Thermal and rheological properties of sponge cake batters and texture and microstructural characteristics of sponge cake made with native corn starch in partial or total replacement of wheat flour

LWT - Food Science and Technology 70 (2016) 46e54

Contents lists available at ScienceDirect

LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt

Thermal and rheological properties of sponge cake batters and texture and microstructural characteristics of sponge cake made with native corn starch in partial or total replacement of wheat flour
rez-Alonso a, E.J. Vernon-Carter b, A.Y. Guadarrama-Lezama a, H. Carrillo-Navas a, b, *, C. Pe b J. Alvarez-Ramirez a b


noma Del Estado de M
Facultad de Química, Universidad Auto exico, 50120, Mexico
ulica, Universidad Auto
noma Metropolitana-Iztapalapa, Apartado Postal 55-534, 09340, Mexico Departamento de Ingeniería de Procesos e Hidra

a r t i c l e i n f o

a b s t r a c t

Article history: Received 3 January 2016 Received in revised form 9 February 2016 Accepted 12 February 2016 Available online 13 February 2016

The effect of substituting wheat flour by native corn starch on the rheological and thermal properties of sponge cake batter formulations, and on the texture and microstructural characteristics of sponge cake were evaluated. Thermal analysis showed that starch granules underwent only incipient swelling due to the limited availability of water in the batter matrix. Increasing replacement of wheat flour by native corn starch endowed increasing order to the batter matrix, but produced a decrease in the apparent viscosity, and a drop in the storage and loss moduli. Creep-recovery tests showed that the retardation time was only slightly affected by native corn starch content, indicating that a consolidated 3D network was formed by interaction of starch granules with other components of the batter formulations, with bonds restoration and fracture taking place at similar rates. The textural characteristics of the sponge cake decreased monotonously as the native corn starch content increased. In brief, the use of native corn starch enabled the modulation of the textural properties of wheat-based breads without sacrificing dough viscoelasticity. © 2016 Elsevier Ltd. All rights reserved.

Keywords: Sponge cake batter Starch Thermal properties Viscoelasticity Textural characteristics

1. Introduction Typical sponge cake recipes include wheat flour, proteins, lipids and water. First, the ingredients are mixed at room conditions to obtain homogenized batter formulations that, after a short time of resting, are used to mold artisanal sponge cake forms, which are then baked at about 180e200
C. Viscoelasticity plays a central role in the malleability of batter formulations, which is an important feature for proper build-up and cooking of specialty sponge cakes. In this regard, gluten is an important component to incorporate elasticity and adhesiveness into the batter microstructure. While the batter formation is basically a homogenization process involving physical phenomena, baking involves important physicochemical transformations. Low availability of water and lipids limits seriously the gelatinization of starch granules (Tester & Sommerville, 2003; Witczak, Juszczak, Ziobro, & Korus, 2012;


noma del Estado * Corresponding author. Facultad de Química, Universidad Auto
xico, 50120, Mexico. de Me E-mail address: [email protected] (H. Carrillo-Navas). http://dx.doi.org/10.1016/j.lwt.2016.02.031 0023-6438/© 2016 Elsevier Ltd. All rights reserved.

Ziobro, Korus, Juszczak, & Witczak, 2013). Thus, starch granules only achieve partial gelatinization, forming a continuous starch network of swollen and interconnected granules (Hugh-Iten, Handschin, Conde-Petit & Escher, 1999). On the other hand, lipids can interact with starch to form complexes (Eliasson, 1994) that retard starch retrogradation and affect largely enzymatic digestion and acid hydrolysis (Ai, Hasjim, & Jane, 2013). Flours from different botanical sources have been considered as partial or total substitutes for wheat flour. Maize flour has shown to improve rheological properties, water binding and gelatinization of doughs and batters (Tegge, 2004). Rice flour in combination with additives can lead to acceptable viscoelastic properties for glutenfree bread-like (bread, cake, cookies, etc.) commercial products (Matos & Rosell, 2013). Despite the large amount of studies on partial or total wheat flour substitution, a detailed understanding on the physicochemical effects of incorporated starch granules in bread dough and matrices is still incomplete (Hemalatha, Leelavathi, Salimath, & Rao, 2014; Hug-Iten et al., 1999; Mohammed, Ahmed, & Senge, 2012). For instance, it has been postulated that bread quality under storage is potentially a consequence of the

