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Effect of multigrains on rheological, microstructural and quality characteristics of north Indian parotta – An Indian flat bread
LWT - Food Science and Technology 44 (2011) 719e724
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Effect of multigrains on rheological, microstructural and quality characteristics of north Indian parotta e An Indian flat bread D. Indrani, P. Swetha, C. Soumya, Jyotsna Rajiv, G. Venkateswara Rao* Flour Milling, Baking and Confectionery Technology, Central Food Technological Research Institute, Mysore 570 020, Karnataka, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 12 August 2010 Received in revised form 11 November 2010 Accepted 11 November 2010
Effect of replacement of whole-wheat flour with multigrain blend, MGB (chick pea split without husk, barley, soya bean and fenugreek seeds) at 10, 20, 30 and 40 g/100 g on rheological characteristics of whole-wheat flour and quality of north Indian parotta (NIP) making was studied. Use of increasing amount of MGB from 0 to 40 g/100 g increased farinograph water absorption, decreased dough stability, extensograph resistance to extension, extensibility, amylograph peak viscosity and overall quality score of NIP from 53 to 38 for the maximum score of 60. Use of combination of dry gluten powder, sodium stearoyl-2-lactylate and hydroxypropylmethylcellulose separately and in combination significantly improved the overall quality of NIP with 30 g/100 g MGB. Addition of multigrains increased the protein, fat, dietary fiber and mineral contents of north Indian parotta. Ó 2010 Elsevier Ltd. All rights reserved.
Keywords: Indian flat bread Multigrains Rheology Microstructure Nutrition
1. Introduction In India, wheat based traditional products are chapati, puri, phulka, tandoori roti, north Indian parotta, south Indian parotta, nan, batura and other similar products. North Indian parotta is prepared from whole-wheat flour, salt, refined oil and water. The dough is sheeted and laminated at least twice. The product is normally triangular in shape, contains 4e6 discrete layers and is slightly thicker than chapati. The baking industry is currently witnessing a situation in which declaration on prepared products such as high fiber, high protein, low calorie etc are very much in style. Blending of whole grains which are rich in protein, dietary fiber, minerals in staple food items are considered beneficial for health. The use of multigrain offers a good opportunity to improve the taste and nutritional quality of north Indian parotta. Chick pea (Cicer arietinum) or bengal gram (Indian name) is grown in tropical, sub-tropical and temperate regions. Chick pea is valued for its nutritive seeds with high protein content, 25.3e28.9% (Hulse, 1991). Chick pea protein is rich in lysine and arginine but most deficient in sulphur containing amino acids, methionine and cystine (Manan, Hussain, & Iqbal, 1984). Hence, it can balance the amino acid and may improve the nutritive value of cereal based products (Singh, Rao, & Singh, 1988). Barley (Hordeum vulgare) is
* Corresponding author. Tel.: þ91 821 2517730; fax: þ91 821 2517233. E-mail address: [email protected] (G. Venkateswara Rao). 0023-6438/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2010.11.017
the world’s fourth most important cereal crop after wheat, maize and rice. Barley grain contains protein of about 9.9% of high biological value, is characterised by the high level of dietary fiber (15.6%), including the most valuable b-glucans, and also contains all native forms of vitamin E (Macgregor & Fincher, 1993). Soya bean is the most commonly employed source of vegetable proteins for enrichment of bakery products. Soya bean has high protein (38e40%), fat (18e20%) and lysine (5e6%) contents, which have great potential in overcoming proteinecalorie malnutrition (Rastogi & Singh, 1989). Fenugreek (Trigonella foenum graecum) seeds can be a good supplement to cereals because of its high protein (25%), lysine (5.7 g/16 g N), soluble (20%) and insoluble (28%) dietary fibres besides being rich in calcium, iron and beta carotene (Shankaracharya, 1973). Use of additives not only brings about improvement in the dough and quality characteristics but also counteracts the deleterious effects caused by the addition of non wheat materials. Gujral and Ambika (2002) reported that chapatis with improved taste, texture and nutritional quality could be made by replacing wholewheat flour with flours from rice, corn, millets and black gram. They opined that additives like wet gluten and sodium caseinate significantly improved the texture of these chapatis. Friend, Waniska, and Rooney (1993) increased the fiber content of wheat tortillas by incorporating 10% oat or rice brans. They reported that addition of 2% gluten increased water absorption, improved machinability and markedly improved shelf stability or rollability of wheat tortillas. SEM provides an appropriate means for
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characterising the physical properties and textural attributes of food ingredients in a formulated product. (Belsie, Raseo, Siffring, & Bruinsma, 1993). Microstructure studies on Indian flat breads like chapati, puri, parontha, south Indian parotta have been reported by many researchers (Indrani, Prabhasankar, Rajiv, & Venkateswara Rao, 2007; Sidhu, Siebel, & Meyer, 1990; Smitha, Jyotsna Rajiv, Khyrunnisa Begum, & Indrani, 2008; Srivastava, Meyer, Haridas Rao, & Siebel, 2002). With this background, work was undertaken to study the influence of multigrain blends consisting of chick pea split without husk, barley, soya bean and fenugreek seeds, on dough properties, microstructure and quality characteristics of north Indian parotta. 2. Materials and methods Whole-wheat flour, chick pea split without husk, barley, soya bean, fenugreek seeds, salt and edible sunflower oil were brought at the local market. Dry gluten powder, sodium stearoyl2-lactylate (P.D. Fine Chemicals, Bangalore, India) and hydroxypropylmethylcellulose (Dow Chemical International Pvt, Ltd, Mumbai, India,) ingredients like water, salt (common food grade sodium chloride) were used for the studies. 2.1. Preparation of blends To provide maximum nutritional benefit in north Indian parotta, chick pea split without husk, barley, soya bean, fenugreek seeds were selected, separately milled to a particle size of approximately 200 mm using a hammer mill (Model No. 79952, Type 120, Falling Number AB, Sweden) and combined in the ratio of 4.0:3.0:2.5:0.5 respectively based on preliminary baking trials. Using the selected blend five different multigrain blends (MGB) namely 0,10, 20, 30 and 40 g/100 g was prepared. The amount of whole-wheat flour þ MGB (chick pea split flour þ barley flour þ soya bean flour þ fenugreek seed flour) in 0 g/100 g MGB was (100 þ 0 þ 0 þ 0 þ 0 g); 10 g/100 g MGB (90 þ 4 þ 3 þ 2.5 þ 0.5 g); 20 g/100 g MGB (80 þ 8 þ 6 þ 5.5 þ 0.5 g); 30 g/100 g MGB (70 þ 12 þ 9 þ 8.5 þ 0.5 g) and 40 g/100 g MGB (60 þ 16 þ 12 þ 11.5 þ 0.5 g) respectively. The whole-wheat flour, chick pea split flour, barley flour, soya bean flour, fenugreek seed flour and different MGB were analysed separately for moisture (method 44-16), ash (method 08-01), protein (method 46-10) and fat (method 30-10) using the American Association of Cereal Chemists (AACC, 2000) methods. Dietary fiber (method 991.43) was determined according to AOAC (1999) method. All estimations were done in triplicate. 2.2. Rheological and north Indian parotta (NIP) making characteristics Effect of 0, 10, 20, 30 and 40 g/100 g MGB, combination of additives e dry gluten powder (DGP) þ sodium stearoyl-2-lactylate (SSL) þ hydroxypropylmethylcellulose (HPMC) to 30 g/100 g MGB on farinograph (method 54-21, AACC, 2000) amylograph (method 22-10, AACC, 2000), extensograph (method 54-10, AACC, 2000) and NIP characteristics of whole-wheat flour was studied. The NIP was prepared using the following formulation: 0/10/20/30/40 g/100 g MGB, combination of additives (2 g/100 g DGP þ 0.5 g/100 g SSL þ 0.5 g/100 g HPMC), salt: 0.5 g/100 g; oil: 5 g/100 g and water: farinograph water absorption. NIPs in quadruplicate were prepared by mixing the ingredients in a Hobart mixer (Model N-50, Hobart, GmbH, Offenburg, Germany) with a flat blade for 4 min at 61 rpm. The dough was placed in a bowl, covered with wet cloth, rested for 20 min in a chamber maintained at 30 C and 75% RH, divided into 30 g each, rounded, sheeted on a square frame of 3 mm using a wooden rolling pin to a round shape. About 2.5 ml of oil was
