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LWT - Food Science and Technology 42 (2009) 464–470

Contents lists avai

LWT - Food Science and Technology

journal homepage: www.elsevier .com/locate/ lwt

Effect of defatted maize germ flour addition on the physicaland sensory quality of wheat bread

M. Siddiq a,*, M. Nasir b, R. Ravi a, M.S. Butt b, K.D. Dolan a,c, J.B. Harte a

a Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, USAb National Institute of Food Science & Technology, University of Agriculture, Faisalabad, Pakistanc Department of Bio-systems & Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA

a r t i c l e i n f o

Article history:Received 13 May 2008Received in revised form 4 September 2008Accepted 4 September 2008

Keywords:Defatted maize germDough textureBread firmnessHunter color

* Corresponding author. Tel.: þ1 517 355 8474.E-mail address: siddiq@msu.edu (M. Siddiq).

0023-6438/$34.00 � 2008 Swiss Society of Food Sciedoi:10.1016/j.lwt.2008.09.005

a b s t r a c t

Maize (Zea mays L.) processing produces large quantities of defatted maize germ (DMG) that is beingused mainly for animal feed. The objective of this study was to exploit use of this nutrient-rich by-product in bread by replacing wheat flour at 5–20 g/100 g levels. Breads prepared with wheat–DMG flourblends were analyzed for loaf volume, density, instrumental dough hardness and bread firmness, Huntercolor (‘‘L’’, ‘‘a’’, ‘‘b’’, chroma, and hue angle), and selected sensory attributes. Loaf volumes decreasedsignificantly, from 318.8 ml to 216.3 ml, as the DMG flour supplementation was increased from 0 to 20 g/100 g; a similar effect was observed for bread specific volume. Increase in dough hardness (7.56–71.32 N)was directly related to increase in DMG flour levels. Instrumental firmness values were significantlyhigher for breads containing DMG flours, 61.58 N in 20 g/100 g DMG bread versus 32.84 N for the controlbread, made with wheat flour only. The control bread was lighter in color, as shown by higher ‘‘L’’ values,than those having DMG flour, with chroma and hue angle values significantly higher in treatment breads.In general, no differences were observed for the sensory attributes of crumb color, cells uniformity,aroma, firmness, mouthfeel, and off-flavor in breads with up to 15 g/100 g DMG flour, while the overallacceptability scores showed a mixed pattern. The results of this study demonstrated that acceptablequality bread could be made with DMG flour addition at �15 g/100 g.

� 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

1. Introduction

Defatted maize (Zea mays L.) germ cake, a by-product of the cornoil industry, is rich in protein content, dietary fiber and minerals(Huang & Zayas, 1991). The germ portion constitutes 5–14 g/100 gthe weight of a maize kernel, depending on the hybrid or variety. Inthe maize milling process, the germ is separated from the kernel foroil production. Given the fact that maize, also referred to as corn inthe U.S., is being used on an increasing level for ethanol production(CRA, 2007), the amount of defatted maize germ (DMG) is expectedto increase further. In spite of high nutritional quality of DMG,presently it is being used mostly as animal feed. Recent globalshortages of food further warrant exploitation of DMG for humanconsumption.

The protein content in DMG flour is of superior nutritionalquality consisting mostly of albumin and globulin (Gupta & Eggum,1998), with protein efficiency ratio (PER) value comparable to thatof soy protein (Satterlee, Marshall, & Tennyson, 1979). Proteins in

nce and Technology. Published by

DMG are rich and balanced in most of the essential amino acids(Gupta & Eggum, 1998) and can meet the amino acid requirementsof preschool children as per FAO/WHO standards (FAO/WHO, 1973).Lysine, a major limiting amino acid in wheat (Kent & Evers, 1994),accounts for 5–6% of the total proteins in DMG, which is more thantwice than that in wheat flour.

