Effect of Barley Flour Incorporation on the Instrumental Texture of Sponge Cake

Abstract

Sponge cakes were prepared by incorporating barley flour (10, 20, 30, and 40% w/w) into wheat flours. The sponge cakes were evaluated for their physical, chemical, nutritional, textural and sensory attributes. All the prepared products exhibited high in fiber, mineral and protein contents when compared with the 100% wheat flour based product. Incorporation of barley flour improved the visual of the cake from pale cream to golden brown and texture found to be softer as indicated by the instrumental texture profile analysis of the resulted cake. The cohesiveness and adhesiveness increased as barley flour incorporation from 0 to 40% and these texture properties was not increased further during storage up to 120 h. Incorporation of 20% barley flour into wheat flour for preparing cake was found to be optimum, containing rich in β-glucan, iron, calcium, zinc and highest sensory scores. While the texture characteristics showed 0.262 cohesivess and 1.39 N mm adhesiveness. The prepared cake sample indicated that the product was nutritionally rich, softer and firmer as compared to the 100% wheat flour. The results indicated that the barley flour had an anti-staling effect during storage up to 120 hr. The addition of vegetable oil to the batter resulted in an improved texture.

Keywords:

• Barley
• Sponge cake
• Texture profile
• Cohesiveness
• Adhesiveness

INTRODUCTION

Barley is the fourth major important cereal crop in the world in terms of total production after wheat, rice and corn.[1] Total world barley production is 132 million metric tons.[2] Barley has previously been utilized mainly for malting and brewing and as animal feed. Very little of this is used for human food and value-added processing. Barley flour has a high content of dietary fiber and high proportion of soluble fiber especially β-glucan which enhance the nutritional and functional properties of the cake.[1] It has therefore become an important cereal crop from a nutritional and functional point of view. There is a need to explore the possibility of value addition to barley and consumption of barley based products as food. Most of the bakery products are develop with incorporation of different nutritionally rich ingredients. Several nutraceuticals have enriched with cereal flours to add value of the product. Dietary fibre plays a very important role in the human diet. Dietary fibre, consisting of indigestible β-glucan, cellulose, hemicellulose, lignin, gums and mucilages, provides a variety of health benefits.[3] Soluble fibre is known for its hypocholesterolemic effect while insoluble fibre is known for reduction in the risk of colon cancer. β-glucan is known for reduction in the risk of colon cancer as well as reduced absorption of glucose in the digestive system.[4–5] High fibre ingredients exhibit many properties that influence the physiological functions of foods. A variety of fibers from plant sources have been used in cookies to improve the texture, colour and aroma with a reduced calorie content.[6–7] Several workers have used fibre sources such as wheat bran, oat bran, corn bran, barley bran, and psyllium husk, among others, to prepare high fibre bread.[8,9,10,11] Brewers' spent grain was used as a source of fibre for incorporation in cookie formulation.[12] Similarly, Knuckles et al.[13] reported that β-glucan enriched barley fraction increased water absorption in bread and pasta. The breads prepared containing 20% barley fraction was highly acceptable. Studies were carried out to see the effect of both hypoglycemic and cholesterolemic effects of barley in bread making.[14]

The bakery industry is one of the largest organized food industries all over the world and in particular biscuits, crackers and cakes are one of the most popular products because of their convenience, ready to eat foam, and long shelf life. Composite flour bakery products have many fold advantages, apart from extending the availability of wheat flour, and they are looked upon as carriers of nutrition.[15–16] Therefore, there is an interesting opportunity prevails to incorporate a combination of wheat-barley flour into cake recipes to improve their nutritional properties.[17] Cookies based on rice, rye, oat flour, and combination have also been studied.[18] Many researchers have done work on composite flour for biscuits and cakes that was reported earlier by Kim and De-Ruiter.[19] The objectives of this investigation were to develop nutritionally rich barley based cake and accessed for effect of barley flour incorporation on its physicochemical, textural, and microbial parameters.

MATERIALS AND METHODS

Materials

Barley grains were obtained from Punjab Agriculture University, Ludhiana, (India). Barley grains (12% moisture content) conditioned to 14% moisture content. Commercial wheat was procured from the local market of Mysore, India. The wheat and husked barley grains were ground to flour in a laboratory centrifugal mill (ZM 100 Retsch Gmbh, Germany) and passed through a 60-mesh sieve (British standard-340 microns). Blends of whole wheat and barley flours were prepared by replacing wheat flour (14% moisture content) with barley flour at 0, 10, 20, 30, and 40% w/w on dry basis levels for cake preparation.