applied, spread all over the surface of the circular dough, folded into half circle, again applied about 2.5 ml of oil, folded into quarter circle, sheeted into a triangular shape of 3 mm thickness. Baking was carried out using hot plate for 2 min at 180 C by turning at every 30 sec, cooled for 15 min and packed in poly propylene pouches and evaluated after 2 h of storage at room temperature (27 C, 65% humidity). The horizontal, vertical axes and thickness of NIP was measured using a vernier calipers. The shear value of NIP was determined by measuring the force required to shear a piece (2 cm width, 6 cm length) of NIP using the texture analyser (Model TAHdi, Stable Microsystems, Surrey, UK) under the following conditions; load cell,10 kg, plunger speed,100 mm/min; WarnereBratzler shear attachment. Ten panellists (age range 25e55 years both male and female) who were familiar with the quality aspects of wheat based traditional products, were further oriented in four sessions involving 2 h of training in each session. 4 samples of NIPs in 4 replicates were evaluated by each panellist following a score card consisting of various quality parameters like appearance (1 ¼ rough surface, dark spots randomly distributed, dry; 10 ¼ smooth surface, light brown spots uniformly distributed, moist); pliability (1 ¼ brittle; 10 ¼ pliable); tearing strength (1 ¼ no resistance to tear; 10 ¼ offers slight resistance to tear); layer separation (1 ¼ fused layers; 20 ¼ thin distinct layers); eating quality (1 ¼ lacks chewiness/highly chewy; 10 ¼ slightly chewy). The overall quality score (max. 60) was taken as the combined score of all five-quality attributes. The above score card for evaluation of NIP was prepared as per the method of evaluation of south Indian parotta of Smitha et al. (2008). 2.3. Scanning electron microscopic studies SEM studies were carried out using Leo scanning electron microscope Model 435 VP (Leo Electronic Systems, Cambridge, UK). The milled grains and seeds used in the studies were defatted with hexane. Developed dough immediately after mixing was thinly sheeted and cut into pieces (size 20 20 mm) without damaging the structure. The sample pieces of the NIP dough were freeze-dried using Heto freeze-dryer Model DW3 (Allerød, Denmark), separately placed on the sample holder with the help of a double scotch tape and sputter-coated with gold (2 min, 2 mbar). Finally, each sample was transferred to the microscope where it was observed at 15 kV and 9.75 105 Torr vacuum. 2.4. Statistical analysis Data were statistically analysed using Duncan’s new multiple range tests (DMRT) with different experimental groups appropriate to the completely randomized design with four replicates each as described by Steel and Torrie (1960). The significant level was established at P 0.05. 3. Results and discussion 3.1. Proximate composition The data (Table 1) shows that the grains are more nutritious than whole-wheat flour, with increase in the percentage of MGB from 0 to 40 g/100 g the nutritional characteristics of whole-wheat flour increases with respect to ash, protein, fat and dietary fiber contents. 3.2. Effect of MGB and additives on the rheological characteristics of whole-wheat flour Use of increasing amount of MGB from 0 to 40 g/100 g increased farinograph water absorption (Table 2) from 74.6 to 75.5%, dough
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Table 1 Chemical characteristicsa (g/100 g) of multigrains and blends. Parameters
Ash Protein Fat Dietary fiber a
Multigrains
Multigrain blends g/100 g
Chick pea split
Barley grain
Soya bean
Fenugreek seeds
0
10
20
30
40
2.7 0.01 20.8 0.20 5.6 0.05 15.3 0.11
1.2 0.01 11.5 0.09 1.3 0.01 15.6 0.12
4.6 0.02 43.2 0.16 19.5 0.18 23.0 0.20
3.0 0.02 26.2 0.17 5.8 0.06 48.6 0.22
1.5 0.02 11.8 0.20 1.7 0.05 12.5 0.12
1.7 0.03 12.61 0.21 2.4 0.06 13.1 0.11
1.9 0.08 13.6 0.18 3.2 0.05 13.7 0.10
2.0 0.09 15.5 0.15 3.7 0.03 14.2 0.22
2.2 0.10 17.5 0.16 4.3 0.08 14.7 0.23
Dry mater basis. Values are means of three replicates standard deviation.
development time from 5.5 to 6.5 min and decreased stability from 4.8 to 2.5 min. The increase in water absorption with the incorporation of MGB is due to the presence of fibres in the multigrains. Mathews, Sharpe, and Clark (1970) studied the effect of replacement of wheat flour with oil seed flours such as cotton seed, peanut, saff flour seed and soy at 25% level on farinograph, extensograph, amylograph and bread making characteristics of wheat flour. They reported an increase in farinograph water absorption, decrease in band width showing poor dough stability, extensograph extensibility, amylograph peak viscosity and loaf volume. According to them the dough weakening is due to the decrease in wheat gluten content and competition between proteins of wheat flour and sesame for water. El-Adawy (1997) also reported an increase in dough development time for wheat flour supplemented with sesame products at protein levels of 14, 16, 18 and 20%; they opined that the increase in dough development time may be due to the differences in the physico-chemical properties of sesame products and that of wheat flour. The results presented in Table 2 shows that, as the level of MGB increased from 0 to 40 g/100 g, extensograph resistance to extension, extensibility and area decreased indicating a decrease in the elasticity, extensibility and strength of the dough with the addition of the MGB. Mathews et al. (1970) also reported a decrease in the dough extensibility and energy values when wheat flour was replaced with oil seed flours such as cotton seed, peanut, safflower seed and soy. These results show that addition of multigrains adversely affected the stretching Table 2 Effect of multigrain blends (MGB) on the rheological characteristics of whole-wheat flour. Parameters
Farinograph Water absorption (g/100 g) Dough development time (min) Dough stability (min) Extensograph Resistance to extension, R (BU) Extensibility, E (mm) Area (cm2) Amylograph Gelatinization temperature ( C) Peak viscosity (BU) Hot paste viscosity (BU) Cold paste viscosity (BU) Breakdown (BU) Setback (BU)
MGB (g/100 g) 0
10
20
30
40
30 þ CA
74.6a
74.8a
75.0b
75.2b
75.5c
77.0c
5.5a
5.5a
6.0b
6.0b
6.5c
7.0d
4.8c
4.5c
4.0b
3.5b
2.5a
6.5d
350c
325b
310b
290a
280a
360c
140d 80d
130c 76c
122c 70c
115b 64b
101a 60a
137d 85d
71.0a
71.5a
72.0b
72.4b
73.6c
72.5b
571e 378e 731e 193e 353d
537d 359d 677d 178d 318c
445c 310c 597c 135c 287b
378b 279b 530b 99b 276b
306a 233a 467a 73a 234a
444c 322c 643d 122c 321c
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). Values in the row with the same letter in superscript are not significantly different from each other at P 0.05.