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

extent of starch granule hydration, swelling, dispersion and extent of reassociation (Patel, Waniska, & Seetharaman, 2005). Also, it has been postulated that different proportions of water incorporation into the crystalline structure of starch during staling and changes in starch fine structure cause the different rates of staling of bread made of composite flours mixes (Mihhalevski et al., 2012). Besides viscoelasticity and texture modification issues, there is a further motivation for exploring the effects of supplements in the textural properties of sponge cake. The consumption of hedonic food products has increased in the recent years as consumers search for new and exotic textures and flavors. In this line, bakery specialties include biscuits, brioche and cakes. The incorporation of native and modified starches allows the tailoring of a series of bakery products with prescribed textural and sensorial features. With the advent of the so-called molecular gastronomy, it is increasingly recognized that foodstuffs in general, and bakery products in particular, can be modeled with the use of native components, such as whey protein isolate, starch and lipids (Barham et al., 2010; Vega & Ubbink, 2008). The aim of this work was to study the effects of partially or totally replacing wheat flour by native corn starch on the thermal and rheological properties of sponge cake batter and upon the texture and microstructure characteristics of the sponge cake obtained by the baking of the sponge cake batter. Here, the native corn starch was considered as an additive to modify the viscoelastic properties of batter and the textural features of sponge cake. 2. Materials and methods 2.1. Materials Materials for sponge cake batter preparation consisted of wheat flour (moisture content 13.10 g.100 g1, protein 7.39 g.100 g1, dietary fiber 0.5 g.100 g1, lipid 0.39 g.100 g1, ash 0.8 g.100 g1) purchased from Cia. Harinera del Parayas S.A. de C.V. (Guadalajara, State of Jalisco, Mexico). Butter, fresh whole egg, sugar, Royal baking powder purchased from Walmart Mexico, ultrapasteurized packaged milk (3.12% of protein, and 2.8% of total fat) were obtained in a supermarket (Walmart, Mexico City, Mexico). Native corn starch (S4126; amylose content of 25.03 ± 0.62 g/100 g) was purchased from SigmaeAldrich (St. Louis, MO, USA). Deionized water was used in all the experiments.

47

calorimetry (DSC) (TA Instruments, Q1000, New Castle, USA) previously calibrated with indium. Batter samples (15.0 ± 1 mg) were hermetically closed in aluminum pans and heated in a calorimeter from 25 to 100
C at constant rate 10
C min1. An empty aluminum pan was used as reference. Temperatures (To - onset, Tp - peak, Tm middle point, Te - end) and enthalpy of thermal transitions (DH, J g1) were determined with the use of instrument's software Universal Analysis 2000 (New Castle, USA).

2.4. Rheological properties of the sponge cake batter formulations Flow and oscillatory measurements were carried out using a Physica MCR 300 rheometer (Physica Mebtechnik GmbH, Germany), with cone-plate geometry, rotating cone 50 mm in diameter, and cone angle of 2
with a gap of 0.05 mm. A batter sample (~1.25 g) was placed in the measuring system, and left to rest for 5 min at 25
C for structure recovery. The edges of samples were covered with oil to reduce water evaporation. Temperature maintenance was achieved with Physica TEK 150P temperature control. Flow curves were obtained by varying the shear rate from 0.00001 to 1000 s1. Amplitude sweeps were carried out in the range of 0.001e1000% at 1 rad s1. The storage modulus (G0 ) and the loss modulus (G00 ) were obtained from the equipment software (US200/ 32 V2.50). For the shear rate range from 0.1 to 10 s1, the experimental data in Fig. 2 was described by power-law equation happ ¼ K,g_ n1 , where happ is the apparent viscosity (Pa s), K is the consistency coefficient (Pa sn), g_ is the shear rate (s1) and n is the flow behavior index. Creep and recovery tests were also performed at a fixed stress of s0 ¼ 1 Pa in the range of proportionality of strain to stress. The experiments were performed under controlled stress mode. Creep phase continued for 150 s, and recovery 300 s. Analysis was performed by triplicate. The experimental creep-compliance data can be fitted by Burger's model (Campos, Steffe, & Ng, 1997), which can be described as follows:

2.2. Preparation of the sponge cake batter formulations Five batter formulations were prepared using the modified sponge cake batter described by Young and Cauvain (2007): (i) A liquid blend (blend A) was prepared by mixing milk (22.5 g), fresh whole egg (75 g, previously homogenized for 1 min before weighting) and deionized water (3 g) with the help of an UltraTurrax T-50 basic homogenizer (IKA Works, Inc., Wilmington, DE, USA) operated at 4000 rpm during 5 min; (ii) A powder blend (blend B) was obtained by mixing flour (75 g) made up 0/100, 25/ 75, 50/50, 75/25, and 100/0 by native corn starch/wheat flour, sugar (75 g) and baking powder (1.9 g); (iii) the totality of blend B, 87.4 g of butter, and half of blend A were mixed in a bowl with a spiral mixer (Taurus, Mexico) operated at 10,000 rpm for 10 min at room temperature; and (iv) the other half of blend A was incorporated and mixed for further 3 min at 10,000 rpm. The resulting batter formulations were coded as B0, B25, B50, B75 and B100, where the subindex refers to native corn starch content. 2.3. Thermal characterization of sponge cake batter formulations Thermal properties were analyzed by differential scanning

Fig. 1. Typical endothermic response of the batter formulations. Two peaks can be observed in the temperature range from 30
C to 60
C. The first one corresponds to the melting of butter components, while the second one to incipient swelling of starch granules.

