Bioactive Carbohydrates and Dietary Fibre 9 (2017) 14–20
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Eﬀect of partial replacement of wheat ﬂour with varying levels of ﬂaxseed ﬂour on physicochemical, antioxidant and sensory characteristics of cookies
Maninder Kaur , Varinder Singh, Rajwinder Kaur Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143005, India
A R T I C L E I N F O
A BS T RAC T
Keywords: Flaxseed Cookies Carbohydrate Antioxidant Sensory Physical
Replacement of wheat ﬂour with varying levels of ﬂaxseed ﬂour (0–30%) on nutritional, functional and antioxidant properties of cookies was investigated. Cookies produced from composite ﬂour mixes were signiﬁcantly (p < 0.05) higher in protein, fat, ash and ﬁber contents than the control. Flaxseed was found to be rich in antioxidant potential as evident from the higher total phenolic content, free radical scavenging activity and reducing power of composite ﬂour cookies in comparison to control. The results indicated that as the concentration of ﬂaxseed ﬂour in the blend increased, the cookies became darker in color with a signiﬁcant (p < 0.05) increase in their spread factor. Sensory panellists rated cookies containing 15% level of ﬂaxseed ﬂour as highly acceptable in relation to their overall acceptability scores. Beyond this level of replacement the texture and ﬂavour of cookies was adversely aﬀected. Principal component analysis revealed that physicochemical and sensory properties of cookies produced by 10% replacement with ﬂaxseed ﬂour were closest to the control cookies.
1. Introduction Flaxseed (Linum usitatissimum L.) also known as linseed, is enjoying an upsurge in popularity as a result of reports on its health beneﬁts to human and its potential to reduce the risk of certain diseases (Oomah & Mazza, 2000). The seed is oval and ﬂat with a pointed tip and has a smooth glossy surface. It diﬀers in dark brown to yellow in color according to its diﬀerent varieties (Freeman, 1995). Flaxseed has a pleasant nutty taste with crisp and chewy texture (Carter, 1996). Although, ﬂaxseed is an oilseed crop, but proximate composition of ﬂaxseed makes it more beneﬁcial for its utilization in various food products as a functional food ingredient. Flaxseed contains approximately 38–45% oil, 28% dietary ﬁber, and 21% protein (Daun, Barthet, Chornick, & Duguid, 2003). The functional components in ﬂaxseed that provide health beneﬁts include α-linolenic acid, lignans and dietary ﬁber (Hall, Tulbek, & Xu, 2006). Antioxidant activity of lignans may contribute to the anticancer activity of ﬂaxseed (Kangas, Saarinen, & Mutanen, 2002; Prasad, 1997; Yuan, Rickard, & Thompson, 1999). Flaxseed is a rich source of diﬀerent types of phenolic compounds such as phenolic acids, ﬂavonoids, phenylpropanoids and tannins (Kasote, 2013). The behavior of proteins in a food system is aﬀected by their techno-functional properties which are mainly dependent on structure of the protein, their hydration mechanisms for solubility and water or
oil retention capacity, rheological characteristics for viscosity and gelation, and their interfacial properties for emulsions and foams (Moure, Sineiro, Dominguez, & Parajo, 2006). The physico-chemical parameters such as temperature, pH, ionic strength and particle size have inﬂuence on the techno-functional properties (Dev & Quensel, 1986; Oomah, Kenaschuk & Mazza, 1995; Krause, Schultz, & Dudek, 2002; Martinez-Flores, Barrera, Garnica-Romo, Penagos, Saavedra & Macazaga-Alvarez, 2006). Flaxseed proteins have real potential for use as techno functional food ingredient in several food products particularly in breads, meat emulsions, and sauces. According to Oomah and Mazza (1998), compositional changes which occur during processing of ﬂaxseed are to be kept in mind when adding value to ﬂaxseed products. Rabetaﬁka, Remoortel, Danthine, Paquot, and Blecker (2011) reported the comparison of functional properties of ﬂaxseed proteins to those of other oilseed proteins. Rathi and Mogra (2013) studied the acceptability of biscuit making quality of ﬂaxseed ﬂour and found that the acceptable level of ﬂaxseed ﬂour in biscuit was 20–40% addition to wheat ﬂour. Rajiv, Indrani, Prabhasankar, and Rao (2011) studied the eﬀect of replacement of roasted and ground ﬂaxseed (RGF) at 5–20% level on the wheat ﬂour dough. The baking test of cookies showed a marginal decrease in spread ratio but beyond replacement of 15% RGF the texture and ﬂavour of the cookies was adversely aﬀected. Khouryieh and Aramouni (2012) investigated the physical and sensory characteristics of cookies prepared from varying levels of replacement of ﬂaxseed
Corresponding author. E-mail address: [email protected]
ﬀmail.com (M. Kaur).