properties of the dough. Use of increasing amount of MGB increased amylograph gelatinization temperature, decreased peak viscosity, hot paste viscosity, cold paste viscosity, set back and breakdown values (Table 2). The aforementioned results indicate that in the presence of MGB containing mixture of starch, protein, dietary fiber, wheat starch has shown delayed onset of initial viscosity, decreased viscosity during heating from 30 to 90 C, cooking at 95 C and cooling from 95 to 50 C. The decreased values for both breakdown and set back indicates less resistance of starch granules to thermal treatment and mechanical shearing and less tendency to retrograde. Ragee and Abdel-Aal (2006) studied the pasting properties of wheat flours, whole grain meals from barley, millet, rye and sorghum and their blends. They reported that the peak viscosity of barley whole grain meal (1355 cP) was comparable to hard wheat flour (1335 cP), millet and rye slurries showing intermediate degree of peak viscosity (1130 and 1084 cP) whereas sorghum slurries exhibited a low peak viscosity (821 cP). They opined that high content of starch in wheat flour compared to whole grain meals contributed to higher peak viscosity. Hung, Maeda, and Morita (2007) studied the pasting proprieties of whole waxy wheat flour (WWF) as well as from 10, 30 and 50% WWF substituted flours. They reported lower peak viscosities for WWF and substituted flours when compared to commercial white wheat flour due to the high amount of dietary fiber and low amount of total carbohydrate present in these samples. Gómez, Oliete, Rosell, Pando, and Fernández (2008) determined viscometric parameters of wheat and different chick peak cultivars using rapid visco analyzer. They reported that chick pea flours resulted in pastes with lower peak viscosity, holding strength, breakdown, final viscosity and total set back than the wheat flour, they observed that it is likely due to their lower carbohydrate content and also their different protein content affecting the viscometric parameters (Morris, King, & Rubenthaler, 1997). The results presented in Table 2 shows that addition of CA (2 g/100 g DGP þ 0.5 g/100 g SSL þ 0.5 g/ 100 g HPMC) increased farinograph water absorption, dough stability, extensograph resistance to extension, extensibility, area and amylograph characteristics of whole-wheat flour with 30 g/ 100 g MGB. The above results indicate that addition of CA significantly increased strength, elasticity and extensibility of the wholewheat flour dough with 30 g/100 g MGB. The peak viscosity also increased with addition of CA indicating influence of CA on the pasting characteristics of multigrain blends. 3.3. Microstructure of grains, whole-wheat flour, NIP dough with MGB and CA Fig. 1 a represents the micrograph of barley grain in which starch granules with adhering protein bodies can be observed. This observation is in line with the study of microstructure of barley by Fornal, Sadowska, Ornowski, Jelinski, and Velikanov (2000). In Fig. 1b, c and d which are the micrographs of soya bean, chick pea split and fenugreek respectively, aggregates of protein bodies can be observed. Other researchers (Huges & Swanson, 1985; McEwen, Drouzek, & Bushuk, 1974; Sefadedeh & Stanley, 1979; Wolf, 1970)
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Fig. 1. Scanning electron micrographs (magnification 2000) of grains and whole-wheat flour. (a) Barley grain; (b) soya bean; (c) chick pea split; (d) fenugreek seed; (e) wholewheat flour. PM: protein matrix; PB: protein bodies; SG: starch granule; LSG: large starch granule.
also reported similar structures in their microstructural study on different legume seeds. Rojas, Rosell, Benedito De Barber, PerezMunuera, and Lluch (2000) stated that large and small starch granules and aggregation of protein matrix were seen in the microstructure of wheat flour which can also be seen in Fig.1e which is the micrograph of whole-wheat flour. Fig. 2aef represents the micrographs of NIP dough with different levels of MGB. Fig. 2a is the control NIP dough wherein large and small starch granules enmeshed in protein matrix can be
seen. In the micrograph of NIP dough containing 10 g/100 g MGB (Fig. 2b) and 20 g/100 g MGB (Fig. 2c), large and small wheat starch granules along with small protein bodies of the multigrains can be seen. In Fig. 2d and e which are the micrographs of NIP dough containing 30 and 40 g/100 g MGB, a disruption in the continuity of protein matrix can be seen. Coated starch granules with adhering protein bodies and pits can be seen in the disrupted matrix (Fig. 2e). Coating of starch granules with guar galactomannan in bread (Brennan et al., 2006) and in parotta dough treated with guar gum
Fig. 2. Scanning electron micrographs (magnification 1000) of north Indian parotta dough with multigrain blend (MGB) and combination of additives. (a) Control dough (0 g/100 g MGB); (b) 10 g/100 g MGB; (c) 20 g/100 g MGB; (d) 30 g/100 g MGB; (e) 40 g/100 g MGB; (f) 30 g/100 g MGB þ combination of additives. PM: protein matrix; PB: protein bodies; SG: starch granule; CSG: coated starch granule; DPM: disrupted protein matrix.
D. Indrani et al. / LWT - Food Science and Technology 44 (2011) 719e724 Table 3 Effect of multigrain blends (MGB) on the quality of north Indian parotta. Parameters
MGB (g/100 g) 0
10
20
30
40
30 þ CA
Physical Horizontal axis (mm) Vertical axis (mm) Thickness, T (mm) Shear force (g)
115b 133e 3.5a 1265a
108b 123d 4.0a 1300b
106b 115c 4.2a 1350c
104a 113b 4.4b 1400d
100a 112a 4.6c 1570e
116c 126f 4.0a 1310b
Sensory Appearance (10) Pliability (10) Tearing strength (10) Layer separation (20) Eating quality (10) Overall quality (60)
9c 9c 8d 18d 9c 53e
9c 9c 7c 17d 9c 51d
8b 8b 7c 16c 8b 47c
8b 7b 6b 15b 8b 44b
7a 6a 5a 13a 7a 38a
8.5c 8.5c 8.5d 17d 8.5c 51d
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). Values in the row with the same letter in superscript are not significantly different from each other at P 0.05.
