food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527

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Food and Bioproducts Processing

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Effect of barley flour and freeze–thaw cycles on texturalnutritional and functional properties of cookies

Mahesh Guptaa,∗, Amarinder Singh Bawab, Nissreen Abu-Ghannama

a School of Food Science and Enviourmental Health, Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Irelandb Defence Food Research Laboratory, DRDO, Siddhartha Nagar, Mysore 570 011, India

a b s t r a c t

Studies were carried out on cookies prepared by incorporating barley flour (10%, 20%, 30%, and 40%) into wheat flour.

The cookies were evaluated for their physical, chemical, nutritional, textural and sensory characteristics. All the

cookie samples showed high fiber, mineral and protein contents when compared to those from 100% wheat flour.

Incorporation of barley flour improved the color of the cookies from pale cream to golden brown. The cookies became

crispier as indicated by the reduction in the breaking strength value from 4.94 to 3.29 kg. Considering the color, taste,

flavor, surface appearance of the cookies, 30% incorporation of barley flour was found to be optimum giving cookies

containing 1.7% �-glucan, 36.6 ppm iron, 31.8 ppm calcium, 22.9 ppm zinc while the texture characteristics showed

that 30% barley incorporated cookies had breaking strength of 4.021 kg lower than wheat cookies and also indicating

that the product was nutritionally rich as compared to the 100% wheat flour cookies. The incorporation of barley

flour increased the antioxidant properties and polyphenolic content and hence increased functional properties of the

cookies compared to the control. The prepared product was safe microbiologically as well as chemically upto 6 months

of storage in different packaging materials under varying temperature conditions. The cookie dough contained 30%

barley flour and 100% wheat flour (control) was allowed to under go frozen storage and freeze–thaw cycles (freeze

for 12 h and thaw for 4 h). After each freeze–thaw cycle, cookie dough was evaluated for its texture profile and also

dough was baked to prepare cookie and assessed for its physical, textural and sensory characteristics. It was found

that cookies prepared after freeze–thawing of dough were crisper than the normal ones.

© 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Keywords: Barley; Cookies; Freeze–thawing; Texture profile analysis

et al., 1977; Sidhu et al., 1999; Wang et al., 2002). Similarly,

1. Introduction

Barley is the fourth major cereal crop produced in the world.Total world barley production is 142 million metric tonnes(FAO, 2006). Barley has previously been utilized mainly formalting and brewing and as animal feed. Very little of thisis used for human food and value-added processing. Stud-ies have shown that barley flour has high content of dietaryfiber and high proportion of soluble fiber especially �-glucan.It is therefore becoming an important cereal crop from a nutri-tional and functional point of view. There is a need to explorethe possibility of increasing consumption of barley and barleyproducts for human food and value-added products. Dietaryfiber, consisting of indigestible �-glucan, cellulose, hemicellu-

lose, lignin, gums and mucilage, provides a variety of health

∗ Corresponding author.E-mail address: sendtomahesh@gmail.com (M. Gupta).Received 26 February 2010; Received in revised form 22 June 2010; Acc

0960-3085/$ – see front matter © 2010 The Institution of Chemical Engidoi:10.1016/j.fbp.2010.07.005

benefits. Soluble fiber is known for its hypocholesterolemiceffect and insoluble fiber is known for reduction in the risk ofcolon cancer. �-Glucan is known for reduction in the risk ofcolon cancer and is known to reduce the absorption of glu-cose in the digestive system (Pomeranz, 1988; Potty, 1996).High fiber ingredients exhibit many properties that influencethe physiological functions of foods. A variety of fibers fromplant sources have been used in cookies to improve the tex-ture, color and aroma with a reduced energy of the finalproduct (Jeltema et al., 1983; Ozturk et al., 2002). Several work-ers have used fiber sources such as wheat bran, oat bran,corn bran, barley bran and psyllium husk, among others toprepare high fiber bread (Laurikainen et al., 1998; Pomeranz

epted 8 July 2010

Knuckles et al. (1997) reported that �-glucan enriched bar-

neers. Published by Elsevier B.V. All rights reserved.

food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527 521

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ey fraction increased water absorption in bread and pasta.he breads prepared containing 20% barley fractions wereighly acceptable. Studies were carried out to see the effectf both hypoglycemic and cholesterolemic effects of barley

n bread making (Vinutha et al., 1998). In barley most of theree phenolics are flavanols and tocopherols, whereas theound phenolics are mainly phenolic acids (ferulic acid and p-oumaric acid) (Holtekjølen et al., 2006). All these are known toave antioxidant activity and therefore, possible health bene-ts (Andreasen et al., 2001; Beecher, 2004).