http://dx.doi.org/10.1016/j.bcdf.2016.12.002 Received 10 August 2016; Received in revised form 12 November 2016; Accepted 19 December 2016 2212-6198/ © 2016 Elsevier Ltd. All rights reserved.
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ﬂour (0–18%) with wheat ﬂour. Alpaslan and Hayta (2006) suggested that ﬂaxseed ﬂour could be added to a typical snack formulation up to levels of 10% with a reasonable acceptance oﬀering promising nutritious and healthy alternative to consumers. Though there have been previous reports on physical and sensory characteristics of ﬂaxseed fortiﬁed cookies, but there has been a scarcity of reports on antioxidant potential of ﬂaxseed and how much level is enhanced and losses which occur upon baking of ﬂaxseed incorporated cookies. This prompted us to undertake the present investigation with the objective to evaluate the physical, chemical, sensory, and antioxidant characteristics of cookies containing various levels of ﬂaxseed ﬂour. Accordingly a level of ﬂaxseed ﬂour substitution to wheat ﬂour was suggested with reasonable acceptable sensory scores and superior nutritive value and antioxidant potential than wheat ﬂour cookies.
2.6. Antioxidant properties The antioxidant properties of ﬂours, composite ﬂour mixes and cookies prepared from them were estimated as follows: 2.6.1. Total phenolic content (TPC) TPC of diﬀerent samples was determined according the Folin– Ciocalteu spectrophotometric method (Sharma & Gujral, 2011). Sample (200 mg) was extracted at room temperature (25 °C) with 4 ml of acidiﬁed methanol (HCl/methanol/water, 1:80:10, v/v/v) for 2 h. An aliquot of extract (200 μl) was added to 1.5 ml freshly diluted (10 fold) Folin–Ciocalteu reagent. After equilibration for 5 min, the extract was then mixed with 1.5 ml of sodium carbonate solution (60 g/ l). It was then incubated at room temperature (25 °C) for 90 min, and the absorbance of the mixture was read at 725 nm (Shimadzu, UV1800, Japan). Acidiﬁed methanol was used as a blank. The results were expressed as μg of gallic acid equivalents (GAE) per gram of sample.
2. Materials and methods 2.1. Materials
2.6.2. Antioxidant activity (AOA) AOA was measured by modiﬁed method of Brand-Williams, Cuvelier, and Berset (1995). Samples (100 mg) were ground and extracted with 1 ml methanol for 2 h and centrifuged at 3000g for 10 min. The supernatant (100 μl) was separated and reacted with 3.9 ml of 6×10−5 mol/l of 2,2-diphenyl-1-picrylhydrazyl (DPPH) solution. Absorbance of the extract (A) at 515 nm was read at 0 and 30 min using methanol as blank. Antioxidant activity was calculated as % discolouration. % Antioxidant activity =(1−(A of sample t=30 / A of control t=0)) ×100.
Flax seeds and wheat ﬂour were procured from the local market of Amritsar, Punjab, India. The seeds were ground in a laboratory grinder and the ﬂour so obtained was stored in an air tight container till further used. All the chemicals and reagents used were of analytical grade. 2.2. Composite ﬂour mixes Besides the control sample (100% wheat ﬂour), various blends of composite ﬂour mixes (95WF:05FF, 90WF:10FF, 85WF:15FF, 80WF:20FF, 75WF:25FF and 70WF:30FF) were formulated and stored in air tight containers.
2.6.3. Reducing power The reducing power of sample was measured as described by Zhao et al. (2008). Sample (0.5g) was extracted with 80% methanol (0.5 ml) on metabolic shaker for 2 h. To the extract (1 ml) was added 2.5 ml potassium ferricyanide (1%) and phosphate buﬀer (2.5 ml, 0.2 mol/l, and pH 6.6) followed by incubation at 50 °C. Trichloroacetic acid solution (10%) was then added to the mixture, and then centrifuged at 10,000g for 10 min. The upper layer of solution (2.5 ml) was mixed with 0.5 ml ferric chloride (0.1%) and 2.5 ml deionized water. The absorbance of the mixture was measured at 700 nm. A standard curve was prepared using various concentration of ascorbic acid and the results were reported as μmol ascorbic acid equivalents/g of sample. Increased absorbance of the mixture indicated increased reducing power.