and hydroxypropyl methyl cellulose (Smitha et al., 2008) has been reported. Fleming and Sosulki (1978) in their study on the microstructure of bread using concentrated plant proteins from legumes reported that the structure of gluten was weak. Fig. 2f represents micrographs of NIP dough with 30 g/100 g MGB þ CA in which the protein matrix is more continuous. Wrapped starch granules enmeshed in protein matrix and protein bodies of the other grains can be seen. Ryu (1999) in their work on the microstructure of waxy barleyewheat flour bread stated that the bread dough made with combinations of additives like ascorbic acid, gluten and hydroxypropylmethylcellulose had a more continuous structure. Evans, Volpe, and Zabik (1977) studied the ultrastructure of bread dough treated with 6% yeast single cell protein and sodium stearoyl-2-lactylate and stated that in the presence of an emulsifier, the bread dough developed a continuous and finer texture. 3.4. Effect of MGB and additives on the NIP making characteristics of whole-wheat flour NIP making characteristics of whole-wheat flour with different levels of MGB showed that with increased addition of MGB from
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0 to 40 g/100 g, the horizontal and vertical axes decreased, as a result of these, the size decreased, thickness increased, shear force increased from 1265 to 1570 g (Table 3 and Fig. 3), the pliability indicating the soft hand feel decreased and the force required to tear the NIP from the edge to centre decreased. The layers which were thin in the control sample became thick and opaque with increase in the amount of MGB. The layers also appeared yellowish in NIPs containing above 30 g/100 g MGB may be due to the presence of chick pea. The eating quality of control NIP showed soft, slightly chewy and easily disintegratable mouthfeel. With increase in MGB from 0 to 40 g/100 g grainy taste increased, there was a loss in chewiness and residue formation in the mouth also increased. These data indicate that the size of the NIP with 40 g/100 g MGB was smaller, possessed yellow coloured thick and opaque layers, lacked chewiness and showed grainy residue in the mouth. Hence use of MGB at 40 g/100 g level was considered as inappropriate and improvement of NIP with 30 g/100 g MGB was carried out with the use of CA. The data presented in Table 3 showed that addition of CA increased horizontal, vertical axes and decreased thickness significantly (P 0.05). The shear force representing the texture of NIP decreased from 1400 to 1310 g indicating improvement in the texture of NIP. The shape of the NIP improved, the NIPs were pliable, showed slight resistance to tearing, the layers were thin and distinct, eating quality showed no residue in the mouth, the NIPs showed familiar grainy taste. The above results confirm that addition of CA significantly improved the quality of NIP with 30 g/100 g MGB. Gujral, Haros, and Rosell (2004) prepared chapatis from rice flour for the benefit of patients suffering from gluten intolerance. They reported that addition of hydrocolloid and/or a-amylase improved the texture of rice flour chapati by keeping them more extensible during storage. Hung et al. (2007) prepared bread from whole waxy wheat flour (WWF) as well as from 10, 30 and 50% WWF substituted flours. They reported a decrease in the specific volume of bread with the increasing amount of substitution. They opined that it is due to the existence of high amount of dietary fiber which diluted the gluten protein and interfered with optimal gluten matrix formation during fermentation and baking. 3.5. Composition of NIP Evaluation of composition of control NIP and NIP with 30 g/ 100 g MGB and CA showed increased contents of ash, fat protein and dietary fiber (Table 4). The ash content of NIP with 30 g/100 g
Fig. 3. Photograph of north Indian parottas with different levels of multigrain blend (MGB). (A) Control (0 g/100 g MGB); (B) 10 g/100 g MGB; (C) 20 g/100 g MGB; (D) 30 g/100 g MGB; (E) 40 g/100 g MGB.
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Table 4 Compositiona (g/100 g) of north Indian parotta. Parameters
Ash Fat Protein Dietary fiber
North Indian parotta 0 g/100 g MGB
30 g/100 g MGB þ CA
1.40 0.01 6.81 0.10 11.12 0.02 11.83 0.08
1.92 0.01 8.71 0.11 14.52 0.03 13.22 0.15
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). a Dry mater basis. Values are means of three replicate standard deviation.
MGB and CA increased by 1.4 times, fat (1.3 times), protein (1.3 times) and dietary fiber (1.1 times) when compared to control NIP. Dhingra and Sudesh (2001) carried out organoleptic and nutritional evaluation of wheat breads supplemented with soy bean and barley flours. They reported that breads made from both barley and defatted soy flours up to 15% level were acceptable, contained appreciable amount of protein, total lysine, dietary fiber, b glucan and minerals. 4. Conclusions Addition of increasing amount of MGB from 0 to 40 g/100 g increased water absorption decreased the strength, elasticity, extensibility of dough and overall quality of NIP. Microstructure of NIP dough showed disruption of continuity of protein matrix with increased addition of MGB. Use of CA increased the strength, elasticity and extensibility of dough with 30 g/100 g MGB. The micrograph of NIP dough with 30 g/100 g MGB and CA showed a uniform and continuous protein matrix. The NIP with 30 g/100 g MGB and CA had improved physical, sensory and nutritional characteristics. These studies have shown the possibility of using multigrains to increase the nutritional quality of NIP. References AACC. (2000). Approved methods of the American Association of Cereal Chemists, methods 44-16, 08-01, 46-10, 30-10, 56-81B, 56-61A, 54-21, 22-10, 54-10 (10th ed.). St. Paul, MN: American Association of Cereal Chemists, Inc. AOAC. (1999). Official methods of analysis of AOAC International, method 991.43 (16th ed.). Maryland, USA: AOAC International. Belsie, P. R., Raseo, B. A., Siffring, K., & Bruinsma, B. (1993). Baking properties and microstructure of yeast raised breads containing wheat bran and carrageenan blends. Food Structure, 12, 489e496. Brennan, C. S., Suter, M., Matia-Merino, L., Luethi, T., Ravindran, G., Goh, K., et al. (2006). Gel and pasting behaviour of fenugreekewheat starch and fenugreekewheat flour combination. Starch/Stärke, 58, 527e535. Dhingra, S., & Sudesh, J. (2001). Organoleptic and nutritional evaluation of wheat breads supplemented with soybean and barley flour. Food Chemistry, 77, 479e488. El-Adawy, T. A. (1997). Effect of sesame seed protein supplementation on the nutritional, physical, chemical and sensory properties of wheat flour bread. Food Chemistry, 59, 7e14. Evans, L. G., Volpe, T., & Zabik, M. E. (1977). Ultrastructure of bread dough with yeast single cell protein and/or emulsifier. Journal of Food Science, 42, 70e74.
