrie, Mattfeldt-Beman, Matsuo, and Ridley (2005) who observed muffin containing 11.6% milled flaxseed by weight was rated as significantly less acceptable than the control muffin. Further the gluten level was optimised at 3(g/ 100 g) level in refined wheat flour bread with 10(g/100 g) roasted ground flaxseed (Table 5). 3.5. Effect of roasted ground flaxseed level on water absorption of refined wheat flour With the increased flaxseed level; an increase in water absorption was observed. This may be due to dietary fibres and gums present in flaxseed. As can be seen from Fig 1 there were significant (p < 0.05) differences observed among 5, 10 and 15(g/100 g) flaxseed substituted refined wheat flour dough. 3.6. Effect of roasted ground flaxseed level on colour and stickiness of dough The effect of different levels of roasted ground flaxseed on dough colour is presented in Table 6. Results indicate that there was increase in redness and greenness value observed. It was further noticed that L and b values were decreased with increased flaxseed concentration. The plausible reason for this could be the darkness of original dough due to darker colour of flaxseed flour made from brown flaxseed variety (Ahmed, 1999). Darkness was more in case of whole wheat dough than refined wheat flour dough because of the bran content of whole wheat flour. Dough stickiness was increased with increased flaxseed. This could be due to increased water absorption as a result of flaxseed gum content in flaxseed flour (Cui, Mazza, & Biliaderis, 1994). High water absorption attributed to decreased water binding capacity of gluten (Dreese, Faubion, & Hoseney, 1988) and thus increased stickiness. Since flaxseed gum shows shear thinning behaviour at higher concentration (Cui et al., 1994), slight decrease in dough stickiness was observed at 15(g/100 g) flaxseed level than at the 10(g/100 g) flaxseed

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003

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P. Marpalle et al. / LWT - Food Science and Technology xxx (2014) 1e6

Table 4 Effect of flaxseed level on sensory parameters of Refined and whole wheat flour bread.a Ingredient (g/100 g)

Crust colour RWF

Control 8.1  0.31 Raw ground flaxseed 5 7.0  0.47 10 6.4  1.17 15 5.4  0.96 Roasted ground flaxseed 5 7.1  0.31 10 5.6  1.42 15 5.5  0.69 a

Crumb grain WWF

RWF

WWF

Crumb texture

Crumb colour

Flavour/Taste

Overall acceptability

RWF

RWF

RWF

RWF

WWF

WWF

WWF

WWF

a

6.8  0.63

7.8  0.78

6.9  0.87

7.8  0.91

6.5  0.84

8.1  0.73

6.9  0.73

7.5  0.52

6.9  0.56

7.8  0.42

6.6a  0.51

6.2  1.03 5.6  0.96 4.9  1.1

7.1  0.73 6.2  0.78 4.6  1.1

6.2  1.03 5.7  0.67 4.9  0.56

6.7  1.25 5.8  0.91 4.5  0.84

6.5  0.70 5.8  0.63 4.6  0.84

6.0  1.05 5.3  1.2 4.3  0.67

5.9  0.56 5.9  0.56 4.8  0.63

5.7  1.15 4.9  0.73 3.4  1.5

5.9  0.73 5  0.47 3.6  0.69

6.1b  1.28 5.4bc  0.96 4.2d  1.03

5.9b  0.87 5.1bc  0.73 3.9d  0.73

6.3  0.94 5.9  1.1 4.9  0.99

6.7  0.94 6.2  0.91 4.5  1.5

6.6  0.69 6.5  0.70 5.7  0.75

6.9  0.73 6.0  0.81 4.7  1.52

6.4  0.84 6  0.66 4.8  0.78

5.9  1.28 5.7  1.33 3.8  1.54

6.4  0.69 6.2  0.63 5.1  0.87

5.8  0.63 5.3  0.94 3.8  1.37

6  1.3 5.4  0.69 3.9  0.56

6.6b  0.96 5.9bc  1.19 4.5d  1.49

6.2ab  1.13 5.7bc  0.94 4.3d  0.79

Means in the same column followed by different letters differ significantly p  0.05; RWF: refined wheat flour, WWF whole wheat flour.