2.3. Preparation of cookies Cookies were prepared from both the control sample and composite ﬂour mixes using AACC method (1995). Formula adopted was shortening 32 g, sugar 70 g, salt 1 g, sodium bicarbonate 1.25 g, dextrose solution (8.9 dextrose in 150 ml distilled water) 16.5 g, distilled water 8 g and ﬂour 112.5 g. Dough was prepared in pin mixture (Morse ED series, USA) and ﬂattened into a sheet of 0.5 cm thickness. It was then cut with the help of a cookie cutter into circular discs of diameter 4.5 cm and transferred to a lightly greased baking tray. Cookies were baked at 200 °C for 11 min in a reel oven (National Mfg. Co. Lincoln, USA). 2.4. Proximate composition
2.7. Physical properties of cookies
The samples of ﬂours and cookies were estimated for their moisture, ash, fat, crude ﬁber and protein (N×6.25) content by employing the standard methods of analysis (AOAC, 1990).
2.7.1. Thickness After baking, the cookies were allowed to cool for 30 min. Five cookies were stacked one upon another on a ﬂat surface and the stack height was measured with the help of vernier calliper. The cookies were restacked and remeasured to get the average thickness in cm. Readings were taken to nearest ½ cm.
2.5. Functional properties The ﬂours from both ﬂaxseed and wheat were analysed for various functional properties. For the determination of bulk density, method given by Kaur and Singh (2005) was adopted. Color measurements of ﬂours and cookies were carried out using Hunter colorimeter Model D 25 optical Sensor (Hunter Associates Laboratory Inc., Reston, VA., U.S.A) on the basis of L*, a* and b* values. Water and oil absorption capacity of the ﬂours was measured by centrifugation method of Sosulski (1962) and Lin, Humbert, and Sosulski (1974), respectively. Least gelation concentration was determined by the method of Coﬀmann and Garcia (1977). The emulsifying activity and stability were determined by the method of Yasumatsu et al. (1972).
2.7.2. Diameter Cookies were laid edge to edge and were measured for diameter. The cookies were rotated through 90 °C and were remeasured for width (cm). Readings were taken to the nearest ½ cm. 2.7.3. Spread factor The spread factor was obtained by ﬁnding the ratio between the average width and thickness of the cookies. It gave an indicator of cookie quality. 15
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the crude ﬁber content of full fat non roasted ﬂaxseed ﬂour to be 8.02% whereas Salehifar and Shahedi (2007) found the crude ﬁber content of wheat ﬂour within the range of 0.12–1.89%. Flaxseed ﬂour was signiﬁcantly (p < 0.05) diﬀerent from wheat ﬂour in exhibiting higher fat, ash, protein and ﬁber contents (Table 1).
2.8. Sensory evaluation of cookies A taste panel performed sensory analysis of cookies formulated from control and composite ﬂour blends. The cookies were evaluated for their color, appearance, texture, ﬂavour and overall acceptability by a sensory panel of ﬁfteen judges (10 female and 5 male, of age 20–38 yrs) using 9 point hedonic scale. Before the sensory evaluation was conducted the panels were trained by using commercial cookies to get familiar with the use of rating method, terminology for each attribute and sensory characteristics of cookies.