Fleming, S. E., & Sosulki, F. W. (1978). Microscopic evaluation of bread fortified with concentrated plant proteins. Cereal Chemistry, 55, 373e382. Fornal, J., Sadowska, J., Ornowski, A., Jelinski, L., & Velikanov, L. (2000). Damage resistance and microstructure of barley kernels. International Agrophysics, 14, 159e166. Friend, C. P., Waniska, R. D., & Rooney, L. W. (1993). Effects of hydrocolloids on processing and qualities of wheat tortillas. Cereal Chemistry, 70, 252e256. Gómez, M., Oliete, B., Rosell, C. M., Pando, V., & Fernández, E. (2008). Studies on cake quality made of wheatechickpea flour blends. LWT e Food Science and Technology, 41, 1701e1709. Gujral, H. S., & Ambika, P. (2002). Effect of composite flours and additives on the texture of chapati. Journal of Food Engineering, 55, 173e179. Gujral, H. S., Haros, M., & Rosell, C. M. (2004). Improving the texture and delaying staling in rice flour chapati with hydrocolloids and a-amylase. Journal of Food Engineering, 65, 89e94. Huges, J. H., & Swanson, B. G. (1985). Microstructural changes in maturing seeds of the common bean (Phaseolus vulgaris L). Food Microstructure, 4, 183e189. Hulse, J. H. (1991). Nature, composition and utilization of grain legumes. In: Uses of tropical legumes: Proceedings of a consultant’s meeting. 27e30 March 1989, ICRISAT, Patancheru, A.P. 502 324, India (pp. 11e27). Hung, P. V., Maeda, T., & Morita, N. (2007). Dough and bread qualities of flours with whole waxy wheat flour substitution. Food Research International, 40, 273e279. Indrani, D., Prabhasankar, P., Rajiv, J., & Venkateswara Rao, G. (2007). Influence of whey protein concentrate on the rheological characteristics of dough, microstructure and quality of unleavened flat bread (parotta). Food Research International, 40, 1254e1260. Macgregor, A. W., & Fincher, G. B. (1993). In A. W. MacGregor, & R. S. Bhatty (Eds.), Barley: Chemistry and technology (pp. 73e130). St. Paul, MN, USA: AACC, Inc. Manan, F., Hussain, T., & Iqbal, P. (1984). Proximate composition and minerals constituents of important cereals and pulses grown in NWFP. Pakistan Journal of Science Research, 36, 45e49. Mathews, R. H., Sharpe, E. J., & Clark, W. M. (1970). The use of some oil seed flours in bread. Cereal Chemistry, 47, 181e189. McEwen, T. J., Drouzek, B. L., & Bushuk, W. (1974). A scanning electron microscopy study of faba bean seed. Cereal Chemistry, 51, 750e757. Morris, C., King, G. E., & Rubenthaler, G. L. (1997). Contribution of wheat flour fractions to peak hot paste viscosity. Cereal Chemistry, 74, 147e153. Ragee, S., & Abdel-Aal, E. S. M. (2006). Pasting properties in starch and protein in selected cereals and quality of the products. Food Chemistry, 95, 9e18. Rastogi, A., & Singh, G. (1989). Effect of addition of full fat soy flour of different varieties on quality characteristics and bread making quality of white flour. Bulletin of Grain Technology, 27, 26e34. Rojas, J. T., Rosell, C. M., Benedito De Barber, C., Perez-Munuera, I., & Lluch, M. A. (2000). The baking process of wheat rolls followed by cryo scanning electron microscopy. European Food Research Technology, 217, 57e63. Ryu, C. H. (1999). Study on bread making quality with mixture of waxy barley wheat flour. 1. Rheological properties of dough made with waxy barleyewheat flour mixture. Journal of Korean Society of Food Science and Nutrition, 28, 1034e1043. Sefadedeh, S., & Stanley, D. W. (1979). The relationship of microstructure of cowpeas to water absorption and dehulling properties. Cereal Chemistry, 56, 379e386. Shankaracharya, N. B. (1973). Chemical composition of raw and roasted fenugreek seed. Journal of Food Science and Technology, 10, 179e181. Sidhu, J. S., Siebel, W., & Meyer, D. (1990). Gelatinization of starch during preparation of Indian unleavened flat breads. Starch/Stärke, 42, 336e342. Singh, D. K., Rao, A. S., & Singh, R. (1988). Amino acid composition of storage protein of a promising chickpea (Cicer arietinum L) cultivars. Journal of the Science of Food and Agriculture, 55, 37e46. Smitha, S., Jyotsna Rajiv, Khyrunnisa Begum, & Indrani, D. (2008). Effect of hydrocolloids on rheological, microstructural and quality characteristics of NIP e an unleavened Indian flat bread. Journal of Texture Studies, 39, 267e283. Srivastava, A. K., Meyer, D., Haridas Rao, P., & Siebel, W. (2002). Scanning electron microscopic study of dough and chapati from gluten reconstituted good and poor quality flour. Journal of Cereal Science, 35, 119e128. Steel, R. G. D., & Torrie, J. H. (1960). Principles and procedures of statistics (pp. 99e131). New York, USA: McGraw-Hill. Wolf, W. J. (1970). Scanning electron microscopy of soybean protein bodies. Journal of American Oil Chemists’ Society, 47, 107e108.
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Effect of multigrains on rheological, microstructural and quality characteristics of north Indian parotta e An Indian flat bread D. Indrani, P. Swetha, C. Soumya, Jyotsna Rajiv, G. Venkateswara Rao* Flour Milling, Baking and Confectionery Technology, Central Food Technological Research Institute, Mysore 570 020, Karnataka, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 12 August 2010 Received in revised form 11 November 2010 Accepted 11 November 2010
Effect of replacement of whole-wheat flour with multigrain blend, MGB (chick pea split without husk, barley, soya bean and fenugreek seeds) at 10, 20, 30 and 40 g/100 g on rheological characteristics of whole-wheat flour and quality of north Indian parotta (NIP) making was studied. Use of increasing amount of MGB from 0 to 40 g/100 g increased farinograph water absorption, decreased dough stability, extensograph resistance to extension, extensibility, amylograph peak viscosity and overall quality score of NIP from 53 to 38 for the maximum score of 60. Use of combination of dry gluten powder, sodium stearoyl-2-lactylate and hydroxypropylmethylcellulose separately and in combination significantly improved the overall quality of NIP with 30 g/100 g MGB. Addition of multigrains increased the protein, fat, dietary fiber and mineral contents of north Indian parotta. Ó 2010 Elsevier Ltd. All rights reserved.
Keywords: Indian flat bread Multigrains Rheology Microstructure Nutrition
1. Introduction In India, wheat based traditional products are chapati, puri, phulka, tandoori roti, north Indian parotta, south Indian parotta, nan, batura and other similar products. North Indian parotta is prepared from whole-wheat flour, salt, refined oil and water. The dough is sheeted and laminated at least twice. The product is normally triangular in shape, contains 4e6 discrete layers and is slightly thicker than chapati. The baking industry is currently witnessing a situation in which declaration on prepared products such as high fiber, high protein, low calorie etc are very much in style. Blending of whole grains which are rich in protein, dietary fiber, minerals in staple food items are considered beneficial for health. The use of multigrain offers a good opportunity to improve the taste and nutritional quality of north Indian parotta. Chick pea (Cicer arietinum) or bengal gram (Indian name) is grown in tropical, sub-tropical and temperate regions. Chick pea is valued for its nutritive seeds with high protein content, 25.3e28.9% (Hulse, 1991). Chick pea protein is rich in lysine and arginine but most deficient in sulphur containing amino acids, methionine and cystine (Manan, Hussain, & Iqbal, 1984). Hence, it can balance the amino acid and may improve the nutritive value of cereal based products (Singh, Rao, & Singh, 1988). Barley (Hordeum vulgare) is
* Corresponding author. Tel.: þ91 821 2517730; fax: þ91 821 2517233. E-mail address: [email protected] (G. Venkateswara Rao). 0023-6438/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2010.11.017
the world’s fourth most important cereal crop after wheat, maize and rice. Barley grain contains protein of about 9.9% of high biological value, is characterised by the high level of dietary fiber (15.6%), including the most valuable b-glucans, and also contains all native forms of vitamin E (Macgregor & Fincher, 1993). Soya bean is the most commonly employed source of vegetable proteins for enrichment of bakery products. Soya bean has high protein (38e40%), fat (18e20%) and lysine (5e6%) contents, which have great potential in overcoming proteinecalorie malnutrition (Rastogi & Singh, 1989). Fenugreek (Trigonella foenum graecum) seeds can be a good supplement to cereals because of its high protein (25%), lysine (5.7 g/16 g N), soluble (20%) and insoluble (28%) dietary fibres besides being rich in calcium, iron and beta carotene (Shankaracharya, 1973). Use of additives not only brings about improvement in the dough and quality characteristics but also counteracts the deleterious effects caused by the addition of non wheat materials. Gujral and Ambika (2002) reported that chapatis with improved taste, texture and nutritional quality could be made by replacing wholewheat flour with flours from rice, corn, millets and black gram. They opined that additives like wet gluten and sodium caseinate significantly improved the texture of these chapatis. Friend, Waniska, and Rooney (1993) increased the fiber content of wheat tortillas by incorporating 10% oat or rice brans. They reported that addition of 2% gluten increased water absorption, improved machinability and markedly improved shelf stability or rollability of wheat tortillas. SEM provides an appropriate means for