48

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

presented. 2.7. Color analysis of the sponge cake formulations The color of the crust of the sponge cake formulations was analyzed using Hunter Lab Colorimeter Model 45/0L (Hunter Associates Lab., Indiana, USA). The color parameters L*, a* and b* are measures of lightness, redness/greenness and yellowness/blueness, respectively. To this end, the instrument was calibrated against a standard white tile (L* ¼ 97.63, a* ¼ 0.78 and b* ¼ 0.25). 2.8. Texture profile analysis (TPA) of sponge cake formulations

Fig. 2. Flow curves of batter formulations showing shear-thickening behavior at very low shear-rate values, and shear-thinning behavior for high shear-rate values.

  t þ J1 1  expt=lret ; for t < t1 h0   t JðtÞ ¼ 1  J1 1  expt=lret ; for t > t1 h0 JðtÞ ¼ J0 þ

(1)

Texture profile analysis (TPA) was performed using a Brookfield CT3-4500 texturometer (MA, USA) equipped with a cylinder probe (TA25/1000, D ¼ 50.8 mm, L ¼ 20 mm). Sponge cake formulations were compressed to 40% of their original height. Texture analyses were performed 3 h after baking. Two cycles were applied using a trigger load of 10 g and a test speed of 1 mm s1. The following parameters were quantified and are defined as (Trinh & Glasgow, 2012): springiness (the height that the sample recovers during the time that elapses between the end of the first cycle and the start of the second cycle), adhesiveness (the negative force area for the first cycle, representing the work necessary to pull the compressing plunger away from the sample), cohesiveness (the ratio of the positive force area during the second compression to that during the first compression). Also quantified were hardness (the absolute peak force on the first downstroke), resilience (ratio between the areas under the compression and decompression curves), and chewiness (hardness  cohesiveness  springiness). Parameters were obtained by analyzing the curves provided by the equipment software. 2.9. Statistical analyses

1

where J is the compliance (Pa ), J0 is the instantaneous compliance (Pa1), J1 is the retardation compliance (Pa1), h0 is the (Newtonian) zero shear stress viscosity (Pa s), lret is the retardation timeconstant (s) and t1 is the time (s) at which the shear stress is removed. 2.5. Sponge cake formulations The batter formulations (100 g) were put into metallic containers whose inner walls had been smeared with a thin layer made by vegetable oil and wheat flour (4:1 ratio), in order to avoid batter adhesion. The metallic recipients were put into a pre-heated static convection oven, and the batter formulations were baked at 180
C for 30 min. The metallic recipients were withdrawn from the oven and let to cool down by about 30 min until a warm temperature was reached. The sponge cake formulations were removed from the containers and let to cool down to until reaching room temperature, and put into water waterproof plastic bags, until required for analysis. Storage conditions were at standard refrigeration (4
C with relative humidity of 25%). 2.6. Scanning electronic microscopy (SEM) of the sponge cake formulations Sponge cake formulations samples were mounted on carbon sample holders using double-side sticky tape and observed using a JEOL JMS 7600F scanning electron microscope (Akishima, Japan) with the LM mode at 15 kV accelerating voltage. Samples were sputtered with 20 nm of gold using a Denton Vacuum DESK IV device. Micrographs at 500  and 2000  magnification are

Data were analyzed using a one way analysis of variance (ANOVA) and a Tukey's test for a statistical significance P  0.05, using the SPSS Statistics 19.0. All experiments were done in triplicate. 3. Results and discussion 3.1. Thermal characteristics of sponge cake batter formulations Fig. 1 presents a typical DSC curve of batter, where two characteristic peaks can be observed. The two endothermic peaks were located between 37
C and 62
C. The low-temperature peak was located at about 37e39
C, and can be attributed to the melting of butter fractions. In fact, the melting temperature of the butter (34e36
C) used for the dough formulations was determined with DSC measurements according with the guidelines given by Nassu and Guaraldo-Goncalvez (1999). The temperature of the first peak showed a slight increase as the native corn starch content increased in the batter formulations. The batter formulation made with only wheat flour (B0) had a peak temperature of 36.7
C, which increased to 38.6
C when it was totally substituted by native corn starch (B100). The increase of the first peak temperature suggests that native corn starch promoted the interaction between starch molecules and lipids (Pareyt, Finnie, Putseys, & Delcour, 2011). It has been suggested that during dough mixing and baking, flour particles (e.g., starch granules) become hydrated and sheared to form a packed microstructure (Delcour & Hoseney, 2010). The rise of the melting temperature from 1.7 W g1 to 4.6 W g1 as the wheat flour was completely substituted by native corn starch indicates enhanced interaction of starch granules with the other batter

