Procedia Food Science 1 (2011) 62 – 67

2211–601X © 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of 11th International Congress on Engineering and Food (ICEF 11) Executive Committee.doi:10.1016/j.profoo.2011.09.011

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Procedia – Food Science 00 (2011) 000–000

Procedia Food Science

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11th International Congress on Engineering and Food (ICEF11)

Rheological properties of maltodextrin based fat - reduced confectionery spread systems

Miroslav Hadnađevaa*, Tamara Dapčević Hadnađeva, Aleksandra Torbicaa, Ljubica Dokićb, Biljana Pajinb, Veljko Krstonošićc

aInstitute for Food Technology,University of Novi Sad, Bul. cara Lazara 1, Novi Sad 21000, Serbia b Faculty of Technology, University of Novi Sad, Bul. cara Lazara 1, Novi Sad 21000, Serbia

c Faculty of Medicine, Hajduk Veljkova 3, University of Novi Sad, Novi Sad 21000, Serbia

Abstract

Vegetable fat for confectionery spreads was partially replaced with two different types of maltodextrin gels (potato and specialty waxy maize maltodextrin gel) used as fat replacers at 20% gel concentration. The fat replacement levels were 15%, 30% and 50%. Fullfat confectionery spread was used as a control sample. Steady shear (hysteresis loop, apparent viscosity and yield stress determination), oscillatory and firmness measurements were performed. Also, melting profile of a confectionery vegetable fat was determined in order to confirm the working temperatures of all tests. Reduced fat systems with fat replacement level above 15% resulted in the formation of a product with inverted phases, so called ′ganache′ no matter of the used maltodextrin gel type. Therefore, only systems with 15% replacement level were observed. The incorporation of both types of maltodextrin gel as fat replacers in reduced fat system resulted in significant increase in degree of thixotropy, yield stress value, apparent viscosity, elastic moduli and firmness value. Also, reduced fat systems prepared with potato maltodextrin gel expressed more significant increase in all tested rheological parameters in comparison to waxy maize maltodextrin gel containing systems. This study showed that incorporation of maltodextrin gels used as fat replacers can be performed up to 15%. However, negative influence on system rheology was observed. Therefore, further studies should focus on changing preparation techniques as well as the addition of different emulsifier. © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICEF11 Executive Committee Members Keywords: vegetable fat; maltodextrin; reduced fat; rheology

1. Introduction

Chocolate and chocolate type products represent semi-solid suspensions of sugar, cocoa, milk powder, hazelnut and other ingredients particles in a continuous fat phase [1]. Chocolate type products,

* Corresponding author. Tel.: +381214853811; fax: +38121450725. E-mail address: miroslav.hadnadjev@fins.uns.ac.rs

© 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of 11th International Congress on Engineering and Food (ICEF 11) Executive Committee.

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confectionery spreads may contain other vegetable fats than cocoa butter, e.g. palm oil, soybean oil etc. [2]. Due to high fat content, these products have high caloric value. However, one of the demands in modern nutrition regarding the increasing human obesity is to decrease fat consumption. Also, it is well known that fat plays one of the major roles in product rheology, texture and sensory properties. It was estimated [3] that large group of functional properties of fat-containing products e.g. spreadability, gloss, graininess or smoothness are governed by the characteristics of the crystal network formed by its constituent lipid species. Also, properties of fat crystal network are influenced by chemical composition, solid fat content, fat polymorphism etc. [4]. According to Hadnađev et al. [5] rheological behaviour of blends in which the part of the vegetable fat is replaced with maltodextrin gel is mainly governed by the properties of maltodextrin phase. It was observed that in a solid state (20°C), waxy maize maltodextrin allowed fat replacement up to a level of 50 %, expressing only a minor decrease in firmness value. In contrast, the potato maltodextrin was found to cause significant decreases in firmness value.

The aim of this work was to investigate the possibility of replacing certain amount of vegetable fat with two different types of maltodextrin gels in chocolate type confectionery spread product. Rheological and textural measurements were performed in order to determine the changes in handling and storage properties in reduced fat systems.

2. Materials & Methods

2.1. Materials

Confectionery vegetable fat, melting range temperature 30-32°C, was donated by oil industry Dijamant Zrenjanin, Serbia.

Two types of maltodextrin were used: potato maltodextrin characterized by DE = 3.5 and moisture w = 4.7% and maltodextrin obtained from waxy maize starch by special enzyme hydrolysis (isoamylase)

characterized by DE = 2 and moisture w = 5.5%. Reduced fat chocolate spread was prepared in the laboratory Ballmill Refiner CAO-B5 (Caotech,

Wormerveer, The Netherlands).

2.2. Preparation conditions

Twenty percent of maltodextrin solutions were prepared and left for 24h at room temperature in order to obtain gels. Consequently, the obtained gels were gently mixed with vegetable fat and incorporated in reduced fat chocolate spreads in modified 50g Farinograph mixing bowl. The mixing was kept for 15 minutes at 30°C. The extent of fat reduction was 15%, 30% and 50%.

2.3. Steady shear measurements

Hysteresis loop method was used to establish the extent of system thixotropy. Shear rate was increased from 0-100 1/s, it was kept at 100 and finally decreased from 100-0 1/s at 30°C using Z20 cylinder geometry. Duration of each step was 240s. All rheological measurements were performed in triplicates by HAAKE MARS, ThermoScientific, Germany. Obtained hysteresis loop areas which refer to system thixotropy were calculated using Origin 6.1 Scientific Graphing and Data Analysis Software (OriginLab Corporation, USA). Moreover, the apparent viscosity at 100 1/s were recorded.