Table 5 Effect of gluten level on sensory parameters of refined wheat flour bread with 10% roasted ground flaxseed.a Ingredient

(g/100 g)

Crust colour

Control Gluten

0 2 3 4

5.6 6.0 6.4 5.7

a

   

Crumb grain

1.42 0.66 0.69 1.05

6.2 6.2 6.7 5.7

   

Crumb texture

0.91 0.63 0.67 0.94

6.0 6.6 6.7 6.4

Means in the same column followed by different letters differ significantly p 

   

0.05

Crumb colour

0.81 0.84 1.05 1.17

5.7 6.2 6.4 5.7

   

Flavour/Taste

1.33 0.63 0.84 0.82

5.3 6.1 5.6 4.8

   

Overall acceptability 5.9a 6.4a 7.1b 5.6ac

0.94 0.73 0.84 1.03

   

1.19 0.69 0.73 0.84

.

increased level of flaxseed that means crumb softness was increased. This may be due to flaxseed gum and fat content in flaxseed. The soluble fibre present in the flaxseed attributed a higher moisture retention in the bread. This could be because of the fact that the rate of firming has inverse relationship to crumb softness and also the rate of firming is a function of bread moisture content i.e. as moisture content increases rate of firmness decreases (Rogers, Zeleznak, Lai, & Hoseney, 1988).

3.8. Effect of roasted ground flaxseed level on crumb and crust colour of bread

Fig. 1. Effect of RGF level on water absorption of refined wheat flour.a Note: All values are mean  SD of three determinations; RGF: roasted ground flaxseed. Different letters differ significantly p  0.05 above the column whiskers.

a

level dough (Table 7). Arabinoxylan was major component responsible for shear thinning behaviour of flaxseed gum (Cui et al., 1994). However the difference was not so significant (p  0.05). 3.7. Effect of roasted ground flaxseed level on bread crumb firmness Table 7 shows effect of flaxseed level on bread crumb. Decrease in force required to compress the bread slice was observed with an

As the roasted ground flaxseed level increased, there was decrease in L values and b values of bread crumb observed (Table 8). Lightness decreased with increased flaxseed level. This may be due to the original darker colour of flaxseed flour. Our findings are in accordance of Ahmed (1999) who reported significant reduction in lightness and increased redness of extruded snacks prepared from corn and flaxseeds. An increase in a value of bread crumb was observed with increased flaxseed level. The difference in redness (a) and yellowness (b) were statistically significant (p < 0.05) . In case of bread crust; decrease in L, a, b values with increase in flaxseed level was observed (Table 8). Similar results were obtained by Koca and Anil (2007) and Garden (1993) who reported that ground flaxseed significantly (p < 0.05) reduced bread crust and

Table 6 Effect of RGF level on dough colour of refined and wheat flour.a Flaxseed (g/100 g)

0 5 10 15 SEM a

L

a

b

dE

Refined wheat flour

Whole wheat flour

Refined wheat flour

Whole wheat flour

Refined wheat flour

Whole wheat flour

Refined wheat flour

Whole wheat flour

74.66a 64.12b 56.33c 49.38d 0.85

65.41a 56.11b 51.86c 49.25d 0.64

2.39a 3.45b 4.84c 5.53d 0.17

5.5a  0.1 5.89ab  0.33 6.06bc0.24 5.97b  0.24 0.20

21.50a  0.72 18.53b  0.85 17.88bc0.62 16.74cd  0.55 0.57

24.63a 21.58b 20.25c 18.67d 0.53

77.73a 66.24b 59.30c 52.36d 0.70

70.10a 60.42b 56.01c 51.01d 0.56

   

1.04 0.77 1.37 0.88

   

0.78 0.50 0.30 0.30

   

0.081 0.26 0.28 0.15

   

0.41 1.09 0.57 0.57

   

0.83 0.59 1.09 0.87

   

0.83 0.06 0.08 0.08

Means in the same column followed by different letters differ significantly p  0.05. .