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

components, including lipids from butter and proteins from egg (Cauvain, 2015). The second temperature peak was located at about 50.0
C and can be related to incipient swelling of starch granules under limited moisture content (less than 50%). This endothermic peak has been attributed to a cooperative, water-mediated melting of starch granules (Chevallier, Colonna, Della Valle, & Lourdin, 2000). The peak temperature values shown in Table 1 are in line with those reported in the literature (Singh, Singh, Kaur, Sodhi, & Gill, 2003), which were related to reduced water availability and changes in the underlying binding nature. Under these conditions, starch granules are unable to undergo a complete gelatinization process, leading only to partial swelling of starch granules (Day, Fayet, & Homer, 2013). The end temperature for the second endothermic peak increased from 54.2
C for B0 to 62.2
C for B100, supporting the postulate that native corn starch promoted the interaction between starch granules and batter components. The enthalpy associated to the second endothermic peak showed an increase from 7.7 W g1 to 10.6 W g1 as the wheat flour was completely substituted by the corn starch. Note that the enthalpy values for the second peak were lower than the gelatinization enthalpies for either wheat flour or native corn starch (about 15e18 W g1), indicating an incomplete gelatinization of starch granules. It has been also reported that the presence of hydrocolloids within the batter matrix can reduce the value of enthalpy under limited water availability (Tester & Sommerville, 2003). The partial gelatinized starch results in an amorphous structure in final bread (Primo-Martin et al., 2006). The above results indicated that the incorporation of native corn starch within the batter matrix promoted interactions with other components (lipids and proteins) via hydrogen and electrostatic bonds (Angioloni & Collar, 2011) and an increase of the batter microstructure order (Cauvain, 2015). The endothermic pattern at higher temperatures arose due to an increased mobility of the lipid, proteins and starch granules within the batter matrix due to thermal effects, leading to homogenization of the microstructure. Also, chemical transformations could have been involved, such as lipidprotein complex formation, protein folding-unfolding, among others (Collar, Martinez, & Rosell, 2001; Angioloni & Collar, 2011).

49

flow direction as the shear rate was increased (Won & Kim, 2004). Considering the power-law expression, all samples were characterized by similar values (i.e., non-significant statistical differences) of the flow behavior index with n ¼ 0.12 ± 0.002, reflecting that in the shear thinning region a relatively fast decay of the apparent viscosity occurred with the shear rate. Note that the values of n were slightly lower than those reported for batter added with resistant starch (Korus, Witczak, Ziobro, & Juszczak, 2009), defatted fruit seeds (Korus et al., 2012) and inulin (Juszczak et al., 2012). 3.3. Viscoelasticity of the sponge cake batter formulations Fig. 3a and 3 b present the strain sweep of the batter formulations. The storage (G0 ) and loss (G00 ) moduli were very close in value

3.2. Apparent viscosity of the sponge cake batter formulations Fig. 2 presents the dependence of the apparent viscosity with the shear rate of the batter formulations. Shear-thickening behavior was exhibited for low shear rate values (up to 104 s1), probably caused by compact packing of the solids (e.g., long-lived particle clusters) within the batter matrix (Wagner & Brady, 2009). As the native corn starch content in the batter formulations increased, a higher maximum in the apparent viscosity value was achieved. At higher shear rate the behavior became shear-thinning, with the apparent viscosity decreasing progressively with the native corn starch content. This change in the behavior of the apparent viscosity might be attributed to alignment of starch granules with the

Table 1 Thermal parameters of sponge cake batter formulations. Sample

Starch gelatinization To (
C)

B0 B25 B50 B75 B100

Fig. 3. Strain sweeps of batter formulations. Decreased values of storage (G0 ) and the loss (G00 ) moduli were induced by the presence of native corn starch granules. The loss angle tan(d) showed a lower crossover when native corn starch was incorporated.

36.72 37.25 37.82 38.04 38.55

± ± ± ± ±

DH1 (J g1)

Tp1 (
C) a

0.92 0.75a 1.13a 0.57a 0.69a

38.60 38.96 39.76 39.90 40.14

± ± ± ± ±

a

0.77 0.70a 0.99a 1.20a 0.88a

1.70 2.53 3.13 3.98 4.60

± ± ± ± ±

Tm (
C) a

0.03 0.05b 0.06c 0.09d 0.07e

44.07 44.32 44.81 45.25 45.28

± ± ± ± ±

DH2 (J g1)

Tp2 (
C) a

1.10 1.64a 1.34a 1.23a 1.08a

49.94 50.72 50.82 50.86 51.33

± ± ± ± ±

a

0.89 1.13a 1.98a 1.27a 2.05a

7.69 8.50 9.23 9.82 10.57

± ± ± ± ±

Te (
C) a

0.27 0.26b 0.18c 0.23c 0.30d

54.19 55.64 56.35 59.67 62.21

± ± ± ± ±

2.17a 1.39a,b 1.69a,b 2.09b,c 1.25c

To, onset temperature; Tp, peak temperature; Tm, middle point temperature; Te, end temperature; DH, enthalpy. Values are means ± standard error, of three replicates. Superscripts with different letters in same column indicate significant differences (P  0.05).