3.2. Functional properties of ﬂours The data regarding the functional properties of the ﬂours is reported in Table 1. Bulk density of FF and WF was found to be 0.58 g/ml and 0.63 g/ml, respectively (Table 1). Hussain et al. (2008) reported bulk density of full fat non roasted ﬂaxseed ﬂour to be 0.78 g/ ml. Water and oil absorption capacity of the two ﬂours are represented in Table 1. Both water absorption (WAC) and oil absorption capacity (OAC) of FF was signiﬁcantly (p < 0.05) lower than WF. Hussain et al. (2008) reported that WAC and OAC of full fat non roasted ﬂaxseed ﬂour to be 1.48 g/g. and 1.20 g/g, respectively. The water holding capacity (%) of coarse fraction and middle fraction of wheat ﬂour was in the range of 50–68% (Blanchard, Labouré, Verel, & Champion, 2012). Protonotarious, Drakos, Evagelious, Ritzoulis, and Mandala (2014) observed the oil holding capacity of wheat ﬂour in the range between 78.0–99.1%. Diﬀerent structures of protein and the presence of diﬀerent hydrophilic carbohydrates might be responsible for variations in the WAC of the ﬂours (Oshodi & Ekperigin, 1989). Flours from ﬂaxseed and wheat diﬀered signiﬁcantly in their abilities to emulsify oil. Emulsifying activity (EA) is deﬁned as the ability of the ﬂour to emulsify oil (Kaur & Singh, 2005). The value of EA for FF and WF was observed to be 85.3% and 20.4% respectively. Though FF showed higher EA, but the emulsions produced by it were less stable as evident from its lower emulsion stability (51.2%) in comparison to WF (88.7%). The EA of wheat ﬂour in present study was higher than reported earlier by Shad et al. (2013). The gelation capacity of FF and WF did not diﬀer signiﬁcantly (p < 0.05) from each other. Flours contain high protein and starch contents and the gelation capacity of ﬂours is inﬂuenced by a physical competition for water between protein gelation and starch gelatinization (Singh, 2001). The color characteristics of WF and FF were determined and the results showed that FF was much darker than WF as evident from its lower L* value. The value of a* and b* for FF were greater than those for WF indicating more reddish and yellow tinge in FF. Protonotariou et al. (2014) reported value of L, a* and b* for WF to be 88.6, −1.91 and 12.18 respectively.
2.9. Statistical analysis The data reported in all the tables are an average of triplicate observations unless otherwise speciﬁed. The data were subjected to statistical analyses using Microsoft Excel. A principal component analysis of cookie properties was carried out to provide diﬀerences and similarities among various composite ﬂour blends using Minitab statistical software (Minitab Inc, State College, PA, USA). 3. Results and discussion 3.1. Proximate composition of ﬂours Proximate composition of whole wheat ﬂour (WF) and ﬂaxseed ﬂour (FF) is reported in Table 1. Moisture content is an important quality factor for the preservation, convenience in packaging and transport. In addition to it, moisture content also constitutes an identity standard (Bradely, 2003). Moisture and fat contents of WF and FF were found to be 12.15% and 2.33% and 6.5% and 40.44%, respectively. Fat content of Canadian ﬂax was observed to be 41% (Morris, 2003). Hadnadev, Torbica, and Hadnadev (2011) found the fat content of wheat ﬂours within the range of 0.75–2.34%. Ash content of FF and WF was 3.52% and 1.03%. which was in close agreement with previously reported value of 3.46% in full fat ﬂax seed ﬂour (Hussain, Anjum, Butt, Khan, & Asghar, 2006) and 0.47–1.14% in wheat ﬂour (Hadnadev et al., 2011). Protein content of FF and WF was observed to be 20.12% and 11.52%, respectively. These values correlated well with the earlier reported values of 11.30% in wheat ﬂour (Hussain et al., 2006) and 10.5–31% in ﬂaxseed (Oomah & Mazza, 1993). Crude ﬁber content in FF and WF was found to be 8.05% and 0.59%, respectively. Hussain, Anjum, Butt, and Sheikh (2008) reported