The frozen dough market has steadily grown in recentears due to consumer demand for convenience and highuality baked products (Berglund and Shelton, 1993). Doughtrength and frozen storage play an important role in theuality of cookies produced from frozen dough, since theyust withstand harsh freezing and thawing conditions.

he ice crystals formed during frozen storage and repeatedreeze–thaw cycles reportedly causes physical damage to theluten protein structure (Marston et al., 1980), resulting in theeakening of hydrophobic bonds, redistribution of water in

he dough gluten network (Rasanen et al., 1998). Berglund andhelton (1993) observed that dough subjected to prolongedrozen storage encountered water migration with concomi-ant dough deterioration. Lu and Grant (1999a) found thatough extension properties are very important when evalu-ting frozen dough because they influence oven spring andoaf volume of the final baked product. Wolt and D’Appolonia1984a) found a decrease in extensibility with an increase inrozen storage time, which was attributed to overall glutenetwork deterioration. Inoue and Bushuk (1991) observed noignificant changes in rheological properties during short-erm storage. However, repeated freeze–thaw cycles producedsignificant decrease in dough resistance and an increase inough extensibility.

The bakery industry is one of the largest organized foodndustries all over the world and in particular biscuits, cook-es and cakes are one of the most popular products becausef their convenience, ready to eat nature, and long shelf

ife. Composite flour bakery products have many fold advan-ages, apart from extending the availability of wheat flour,nd they are looked upon as carriers of nutrition (Robbelen,979; Ricardo, 1989). There is a great opportunity for employ-ng wheat–barley mixtures in programmes to improve the dietMarroquin et al., 1985). The objectives of the present studyere (1) to study the effect of barley flour content on itshysico-chemical, nutritional, antioxidant and textural prop-rties as compared to 100% wheat based product and (2) totudy the effects of freeze–thaw cycles on texture of doughnd its baked cookies prepared from barley incorporated andheat flour dough.

. Materials and methods

.1. Materials

arley grain was procured from Punjab Agriculture University,udhiana, Punjab (India). Barley grains were conditioned to4% moisture content. Commercially available Wheat grainsere procured from the local market (India). The milled wheatnd barley grain both was ground to flour in a laboratoryentrifugal mill, passed through a 60-mesh (British standard-40 �m) sieve. Blends of wheat flour and barley flour were

repared by replacing wheat flour with barley flour at 0%, 10%,0%, 30% and 40%.

2.2. Cookie preparation

Cookie dough was mixed in a single speed pinhead labora-tory mixer (National Manufacturing Company, Lincoln, NE)as described in AACC (1995) methods (10-50D) by adding 0%,10%, 20%, 30% and 40% barley and wheat flour. Shortening64 g, sugar 130 g, salt 2.1 g and bicarbonate of soda 2.5 g werecreamed together in a Hobart mixer (Model N50, Canada) for3 min at low speed. The dextrose solution (5.95%) concentra-tion 33 mL and distilled water 16 mL was added and mixedfor 1 min at low speed and 1 min at medium speed. Flour 225 gwas added and mixing done for 2 min at low speed. The doughwas then sheeted to a thickness of 1 cm with the help of arolling pin. The cookies were cut with a cookie die of diam-eter 7.0 cm and transferred to a lightly greased baking tray.The cookies were baked at 205 ◦C for 12 min in a revolvingreel oven mixer (National Manufacturing Company, Lincoln,NE). The baked cookies were cooled to room temperature andpacked in airtight containers.