Preparation of Cake Batter and Baking

Fresh eggs were broken and separated into two parts: albumen and yolk. Egg albumen (100 g) was whipped for 1 min at speed 3 with a wire whisk in a laboratory mixer (Hobart N 50, Ontario, Canada). Sugar (100 g) and Egg yolk (70 g) was then added and mixed 1 min at speed 2. Wheat flour (100 g) and baking powder (2.2 g, Wakefield, Pune, India) sifted together then added and mixed for 45s. Cake gel i.e. blend of emulsifier with vegetable oil (10 g) and refined sunflower oil (1.5 g) were then added and mixed again for 45 s, scraped down and again mixed for 1 min at speed 1. The cake batter (300 g) was transferred into baking trays measuring 18 × 18 × 4 cm, and baked at 200°C for 16 min in a laboratory oven (National Manufacturing Company, Lincoln, NE). All samples were prepared in triplicates.

Analytical Methods

Physical properties of cake

The physical properties were carried out in triplicates. The cake was cooled for 1 h and then cut from the centre to measure physical properties like volume index, symmetry index and uniformity index using the cake measuring template as described in 10–91 AACC.[20] Specific gravity of batter was determined by dividing the weight of a constant volume of batter by the weight of a constant volume of water.

Proximate analysis and mineral content of cake

β-glucan was determined using the method of Aastrup and Jorgensen.[21] Proximate composition was analyzed like Proximate composition was analyzed according to AOAC.[22] All analyses were carried out in triplicate. Mineral matters were determined using Atomic Absorption Spectrophotometer. The cake was converted into ash in muffle furnace. After ashing, 15 mL of 3N HCl was added to the crucible and crucible with ash material and HCl was boiled until it was reduced to 2–3 mL. The volume was made up in volumetric flask to 50 mL and mineral content estimated by Atomic Absorption Spectrophotometer (AAS Vario6, Analytik Jena AG, Germany) by flame mode and results were expressed in mg/100g of the sample.

Instrumental textural profile analysis of cake crumb

Cake crumb samples in the form of 2.54 cm thick cubes were cut from the centre of the cake. Sample was placed on the platform of a Texture Analyzer (Lloyd Instruments LR 30K, UK) and compressed to 50% of its initial height twice in two cycles with a flat circular plunger having a diameter of 50 mm, traveling with test speed 15 mm/min and trigger 10 mm/min. Time between the two strokes was 20 s. The force versus displacement data were plotted to obtain the texture profile curve from which the textural parameters like cohesiveness and firmness were determined as described earlier by Bell.[23] Cake crumb samples sealed in polyethylene pouches were stored in a Polyethylene Terephthalate (PET) jars for texture profile analysis after 0, 48, 96, and 120 h storage at 25°C to study the effects of staling on cake texture. The crumb firmness data for control and samples containing varying amount of barley flour was subjected to analysis of textural properties like cohesiveness, adhesiveness, springiness, and chewiness in replicates. The specific volume (kg/m³) of baked cake samples was determined by the rape seed displacement method AACC.[24]

Sensory evaluation of cake

Sensory evaluation was conducted on a nine point hedonic scale to evaluate the overall acceptability of the barley and wheat flour based cake samples. Sensory attributes included color, texture, appearance, flavor, and overall quality of the cookies. Sensory evaluation was done by 10 semi-trained judges in the age group 20 to 50 years comprising of professionals, students and consumers. This test was performed 7–8 times with different groups of 10 semi-trained judges of the age group 20 to 50 in lighting and separate sensory booths arrangement.

Packaging and storage of cake

Two packaging materials were selected and used for packing and storage of cake samples. One is PFP i.e. paper (45 GSM)-Al. foil (20 μ) - polyethylene (37.5 μ) laminate and another one Met. PET i.e. 12 μ Met. PET (2.9 OD) LD/ LLD – 75 μ. Cake samples were stored at room 26°C and 37°C and analyzed at regular intervals for sensory attributes and microbiological counts of total plate count (TPC), coliforms, yeast and molds.[25]

Statistical analysis

Data analysis for Duncan multiple comparison test at p > 0.05 and response optimization were done using Statistical Analysis System, STATISTICA statsoft software release 8.0 package.