3.3. Antioxidant properties of ﬂours
Table 1 Proximate composition, functional properties, color characteristics and antioxidant activity of flaxseed and wheat flours. Parameters
Fat (%) Ash (%) Protein (%) Fiber (%) Bulk density (g/ml) WAC (g/g) OAC (g/g) EA (%) ES (%) LGC (%) L a* b* Total Phenolic content (mgGAE/100 g) Free radical scavenging activity (%) Reducing power (µmol AAE/g)
40.4 ± 0.03b 3.52 ± 0.12b 20.12 ± 0.05b 8.05 ± 0.14b 0.58 ± 0.23a 1.50 ± 0.12a 1.28 ± 0.09a 85.3 ± 0.09b 51.2 ± 0.07a 10.00a 59.1 ± 1.56a 6.06 ± 0.04b 14.3 ± 0.13b 91.8 ± 0.24b 48.24 ± 0.11b 24.57 ± 0.02b
2.3 ± 0.04a 1.03 ± 0.05a 11.52 ± 0.06a 0.59 ± 0.23a 0.63 ± 0.14b 2.68 ± 0.20b 2.36 ± 0.04b 20.4 ± 0.02a 88.7 ± 0.03b 10.00a 84.2 ± 0.23b 0.51 ± 0.01a 6.94 ± 0.42a 8.23 ± 0.18a 6.35 ± 0.13a 4.29 ± 0.01a
Results of total phenolic content (TPC) of the ﬂours are represented in Table 1. The value of TPC for FF was much higher (91.8 mg GAE/ 100 g) as compared to WF (8.23 mg GAE/100 g). Adom, Sorrells, and Liu (2003) reported TPC for diﬀerent wheat varieties within the range of 710–860 μmol gallic acid/g. Dharshini, Sumayaa, and Thirunalasundari (2013) found the total phenolic and tannin content of ﬂaxseed ﬂour to be 47.0 mg GAE/100 g. Flaxseed has been reported to contain 8–10 g/kg total phenolic acids (Oomah, Kenaschuk & Mazza, 1995). The antioxidant activity (AOA) of FF as determined by DPPH was signiﬁcantly higher (48.24%) in comparison to WF (6.35%) (Table 1). According to Anwar and Przybylski (2012), the free radical scavenging activity of ﬂaxseed ﬂour using DPPH was observed to be 42.2% which was in close agreement with the values of ﬂaxseed observed in the present study. The total antioxidant activity of wheat varieties ranged from 36.9 to 51.2μmol of Vitamin C equiv/100 g ﬂour (Adom et al., 2003). The reducing power is also an indicator of antioxidant activity. The value of reducing power for FF and WF was evaluated as 24.57(µmol AAE/g) and 4.29 (µmol AAE/g), respectively. There is a direct relation between absorbance and reducing power. Higher the absorption, higher the value of reducing power of the sample. Gujral, Sharma, Gill, and Kaur (2013) reported the reducing power of wheat ﬂour to be 7.7 μmol AAE/g.
Values are an average of triplicate observations; ± standard deviation; Values followed by similar superscript in a row do not differ significantly (P < 0.5). WAC - Water absorption capacity; OAC – Oil absorption capacity; EA – Emulsifying activity; ES – Emulsion stability; LGC – Least gelation concentration
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Table 2 Proximate composition of composite ﬂour mixes. Parameters (%)
(WF 95%+FF 5%)
(WF 90% + FF 10%)
(WF 85% +FF 15%)
(WF 80%+ FF 20%)
(WF 75%+ FF 25%)
(WF 70%+FF 30%)
Moisture Fat Ash Protein Fiber
8.18 ± 0.20b 3.60 ± 0.19a 1.30 ± 0.02a 13.60 ± 0.01a 1.13 ± 0.07a
7.75 ± 0.04ab 6.08 ± 0.04b 1.33 ± 0.03a 14.53 ± 0.03ab 1.43 ± 0.03ab
7.57 ± 0.07ab 8.02 ± 0.03bc 1.45 ± 0.01ab 15.14 ± 0.03ab 1.68 ± 0.03ab
7.52 ± 0.07ab 9.58 ± 0.36c 1.54 ± 0.05ab 15.67 ± 0.02ab 1.91 ± 0.06b
7.31 ± 0.06a 11.63 ± 0.07 cd 1.65 ± 0.06b 17.07 ± 0.04b 2.08 ± 0.04b
7.16 ± 0.2a 13.56 ± 0.01d 1.73 ± 0.03b 17.24 ± 0.01b 2.22 ± 0.03c