2.3. Dough preparation for freeze–thaw cycles

Dough was prepared as described by AACC (1995) with 0% and30% barley flour (more acceptable blend resulted from sen-sory scores) incorporation into wheat flour. Prepared doughwas then sheeted to a thickness of 1 cm with a rolling pin.The cookies were cut with a cookie die of diameter 7.0 cm andtransferred to a tray lined with aluminum foil and coveredthen placed into the deep freezer for freezing. Sample wasremoved after every 12 h and thaw for 4 h for one freeze–thawcycle. It was continued for 4 cycles. After every cycle one sam-ple was removed and then baked at 205 ◦C for 12 min in arevolving reel oven mixer (National Manufacturing Company,Lincoln, NE). The baked cookies were cooled to room temper-ature and packed in airtight containers for further analysis.

2.4. Physical properties of cookies

The spread factor was measured as described in AACC (1995)methods. Spread ratio was calculated from the ratio of spreadto thickness (W/T). Four cookies were placed next to eachother on a surface and the total diameter was measured andstacked one another for thickness. Then all the four cookieswere rotated by 90◦ and the new diameter and thickness weremeasured. The average of the two measurements divided byfour was taken as the final diameter, thickness and spreadfactor of the cookies.

2.5. Chemical and nutritional properties of cookies

�-Glucan was determined using the method of Aastrup andJorgensen (1988). Moisture, protein and fat contents were mea-sured according to Association of Official Analytical Chemists(1998). All the analyses were the means of three replicates.Mineral matters were evaluated by using atomic absorptionspectrophotometer, as ashing of the extruded roasted sam-ple should be done in muffle furnace. Then after ashing add15 mL 3N HCL and boil the crucible with ash material and HCLuntil reach to 2–3 mL then make up the volume in volumet-ric flask to 50 mL and mineral content is estimated by atomicabsorption spectrophotometer (AAS Vario6, Analytik Jena AG,Germany) by flame mode and results should be in mg/100 g

of samples. Color values were determined using ChromaflashTristimulus Colorimetre, color values L*, a*, b* and �E as mea-

522 food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527

Fig. 1 – Representative graph of texture profile analysis offreeze–thaw wheat and barley cookie dough.

sures of lightness, redness–greenness, yellowness–bluenessand overall color difference, respectively, were recorded foreach sample and compared with a standard.

2.6. Total phenolic content

The total phenolics content of the extracts was determinedwith the Folin–Ciocalteau method with little change (Bonoli etal., 2004). Briefly, 0.5 mL diluted extract solution was shakenfor 1 min with 100 �l of Folin–Ciocalteau reagent and 6 mL ofdistilled water. After the mixture was shaken, 2 mL of 15%Na2CO3 was added and the mixture was shaken once againfor 0.5 min. Finally, the solution was brought up to 10 mL byadding distilled water. After 1.5 h, the absorbance at 750 nmwas evaluated using a spectrophotometer. The results wereexpressed as gallic acid equivalents.

2.7. Total antioxidant capacity

The radical cation (2,20-azino-di-[3-ethylbenzthiazolinesulphonate]) (ABTS +) scavenging capacity (Kahkonenet al., 1999) was measured using a Randox Laboratoriesassay kit (San Francisco, CA). Trolox (6-hydroxy 2,5,7,8-tetramethylchroman-2-carboxylic acid) provided in the kitwas used as an antioxidant standard and for the calculationof scavenging capacity of grain extracts as trolox equivalent.The scavenging activity of grain extracts was calculated as lmole ABTS/g sample at different times (3, 5, 6 and 9 min) forvalid comparison between samples.

2.8. Textural properties of cookies

The fracture force test was conducted on the cookies usingtexture analyzer (Llyod Instrument Ameket Inc, TA Plus) andconducting a ‘measure force in compression’ test with asharp blade-cutting probe. The analyzer was set at a ‘returnto start’ cycle, a speed of 1 mm/s and a distance of 3 mm.A force/penetration distance plot was made for every test.Hardness and brittleness of the cookies can be estimatedby the maximum force (N) and the mean slope (N/s) of theforce/deformation curve respectively.

Texture profile analysis of cookie dough was performedusing texture analyser (Llyod Instrument Ameket Inc, TA Plus)as described by Bourne (1982). A dough ball (50 g) was placedon the platform under texture analyser and a circular plateof 5 cm diameter attached to a 2 kN load cell compressedthe sample to thickness of 5 mm at a crosshead speed of100 mm/min twice in two cycles (shown in Fig. 1).