50

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

for all the batter formulations in the linear region, which extended to strain values of up 0.06% for G0 and of 1.2% for G00 . However, the incorporation of native corn starch led to faster decay of both moduli at higher strain values. The higher the native corn starch content, the faster the moduli decaying rate. This means that the substitution of wheat flour by native corn starch produced more fragile batter. Gluten plays an important role on the structuring of the 3D dough network. In this way, the reduction of gluten content might lead to fragile 3D networks since the links induced by the gluten are lost. Fig. 3 c presents the loss angle tan(d) ¼ G00 /G' as function of the strain. tan(d)<1 reflects solid-like behavior, while tan(d)>1 denotes liquid-like behavior. For the batter formulation B0 the crossover from solid-like to liquid-like behavior was located at about 25% strain. The crossover value was drastically reduced to about 1e2.5% for the batter formulations containing native corn starch. Since gluten is the basic structure-building protein, its reduction leads to batter formulations with increased tendency to flow, suggesting the formation of fragile 3D microstructures (Mariotti, Iametti, Cappa, Rasmussen, & Lucisano, 2011). 3.4. Creep-recovery curves of sponge cake batter formulations Fig. 4 exhibits the creep and recovery curves of the batter formulations. In line with the strain sweeps (Fig. 3), the creeprecovery patterns are consistent with viscoelastic material behavior. Creep and recovery under the action of a very small constant shear stress have been linked to reorientation of bonds and the alignment of microstructures in the viscoelastic material (Onyango, Mutungi, Unbehend, & Lindhauer, 2010). The so-called instantaneous compliance J0 can be related to the elastic stretching energy of bonds. Fig. 4 shows that the addition of native corn starch caused a gradual decrease of the compliance values. The greater the native corn starch content, the smaller the compliance values. Table 2 presents the parameters of Burger's model Eq. (1) obtained by fitting the experimental data in Fig. 4 (StatSoft Inc., USA). The formulation containing only wheat flour (B0) presented the highest value of the instantaneous compliance, and this value decreased as the native corn starch content was increased. Also, the smallest value of the zero shear stress viscosity h0 was obtained for

Table 2 Parameters of Burger's model of sponge cake batter formulations. Sample

J0  102 (Pa1)

B0 B25 B50 B75 B100

2.09 1.92 1.84 1.59 1.49

± ± ± ± ±

0.10a 0.12a 0.16b 0.08c 0.09c

J1  102 (Pa1) 7.98 6.91 6.63 6.31 5.64

± ± ± ± ±

0.23a 0.26b 0.19b,c 0.20c,d 0.18e

h0  103 (Pa s)

lret (s) 49.33 48.73 49.41 51.61 50.60

± ± ± ± ±

0.43a 0.62a 0.48a 0.65a 0.62a

1.47 1.55 1.61 1.68 1.86

± ± ± ± ±

0.23a 0.24a,b 0.29b,c 0.33c 0.31d

Jo, instantaneous compliance; J1, retardation compliance; lret, retardation timeconstant; h0, zero shear stress viscosity. Values are means ± standard error, of three replicates. Superscripts with different letters in same column indicate significant differences (P  0.05).

B0. The retardation time-constant lret showed only slight variations with the native corn starch content, with values of about 51.0 s. This value is smaller than those previously reported (58e77 s) for dough where wheat flour was substituted with resistant starch (Witczak et al., 2012). The difference can be attributed to differences of swelling capacity of resistant and native starches. It has been pointed out that the hydration capacity of batter depends strongly on protein content (Huttner, Dal Bello, & Arendt, 2010). This effect is related to the ability of protein to form strongly interconnected 3D networks, which in turn promote water retention under limited water availability. 3.5. Morphology of sponge cake formulations Fig. 5 presents SEM images of the sponge cakes obtained from baking of the sponge cake batters. Left and right panels correspond to 500  and 2000  magnification, respectively. The sponge cake corresponding to B0 exhibited irregular distribution of solids corresponding to wheat starch granules and debris of them resulting of the milling process to produce the flour (in Fig. 5a and 5b). These solids are covered by products of the batter baking, consisting of lipids, proteins and amylose/amylopectin. These components can lead to interactions to form pairwise complexes, including amylose-lipids and lipid-protein (Gerits, Pareyt, & Delcour, 2014). The incorporation of native corn starch produced a granular-like microstructure where the starch granules can be easily observed. Fig. 5h and 5j displays native corn starch granules covered by the products produced upon baking. In turn, the microstructure of the sponge cake formulations containing increased native corn starch content were more ordered, which was reflected in the enthalpies of the corresponding batter formulations (Table 1). 3.6. Color analysis of the sponge cake formulations

Fig. 4. Batter formulations creep-recovery response. In all cases, the response is typical of viscoelastic materials.

Physicochemical characteristics (moisture, pH, reducing sugar, and microstructure) of the batter are determinants of color characteristics (Esteller & Lannes, 2008). Fig. 6 illustrates the crust appearance of the sponge cake formulations. The crust color of B0 was not homogeneous, presenting regions from yellow to brown. The addition of native corn starch led to a more homogeneous color distribution. Crust hydrothermal pathways determine the content of non-gelatinized starch and hence of the surface homogeneity of re, & Re
guerre, 2012). bread crust (Della Valle, Chiron, Jury, Raitie Also, browning caused by Maillard reactions between proteins and sugars was influenced by distribution and availability of water in the batter matrix (Vanin, Lucas, & Trystram, 2009). The homogeneous crust color distribution suggests that the addition of native corn starch granules induced a more homogeneous and ordered batter microstructure (see Table 1). It is also apparent that batter components had larger mobility for low native corn starch content, which caused the inhomogeneous aggregation of moisture on the

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

Fig. 5. SEM images (500  for left panel, and 2000  for right panel) of the sponge cake formulations: (a), (b) B0, (c), (d) B25, (e), (f) B50, (g), (h) B75, and (i), (j) B100.