Values are an average of triplicate observations; ± standard deviation; Values followed by similar superscript in a row do not differ significantly (P < 0.5). WF- wheat flour; FF- flaxseed flour
Table 3 Proximate composition, color characteristics and physical parameters of cookies prepared from blends of flaxseed and wheat flour. Parameters Moisture (%) Fat (%) Ash (%) Protein (%) Fiber (%) L a* b* Diameter (cm) Thickness (cm) Spread factor
(WF 100%) c
4.95 ± 0.13 13.54 ± 0.04a 1.24 ± 0.07a 7.40 ± 0.1a 0.42 ± 0.004a 61.66 ± 0.87c 9.96 ± 0.21b 26.33 ± 0.43b 5.14 ± 0.3a 0.71 ± 0.1a 7.23b
(WF 95%+5% FF) bc
4.34 ± 0.2 18.49 ± 0.06b 1.29 ± 0.05a 7.70 ± 0.3ab 0.5 ± 0.003a 57.59 ± 2.04b 7.21 ± 0.07a 25.19 ± 0.65ab 5.54 ± 0.1ab 0.85 ± 0.2b 6.51a
(WF 90%+10% FF) b
4.18 ± 0.07 19.26 ± 0.04b 1.35 ± 0.06ab 8.14 ± 0.1b 0.63 ± 0.01b 56.71 ± 0.3b 7.74 ± 0.54a 23.37 ± 0.97a 5.53 ± 0.2ab 0.83 ± 0.15b 6.66a
(WF 85%+15% FF) b
3.93 ± 0.02 20.4 ± 0.07bc 1.47 ± 0.07b 8.84 ± 0.2bc 0.84 ± 0.04bc 53.78 ± 0.25ab 8.55 ± 0.31ab 25.13 ± 0.33ab 5.56 ± 0.1ab 0.84 ± 0.2b 6.61a
(WF 80%+20% FF) ab
3.69 ± 0.05 21.02 ± 0.03bc 1.56 ± 0.1bc 9.01 ± 0.2bc 0.91 ± 0.03bc 53.43 ± 0.09ab 8.55 ± 0.07ab 25.13 ± 0.34ab 5.86 ± 0.2b 0.85 ± 0.3b 6.89ab
(WF 75%+25% FF) ab
3.53 ± 0.02 21.87 ± 0.06c 1.63 ± 0.04bc 9.28 ± 0.3c 1.12 ± 0.5c 53.43 ± 0.56ab 7.79 ± 0.09a 24.07 ± 0.24ab 5.86 ± 0.2b 0.84 ± 0.2b 6.97ab
(WF 70%+30% FF) 2.92 ± 0.14a 22.5 ± 0.01c 1.71 ± 0.05c 9.54 ± 0.4c 1.42 ± 0.02d 50.43 ± 0.57a 8.11 ± 0.34ab 23.57 ± 0.56a 5.88 ± 0.1b 0.83 ± 0.15b 7.08b
Values are an average of triplicate observations; n=3( ± Standard Deviation); Values followed by similar superscript in a row do not differ significantly (P < 0.5). FF – Flaxseed flour; WF – Wheat flour
increased from 5% to 30% in ﬂour mixes, a signiﬁcant (p < 0.05) decrease in moisture content was observed. Fat, ash, protein and ﬁber content of composite ﬂour mixes increased as the concentration of FF increased progressively in the ﬂour mixes (Table 2). The cookies prepared from diﬀerent blends of FF and WF was also analysed for their chemical composition. FF had a signiﬁcant (p < 0.05) eﬀect on moisture content of the cookies relative to the control with a decrease in moisture content from 4.95% to 2.92% with the increase in concentration of FF to the blend (Table 3). In an earlier study it was observed that as the FF concentration increased in the blend, the moisture content of cookies decreased (Khouryieh & Aramouni, 2012). Due to low moisture content of the cookies, they were not susceptible to any microbial or chemical activities. There was a progressive increase in the fat, ash, protein, ﬁber content of cookies as the concentration of FF increased in the blend. Thus FF cookies were found to be nutritionally superior to 100% WF cookies at diﬀerent levels of replacement. 3.4.2. Color characteristics of cookies The data regarding color characteristics of the cookies from diﬀerent ﬂour mixes are given in Table 3 and shown in Fig. 1. It was observed that as the concentration of FF in the blend increased, the cookies became darker in color as evident from lower L (61.66) value of the blends in comparison to control cookies. The highest value of L* was for control sample (61.66) and the lowest value (50.43) was for 30% ﬂaxseed cookies. The value of a* and b* of FF incorporated cookies were less than a* and b* value of control cookies at diﬀerent levels of replacement.
Fig. 1. Cookies prepared from diﬀerent levels (5–30%) of incorporation of ﬂaxseed ﬂour to wheat ﬂour.