Among different food systems, baked products provide anexcellent opportunity to incorporate food-grade fractions fromgrains, legumes, or other non-traditional food sources. Bread, oneof the major products among baked foods, is consumed worldwidein relatively large amounts (Bakke & Vickers, 2007). With appro-priate formula modifications or process optimization, breads withacceptable quality can be made with the addition of non-traditionalingredients. A variety of wheat flour substitutions have been triedin bread formulations with varying success; for example, soy ordefatted soy flour (Junqueira, Cocato, Colli, & Castro, 2008; Ryanet al., 2002), raw wheat germ (Sidhu, Al-Hooti, Al-Saqer, & Al-Othman, 2001), flaxseed (Alpaslan & Hayta, 2006; Koca & Anil,2007), and sunflower seed (Skrbic & Filipcev, 2008). However, thereis limited information available on the use and evaluation ofdefatted maize germ in wheat breads; one such study by Zaharia,Sutescu, Popescu, and Gontea (1973) reported on preparation ofacceptable quality breads with maize flour and other ingredients.

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M. Siddiq et al. / LWT - Food Science and Technology 42 (2009) 464–470 465

The DMG flour, owing to its high nutrient content, has potentialfor use in baked products, such as bread. Additionally, DMG flourcontains fewer sulfhydryl compounds than wheat germ; thus, heattreatment and high dosage of oxidant are not required to improvethe baking performance of the maize germ added wheat flour(Tsen, Mojibian, & Inglett, 1974). Based on literature survey, there isa lack of knowledge on the physical properties and quality of breadscontaining DMG flour. Studies on the development of new productswith acceptable physico–chemical characteristics and organolepticproperties are essential for exploiting value-added uses of DMGflour. The main objectives of this study were to assess the physicalcharacteristics, textural properties, and overall quality of breadsmade with added DMG flour at different levels.

2. Materials and methods

2.1. Preparation of DMG flour

The 100-g samples of maize germ (Sanghera Agricultural Farm,Okara, Pakistan) were defatted with 15-x volume of n-hexane usingSoxhlet apparatus with continuous flux, according to the method ofTate, Chavan, Patil, and Kadam (1990). The DMG mass thus obtainedwas dried at room temperature overnight. The dried material wasground in a Disk Mill (Model FFC-15, Shandong-Jimo AgriculturalMachinery, China) at 8800 RPM and sieved through a 250 mm sieve(no. 60, W.S. Tyler Co, Mentor, Ohio, U.S.A.). The proximatecomposition of DMG flour, analyzed by standard AOAC method(AOAC, 2006), consisted of 27.6, 5.1, 13.1, 7.5, and 46.7 g/100 g ofcrude protein, crude fat, crude fiber, ash and NFE (nitrogen freeextract), respectively. The flour samples were stored in poly-ethylene bags at 4�1 �C until further use.

2.2. Wheat–DMG flour blends

Commercially available all-purpose wheat flour (King MillingCo., Howell, Michigan, USA) with a moisture content of 12.28 g/100 g was used for preparing Wheat–DMG flour blends. DMG flourwas added to wheat flour at 5, 10, 15, and 20 g/100 g levels. Eachtreatment, containing both types of flours, was mixed thoroughlyby sieving 3 times to achieve uniformity in distribution of flourparticles. Wheat–DMG flour blends thus prepared were stored at4�1 �C in polyethylene bags until required for bread making.