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characterising the physical properties and textural attributes of food ingredients in a formulated product. (Belsie, Raseo, Siffring, & Bruinsma, 1993). Microstructure studies on Indian flat breads like chapati, puri, parontha, south Indian parotta have been reported by many researchers (Indrani, Prabhasankar, Rajiv, & Venkateswara Rao, 2007; Sidhu, Siebel, & Meyer, 1990; Smitha, Jyotsna Rajiv, Khyrunnisa Begum, & Indrani, 2008; Srivastava, Meyer, Haridas Rao, & Siebel, 2002). With this background, work was undertaken to study the influence of multigrain blends consisting of chick pea split without husk, barley, soya bean and fenugreek seeds, on dough properties, microstructure and quality characteristics of north Indian parotta. 2. Materials and methods Whole-wheat flour, chick pea split without husk, barley, soya bean, fenugreek seeds, salt and edible sunflower oil were brought at the local market. Dry gluten powder, sodium stearoyl2-lactylate (P.D. Fine Chemicals, Bangalore, India) and hydroxypropylmethylcellulose (Dow Chemical International Pvt, Ltd, Mumbai, India,) ingredients like water, salt (common food grade sodium chloride) were used for the studies. 2.1. Preparation of blends To provide maximum nutritional benefit in north Indian parotta, chick pea split without husk, barley, soya bean, fenugreek seeds were selected, separately milled to a particle size of approximately 200 mm using a hammer mill (Model No. 79952, Type 120, Falling Number AB, Sweden) and combined in the ratio of 4.0:3.0:2.5:0.5 respectively based on preliminary baking trials. Using the selected blend five different multigrain blends (MGB) namely 0,10, 20, 30 and 40 g/100 g was prepared. The amount of whole-wheat flour þ MGB (chick pea split flour þ barley flour þ soya bean flour þ fenugreek seed flour) in 0 g/100 g MGB was (100 þ 0 þ 0 þ 0 þ 0 g); 10 g/100 g MGB (90 þ 4 þ 3 þ 2.5 þ 0.5 g); 20 g/100 g MGB (80 þ 8 þ 6 þ 5.5 þ 0.5 g); 30 g/100 g MGB (70 þ 12 þ 9 þ 8.5 þ 0.5 g) and 40 g/100 g MGB (60 þ 16 þ 12 þ 11.5 þ 0.5 g) respectively. The whole-wheat flour, chick pea split flour, barley flour, soya bean flour, fenugreek seed flour and different MGB were analysed separately for moisture (method 44-16), ash (method 08-01), protein (method 46-10) and fat (method 30-10) using the American Association of Cereal Chemists (AACC, 2000) methods. Dietary fiber (method 991.43) was determined according to AOAC (1999) method. All estimations were done in triplicate. 2.2. Rheological and north Indian parotta (NIP) making characteristics Effect of 0, 10, 20, 30 and 40 g/100 g MGB, combination of additives e dry gluten powder (DGP) þ sodium stearoyl-2-lactylate (SSL) þ hydroxypropylmethylcellulose (HPMC) to 30 g/100 g MGB on farinograph (method 54-21, AACC, 2000) amylograph (method 22-10, AACC, 2000), extensograph (method 54-10, AACC, 2000) and NIP characteristics of whole-wheat flour was studied. The NIP was prepared using the following formulation: 0/10/20/30/40 g/100 g MGB, combination of additives (2 g/100 g DGP þ 0.5 g/100 g SSL þ 0.5 g/100 g HPMC), salt: 0.5 g/100 g; oil: 5 g/100 g and water: farinograph water absorption. NIPs in quadruplicate were prepared by mixing the ingredients in a Hobart mixer (Model N-50, Hobart, GmbH, Offenburg, Germany) with a flat blade for 4 min at 61 rpm. The dough was placed in a bowl, covered with wet cloth, rested for 20 min in a chamber maintained at 30 C and 75% RH, divided into 30 g each, rounded, sheeted on a square frame of 3 mm using a wooden rolling pin to a round shape. About 2.5 ml of oil was
applied, spread all over the surface of the circular dough, folded into half circle, again applied about 2.5 ml of oil, folded into quarter circle, sheeted into a triangular shape of 3 mm thickness. Baking was carried out using hot plate for 2 min at 180 C by turning at every 30 sec, cooled for 15 min and packed in poly propylene pouches and evaluated after 2 h of storage at room temperature (27 C, 65% humidity). The horizontal, vertical axes and thickness of NIP was measured using a vernier calipers. The shear value of NIP was determined by measuring the force required to shear a piece (2 cm width, 6 cm length) of NIP using the texture analyser (Model TAHdi, Stable Microsystems, Surrey, UK) under the following conditions; load cell,10 kg, plunger speed,100 mm/min; WarnereBratzler shear attachment. Ten panellists (age range 25e55 years both male and female) who were familiar with the quality aspects of wheat based traditional products, were further oriented in four sessions involving 2 h of training in each session. 4 samples of NIPs in 4 replicates were evaluated by each panellist following a score card consisting of various quality parameters like appearance (1 ¼ rough surface, dark spots randomly distributed, dry; 10 ¼ smooth surface, light brown spots uniformly distributed, moist); pliability (1 ¼ brittle; 10 ¼ pliable); tearing strength (1 ¼ no resistance to tear; 10 ¼ offers slight resistance to tear); layer separation (1 ¼ fused layers; 20 ¼ thin distinct layers); eating quality (1 ¼ lacks chewiness/highly chewy; 10 ¼ slightly chewy). The overall quality score (max. 60) was taken as the combined score of all five-quality attributes. The above score card for evaluation of NIP was prepared as per the method of evaluation of south Indian parotta of Smitha et al. (2008). 2.3. Scanning electron microscopic studies SEM studies were carried out using Leo scanning electron microscope Model 435 VP (Leo Electronic Systems, Cambridge, UK). The milled grains and seeds used in the studies were defatted with hexane. Developed dough immediately after mixing was thinly sheeted and cut into pieces (size 20 20 mm) without damaging the structure. The sample pieces of the NIP dough were freeze-dried using Heto freeze-dryer Model DW3 (Allerød, Denmark), separately placed on the sample holder with the help of a double scotch tape and sputter-coated with gold (2 min, 2 mbar). Finally, each sample was transferred to the microscope where it was observed at 15 kV and 9.75 105 Torr vacuum. 2.4. Statistical analysis Data were statistically analysed using Duncan’s new multiple range tests (DMRT) with different experimental groups appropriate to the completely randomized design with four replicates each as described by Steel and Torrie (1960). The significant level was established at P 0.05. 3. Results and discussion 3.1. Proximate composition The data (Table 1) shows that the grains are more nutritious than whole-wheat flour, with increase in the percentage of MGB from 0 to 40 g/100 g the nutritional characteristics of whole-wheat flour increases with respect to ash, protein, fat and dietary fiber contents. 3.2. Effect of MGB and additives on the rheological characteristics of whole-wheat flour Use of increasing amount of MGB from 0 to 40 g/100 g increased farinograph water absorption (Table 2) from 74.6 to 75.5%, dough
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Table 1 Chemical characteristicsa (g/100 g) of multigrains and blends. Parameters
Ash Protein Fat Dietary fiber a
Multigrains
Multigrain blends g/100 g
Chick pea split
Barley grain
Soya bean
Fenugreek seeds
0
10
20
30
40
2.7 0.01 20.8 0.20 5.6 0.05 15.3 0.11
1.2 0.01 11.5 0.09 1.3 0.01 15.6 0.12
4.6 0.02 43.2 0.16 19.5 0.18 23.0 0.20
3.0 0.02 26.2 0.17 5.8 0.06 48.6 0.22
1.5 0.02 11.8 0.20 1.7 0.05 12.5 0.12
1.7 0.03 12.61 0.21 2.4 0.06 13.1 0.11
1.9 0.08 13.6 0.18 3.2 0.05 13.7 0.10
2.0 0.09 15.5 0.15 3.7 0.03 14.2 0.22
2.2 0.10 17.5 0.16 4.3 0.08 14.7 0.23
Dry mater basis. Values are means of three replicates standard deviation.