SEM: standard error of means (n ¼ 9); RGF: roasted ground flaxseed

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003

P. Marpalle et al. / LWT - Food Science and Technology xxx (2014) 1e6

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Table 7 Effect of RGF level on stickiness of dough, bread firmness and bread quality characteristics.a Bread firmness (g)

Dough stickiness (g) (Refined wheat flour dough)

Flaxseed (g/100 g)

a

0 5 10 15 SEM a

47.17 47.42a 52.66b 49.96ab 2.04

   

Bread quality characteristics Volume of loaf (cm3)

(Whole wheat flour dough) a

4.08 4.61 5.59 2.45

30.80 39.41b 46.55c 45.68cd 1.60

   

a

a

680.85 5.7 561.59b  16.56 393.75c  30.72 376.70cd  24.45 17.55

4.12 3.30 3.62 2.28

701.00 701.66ab 655.67c 650.33d 0.91

   

Sp.volume (cm3/g) 2.68a  2.64b  2.42c  2.33d  0.004

1.00 1.50 1.10 0.57

0.001 0.006 0.006 0.006

Means in the same column followed by different letters differ significantly p  0.05 SEM: standard error of means (n ¼ 9); RGF: roasted ground flaxseed.

Table 8 Effect of RGF level on crumb and crust colour of refined wheat flour bread.a Flaxseed (g/100 g) 0 5 10 15 SEM a

L

a

Crumb a

75.12 65.68b 60.21c 52.87d 0.84

Crust    

1.20 0.18 0.14 1.66

b

Crumb a

51.65 50.21b 50.98ab 41.14c 0.52

   

0.79 0.59 0.52 0.62

a

0.97  2.76b  3.15c  4.10d  0.062

Crust 0.07 0.08 0.07 0.07

dE

Crumb a

11.31 9.56b 7.38c 10.74d 0.24

   

0.55 0.10 0.11 0.09

a

19.61 17.12b 15.59cd 15.70d 0.22

Crust    

0.32 0.20 0.35 0.14

Crumb a

24.22 22.40b 19.84c 19.54cd 0.30

   

0.57 0.43 0.18 0.09

a

77.64 67.83b 62.27c 56.26d 0.52

Crust    

1.25 0.12 0.12 0.09

58.16a 55.80b 55.20bc 46.80d 0.49

   

0.56 0.73 0.52 0.56

Means in the same column followed by different letters differ significantly p  0.05 SEM: standard error of means (n ¼ 9); RGF: roasted ground flaxseed.

crumb colour values due to the possibility of maillard reaction due to proteins and phenolic compounds in flaxseed. 3.9. Effect of RGF level on bread quality characteristics The bread loaf volume and specific volume were the parameters used for measuring bread quality. Table 7 inferences that the volume of loaf was not much affected when 5(g/100 g) flaxseed was substituted in the bread. However, beyond 5(g/100 g) there was significant (p < 0.05) decrease in bread loaf volume was observed. This may be due to the dilution of gluten and interference of lignans and dietary fibres in the gluten network (Wang, Rosell, & Benedito de Barber, 2002). 4. Conclusions The present study on effect of flaxseed flour addition on physicochemical and sensory properties of functional bread has established some new findings. Significant increase in water absorption was observed with increased flaxseed level. Dough stickiness was increased significantly upto 10(g/100 g) flaxseed levels. Softness of bread crumb increased with increased flaxseed level. Darkness of bread crust and crumb were increased significantly with increased flaxseed level. Loaf volume and specific volume of flaxseed flour substituted bread were affected by flaxseed. Flaxseed flour substituted breads showed higher moisture, ash, fat and protein and dietary fibre. The standardized bread was acceptable up to 10(g/100 g) roasted ground flaxseed level based on sensory attributes of bread. Acknowledgement The authors wish to thank General Mills Pvt India Ltd., Mumbai for providing raw materials during this research work. The authors also thank Department of Biotechnology (DBT), Government of India (2741/DBT/FBT) for their financial support for carrying out this work. References AACC. (1992). Official methods of the AACC. Method 44-15A, approved October 1975, revised October 1981; Method 76-30A, approved May 1969, revised October