2.3. Dough texture analysis

The texture analysis of dough under compression mode wasmeasured using a Stable Micro Systems texture analyzer (Model:TA-XT2i, Texture Technologies, Scarsdale, New York, U.S.A.),equipped with a 500-N load cell and a 35-mm cylindrical probe. Allanalyses were done using three replicates. The flour samples werekneaded using a Hobart mixer N-50 (Hobart Corp., Troy, Ohio, USA)for 3 min by adding water (60 ml/100 g flour). This amount of waterwas selected based on some preliminary trials for making bestquality bread (Siddiq, Nasir, Ravi, Dolan, & Butt, in press). Doughsamples for texture analysis were obtained by sheeting witha rolling pin over a rectangular platform and frame of 10-mmheight to form cylindrical doughs (10� 35 mm). The dough piecesthus obtained were subjected to uniaxial compression (Ravi& Sushelamma, 2004). A crosshead speed of 100 mm/min was usedto compress the doughs to 50% of their original height. Theparameters derived from the force-deformation curve includedhardness, the maximum resistance for the compression peak(height of peak) and stickiness, the maximum value of the negativepeak of the compression.

2.4. Bread preparation

Control and treatment breads were prepared according to themodified AACC method: 10-10B (AACC, 2000). Briefly, 100-g wheatflour or blends containing 5–20 g/100 g DMG flour were dry-mixedfirst in a Hobart mixer N-50 (Hobart Corp., Troy, Ohio, U.S.A.) for1 min. Next, 3-g active dry yeast (Stock# 40034; Bulkfoods.com,Toledo, Ohio, U.S.A.) and 5-g sugar dissolved in 60 ml water forcontrol bread were added (7, 13, 19, and 24 ml extra water wasadded for 5, 10, 15, and 20 g/100 g DMG added flour breads,respectively), followed by the addition of 3-g shortening and 1-gsalt and mixing continued for a total of 3 min. After 90-minfermentation, doughs were punched down to remove gases, andthen proofed for 30 min. Doughs were placed in greased bakingpans and baked at 218.3 �C in the baking oven (Kenmore Co., Chi-cago, Ill., U.S.A.) for 20 min. Baked loaves were cooled to roomtemperature (23�1 �C) and stored overnight in polyethylene bagsbefore quality evaluation.

2.5. Bread volume and specific volume

Bread volume was determined by AACC rapeseed displacementmethod, 10-10B (AACC, 2000). Weights were recorded by using a2-decimal digital weighing scale. The specific volume (ml/g) of thebread was determined as: bread loaf volume/bread loaf weight(Penfield & Campbell, 1990).

2.6. Hunter color, hue, and chroma

The color of the bread crumb was measured with Hunter colormeter (Model: D25 L optical sensor, Hunter Associates Lab., Reston,Virginia, USA), using four replicates. Bread crumb pieces were mademanually after cutting off the bread crust and outer portions.Approximately 150 g of crumb pieces were placed in the samplecup and color values were recorded as ‘‘L’’ (0, black; 100, white), ‘‘a’’(�a, greenness; þa, redness), and ‘‘b’’ (�b, blueness; þb, yellow-ness). The data thus obtained were used to calculate chroma andhue angle according to the method of Little (1975), as follows:

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2.7. Bread texture analysis

Textural analysis of control and treatment breads, as forcerequired to compress 50% of the original height of the bread slicesof 25-mm thickness was done using a Stable Micro System (SMS)Texture Analyzer (Model: TA-XT2i, Texture Technologies Corp.,Scarsdale, New York, U.S.A.). The individual bread slices were testedunder the compression mode using 35-mm diameter compressionprobe. A crosshead speed of 100 mm/min was used to record themaximum force expressed as the hardness of the bread in Newtons(N). All textural measurements were done in triplicate.

2.8. Sensory evaluation

A 12-member panel was recruited for sensory evaluation ofselected attributes; the panelists had previous experience in bakeryproducts evaluation. The panel comprised of students, faculty andstaff at Michigan State University, with panelists spread across