RESULTS AND DISCUSSION

Chemical Characteristics of Wheat and Barley Flour

The proximate composition of the wheat flour revealed: moisture, 12.4%; protein, 11.5%; fat, 1.49%; ash, 1.59%; sedimentation value, 26mL; gluten content (dry) 8.17%, and carbohydrates, 71.1%. while the barley flour had: moisture, 13.1%; protein, 8.2%; crude lipid, 5.4%; ash, 1.45%, β –glucan 4.40%; sedimentation value, 14mL; gluten content (dry) 6.04%, and carbohydrates, 75.7%.

Physical Properties of Cake

The physical properties like volume index changed during incorporation of barley flour into wheat flour for preparing cake. Both the volume index and symmetry index demonstrated decreasing trends from 14.6–12.5 cm and 0.9–0.4 cm, respectively, with higher substitution level of 10–40% w/w. In parallel the uniformity index increased from 0.3 to 0.5 cm with the increase in level of barley flour in cake being more significant showed in Table 1. The results were means of three with standard deviation. Symmetry index is an indicator of surface contours, while uniformity index is a measure of cake symmetry. The control sample had a higher symmetry index indicating that the cake had more height in the centre and less at the sides and a convex shape. The lowering of symmetry index indicated that the cakes showed a flatter surface at higher level of barley flour. Higher uniformity index values revealed that the cake had uneven surface. The egg albumen when whipped for 1 min resulted in white foam having specific gravity of 0.474. The addition of barley flour into wheat flour during formation of cake batter resulted in a decrease in specific gravity of the cake batter from 0.756 to 0.624 (Table. 1).

Table 1 Physical properties of cakes containing barley flour

Barley flour (%)	Volume index (cm)	Uniformity index (cm)	Symmetry index (cm)	Sp. gravity of batter
0	14.5^a	0.3^c	0.9^a	0.756^a
10	14.6^a	0.3^c	0.9^a	0.724^a
20	14.6^a	0.3^c	0.8^b	0.699^b
30	13.4^b	0.4^b	0.5^c	0.650^c
40	12.5^c	0.5^a	0.4^d	0.624^c
Mean values with the same superscript letters within the same column do not differ significantly (P > 0.05).

Chemical and Nutritional Properties of Cake

By proximal analysis (Table 2), both control and mixed barley flour containing cakes had high fat contents since the fat content in the formulations did not differ much. The protein, ash, β-glucan, carbohydrate, and moisture contents did not differ either. As the barley flour content was increased in the cake, β-glucan content also significantly increased from 0.10 to 1.68%, which is an important dietary fiber of diet. The β -glucan content of barley has been reported to be between 2 and 10%,[26] and the results obtained from this study were also in the same range. It has been reported that some of barley cultivars have low β -glucan content while some other may have high.[27] Storsley et al.[28] suggested hulless barley to be good source of non-starchy polysaccharides, especially β-glucan and pentosans. In this investigation, the hulless barley was used to increase the β–glucan. Apart from having a nutritive value comparable to wheat have the cholesterol lowering effect,[29–30] regulating blood glucose level and insulin response in diabetics,[31] and even reducing risk of cancer.[32] Ash contents of barley flour incorporated cakes increased from 1.42 to 1.97% indirectly indicating the nutritional significance of the product. Mineral content of barley rich cake was high. Iron content also increased from 18.9 to 42.6 ppm; calcium content from 5.51 to 50.8 ppm; zinc content from 3.69 to 14.6 ppm (Table 2).

Table 2 Chemical and nutritional components of cake containing barley flour

Barley flour (%)	Protein %	Fat (%)	Ash	β-glucan (%)	Zn ppm	Fe ppm	Ca ppm	Na ppm	K ppm
0	11.2^a	35^b	1.42d	0.10d	3.69c	18.9d	5.51c	239d	372c
10	10.3^b	35^b	1.60c	0.45cd	13.7^b	22.0c	48.3^b	5788c	1680^b
20	9.7^b	36^a	1.77^b	0.92c	14.0^b	23.3c	47.0^b	7470^ab	1706^b
30	9.3^bc	36^a	1.89^a	1.25^b	14.8^a	34.0^b	50.3^a	7211^b	1853^a
40	8.9c	36^a	1.97^a	1.68a	14.6^a	46.2a	50.8^a	8743a	1856^a
Mean values with the same superscript letters within the same column do not differ significantly (P > 0.05).