3.4.3. Physical parameters of cookies Spread factor of cookies has long been used to determine the quality of ﬂour for producing cookies (Gaines, 1990). Spread factor is the ratio that depends on the values of the thickness and diameter of the cookies. Highest spread factor was observed in control sample. With the increase in concentration of FF, spread factor of cookies increased
3.4. Physicochemical properties of cookies 3.4.1. Proximate composition of composite ﬂour mixes and cookies Diﬀerent composite ﬂour mixes were analysed for their chemical composition (Table 2). The results showed that as the amount of FF 17
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Table 4 Total phenolic content (TPC), free radical scavenging activity (DPPH) and reducing power of composite flour mixes and cookies prepared from blends of flaxseed and wheat flour. Parameters
(WF 95%+5% FF)
TPC (mg GAE/100 g) Flour mixes 8.23 ± 0.23a 12.05 ± 0.12ab Cookies 6.56 ± 0.15a 8.96 ± 0.24ab DPPH (%) Flour mixes 6.35 ± 0.4a 8.24 ± 0.8ab Cookies 5.5 ± 0.7a 7.93 ± 0.3ab Reducing power (µmol AAE/g) Flour mixes 4.29 ± 0.02a 5.00 ± 0.01a Cookies 1.86 ± 0.01a 2.14 ± 0.03a
(WF 90%+10% FF)
(WF 85%+15% FF)
(WF 80%+20% FF)
(WF 75%+25% FF)
(WF 70%+30% FF)
14.57 ± 0.24b 9.82 ± 0.19ab
17.76 ± 0.13bc 12.16 ± 0.21b
19.08 ± 0.15bc 14.07 ± 0.14bc
21.28 ± 0.16bc 18.46 ± 0.25c
22.18 ± 0.18c 19.32 ± 0.22c
8.59 ± 0.3ab 8.13 ± 0.5b
9.36 ± 0.5b 9.05 ± 0.8b
10.32 ± 0.2bc 10.14 ± 0.3bc
11.16 ± 0.7bc 11.03 ± 0.9bc
12.54 ± 0.3c 12.25 ± 0.2c
6.43 ± 0.03ab 3.57 ± 0.03b
6.43 ± 0.02ab 3.57 ± 0.02b
7.86 ± 0.04ab 5.00 ± 0.03bc
7.86 ± 0.03ab 5.00 ± 0.01bc
9.29 ± 0.02b 6.43 ± 0.02c
Values are an average of triplicate observations; n=3( ± Standard Deviation); Values followed by similar superscript in a row do not differ significantly (P < 0.5). FF – Flaxseed flour; WF – Whole wheat flour; TPC – Total phenolic content; DPPH – (1,1- Diphenyl 2 picrylhydrazyl)
from 6.51 to 7.08 but was lower than control sample (7.23). Bala, Gul, and Riar (2015) reported the spread factor of WF cookies to be 7.26. Both diameter and thickness of cookies increased as the concentration of FF increased from 0% to 30% in the blend. FF cookies had higher thickness than the control sample.
Table 5 Sensory evaluation scores of cookies prepared from blends of flaxseed and wheat flour. Sample (WF (WF (WF (WF (WF (WF (WF
3.4.4. Antioxidant activity of ﬂour mixes and cookies The antioxidant properties of composite ﬂour mixes and cookies prepared from them are shown in Table 4. TPC of ﬂour mixes increased with increase in concentration of FF in the blend. Upon baking a substantial decrease in TPC of cookies in comparison to ﬂour mixes was observed. This decrease may be attributed to the loss of phenolic components during baking (Jonsson, 1991). Highest decrease in TPC was observed in blend containing 10% FF which showed 32.60% loss of TPC upon baking and lowest was recorded for blend containing 30% FF which showed 12.89% loss of TPC. Free radical scavenging activity of ﬂour mixes also increased with an increase in level of FF to WF in the blends. Highest DPPH activity was exhibited by ﬂour mixes containing 30% FF (12.54%). Cookies prepared from composite ﬂour mixes showed a decrease in their DPPH activity upon baking. Highest decrease in DPPH activity was exhibited by control sample (13.36%) and lowest (1.16%) was shown by blend containing 25% level of FF upon baking. This may be due more eﬀect of baking on the antioxidant activity of WF as compared to FF. Reducing power (RP) also followed a similar trend to TPC and free radical scavenging activity (Table 4). Diﬀerent ﬂour mixes showed higher RP values than cookies prepared from it. A signiﬁcant increase in RP with an increase in level of FF to the blend was observed. The reducing power of an antioxidant compound is associated with the presence of reductones and their antioxidant capacity is based on the breaking of the free radical chain reaction by donating a hydrogen atom, and preventing peroxide formation (Sharma & Gujral, 2011). A signiﬁcant reduction in RP upon baking with higher loss in control sample than composite ﬂour mixes cookies was observed.