M. Siddiq et al. / LWT - Food Science and Technology 42 (2009) 464–470466

a wide range of age. Sensory evaluation was done according to themethod of Stone and Sidel (2004), by using a 15-cm unstructuredscale. All evaluations were conducted under cool white incandes-cent light at room temperature (23�1 �C) in a single session.Breads were prepared a day ahead of sensory evaluation and storedin polyethylene bags at room temperature. On the day of evalua-tion, bread slices of 25-mm thickness were placed in small cupslabeled with 3-digit random codes. Panelists were provided withdistilled water and unsalted crackers to clean their mouthsbetween samples, and asked to wait for 15 s between samples. Thebread samples were presented in random order and panelists wereasked not to disturb the order of presentation. The panelists wereasked to place an ‘‘x’’ on the 15-cm line and the data thus obtainedwere converted to numerical scores using a metric scale. Attributesevaluated were crust color (intensity of ‘‘golden brown’’ color),crumb color (‘‘whitish’’ or ‘‘creamish’’ color), cells, uniformity(uniformity of air cells or porosity), aroma (degree of intensityassociated with typical white bread), firmness (resistance experi-enced by the ‘‘compactness of crumb’’ by finger feel), mouthfeel(intensity of perceived taste of a typical white bread slice), off-fla-vor (any off-flavor, e.g. oily, oxidized, rancid, or pulse-like, andoverall quality (overall impression of the bread based on aboveattributes)). The sensory analysis of breads was repeated ona different day but under similar test conditions as described above.

2.9. Statistical analysis

The separation of means or significant difference comparisonswere done using Tukey’s HSD test, the statistical significance wasdefined as (p< 0.05). All data were analyzed using JMP IN software,version 5.1 (SAS Institute, Inc., Cary, North Carolina, U.S.A.).

3. Results and discussion

3.1. Dough texture

Fig. 1 depicts the force-deformation curve recorded for doughsprepared from different DMG flour blends. The viscoelastic

Fig. 1. Effect of DMG flour addition on dough texture (0-DMG, 5-DMG, 10-DMG,15-DMG, and 20-DMG represent 0, 5, 10, 15, and 20 g/100 g DMG flour levels,respectively).

properties that affect dough machinability depend strongly onwater distribution into the dough (Ruan et al., 1999). The doughhardness values increased significantly (p< 0.05) with increasinglevel of DMG flour in the blend; it increased from 7.56 N to 71.32 N,when the DMG flour level increased to 20 g/100 g. The increase indough hardness values possibly can be attributed to the higherwater absorption capacity of the DMG flour. Similar to hardness, thedough stickiness also increased significantly (p< 0.05), from�0.37 N (control) to �4.41 N in 20 g/100 g added DMG flour dough.Based on our previous study (Siddiq et al., in press), 60% waterabsorption of wheat flour was selected to get best quality bread.Letang, Piau, and Verdier (1999) have reported that water, in thewheat flour dough system, interacts with gluten and starch to forma continuous network with dispersed particles, making the doughwith elasticity and extensibility properties. Other factors likedispersed starch phase, the continuous gluten phase and interac-tion between the components also contribute to the dough visco-elastic properties. Rolee and Le Meste (1999) reported that thechange of the storage modulus (G0) in wheat starch preparations atdifferent water content increased the initial modulus when themoisture content was decreased. The presence of numerouscomponents such as starch, gluten, lipids as flour constituents,sucrose at different physical states and added fat makes the waterdistribution in dough very complex to study.

3.2. Loaf volume and specific volume

Bread loaf volumes decreased significantly, from 318.8 to216.3 ml, as the DMG flour level was increased from 0 to 20 g/100 g(Table 1); similar effect was observed on bread specific volume withDMG flour addition. Both of these effects were expected, as theamount of gluten, which imparts higher volume in bread loaf, wasdecreased as a result of gluten-free DMG flour in bread formulation.Partial replacement of wheat flour with non-glutinous flour hasbeen shown to result in lower bread volumes; as reported by Banks,Wang, and Susan (1997) who observed a significant decrease inbaked volume of muffins made with added defatted soy flour.Addition of DMG flour had a significant effect on loaf specificvolumes as was shown by a 35% decrease, from 1.77 to 1.15 ml/g in20 g/100 g DMG flour bread. This was probably due to higher waterabsorption and holding capacity of DMG flour as compared to wheatflour. Moreover, DMG does not contain any gluten; this may havepartially contributed to high density in DMG flour added bread.