Instrumental Textural Profile Analysis of Cake Crumb

Cohesiveness is a dimensionless unit obtained by dividing the energy consumed during second compression by the energy consumed during first compression. Cohesiveness during storage of cake crumb showed a slight increasing trend (Table 3). The adhesiveness value of cake crumb did not show any significant change during storage up to 120 h. The firmness value of cake crumb increased from 5.94 to 6.71 N (Figure 1) with the incorporation of barley flour from 0 to 40% w/w level, however the changes were significant during storage up to 120 h since firmness value of barley incorporated cake did not change much and cake became softer and firmer as that of fresh cake than control. The firmness value of (100% wheat flour cake) control was 7.57 N while the 40% barley flour incorporated cake had 7.07 N after 120 hrs storage at 25°C indicating the anti-staling properties of barley flour in cake. Similar results have been reported by author's Inagaki and Seib[33] as use of barley improved the firmness of bread crumb during storage and aging. Barley flour, ascorbic acid and wet gluten have been shown to produce anti-staling and synergistic effects on bread crumb.[34] Springiness value decreased while the chewiness value increased with the incorporation of barley flour as well as during storage up to 120 hrs (Table 3). The specific volume (g/cm³) of baked cake samples varied between 1.4–1.0 g/cm³ as determined by the rape seed displacement method AACC.[24] There was no significant change in specific volume of different barley flour containing cake samples as compared to control.

Table 3 Textural properties of cakes containing barley flour

Barley flour (%)	Cohesiveness	Springiness mm	Firmness N	Chewiness N mm	Adhesiveness N mm
0 Hours (Fresh)
0	0.26 ± 0.05*	29.55 ± 0.08	5.94 ± 0.04	34.68 ± 0.16	1.24 ± 0.09
10	0.22 ± 0.02	28.49 ± 0.05	6.11 ± 0.05	35.39 ± 0.19	1.46 ± 0.08
20	0.26 ± 0.01	27.82 ± 0.03	6.43 ± 0.02	48.85 ± 0.15	1.39 ± 0.07
30	0.27 ± 0.05	25.93 ± 0.04	6.59 ± 0.06	47.81 ± 0.20	1.46 ± 0.09
40	0.27 ± 0.01	24.70 ± 0.05	6.71 ± 0.03	49.65 ± 0.12	1.454 ± 0.08
48 Hours
0	0.31 ± 0.04	28.33 ± 0.03	6.56 ± 0.05	36.22 ± 0.09	1.49 ± 0.07
10	0.27 ± 0.06	28.11 ± 0.04	6.49 ± 0.04	36.99 ± 0.15	1.45 ± 0.05
20	0.30 ± 0.02	27.91 ± 0.06	6.69 ± 0.01	47.99 ± 0.24	1.47 ± 0.09
30	0.32 ± 0.03	24.76 ± 0.04	6.71 ± 0.05	48.16 ± 0.11	1.60 ± 0.08
40	0.32 ± 0.05	23.99 ± 0.05	6.86 ± 0.02	51.53 ± 0.21	1.49 ± 0.05
96 Hours
0	0.35 ± 0.04	27.22 ± 0.03	7.34 ± 0.02	37.33 ± 0.19	1.60 ± 0.08
10	0.32 ± 0.06	26.89 ± 0.06	6.71 ± 0.10	38.56 ± 0.18	1.57 ± 0.06
20	0.33 ± 0.07	24.99 ± 0.04	6.83 ± 0.04	48.33 ± 0.15	1.59 ± 0.07
30	0.35 ± 0.05	22.55 ± 0.01	6.90 ± 0.05	48.99 ± 0.22	1.52 ± 0.09
40	0.34 ± 0.09	21.43 ± 0.02	7.05 ± 0.08	51.92 ± 0.12	1.52 ± 0.06
120 Hours
0	0.37 ± 0.08	27.55 ± 0.01	7.57 ± 0.03	37.85 ± 0.11	1.59 ± 0.08
10	0.34 ± 0.06	25.78 ± 0.08	7.03 ± 0.05	39.66 ± 0.21	1.68 ± 0.06
20	0.35 ± 0.04	23.88 ± 0.04	7.02 ± 0.06	50.00 ± 0.15	1.69 ± 0.08
30	0.36 ± 0.07	22.77 ± 0.03	7.08 ± 0.07	50.55 ± 0.12	1.70 ± 0.04
40	0.38 ± 0.02	21.00 ± 0.04	7.07 ± 0.04	52.44 ± 0.10	1.62 ± 0.05
*Mean ± Standard Deviation.