51

52

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

Fig. 6. Appearance of the sponge cake formulations crust: (a) B0, (c) B25, (e) B50, (g) B75, and (i) B100. The crust color of B0 is not homogeneous, presenting some variations from yellow to brown regions. The addition of native corn starch led to a more homogeneous color distribution. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

sponge cake surface. According with the standard HunterLab parametrization, a* ranging from 120 to 120 takes positive values for reddish colors and negative values for the greenish ones. On the other hand, b* with values in the range from 120 to 120 takes positive values for yellowish colors and negative values for the bluish ones. Besides, L* with values ranging from 0 to 100 is an approximate measurement of luminosity, which is the property that assign a color to an equivalent of the greyscale (Pathare, Opara, & Al-Said, 2013). Table 3 presents the color parameters of the sponge cake formulations. The luminosity decreased with native corn starch content. Reddish color reflected by the values of a* showed a slight rise as the native corn starch was incorporated. In contrast, yellowish color reflected by the values of b* decreased when native corn starch was incorporated. The higher availability of carbohydrates as native corn starch was incorporated promoted the extent of Maillard reactions and hence of the decrease of yellowish colors. Nonsignificant differences (P < 0.05) in color parameters were found for batter formulations with native corn starch contents of 50% and higher.

The textural characteristics can display either a linear behavior (as for springiness) or a sigmoid pattern (as for hardness), which can be described as

TP ¼ A2 þ

A1  A2 1 þ exp½ðX  X0 Þ=dx

(2)

where TP denotes a textural characteristic and X is the wheat flour content (%).A1,A2,X0 and dx are fitting parameters. For large values of the parameter dx, the sigmoid function was close to a linear behavior. In this way, the larger the value of dx, the more likely the linear behavior. Table 5 summarizes the estimated parameters (StatSoft Inc., USA). Springiness, cohesiveness and adhesiveness exhibited the larger values of the parameter dx, indicating that the fluctuation of these textural characteristics followed a linear-like behavior. In contrast, chewiness, resilience and hardness displayed the smaller values, which reflected a sigmoid-like behavior of these characteristics. In turn, sigmoid behavior suggested that native corn starch granules acted not only as fillers of the baked batter, but also as active ingredients that interacted with the other batter components (e.g., lipids and proteins).

3.7. Textural characteristics of the sponge cake formulations Table 4 summarizes the textural properties of the sponge cake formulations. Interestingly, all properties decreased monotonically with the native corn starch content, with the fluctuations being statistically significant as corn starch content increased in the batter formulations. As already observed in SEM images of Fig. 5, the above indicated that the incorporation of native corn starch had important effects in the microstructure of the sponge cake formulations. For instance, hardness changed from 4893.5 g for B0 to 3402.5 g for B100. The effect of the native corn starch granules was also relevant for cohesiveness, which decreased from 0.56 to 0.23. The microstructure of the sponge cake formulations containing native corn starch granules showed reduced consolidation as compared to that from the pure wheat flour formulation. When represented in terms of the wheat flour content, the textural characteristics increased monotonically as shown in Fig. 7.

Table 3 Color parameters of the sponge cake formulations. Sample

L*

B0 B25 B50 B75 B100

61.04 58.12 55.27 54.21 54.34

a* ± ± ± ± ±

1.2a 0.9b 1.1c 1.2c 1.1c

9.92 10.36 11.60 11.42 11.73

b* ± ± ± ± ±

0.7a 0.8b 0.7b 0.9b 0.7b

26.43 25.56 22.88 22.12 22.24

± ± ± ± ±

1.2a 1.1b 0.9b 1.0b 0.9b

L*, lightness; a*, redness/greenness; b*, yellowness/blueness. Values are means ± standard error, of three replicates. Superscripts with different letters in same column indicate significant differences (P  0.05).

4. Conclusions The results obtained in this study showed that the partial or total substitution of wheat flour by native corn starch significantly modified the thermal and rheological properties of sponge cake batter and the texture and microstructure of sponge cakes obtained from them. Modified properties included enhanced steady-state viscosity and increased trend to flow as the shear rate was increased. Thermal analysis revealed incipient gelatinization of starch granules as resulting of limited water availability within the batter matrix. In this way, batter can be seen as weak gel filled with active fillers given by wheat flour and/or native corn starch granules. Addition of corn starch produced more ordered batter microstructure, reflected by the increase of the gelatinization enthalpy. The consolidation of the batter microstructure by native corn starch granules led to decreased viscoelastic (storage and loss moduli) properties. Interaction between starch molecules and lipids/proteins seems to be an important factor in modifying rheological and thermal behavior of batter formulations. The limited swelling of native corn starch granules resulted in lower hydration of the microstructure forming hydrocolloids, and hence of batter weakling. This effect was also reflected in the textural analysis of the sponge cakes, which showed that the texture characteristics decreased monotonously with native corn starch content.