3.3. Bread crumb color

The control (wheat flour only) bread was lighter in color, asdepicted by higher ‘‘L’’ value (50.90), and ‘whiter’ than the breadscontaining DMG flour (Fig. 2). Generally, lightness ‘‘L’’ valuesdecreased with DMG flour addition, to 44.58 in bread containing20 g/100 g, however, this decrease was significant (p< 0.05) atlevels >10 g/100 g DMG flour only. Hunter color ‘‘a’’ and ‘‘b’’ valuesincreased significantly with DMG flour addition in bread

Table 1Effect of DMG flour addition on the volume and specific volume of Wheat–DMGflour breads

DMG flour level (g/100 g) Bread volume (ml) Bread specific volume (ml/g)

0 318.75� 18.57aa 1.77� 0.16a5 298.75� 19.08b 1.59� 0.12b10 270.00� 15.65c 1.41� 0.10c15 261.25� 13.47cd 1.34� 0.11cd20 216.25� 10.82e 1.15� 0.09e

Values are mean� standard deviation.a Means sharing the same letters in columns are not significantly different fromeach other (Tukey’s HSD test, p< 0.05).

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Fig. 2. Effect of DMG flour addition on the Hunter color ‘‘L’’, ‘‘a’’, and ‘‘b’’ values ofbread crumb (individual bars represent data as means of 3 replicates� standarddeviation).

Table 2Effect of DMG flour addition on the chroma and hue angle values of Wheat–DMGflour bread crumb

DMG Flour Level (g/100 g) Chroma Hue angle

0 11.24� 0.07ba �83.74� 0.16a5 12.37� 0.13a �85.25� 0.52a10 12.64� 0.16a �86.83� 0.34b15 12.68� 0.02a �89.10� 0.45c20 12.75� 0.17a �89.44� 0.11c

Values are mean� standard deviation.a Means sharing the same letters in columns are not significantly different fromeach other (Tukey’s HSD test, p< 0.05).

Fig. 3. Effect of DMG flour addition on the texture/firmness of bread crumb (0-DMG,5-DMG, 10-DMG, 15-DMG, and 20-DMG represent 0, 5, 10, 15, and 20 g/100 g DMGflour levels, respectively).

M. Siddiq et al. / LWT - Food Science and Technology 42 (2009) 464–470 467

formulations, the only exception being 5 g/100 g DMG flour levelwhere ‘‘a’’ values were not different than the control. Increasing ‘‘b’’values represent an increase in ‘yellowness’ of the samples, as wasevident from ‘‘b’’ values of 11.18 in control versus 12.75 in 20 g/100 g DMG flour added bread. The values for chroma and hue anglealso increased significantly (p< 0.05) with the addition of DMGflour in bread (Table 2). These results clearly indicated that theaddition of DMG flour significantly decreased the lightness andincreased the yellowness of the bread crumb.

Greene and Benjamin (2004) also observed that bread L* valuesdecreased with decreasing levels of sweet potato, whereas, whole-wheat flour showed an inverse effect. The lower L* values observedin their study were possibly due to Maillard browning and car-amelization, which are influenced by the distribution of water andthe reaction between reducing sugars and amino acids (Kent& Evers, 1994). Banks et al. (1997) reported that muffins containingpartially defatted soy flour were lighter and redder in color than

control. Koca and Anil (2007) reported that the crumb ‘‘L’’ and ‘‘b’’values decreased and ‘‘a’’ values increased with increasing flaxseedflour levels in bread formulation. Similar trends were also shown inflaxseed containing bread, as reported by Alpaslan and Hayta(2006).