2.9. Sensory analysis of cookies

Sensory evaluation was conducted on nine-point hedonicscale to evaluate the overall acceptability of the barley andwheat flour based cookies. Sensory attributes included odor,color, texture, appearance, taste, and overall quality of thecookies. Sensory evaluation was done by 20 judges in the agegroup 20–50 years comprising of professional, student andconsumers.

2.10. Packaging and storage

Following packaging materials were procured from the

reputed manufacturers and used for packing of cookies. (1)Paper (45 GSM)-Al foil (20 �)-polyethylene (37.5 �) laminate

(PFP). (2) 12 � Met. PET (2.9 OD) LD/LLD–75 � (Met.Pet.). Cookiessamples were stored at room temperature (26 ◦C) and highertemperature (37 ◦C). It was analyzed initially and at regularintervals for various physical and chemical parameters. Dur-ing the investigation sensory evaluation and various physicaland chemical parameters like moisture, peroxide value, freefatty acid value, thiobarbituric acid value and microbiologi-cal analysis were carried out. Peroxide value was estimated bythe method of AOCS (1973). Free fatty acids were determinedaccording to methods of AOCS (1973). Thiobarbituric acid (TBA)value in food samples was determined by the method ofTarledgis et al. (1960).

2.11. Statistical analysis

Data analysis were done using Statistica statsoft ver8.0 statis-tical package.

3. Results and discussion

3.1. Chemical characteristics of wheat and barley flour

The proximate composition of the wheat flour was: moisture,12.4%; protein, 11.5%; fat, 1.49%; ash, 1.59%; gluten content(dry) of 8.17%, carbohydrates, 71.1%; total phenolic content,310 (�l/g), and antioxidant capacity, 5.4 (�mole/g) and of bar-ley flour was: moisture, 13.1%; protein, 8.2%; crude lipid, 5.4%;ash, 1.45%, �-glucan 4.40%; gluten content (dry) of 6.04%;carbohydrates, 69.7%, total phenolic content, 655 (�l/g), andantioxidant capacity, 8.6 (�mole/g).

3.2. Effect of incorporation of barley flour on cookiequality

3.2.1. Physical characteristicsResults of experiments on the incorporation of barley to wheatflour on the quality of cookies (Table 1) showed that spread ofthe cookies decreased significantly at 10–20% level as com-pared to cookies made from wheat flour. Increase in the levelof barley flour, a marginal additional reduction in the spreadwas observed. Thickness of the cookies increased with addi-tion of barley flour to 20% level, and with further increase inthe level of barley flour, the increase in thickness observed

was marginal. The spread ratio of the cookies decreased from7.82 to 6.52 as barley flour incorporated increased from 0% to

food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527 523

Table 1 – Physical and textural properties of cookies containing barley flour.

Barley flour (%) Weighta

(g)Diametera (W,mm)

Thicknessb (T,mm)

Spread ratioa

(W/T)Breakingstrengtha (kg)

Whitenessa

(%)Colordifferencea

(�E)

0 19.46c ± 0.11 85.6a ± 0.66 10.9d ± 0.08 7.82a ± 0.03 4.935a ± 0.19 18.90cf ± 0.04 45.65j ± 0.0510 18.90d ± 0.21 81.30b ± 0.55 12.2a ± 0.08 6.69b ± 0.03 4.701a ± 0.28 16.60c ± 0.08 47.40j ± 0.0920 19.72b ± 0.23 79.0bc ± 0.81 12.1ab ± 0.09 6.52c ± 0.14 4.587a ± 0.21 15.94d ± 0.12 47.92i ± 0.1630 19.90a ± 0.13 77.6cd ± 0.72 11.9b ± 0.11 6.52c ± 0.09 4.021bc ± 0.22 14.69e ± 0.15 50.03gh ± 0.1840 19.72b ± 0.15 75.0dc ± 0.95 11.5c ± 0.13 6.52c ± 0.04 3.293d ± 0.32 14.39ef ± 0.24 51.72e ± 0.22

SEM (±) 0.1 0.15 0.13 0.08 0.12 0.10 0.11

Values for a particular column followed by different letters differ significantly (p < 0.05). Values are mean ± standard deviations. SEM, standarderror of mean.a n = 4.b n = 10.

Fig. 2 – Representative graph of breaking strength of wheatand barley cookies.