1982, and October 1984; Method 76-31, approved September 1992; Method 8060, approved April 1961, revised October 1982 (8th ed.). St. Paul, MN, USA: The Association. AACC. (1995) (9th ed.). Bread firmness by universal testing machine, in approved methods of AACC (9th ed.), (Vol. II). St. Paul, MN, USA: American Association of Cereal Chemists. Ahmed, Z. S. (1999). Physico-chemical, structural and sensory quality of corn-based flax-snack. NahrungeFood, 43, 253e258. Amendola, & Rees. (2002). Understanding baking: The art and science of baking (3rd ed.) (pp. 151e168). John Wiley & Sons, Inc. AOAC. (1990). Official methods of analysis. Association of official analytical chemists (15th ed.) Washington, DC, USA. AOAC. (1995). Official methods of analysis. Association of official analytical chemists (16th ed.) Washington, DC, USA. Cameron, S. J., & Hosseinian, F. (2013). Potential of flaxseed in the development of Omega-3 Rice paper with antioxidant activity. LWT e Food Science and Technology, 53(1), 170e175. Chen, Z. Y., Ratnayake, W. M. N., & Cunnane, S. C. (1994). Oxidative stability of flaxseed lipids during baking. Journal of the American Oil Chemists Society, 71, 629e632. Cui, W., Mazza, G., & Biliaderis, C. G. (1994). Chemical structure, molecular size distributions, and rheological properties of flaxseed gum. Journal of Agricultural and Food Chemistry, 42, 1891e1895. Dodin, S., Cunnane, S. C., Mâsse, B., Lemay, A., Jacques, H., Asselin, G., et al. (2008). Flaxseed on cardiovascular disease markers in healthy menopausal women: a randomized, double-blind, placebo-controlled trial. Nutrition, 24, 23e30. Dreese, P. C., Faubion, J. M., & Hoseney, R. C. (1988). Dynamic rheological properties of flour, gluten, and gluten-starch doughs. 2. Effect of various processing and ingredient changes. Cereal Chemistry, 65, 354e359. Garden, J. (1993). Flaxseed gum: Extraction, characterization and functionality. PhD dissertation. Fargo, ND USA: Department of Cereal Science, North Dakota State University. Hall, C. A., III, Manthey, F. A., Lee, R. E., & Niehaus, M. (2005). Stability of a-linolenic acid and secoisolariciresinol diglucoside in flaxseed-fortified macaroni. Journal of Food Science, 70, 483e489. Hao, M., & Beta, T. (2012). Development of Chinese steamed bread enriched in bioactive compounds from barley hull and flaxseed hull extracts. Food Chemistry, 133(4), 1320e1325. Hoseney, R. C., & Smewig. (1999). Instrumental measurement of stickiness of dough and other foods. Journal of Texture Studies, 30, 123e136. Hutchins, A. M., Cunnane, S. C., Domitrovich, S. G., Adams, E. R., & Bobowiec, C. E. (2013). Daily flaxseed consumption improves glycemic control in obese men and women with pre-diabetes: a randomized study. Nutrition Research, 33(5), 367e375. Koca, A. F., & Anil, M. (2007). Effect of flaxseed and wheat flour blends on dough rheology and bread quality. Journal of the Science of Food and Agriculture, 87, 1172e1175. Kristensen, M., Savorani, F., Christensen, S., Engelsen, S. B., Bügel, S., Toubro, S., et al. (2013). Flaxseed dietary fibers suppress postprandial lipemia and appetite sensation in young men. Nutrition Metabolism and Cardiovascular Diseases, 23(2), 136e143. Lowcock, E. C., Cotterchio, M., & Boucher, B. A. (2013). Consumption of flaxseed, a rich source of lignans, is associated with reduced breast cancer risk. Cancer Causes and Control, 24, 813e816.