development time from 5.5 to 6.5 min and decreased stability from 4.8 to 2.5 min. The increase in water absorption with the incorporation of MGB is due to the presence of fibres in the multigrains. Mathews, Sharpe, and Clark (1970) studied the effect of replacement of wheat flour with oil seed flours such as cotton seed, peanut, saff flour seed and soy at 25% level on farinograph, extensograph, amylograph and bread making characteristics of wheat flour. They reported an increase in farinograph water absorption, decrease in band width showing poor dough stability, extensograph extensibility, amylograph peak viscosity and loaf volume. According to them the dough weakening is due to the decrease in wheat gluten content and competition between proteins of wheat flour and sesame for water. El-Adawy (1997) also reported an increase in dough development time for wheat flour supplemented with sesame products at protein levels of 14, 16, 18 and 20%; they opined that the increase in dough development time may be due to the differences in the physico-chemical properties of sesame products and that of wheat flour. The results presented in Table 2 shows that, as the level of MGB increased from 0 to 40 g/100 g, extensograph resistance to extension, extensibility and area decreased indicating a decrease in the elasticity, extensibility and strength of the dough with the addition of the MGB. Mathews et al. (1970) also reported a decrease in the dough extensibility and energy values when wheat flour was replaced with oil seed flours such as cotton seed, peanut, safflower seed and soy. These results show that addition of multigrains adversely affected the stretching Table 2 Effect of multigrain blends (MGB) on the rheological characteristics of whole-wheat flour. Parameters
Farinograph Water absorption (g/100 g) Dough development time (min) Dough stability (min) Extensograph Resistance to extension, R (BU) Extensibility, E (mm) Area (cm2) Amylograph Gelatinization temperature ( C) Peak viscosity (BU) Hot paste viscosity (BU) Cold paste viscosity (BU) Breakdown (BU) Setback (BU)
MGB (g/100 g) 0
10
20
30
40
30 þ CA
74.6a
74.8a
75.0b
75.2b
75.5c
77.0c
5.5a
5.5a
6.0b
6.0b
6.5c
7.0d
4.8c
4.5c
4.0b
3.5b
2.5a
6.5d
350c
325b
310b
290a
280a
360c
140d 80d
130c 76c
122c 70c
115b 64b
101a 60a
137d 85d
71.0a
71.5a
72.0b
72.4b
73.6c
72.5b
571e 378e 731e 193e 353d
537d 359d 677d 178d 318c
445c 310c 597c 135c 287b
378b 279b 530b 99b 276b
306a 233a 467a 73a 234a
444c 322c 643d 122c 321c
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). Values in the row with the same letter in superscript are not significantly different from each other at P 0.05.
properties of the dough. Use of increasing amount of MGB increased amylograph gelatinization temperature, decreased peak viscosity, hot paste viscosity, cold paste viscosity, set back and breakdown values (Table 2). The aforementioned results indicate that in the presence of MGB containing mixture of starch, protein, dietary fiber, wheat starch has shown delayed onset of initial viscosity, decreased viscosity during heating from 30 to 90 C, cooking at 95 C and cooling from 95 to 50 C. The decreased values for both breakdown and set back indicates less resistance of starch granules to thermal treatment and mechanical shearing and less tendency to retrograde. Ragee and Abdel-Aal (2006) studied the pasting properties of wheat flours, whole grain meals from barley, millet, rye and sorghum and their blends. They reported that the peak viscosity of barley whole grain meal (1355 cP) was comparable to hard wheat flour (1335 cP), millet and rye slurries showing intermediate degree of peak viscosity (1130 and 1084 cP) whereas sorghum slurries exhibited a low peak viscosity (821 cP). They opined that high content of starch in wheat flour compared to whole grain meals contributed to higher peak viscosity. Hung, Maeda, and Morita (2007) studied the pasting proprieties of whole waxy wheat flour (WWF) as well as from 10, 30 and 50% WWF substituted flours. They reported lower peak viscosities for WWF and substituted flours when compared to commercial white wheat flour due to the high amount of dietary fiber and low amount of total carbohydrate present in these samples. Gómez, Oliete, Rosell, Pando, and Fernández (2008) determined viscometric parameters of wheat and different chick peak cultivars using rapid visco analyzer. They reported that chick pea flours resulted in pastes with lower peak viscosity, holding strength, breakdown, final viscosity and total set back than the wheat flour, they observed that it is likely due to their lower carbohydrate content and also their different protein content affecting the viscometric parameters (Morris, King, & Rubenthaler, 1997). The results presented in Table 2 shows that addition of CA (2 g/100 g DGP þ 0.5 g/100 g SSL þ 0.5 g/ 100 g HPMC) increased farinograph water absorption, dough stability, extensograph resistance to extension, extensibility, area and amylograph characteristics of whole-wheat flour with 30 g/ 100 g MGB. The above results indicate that addition of CA significantly increased strength, elasticity and extensibility of the wholewheat flour dough with 30 g/100 g MGB. The peak viscosity also increased with addition of CA indicating influence of CA on the pasting characteristics of multigrain blends. 3.3. Microstructure of grains, whole-wheat flour, NIP dough with MGB and CA Fig. 1 a represents the micrograph of barley grain in which starch granules with adhering protein bodies can be observed. This observation is in line with the study of microstructure of barley by Fornal, Sadowska, Ornowski, Jelinski, and Velikanov (2000). In Fig. 1b, c and d which are the micrographs of soya bean, chick pea split and fenugreek respectively, aggregates of protein bodies can be observed. Other researchers (Huges & Swanson, 1985; McEwen, Drouzek, & Bushuk, 1974; Sefadedeh & Stanley, 1979; Wolf, 1970)
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Fig. 1. Scanning electron micrographs (magnification 2000) of grains and whole-wheat flour. (a) Barley grain; (b) soya bean; (c) chick pea split; (d) fenugreek seed; (e) wholewheat flour. PM: protein matrix; PB: protein bodies; SG: starch granule; LSG: large starch granule.
also reported similar structures in their microstructural study on different legume seeds. Rojas, Rosell, Benedito De Barber, PerezMunuera, and Lluch (2000) stated that large and small starch granules and aggregation of protein matrix were seen in the microstructure of wheat flour which can also be seen in Fig.1e which is the micrograph of whole-wheat flour. Fig. 2aef represents the micrographs of NIP dough with different levels of MGB. Fig. 2a is the control NIP dough wherein large and small starch granules enmeshed in protein matrix can be
seen. In the micrograph of NIP dough containing 10 g/100 g MGB (Fig. 2b) and 20 g/100 g MGB (Fig. 2c), large and small wheat starch granules along with small protein bodies of the multigrains can be seen. In Fig. 2d and e which are the micrographs of NIP dough containing 30 and 40 g/100 g MGB, a disruption in the continuity of protein matrix can be seen. Coated starch granules with adhering protein bodies and pits can be seen in the disrupted matrix (Fig. 2e). Coating of starch granules with guar galactomannan in bread (Brennan et al., 2006) and in parotta dough treated with guar gum
Fig. 2. Scanning electron micrographs (magnification 1000) of north Indian parotta dough with multigrain blend (MGB) and combination of additives. (a) Control dough (0 g/100 g MGB); (b) 10 g/100 g MGB; (c) 20 g/100 g MGB; (d) 30 g/100 g MGB; (e) 40 g/100 g MGB; (f) 30 g/100 g MGB þ combination of additives. PM: protein matrix; PB: protein bodies; SG: starch granule; CSG: coated starch granule; DPM: disrupted protein matrix.