4tcttbt

0%. Similar results were found (Tangkanakul et al., 1995) thathe spread factor decreases with increase in fiber content inookies. Breaking strength of cookies was measured by tex-ure analyser that showed the force required to break/snaphe cookies that significantly decreased with incorporation of

arley flour (Lorenz and Collins, 1981) from 4.94 to 3.29 kg ashe level of barley flour increased from 0 to 40% (Fig. 2). Sim-

Table 2 – Chemical composition and mineral content of cookies

Proximate

0 10

Moisture 8.2 ± 0.1a 8.4 ± 0.5aCrude protein 11.3 ± 0.6c 10.2 ± 0.7bEther extract 13.2 ± 0.6a 13.3 ± .0.1aAsh 1.2 ± 0.1b 1.6 ± 0.4a�-Glucan 0.4 ± 0.2a 0.9 ± 0.1aCarbohydrate (by difference) 63.4 ± 1.0a 58.6 ± 0.7bEnergy [kcal/(100 g)] 419.2 ± 1.2a 418.9 ± 0.8aMinerals [ppm]

Calcium 9.33 ± 0.4c 26.39 ± 1.2bSodium 333.1 ± 1.8c 5065 ± 0.9bPotassium 496.4 ± 0.7d 1830 ± 0.9cIron 15.77 ± 0.3d 20.04 ± 0.1cZinc 4.13 ± 0.7d 11.0 ± 1.2c

Mean ± SD of triplicate determinations. Mean values with the same super

ilar results in case of cookies from sorghum–wheat blendsand oat–wheat blends were observed (Chavan and Kadam,1993). Hoseney and Rogers (1994) reported that hardness of thecookies is caused by the interaction of proteins and starch byhydrogen bonding. Surface cracking is another critical factor,especially in cookies. The cracking pattern became anotherimportant physical properties and it became increased asbarley flour content increased in cookie dough and not sig-nificantly change with storage time.

3.2.2. Mineral content and color characteristicsAs barley flour content increased from 0% to 40% in wheatflour the mineral matters particularly iron, calcium, sodiumzinc and potassium content was increased and improve thenutritional quality characteristics of cookies. Iron content wasincreased from 15.77 to 45.0 ppm, calcium 9.33 to 35.0 ppm,sodium 333.1 to 4331 ppm and zinc 4.13 to 19.0 ppm (Table 2).The color values that measured by tristimulus colorimetershowed that significant color differences (�E) were observed.Its whiteness decreases and cookies became change to palegolden color as barley flour incorporated into wheat flour.�E value varies between 45.6 and 51.7 and whiteness valuedecrease from 18.9% to 14.3% (Table 1).

3.2.3. Total phenolic contentPhenolics are very unstable and reactive compounds

(Cheynier, 2005) and certainly some degradation of phe-nolics will occur due to heat and oxidation during the baking

containing barley flour.

Composition (%)

20 30 40

8.5 ± 0.2a 8.6 ± 0.4a 8.7 ± 0.3a9.5 ± 0.4b 8.9 ± 0.8a 8.6 ± 0.5a

13.6 ± 0.3a 13.8 ± 0.7a 13.8 ± 0.7a1.7 ± 0.0a 1.9 ± 0.6a 2.0 ± 0.6a1.1 ± 0.3a 1.7 ± 0.4a 1.9 ± 0.4a

54.9 ± 0.6b 51.4 ± 0.5c 50.4 ± 0.7c418.8 ± 0.6a 420.6 ± 1.0a 421.0 ± 0.8a

29.51 ± 0.7b 31.77 ± 0.8a 35.01 ± 1.0a5140 ± 0.8b 6254 ± 0.7a 6331 ± 1.1a2091 ± 1.5b 2180 ± 1.0a 2239 ± 0.8a

33.31 ± 0.4b 36.60 ± 0.2b 45.00 ± 0.2a19.0 ± 1.0b 22.9 ± 1.2a 22.4 ± 0.9a

script letters within the same row do not differ (p < 0.5).

524 food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527

Table 3 – Total phenols content and antioxidant properties of dough and its cookies containing barley flour.