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003

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P. Marpalle et al. / LWT - Food Science and Technology xxx (2014) 1e6

Manthey, F. A., Lee, R. E., & Hall, C. A., 3rd (2002). Processing and cooking effects on lipid content and stability of a-linolenic acid in spaghetti containing ground flaxseed. Journal of Agricultural and Food Chemistry, 50, 1668e1671. Marpalle, P., Sonawane, S. K., & Arya, S. S. (2014). Flaxseed: a nutrition booster and its role in quality of food. Agro Food Industry Hi Tech, 25(1), 20e23. Morris, D. H. (2001). Essential nutrients and other functional compounds in flaxseed. Nutrition Today, 36, 159e162. Muir, A. D., & Westcott, N. D. (2000). Quantitation of the lignan secoisolariciresinol diglucoside in baked goods containing flax seed or flax meal. Journal of Agricultural and Food Chemistry, 48, 4048e4052. Oomah, B. D., & Mazza, G. (1993). Flaxseed proteinsda review. Food Chemistry, 48, 109e114. Park, J. B., & Velasquez, M. T. (2012). Potential effects of lignan-enriched flaxseed powder on bodyweight, visceral fat, lipid profile, and blood pressure in rats. Fitoterapia, 83(5), 941e946. Ramcharitar, A., Badrie, N., Mattfeldt-Beman, M., Matsuo, H., & Ridley, C. (2005). Consumer acceptability of muffins with flaxseed (Linum usitatissimum). Journal of Food Science, 70, S504eS507. Rodrigues, F. T., Fanaro, G. B., Duarte, R. C., Koike, A. C., Anna Lucia, C. H., & Villavicencio. (2012). A sensory evaluation of irradiated cookies made from flaxseed meal. Radiation Physics and Chemistry, 81(8), 1157e1159.

Rogers, D. E., Zeleznak, K. J., Lai, C. S., & Hoseney, R. C. (1988). Effect of nativelipids, shortening and bread moisture on bread firming. Cereal Chemistry, 65, 398e401. Stone, H., & Sidel, J. (2004). Sensory evaluation practices (3rd ed.) (pp. 262e271). San Diego, CA: Academic Press. Thakur, G., Mitra, A., Pal, K., & Rousseau, D. (2009). Effect of flaxseed gum on reduction of blood glucose and cholesterol in type 2 diabetic patients. International Journal of Food Sciences and Nutrition, 22, 1e11. Thompson, L. U. (2003). Flaxseed, lignans and cancer. In S. C. Cunnane, & L. U. Thompson (Eds.), Flaxseed in human nutrition (2nd ed.) (pp. 194e222). Illinois: AOCS Press. Tzang, B. S., Yang, S. F., Fu, S. G., Yang, H. C., Sun, H. L., & Chen, Y. C. (2009). Effects of dietary flaxseed oil on cholesterol metabolism of hamsters. Food Chemistry, 114, 1450e1455. Wahba, H. M. A., & Al-Zahrany, M. S. H. (2013). Effect of feeding on diets supplemented by some vegetable oils on blood lipids and bone mineral content in osteoporotic rats. Life Science Journal, 10(1), 1458e1465. Wang, J., Rosell, C. M., & Benedito de Barber, C. (2002). Effect of the addition of different fibres on wheat dough performance and bread quality. Food Chemistry, 79, 221e226.

Please cite this article in press as: Marpalle, P., et al., Effect of flaxseed flour addition on physicochemical and sensory properties of functional bread, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.003