3.4. Bread crumb texture

The texture parameters were greatly affected by the addition ofDMG flour in breads. The hardness values increased with increasinglevels of DMG flour, from 32.84 N recorded for the control bread to61.58 N in 20 g/100 g DMG bread (Fig. 3). The addition of DMG flourinfluenced the crumb structure by retaining more moisture thusincreasing the hardness values of the bread and also modifying thequantity and quality of protein in the Wheat–DMG flour breadsystem. Additionally, high levels of DMG flour addition led to lack ofuniform crumb structure. Although higher levels of DMG flourresulted in firmer bread (Fig. 3), the bread up to 15 g/100 g DMGflour was still acceptable in the sensory tests. Murase, Kojima,Yamamoto, and Ishikawa (2001) found that the lack of a uniformstructure changes the textural characteristics, mainly firmness ofbreads. Alpaslan and Hayta (2006) reported that the ground flax-seed, soy and corn flours had a significant effect on the texturalparameters of flaxseed containing breads. The rye flour additionwas also shown to increase bread firmness from 0.61 N to 14.83 N(Esteller & Lannes, 2008). Many factors can contribute to changes in

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M. Siddiq et al. / LWT - Food Science and Technology 42 (2009) 464–470468

the bread texture, such as amount of water in dough, differentwater retention capacities of wheat and DMG flours and any changein the protein content. The addition of DMG flour probably influ-enced all the factors mentioned above. Due to the high waterabsorption capacity, DMG flour addition probably affected thewater requirement of the dough and its consistency. The highprotein content of DMG flour may also have affected the ‘poly-merization of proteins’, resulting in a more plasticized dough,which was eventually reflected in the increased hardness of thecrumb.

Evaluation of texture by instrumental and sensory analysis isimportant for new product development (Dubost, Shewfelt,& Eitenmiller, 2003). Texture analysis is one of the many tests usedto measure firmness, compressibility, cohesiveness, and springi-ness of bread (Sidhu, Al-Saqer, & Al-Zenki, 1997). Instrumentalevaluation of bread texture parameters, which are analogous to thesubjective method by touch or mouthfeel have been shown tocorrelate well with sensory measurements (Esteller, Amaral,& Lannes, 2004), as was evidenced in the present study too.

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3.5. Sensory evaluation of breads

Results of all sensory attributes evaluated are shown in Fig. 4. Ingeneral, no significant differences were observed for the sensoryattributes of crumb color, cells uniformity, aroma, firmness,mouthfeel, and off-flavor in breads with up to 15 g/100 g DMGflour; though the sensory overall quality scores showed a mixedtrend. However, the DMG flour addition at 20 g/100 g was shown tohave a significant negative effect on most of the sensory attributes.A detailed discussion of selected sensory attributes follows.

Bread crust color scores decreased significantly with DMG flouraddition, with this effect more pronounced in 20 g/100 g DMG flourbread. The desirable crust color of bread is ‘‘golden brown,’’ whichbecame darker brown with successive DMG flour additions. Bankset al. (1997) reported that soy flour containing muffins crusts weredarker and more uneven than that of the control. The change incrust color may be attributed to the Maillard reactions betweenreducing sugars and proteins (Raidi & Klein, 1983). Esteller andLannes (2008) observed that, during baking, amount of water onthe dough surface quickly decreased providing favorable conditionsfor Maillard reactions resulting in darker brown color. The scores

Fig. 4. Effect of DMG flour addition on the sensory attributes of bread; control (filledsquare, -), 5 g/100 g DMG (empty triangle, 6), 10 g/100 g DMG (filled triangle, :),15 g/100 g DMG (empty circle, B), and 20 g/100 g DMG (filled circle, C). Ta

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M. Siddiq et al. / LWT - Food Science and Technology 42 (2009) 464–470 469

for crumb color also decreased significantly from 12.18 to 7.33 in20 g/100 g DMG–wheat flour bread. Typical bread has white or paleyellowish color depending on the extraction rate during flourmilling and the color pigments presents in the flour. Koca and Anil(2007) suggested that bread containing up to 20 g/100 g flaxseedflour could be baked with acceptable sensory quality. Hall andJohnson (2004) reported mean acceptability for bread with 10 g/100 g Australian sweet lupin flour was rated at ‘‘higher thanacceptable.’’