Barley flour (%) Total phenols as gallic acid equivalent (�l/g) ABTS scavenging capacity at 3 min (�mole/g)

Dough Cookies Dough Cookies

0 310.8 ± 0.51 190 ± 0.35 5.40 ± 0.28 4.41 ± 0.5110 333.5 ± 0.25 209 ± 0.29 5.86 ± 0.35 4.10 ± 0.3220 369.8 ± 0.28 239 ± 0.21 5.80 ± 0.52 4.10 ± 0.3930 416.4 ± 0.23 244 ± 0.31 6.10 ± 0.63 4.30 ± 0.2540 432.8 ± 0.25 249 ± 0.27 6.74 ± 0.76 4.28 ± 0.29

Values for a particular column followed by different letters differ significantly (p < 0.05). SEM, standard error of mean.

process. As barley flour content increased from 0% to 40%in wheat flour dough, the total phenolic content of doughincreased from 310.8 to 432.8. The phenolic content decreasedfrom 310.8 to 190.4, when the 0% to 40% barley incorporateddough were baked to cookies shown in Table 3. Phenoliccontent decreased probably due to decomposition (Kikugawaet al., 1990), volatilization (Hamama and Nawar, 1991) andinteraction of the phenolics including the tannins content(Dykes and Rooney, 2006) with other components of thedough.

3.2.4. Total antioxidant capacityThe antioxidant activities of the cookies containing barleyflour are higher than control ones. The antioxidant activity ofbarley incorporated dough ranged from 5.86 to 6.74 �mole/gand it decrease slightly during baking to cookies shownin Table 3. But barley also contains more proanthocyani-dines (PAs) than does wheat, and these might decrease bydegradation as a consequence of the heat/thermal processduring baking. Antioxidant activities decreased seemingly dueto a decrease in phenolic content. However, PAs are alsoreported to complex with carbohydrate and protein fractions(McCallum & Walker, 1990), making them less extractable.They can also be modified by active oxidative enzymes (i.e.,polyphenol oxidase) (Quinde & Baik, 2006; Quinde et al., 2004)or oxidized by available O2. Further, these compounds cancomplex with metal ions (ferric iron or copper) (McCallum& Walker, 1990; McDonald et al., 1996), which is likely tointerfere with the TPC estimation. Also, it is reported that,during the caramelization and breakdown of sugars (espe-cially pentosans, notably arabinoxylans) in wheat, the furfuralderivatives formed may undergo condensation with PAs dur-ing baking (McCallum & Walker, 1990). However some lossesof antioxidants during dough mixing and baking are alsoreported (Leenhardt et al., 2006).

3.2.5. Sensory characteristicsSurface color of the cookie was pale cream upto 10% level;

thereafter it was golden brown in color when 20% and 30%wheat flour was substituted with barley flour (Table 3). The

Table 4 – Sensory qualities of cookies containing barley flour.

Barley flour (%) Color Texture

0 8.0a 8.1a10 8.1a 8.2a20 8.2a 7.9a30 7.9a 8.0a40 7.2b 7.1b

A nine-point hedonic scale with 1 dislike extremely and 9 like extremelysame column do not differ significantly (p > 0.05).

surface of control cookies had uniform and small size islands.With the addition of barley flour, the size of the islands becamelarger and was uniform at 30% level of barley flour in the blend.The flavor of the cookies was malty and sweet at 20% and30% levels of substitution (Table 4). The cookies became ten-der with increase in the level of barley flour, which is in parwith the texture measurements. Based on the above resultscookies containing 30% barley seed flour was found to be mostacceptable by the panelists.

3.2.6. Storage stabilityThe prepared samples of 0%, 10%, 20%, 30%, 40% barley incor-porated cookies were packed in PFP and Met. PET pouches.These cookie samples were stored at room temperature (26 ◦C)and higher temperature (37 ◦C). It was analyzed initially andat regular intervals for sensory, chemical and microbiologicalparameters upto 6 months. The results showed that Peroxidevalue (PV) was increase from 1.1 to 3.1 mequiv. O2/kg in PFP and0.8 to 3.2 mequiv. O2/kg in met-polyester during storage upto 6months. Free fatty acids (FFA) were increased from 0.3% to 0.9%oleic acid in PFP and 0.4% to 1.0% oleic acid in met-polyesterduring storage upto 6 months. Thiobarbituric acid (TBA) valuewas increased from 0.057 to 0.090 mgMA/kg in PFP and 0.060 to0.088 mgMA/kg in met-polyester during storage upto 6 monthsshowed in Table 6. The prepared samples were also investi-gated for its microbiological stability. The results showed thatTPC, coliform and yeast and mould activity was nil duringstorage upto 6 months both in PFP and met-polyester packag-ing material and both at room temperature (26 ◦C) and highertemperature (37 ◦C) Table 5.