D. Indrani et al. / LWT - Food Science and Technology 44 (2011) 719e724 Table 3 Effect of multigrain blends (MGB) on the quality of north Indian parotta. Parameters
MGB (g/100 g) 0
10
20
30
40
30 þ CA
Physical Horizontal axis (mm) Vertical axis (mm) Thickness, T (mm) Shear force (g)
115b 133e 3.5a 1265a
108b 123d 4.0a 1300b
106b 115c 4.2a 1350c
104a 113b 4.4b 1400d
100a 112a 4.6c 1570e
116c 126f 4.0a 1310b
Sensory Appearance (10) Pliability (10) Tearing strength (10) Layer separation (20) Eating quality (10) Overall quality (60)
9c 9c 8d 18d 9c 53e
9c 9c 7c 17d 9c 51d
8b 8b 7c 16c 8b 47c
8b 7b 6b 15b 8b 44b
7a 6a 5a 13a 7a 38a
8.5c 8.5c 8.5d 17d 8.5c 51d
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). Values in the row with the same letter in superscript are not significantly different from each other at P 0.05.
and hydroxypropyl methyl cellulose (Smitha et al., 2008) has been reported. Fleming and Sosulki (1978) in their study on the microstructure of bread using concentrated plant proteins from legumes reported that the structure of gluten was weak. Fig. 2f represents micrographs of NIP dough with 30 g/100 g MGB þ CA in which the protein matrix is more continuous. Wrapped starch granules enmeshed in protein matrix and protein bodies of the other grains can be seen. Ryu (1999) in their work on the microstructure of waxy barleyewheat flour bread stated that the bread dough made with combinations of additives like ascorbic acid, gluten and hydroxypropylmethylcellulose had a more continuous structure. Evans, Volpe, and Zabik (1977) studied the ultrastructure of bread dough treated with 6% yeast single cell protein and sodium stearoyl-2-lactylate and stated that in the presence of an emulsifier, the bread dough developed a continuous and finer texture. 3.4. Effect of MGB and additives on the NIP making characteristics of whole-wheat flour NIP making characteristics of whole-wheat flour with different levels of MGB showed that with increased addition of MGB from
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0 to 40 g/100 g, the horizontal and vertical axes decreased, as a result of these, the size decreased, thickness increased, shear force increased from 1265 to 1570 g (Table 3 and Fig. 3), the pliability indicating the soft hand feel decreased and the force required to tear the NIP from the edge to centre decreased. The layers which were thin in the control sample became thick and opaque with increase in the amount of MGB. The layers also appeared yellowish in NIPs containing above 30 g/100 g MGB may be due to the presence of chick pea. The eating quality of control NIP showed soft, slightly chewy and easily disintegratable mouthfeel. With increase in MGB from 0 to 40 g/100 g grainy taste increased, there was a loss in chewiness and residue formation in the mouth also increased. These data indicate that the size of the NIP with 40 g/100 g MGB was smaller, possessed yellow coloured thick and opaque layers, lacked chewiness and showed grainy residue in the mouth. Hence use of MGB at 40 g/100 g level was considered as inappropriate and improvement of NIP with 30 g/100 g MGB was carried out with the use of CA. The data presented in Table 3 showed that addition of CA increased horizontal, vertical axes and decreased thickness significantly (P 0.05). The shear force representing the texture of NIP decreased from 1400 to 1310 g indicating improvement in the texture of NIP. The shape of the NIP improved, the NIPs were pliable, showed slight resistance to tearing, the layers were thin and distinct, eating quality showed no residue in the mouth, the NIPs showed familiar grainy taste. The above results confirm that addition of CA significantly improved the quality of NIP with 30 g/100 g MGB. Gujral, Haros, and Rosell (2004) prepared chapatis from rice flour for the benefit of patients suffering from gluten intolerance. They reported that addition of hydrocolloid and/or a-amylase improved the texture of rice flour chapati by keeping them more extensible during storage. Hung et al. (2007) prepared bread from whole waxy wheat flour (WWF) as well as from 10, 30 and 50% WWF substituted flours. They reported a decrease in the specific volume of bread with the increasing amount of substitution. They opined that it is due to the existence of high amount of dietary fiber which diluted the gluten protein and interfered with optimal gluten matrix formation during fermentation and baking. 3.5. Composition of NIP Evaluation of composition of control NIP and NIP with 30 g/ 100 g MGB and CA showed increased contents of ash, fat protein and dietary fiber (Table 4). The ash content of NIP with 30 g/100 g
Fig. 3. Photograph of north Indian parottas with different levels of multigrain blend (MGB). (A) Control (0 g/100 g MGB); (B) 10 g/100 g MGB; (C) 20 g/100 g MGB; (D) 30 g/100 g MGB; (E) 40 g/100 g MGB.
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Table 4 Compositiona (g/100 g) of north Indian parotta. Parameters
Ash Fat Protein Dietary fiber
North Indian parotta 0 g/100 g MGB
30 g/100 g MGB þ CA
1.40 0.01 6.81 0.10 11.12 0.02 11.83 0.08
1.92 0.01 8.71 0.11 14.52 0.03 13.22 0.15
MGB: multigrain blend; CA: combination of additives e dry gluten powder (2 g/ 100 g) þ sodium stearoyl-2-lactylate (0.5 g/100 g) þ hydroxypropylmethylcellulose (0.5 g/100 g). a Dry mater basis. Values are means of three replicate standard deviation.
MGB and CA increased by 1.4 times, fat (1.3 times), protein (1.3 times) and dietary fiber (1.1 times) when compared to control NIP. Dhingra and Sudesh (2001) carried out organoleptic and nutritional evaluation of wheat breads supplemented with soy bean and barley flours. They reported that breads made from both barley and defatted soy flours up to 15% level were acceptable, contained appreciable amount of protein, total lysine, dietary fiber, b glucan and minerals. 4. Conclusions Addition of increasing amount of MGB from 0 to 40 g/100 g increased water absorption decreased the strength, elasticity, extensibility of dough and overall quality of NIP. Microstructure of NIP dough showed disruption of continuity of protein matrix with increased addition of MGB. Use of CA increased the strength, elasticity and extensibility of dough with 30 g/100 g MGB. The micrograph of NIP dough with 30 g/100 g MGB and CA showed a uniform and continuous protein matrix. The NIP with 30 g/100 g MGB and CA had improved physical, sensory and nutritional characteristics. These studies have shown the possibility of using multigrains to increase the nutritional quality of NIP. References AACC. (2000). Approved methods of the American Association of Cereal Chemists, methods 44-16, 08-01, 46-10, 30-10, 56-81B, 56-61A, 54-21, 22-10, 54-10 (10th ed.). St. Paul, MN: American Association of Cereal Chemists, Inc. AOAC. (1999). Official methods of analysis of AOAC International, method 991.43 (16th ed.). Maryland, USA: AOAC International. Belsie, P. R., Raseo, B. A., Siffring, K., & Bruinsma, B. (1993). Baking properties and microstructure of yeast raised breads containing wheat bran and carrageenan blends. Food Structure, 12, 489e496. Brennan, C. S., Suter, M., Matia-Merino, L., Luethi, T., Ravindran, G., Goh, K., et al. (2006). Gel and pasting behaviour of fenugreekewheat starch and fenugreekewheat flour combination. Starch/Stärke, 58, 527e535. Dhingra, S., & Sudesh, J. (2001). Organoleptic and nutritional evaluation of wheat breads supplemented with soybean and barley flour. Food Chemistry, 77, 479e488. El-Adawy, T. A. (1997). Effect of sesame seed protein supplementation on the nutritional, physical, chemical and sensory properties of wheat flour bread. Food Chemistry, 59, 7e14. Evans, L. G., Volpe, T., & Zabik, M. E. (1977). Ultrastructure of bread dough with yeast single cell protein and/or emulsifier. Journal of Food Science, 42, 70e74.
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