The cells, uniformity, except for bread with 20 g/100 g DMGflour, was not affected significantly, as the scores decreased onlyslightly from 12.23 (control) to 11.03 in 15 g/100 g DMG bread.Skrbic and Filipcev (2008) reported that 12–16 g/100 g sunflowerseed flour addition significantly reduced the crumb elasticity andalso affected the shape of the breads yielding flatter products.Esteller and Lannes (2008) suggested that the amount of water lostcould be correlated to porosity as a function of time. They alsoshowed that the non-uniform crumb structure of bread comprisedof a wide distribution of cell sizes, with some regions having largenumbers of small cells while others have only a few large cells.Moreover, any changes in bread porosity affect the bulk density,water-holding capacity, and modifies the dough spread and liquiduptake.

Firmness is another major sensory perception contributingsignificantly to the structure of bread with soft and uniform cellularstructure with optimal moistness. Firmness values showeda decreasing order in DMG flour added breads, though not signifi-cantly up to 15 g/100 g DMG flour. Koca and Anil (2007) observedno significant differences in crust color, crumb grain and structure,flavor, taste and overall acceptability between control and flaxseedadded breads. The addition of active soybean flour and ascorbic acidwas shown to result in softer and springier breads than the control(Junqueira et al., 2008). Addition of DMG flour at �15 g/100 g didnot affect the bread aroma, mouthfeel characteristics or off-flavor.The 20 g/100 g DMG flour level appeared to have negative effect onsensory quality, however, it is possible to overcome some of suchnegative perceptions by optimizing the formulations and/orchanging processing conditions.

3.6. Correlation between bread quality attributes

In order to explore interactions between different qualityattributes, a correlation analysis was done, as shown in Table 3. Theloaf volume was negatively correlated (�0.970) with density, andpositively with specific volume (0.983), crumb color (0.955) andcells uniformity (0.931). Loaf density negatively correlated withspecific volume (�0.931), crumb color (�0.949), and cell uniformity(�0.921). As expected, instrumental color parameters ‘‘L’’, ‘‘a’’, ‘‘b’’,chroma and hue angle were highly correlated with each other, asthese parameters are basically inter-related. The bread crust colorwas highly correlated with crumb color (0.861) and cells uniformity(0.831), and showed a significant positive correlation (0.964) withoverall quality. Similarly, crumb color and cell uniformity shareda highly significant positive relationship (0.926); same wasobserved for cells uniformity with firmness (0.939) and overallquality (0.935). Aroma showed a positive relationship withmouthfeel and overall quality, with correlation values of 0.987 and0.947, respectively. Both mouthfeel (0.985) and off-flavor (�0.985)were also strongly correlated positively and negatively, respec-tively, with overall quality.

4. Conclusion

The results of this study showed that dough hardness and breadfirmness increased as the level of DMG flour was increased from0 to 20 g/100 g. The instrumental crumb color parameters were

also affected by DMG flour addition. Our results further supportthat acceptable quality bread could be made with up to 15 g/100 gDMG flour, as no differences were noticed for most of the sensoryattributes. The DMG flour at only 20 g/100 g level was shown tohave a significant negative effect on the sensory attributes. Thehigher levels (>15 g/100 g) of DMG flour addition are not recom-mended as most quality attributes were shown to have affectednegatively in 20 g/100 g DMG flour breads. Optimizing the breadformulations and/or altering processing conditions could overcomeany of the negative effects of DMG flour addition at higher level.This study demonstrated that DMG bread a by-product from cornmilling/oil industry, offers a great potential to be used in a variety offood products to enhance their nutritional quality.

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