3.3. Effect of freeze–thaw cycles on dough and cookiequality

Cookies are made from rheologically complex dough’s anddetermining the rheological properties of dough yields valu-able information concerning the quality of the raw materials,the machining properties of the dough and possibly the tex-

tural characteristics of the finished product. Increasing levelof fiber rich barley flour increased both cohesiveness and

Flavor Overall acceptability

8.0a 8.0a8.0a 8.1a8.1a 8.0a8.0a 8.0a7.0b 7.0b

was used. Mean values with the same superscript letters within the

food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527 525

Table 5 – Effect of storage on microbiological and chemical characteristics of cookies containing barley flour.

Parameters Barley flour (%) Control (0 M) PFP Met-polyester

1 M 3 M 6 M 1 M 3 M 6 M

PV mequiv. O2/kg 0 0 1.1 2.5 2.7 0.9 2.8 3.110 0 1.2 2.6 2.9 0.9 2.9 3.220 0 1.1 2.4 2.6 0.8 2.7 3.230 0 1.3 2.8 3.1 1.0 2.9 3.240 0 1.5 2.5 2.8 0.9 2.9 3.2

FFA % oleic acid 0 0.21 0.3 0.6 0.9 0.4 0.6 0.810 0.20 0.3 0.7 0.8 0.5 0.6 0.920 0.21 0.5 0.6 0.8 0.4 0.7 0.930 0.22 0.4 0.5 0.8 0.6 0.6 0.840 0.21 0.3 0.8 0.9 0.4 0.8 0.9

TBA mg MA/kg 0 0.045 0.058 0.074 0.087 0.060 0.071 0.08810 0.047 0.059 0.078 0.089 0.065 0.072 0.08720 0.045 0.057 0.081 0.090 0.064 0.070 0.08630 0.049 0.058 0.074 0.087 0.060 0.071 0.08840 0.045 0.058 0.077 0.088 0.064 0.072 0.088

TPC 0 Nil Nil 1 × 101 4.1 × 102 Nil 3 × 101 4.3 × 102

10 Nil Nil Nil 3.1 × 102 Nil Nil 3.9 × 102

20 Nil Nil Nil 3.0 × 102 Nil Nil 2.8 × 102

30 Nil Nil Nil 2.1 × 102 Nil Nil 2.4 × 102

40 Nil Nil Nil 2.0 × 102 Nil Nil 2.1 × 102

Coliform 0 Nil Nil Nil Nil Nil Nil Nil10 Nil Nil Nil Nil Nil Nil Nil20 Nil Nil Nil Nil Nil Nil Nil30 Nil Nil Nil Nil Nil Nil Nil40 Nil Nil Nil Nil Nil Nil Nil

Y&M 0 Nil Nil Nil Nil Nil Nil Nil10 Nil Nil Nil Nil Nil Nil Nil20 Nil Nil Nil Nil Nil Nil Nil30 Nil Nil Nil Nil Nil Nil Nil40 Nil Nil Nil Nil Nil Nil Nil

PV, Polanski value; FFA, free fatty acids; TBA.

Table 6 – Physical and textural properties of freeze–thaw dough and cookies containing barley flour.