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

53

Table 4 Textural profile analysis (TPA) of sponge cake formulations. Sample

Hardness (g)

B0 B25 B50 B75 B100

4893.50 4633.50 4185.00 3749.00 3402.50

± ± ± ± ±

Adhesiveness (mJ)

97.87e 78.76d 75.33c 82.48b 95.27a

0.92 0.75 0.60 0.58 0.43

± ± ± ± ±

0.03d 0.01c 0.02b 0.02b 0.01a

Resilience 0.19 0.17 0.14 0.13 0.11

± ± ± ± ±

Cohesiveness

0.02c 0.01b,c 0.01a,b 0.01a 0.01a

0.56 0.45 0.37 0.32 0.23

± ± ± ± ±

0.01e 0.02d 0.02c 0.01b 0.01a

Springiness (mm) 12.91 11.30 9.86 8.42 6.73

± ± ± ± ±

0.32e 0.35d 0.20c 0.25b 0.16a

Chewiness (mJ) 319.72 228.68 150.30 99.92 78.61

± ± ± ± ±

4.80e 5.72d 3.01c 2.80b 1.97a

Values are means ± standard error, of three replicates. Superscripts with different letters in same column indicate significant differences (P  0.05).

Fig. 7. Sponge cake formulations typical textural properties behavior as a function of the wheat flour content. A sigmoid function was used to fit the experimental data.

Table 5 Parameters of sigmoid equation for fitting experimental data. Texture characteristic

A1

A2

X0 (%)

dx (%)

Hardness Adhesiveness Resilience Cohesiveness Springiness Chewiness

3086.32 0.18 0.08 0.17 243.49 62.14

5141.06 150.22 0.28 30.28 81.16 451.64

45.64 637.65 89.16 735.39 1107.26 82.52

27.00 101.25 53.65 171.09 912.69 26.16

A1, A2, X0, dx, fitting parameters. Values are means ± standard error, of three replicates. Superscripts with different letters in same column indicate significant differences (P  0.05).

Conflict of interest The authors declare no conflict of interest. References Ai, Y., Hasjim, J., & Jane, J. L. (2013). Effects of lipids on enzymatic hydrolysis and physical properties of starch. Carbohydrate Polymers, 92, 120e127. Angioloni, A., & Collar, C. (2011). Significance of lipid binding on the functional and nutritional profiles of single and multigrain matrices. European Food Research and Technology, 233, 141e150. Barham, P., Skibsted, L. H., Bredie, W. L., Bom Frøst, M., Møller, P., Risbo, J., et al. (2010). Molecular gastronomy: a new emerging scientific discipline. Chemical Reviews, 110, 2313e2365. Campos, D. T., Steffe, J. F., & Ng, P. K. (1997). Rheological behavior of undeveloped and developed wheat dough. Cereal Chemistry, 74, 489e494. Cauvain, S. (2015). Principles of dough formation. In Technology of breadmaking (pp. 303e337). Springer International Publishing. Chevallier, S., Colonna, P., Della Valle, G., & Lourdin, D. (2000). Contribution of major ingredients during baking of biscuit dough systems. Journal of Cereal Science, 31, 241e252. Collar, C., Martinez, J. C., & Rosell, C. M. (2001). Lipid binding of fresh and stored formulated wheat breads. Relationships with dough and bread technological performance. Food Science and Technology International, 7, 501e510. Day, L., Fayet, C., & Homer, S. (2013). Effect of NaCl on the thermal behaviour of