100%) 95% + 90% + 85% + 80% + 75% + 70% +
5% FF) 10% FF) 15% FF) 20% FF) 25% FF) 30% FF)
7.62 7.45 7.72 7.63 7.36 7.36 7.63
7.45 7.36 7.45 7.72 7.09 7.09 6.81
7.33 7.36 7.45 7.63 7.62 7.54 7.09
7.46 7.39 7.54 7.66 7.39 7.33 7.51
N – Number of panellists (15); values are means of 15 observations; FF- Flaxseed flour; WF – Wheat flour
prepared from 25% and 30% were given lowest scores with respect to overall acceptability. The results of the sensory evaluation of the biscuits prepared from the diﬀerent treatments of the composite ﬂour are according to the ﬁndings of Gambus, Mikulec, and Matusz (2003) who reported increasing the level of ﬂaxseed ﬂour, matri ﬂour, and cowpea ﬂour in the biscuits resulted in the signiﬁcant decrease in the sensory attributes of the cookies. In a study reported by Khouryieh and Aramouni (2012) it was observed that ﬂaxseed ﬂour can be incorporated in cookies as a partial replacement up to 12% of wheat ﬂour without negatively aﬀecting the physical and sensory quality. 188.8.131.52. Principal component analysis. The results of principal component analysis of various physical, chemical and antioxidant properties of cookies prepared from composite ﬂour blends and wheat ﬂour are shown in Fig. 2a. The ﬁrst and second principal component described 75.6% and 17.7% of the variances, respectively. Together the ﬁrst two principal components represented 93.3% of the total variability. The loading plot of the two principal components provided information about several correlations between measured properties (Fig. 2a). A negative correlation of lightness with fat (r =−0.964), ash (r =−0.938), protein (r =−0.962), and ﬁber (r =−0.925) highly signiﬁcant at p < 0.01 was observed. Cookie diameter was positively correlated to fat, ash, protein and ﬁber but negatively correlated to lightness at signiﬁcance level of p < 0.01. TPC, AOA and RP showed a signiﬁcant (p < 0.01) positive correlation with diameter, fat, ash, protein and ﬁber and a negative with lightness. Highly signiﬁcant interrelationships between antioxidant parameters were observed. TPC was positively correlated with AOA (r =0.970, p < 0.01) and RP (r =0.941 p < 0.01) whereas AOA showed a signiﬁcant positive correlation with RP (r =0.949, p < 0.01).
3.4.5. Sensory evaluation of cookies The direct and ultimate method for accessing the acceptability of cookies is by sensory evaluation. Sensory evaluation methods are more eﬀective, require small sample size, less time and do not require trained panelist (Miskelly & Moss, 1985). The descriptive sensory evaluation values of cookies prepared from control and composite ﬂour mixes are presented in Table 5. The sensory panellists rated control sample with highest score for color and ﬂavour. These were closely followed by blend containing 15% FF. Highest overall acceptability scores (7.66) were for 15% ﬂaxseed cookies and after this level of substitution a decrease in acceptability scores was observed. Hussain et al. (2006) prepared cookies by addition of ﬂaxseed ﬂour in wheat ﬂour. These workers observed that maximum score was obtained by cookies prepared from whole wheat ﬂour while minimum scores were given to cookies prepared from 25% and 30% ﬂaxseed ﬂour addition. Cookies
The sensory evaluation scores of the cookies were also subjected to PCA. The score plot (Fig. 2b) showed that control sample and cookies prepared from 10% and 15% FF addition were located at the far left of the score plot with a negative score while all other cookies were located 18
Bioactive Carbohydrates and Dietary Fibre 9 (2017) 14–20
M. Kaur et al.
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Fig. 2. a: Principal component analysis: loading plot of ﬁrst principal component (PC1) and second principal component (PC2) describing the overall variation among measured properties of cookies from control sample and diﬀerent composite ﬂour mixes. Fig. 2b: Principal component analysis: score plot of PC1 and PC2 describing the variation among sensory evaluation scores of cookies from control sample and diﬀerent composite ﬂour mixes.
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