Figure 1 Representative curve of Texture profile analysis of Cakes Containing Barley Flour.

Sensory Evaluation of Cake

The texture, color, flavors and overall acceptability scores of judges panel showed that barley flour incorporated cake were in the acceptable range. Surface color of the cake was pale cream up to 10% level; thereafter it turned golden brown at 20 and 30% substitution of wheat flour with barley flour that was observed by the trained judges of sensory panel (Table 4). The flavor of the cake was malty and sweet at 20 and 30% levels of substitution as judges commented on sensory score cards. The cake became softer as with 100% wheat flour, while an increase in the barley flour content caused its firmness to decrease, which was in par with the texture measurements. Based on the above results, cake containing 20% barley flour was rated as the most acceptable. In other words, the results of the evaluation showed that incorporation of barley flours in cake preparation up to 20% gave most of sensory parameters in the acceptable range.

Table 4 Sensory parameters of cakes containing barley flour

Barley flour (%)	Color*	Flavor*	Texture*	Overall acceptability*
0	8.0^a	8.1^a	8.0^a	8.0^a
10	8.1^a	8.2^a	8.0^a	8.1^a
20	8.2^a	7.9^a	8.1^a	8.0^a
30	7.8^a	7.8^a	7.8^a	7.7^a
40	6.3^b	6.8^b	6.0^b	6.2^b
*A nine-point hedonic scale with 1¼ dislike extremely and 9¼ like extremely was used. Mean values with the same superscript letters within the same column do not differ significantly (P > 0.05).

Packaging and Storage of Cake

The prepared cake samples with different barley flour content were stored in Paper (45 GSM)-Al. foil (20 μ) - polyethylene (37.5 μ) laminate (PFP) and 12 μ Met. PET (2.9 OD) LD/ LLD − 75 μ (Met. Pet.) at room temperature (26°C) and higher temperature (37°C) respectively. The product was analyzed initially and at regular intervals for microbial and sensory parameters. The results showed that all the cake samples were safe microbiologically up to four days (Table 5) and sensory point of views. It became unacceptable after four days due to increase of microbial content. After four days total plate count, yeast and mold count were observed to be high.

Table 5 Microbiological analysis of cakes containing barley flour

Barley flour	0%	10%	20%	30%	40%
Fresh
TPC	Nil	Nil	Nil	Nil	Nil
Coliform	Nil	Nil	Nil	Nil	Nil
Yeast & moulds	Nil	Nil	Nil	Nil	Nil
After 5 Days
TPC	7 × 10^0	8 × 10^0	7 × 10^0	1 × 10^1	8 × 10^0
Coliform	Nil	Nil	Nil	Nil	Nil
Yeast & moulds	2 × 10^0	2 × 10^0	3 × 10^0	2 × 10^0	4 × 10^0
After 8 Days
TPC	42 × 10^1	8 × 10^3	7 × 10^3	19 × 10^2	20 × 10^2
Coliform	Nil	Nil	Nil	Nil	Nil
Yeast & moulds	20 × 10^1	28 × 10^1	14 × 10^1	25 × 10^1	13 × 10^0

CONCLUSION

The incorporation of 10, 20, 30, and 40% barley flour lead to a significant anti-staling effect on cake as compared to control cake during storage up to 120 h. The cakes containing 20% barley flour were more acceptable with firmer and softer texture than control. Barley flour incorporated cakes had higher content of iron, calcium, zinc, sodium and potassium. This study showed a potential use for barley flour in the preparation of bakery products such as cake, etc. However, in recent years, there has been a growing research interest for the utilization of barley in a wide range of food applications.[35–36,26]