wheat starch in excess and limited water. Carbohydrate Polymers, 94, 31e37. Delcour, J. A., & Hoseney, R. C. (2010). Principles of cereal science and technology (3rd ed.). St. Paul: AACC International. re, M., & Re
guerre, A. L. (2012). Kinetics of Della Valle, G., Chiron, H., Jury, V., Raitie crust formation during conventional French bread baking. Journal of Cereal Science, 56, 440e444. Eliasson, A. C. (1994). Interactions between starch and lipids studied by DSC. Thermochimica Acta, 246, 343e356. Esteller, M. S., & Lannes, S. (2008). Production and characterization of sponge-dough bread using scalded dye. Journal of Texture Studies, 39, 56e67. Gerits, L. R., Pareyt, B., & Delcour, J. A. (2014). A lipase based approach for studying the role of wheat lipids in bread making. Food Chemistry, 156, 190e196. Hemalatha, M. S., Leelavathi, K., Salimath, P. V., & Rao, U. P. (2014). Control of chapati staling upon treatment of dough with amylases and xylanase. Food Bioscience, 5, 73e84. Hug-Iten, S., Handschin, S., Conde-Petit, B., & Escher, F. (1999). Changes in starch microstructure on baking and staling of wheat bread. LWT-Food Science and Technology, 32, 255e260. Huttner, E. K., Dal Bello, F., & Arendt, E. K. (2010). Rheological properties and bread making performance of commercial wholegrain oat flours. Journal of Cereal Science, 52, 65e71. Juszczak, L., Witczak, T., Ziobro, R., Korus, J., Cie
slik, E., & Witczak, M. (2012). Effect of inulin on rheological and thermal properties of gluten-free dough. Carbohydrate Polymers, 90, 353e360.
jka, M. (2012). Korus, J., Juszczak, L., Ziobro, R., Witczak, M., Grzelak, K., & So Defatted strawberry and blackcurrant seeds as functional ingredients of glutenfree bread. Journal of Texture Studies, 43, 29e39. Korus, J., Witczak, M., Ziobro, R., & Juszczak, L. (2009). The impact of resistant starch on characteristics of gluten-free dough and bread. Food Hydrocolloids, 23, 988e995. Mariotti, M., Iametti, S., Cappa, C., Rasmussen, P., & Lucisano, M. (2011). Characterisation of gluten-free pasta through conventional and innovative methods: evaluation of the uncooked products. Journal of Cereal Science, 53, 319e327. Matos, M. E., & Rosell, C. M. (2013). Quality indicators of rice-based gluten-free bread-like products: relationships between dough rheology and quality characteristics. Food and Bioprocess Technology, 6, 2331e2341. Mihhalevski, A., Heinmaa, I., Traksmaa, R., Pehk, T., Mere, A., & Paalme, T. (2012). Structural changes of starch during baking and staling of rye bread. Journal of Agricultural and Food Chemistry, 60, 8492e8500. Mohammed, I., Ahmed, A. R., & Senge, B. (2012). Dough rheology and bread quality of wheat-chickpea flour blends. Industrial Crops and Products, 36, 196e202. Nassu, R. T., & Guaraldo Gonçalves, L. A. (1999). Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC) technique. Grasas y Aceites, 50, 16e21. Onyango, C., Mutungi, C., Unbehend, G., & Lindhauer, M. G. (2010). Rheological and baking characteristics of batter and bread prepared from pregelatinised cassava starch and sorghum and modified using microbial transglutaminase. Journal of Food Engineering, 97, 465e470. Pareyt, B., Finnie, S. M., Putseys, J. A., & Delcour, J. A. (2011). Lipids in bread making: sources, interactions, and impact on bread quality. Journal of Cereal Science, 54, 266e279. Patel, B. K., Waniska, R. D., & Seetharaman, K. (2005). Impact of different baking processes on bread firmness and starch properties in breadcrumb. Journal of Cereal Science, 42, 173e184. Pathare, P. B., Opara, U. L., & Al-Said, F. A. J. (2013). Colour measurement and analysis in fresh and processed foods: a review. Food and Bioprocess Technology, 6, 36e60. Primo-Martin, C., Van de Pijpekamp, A., Van Vliet, T., De Jongh, H. H. J., Plijter, J. J., & Hamer, R. J. (2006). The role of the gluten network in the crispness of bread crust. Journal of Cereal Science, 43, 342e352. Singh, N., Singh, J., Kaur, L., Sodhi, N. S., & Gill, B. S. (2003). Morphological, thermal and rheological properties of starches from different botanical sources. Food Chemistry, 81, 219e231. Tegge, G. (2004). Starke and starke derivate (3rd ed.). Hamburg: Behr'sVerlag. Tester, R. F., & Sommerville, M. D. (2003). The effects of non-starch polysaccharides on the extent of gelatinisation, swelling and a-amylase hydrolysis of maize and wheat starches. Food Hydrocolloids, 17, 41e54. Trinh, K. T., & Glasgow, S. (2012). On the texture profile analysis test Accessed 05.01.16. www.conference.net.au/chemeca2012/papers/202.pdf Vanin, F., Lucas, T., & Trystram, G. (2009). Crust formation and its role during bread baking. Trends in Food Science & Technology, 20, 333e343.

54

A.Y. Guadarrama-Lezama et al. / LWT - Food Science and Technology 70 (2016) 46e54

Vega, C., & Ubbink, J. (2008). Molecular gastronomy: a food fad or science supporting innovative cuisine? Trends in Food Science & Technology, 19, 372e382. Wagner, N. J., & Brady, J. F. (2009). Shear thickening in colloidal dispersions. Physics Today, 62, 27e32. Witczak, M., Juszczak, L., Ziobro, R., & Korus, J. (2012). Influence of modified starches on properties of gluten-free dough and bread. Part I: rheological and thermal properties of gluten-free dough. Food Hydrocolloids, 28, 353e360.

Won, D., & Kim, C. (2004). Alignment and aggregation of spherical particles in viscoelastic fluid under shear flow. Journal of Non-Newtonian Fluid Mechanics, 117, 141e146. Young, L., & Cauvain, S. P. (2007). Technology of breadmaking. Berlin: Springer. Ziobro, R., Korus, J., Juszczak, L., & Witczak, T. (2013). Influence of inulin on physical characteristics and staling rate of gluten-free bread. Journal of Food Engineering, 116, 21e27.