Sample I.D Cohesiveness(A2/A1)

Adhesiveness(A3) Ns

Thickness(mm)

Diameter(mm)

Spreadfactor

Peak force(kg)

Deformation(mm)

Wt.loss(%)

Controlwheatdough

0.167 07.23 0.90 74 7.82 4.935 0.984 8.7

Controlbarleydougha

0.177 21.32 1.01 85 8.40 4.887 1.640 9.1

Wheat dough1 FT

0.170 06.37 0.98 73 7.51 4.045 0.738 8.1

Barley dough1 FT

0.179 16.44 1.10 83 7.63 4.258 0.656 8.8

Wheat dough2 FT

0.197 04.52 1.03 74 7.26 3.772 0.655 7.7

Barley dough2 FT

0.197 12.12 1.15 84 7.30 4.002 0.984 8.1

Wheat dough3 FT

1.206 03.48 0.97 70 7.37 3.441 1.394 7.8

Barley dough3 FT

0.185 10.71 1.09 85 7.73 3.789 1.312 7.9

Wheat dough4 FT

1.228 02.01 0.97 72 7.51 3.158 1.235 7.5

Barley dough4 FT

0.174 10.56 1.10 85 7.75 3.245 0.984 8.0

FT, freeze–thaw cycle.a 30% barley incorporated wheat cookie dough.

526 food and bioproducts processing 8 9 ( 2 0 1 1 ) 520–527

adhesiveness of the cookie dough. Cookie dough is cohesivebut lack the pliancy and viscoelasticity of the dough. Rotarymolded dough must be sufficient cohesive to hold togetherduring baking and dough spread and rise should be minimum.In case of wire cut cookies the dough must be cohesive enoughto hold together on the belt so as to separate cleanly whencut by the wire. Cohesiveness is a dimensionless unit thatis obtained by dividing the energy consumed during, secondcompression by the energy consumed during first compres-sion. Lower value of cohesiveness indicates that less energy isrequired during first compression. Adhesiveness of the doughis of great significance during the sheeting and forming pro-cess. The increased adhesiveness can be attributed to thehigher levels of water-soluble carbohydrates in cookie dough.The presence of high molecular weight polysaccharides suchas pentosans affect the water absorbing capacity of the cookiedough during mixing and thus affect the rheological prop-erties of the dough (Faridi, 1990). Wheat cookie dough andoptimum barley cookie dough was freeze for 12 h and thaw for4 h. This cycle was repeated for four times, during this treat-ment to cookie dough the cohesiveness value was increasedinitial from 0.1673 to 1.2286 for 100% wheat flour (control)cookie dough after four freeze–thaw cycles and cohesivenessincreased from 0.1778 to 0.1978 upto two freeze–thaw cycleand then again come back to 0.1741 after fourth freeze–thawcycles for 30% barley incorporated cookie dough. Adhesive-ness value decreased from 7.23 to 2.01(Ns) for 100% wheat flour(control) cookie dough after four freeze–thaw cycles and for30% barley incorporated cookie dough adhesiveness decreaseinitial from 21.32 to 10.56 (Ns) after four freeze–thaw cycle butbecome constant after third freeze–thaw cycle (Table 6).

The cookies prepared during freeze–thawing of dough wasalso showed significant results after baking. The thicknessof the freeze–thaw cookies was higher than normal one anddiameter was almost same as that of normal ultimatelyspread ratio became decrease from 7.82 to 7.51 for 100%wheat flour (control) cookie and 8.40 to 7.51 for 30% barleyincorporated cookies. The textural properties like peak force(breaking strength) was showed significant results that peakforce decreased from 4.935 to 3.158 kg and 4.887 to 3.245 kg for100% wheat flour (control) and 30% barley incorporated cook-ies respectively. But it has been found that the baking lossduring baking of freeze–thaw dough cookies was higher (i.e.10–15%) and this was increased with increased freeze–thawcycles showed in Table 6.

4. Conclusion

Whole barley flour as a good source of fiber, minerals seemsto be suitable for the preparation of cookies. This study hasshown that barley flour supplemented with wheat flour at30% level produced acceptable cookies with increased fibercontent, calcium, iron, zinc and golden yellow in color. Theincorporation of barley increased the total phenolic contentand antioxidant properties but it decreases slightly duringbaking to cookies. Cookies became less hard with increasinglevel of the barley flour and surface cracking of the cookiesalso improved. After four freeze–thaw cycles of 30% barleyincorporated and 100% wheat flour (control) dough undergoincrease cohesiveness and decrease adhesiveness that alsogives more crispiness to the baked cookies. It significantly

affects the texture of cookie dough and cookie after baking.As barley flour added in cookies, high sensory scores showed

that it gave anti-staling effect during storage upto 6 monthsand safe chemically and microbiologically after 6 months ofstorage at different packaging materials at different tempera-tures.

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