64 Miroslav Hadnadev et al. / Procedia Food Science 1 (2011) 62 – 67 Miroslav Hadnađev / Procedia – Food Science 00 (2011) 000–000 3

2.4. Yield stress measurements

Determination of yield stress was performed as stress ramp in controlled stress (CS) mode by increasing shear stress from 1 – 500 Pa in duration of 180 s. The measurements were conducted at 30°C using parallel plate geometry (PP35 Ti).

2.5. Oscillatory measurements

Stress sweep tests at 1 and 10 Hz frequencies were conducted as preliminary tests and a stress of 1 Pa, which was within linear viscoelastic region, was selected for frequency sweep measurements. Frequency sweep measurements were performed at 30 °C using parallel plate geometry (PP35 Ti). The frequency was increased from 1 – 10 Hz at constant stress of 1 Pa and elastic G´ and viscous moduli G′′ were recorded.

2.6. Determination of melting profile of confectionery fat

Oscillation temperature ramp in controlled deformation (CD) mode was performed in order to determine melting profile of confectionery fat. Temperature was linearly increased from 10.00 °C - 40.00 °C, within 1800 s at constant deformation, γ = 0.001 and frequency f = 1 Hz using parallel plate geometry (PP35 Ti).

2.7. Firmness measurements

Firmness of confectionery chocolate spreads was investigated using TA.XTplus Texture Analyser (Stable Micro Systems, UK) using a 5 load cell. Measurements were performed using the cone sensors for spreadability measurements (TTC Spreadability Rig) applying the protocol for Chocolate spreads (Texture Exponent 32 software version 4.0.11.0 - Stable Micro Systems). The maximum compression force in grams, which refers to as sample firmness, was determined in eight replicates.

2.8. Statistical analysis

Results were expressed as means of replicate analyses. Analysis of Variance (ANOVA) and Tukey test were used to test the significance of differences among the mean values at the 0.05 significance level. The statistical analyses were performed by software Statistica 8.0 (Statsoft, USA).

3. Results & Discussion

According to melting curve profile of used confectionery fat, the presence of 3 peaks can be observed in Fig. 1 related to fat polymorphisms and gradual melting of less stable fat crystals having lower melting temperature. This can be attributed to a different triacylglycerol composition found in tested confectionery fat.

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10 15 20 25 30 35 40

0,1

0,2

0,3

0,4

0,5

0,6

0,7

tan δ

Temperature (oC)

Fig.. 1.Melting range profile of confectionery fat

First peak can be observed at 21.5°C, second at 25.5°C and third broaden peak at temperature range 29-32 °C. According to Bell [6], in their melting temperature range, fats during crystallization process express characteristics of weak viscoelastic gels. Therefore, all further measurements were performed at 30°C.

Reduced fat systems with 15%, 30% and 50% fat replacement were prepared. However, systems preparation with 30% and 50% fat replacement using both types of maltodextrin gels resulted in the formation of so called “ganache” that is confectioner’s term for a phase inverted (i.e. oil – in – water) chocolate product [7]. The obtained product expressed sticky behaviour, it was less firm and it had changed sensory properties. According to steady shear measurements, these systems expressed rheopectic behaviour which is characterized by structural formation during the applied shear rate (Fig 2).

0 100 200 300 400 500-500

0

500

1000

1500

2000

2500

3000

3500

Shea

r stre

ss (P

a)

Shear rate (1/s)

Fig. 2.Flow curve behavior of 50% reduced fat system prepared with 20% waxy maize maltodextrin gel

Also, dynamic oscillatory measurements proved that viscous moduli were higher in comparison to elastic moduli in whole frequency range. Moreover, constant increase in both moduli, especially in viscous moduli with frequency can be observed (Fig 3).

66 Miroslav Hadnadev et al. / Procedia Food Science 1 (2011) 62 – 67 Miroslav Hadnađev / Procedia – Food Science 00 (2011) 000–000 5

1 10

500

1000

G' G

'' (Pa

)frequency (Hz)

G' G''

Fig. 3.Viscoelastic behavior of 50% reduced fat system prepared with 20% waxy maize maltodextrin gel

However, systems with 15% fat replacement level could be prepared and results of rheological and textural measurements are summarized in Table 1.

Table 1. Rheological and textural parameters of control and reduced fat systems

Fat replacement (%)

Thixotropic

loop area,

A (Pa/s)

Apparent viscosity, η (Pas)

Yield stress

(Pa)

Elastic modulus

(Pa)

Firmness

(g)

control 2742a 1.97a 13.18a 22985a 2542а

15% potato maltodextrin 51120b 10.22b 196.45b 114200b 9140b

15% waxy maize maltodextrin 61160c 12.42c 199.2b 209550c 19292c

(a) Values in the column followed by the same superscripts are not significantly different (P > 0.05). (b) Viscosity has been measured at a shear rate of 100 s-1. (c) Storage modulus has been measured at a frequency of 10 Hz.

Observing the steady shear measurements, i.e. hysteresis loop area and apparent viscosity, it can be

noticed that incorporation of both maltodextrin gels resulted in significant (P<0.05) increase in thixotropic loop area as well as values of apparent viscosity. Yield stress measurements showed that maltodextrin gel addition also resulted in significant increase in yield stress value in comparison to control sample. The difference between yield stress values was not influenced by the type of maltodextrin gel. According to Beckett [2] small increase in moisture content in chocolate and chocolate like systems result in significant increase in apparent viscosity as well as yield stress value. Namely, fat has a major role as lubricating material of polar hydrophilic sugar particles enabling its desirable flow properties. Therefore, water addition in these systems increased interactions between sugar particles and hence, increased viscosity and yield stress values. There are a lot of papers regarding the water addition in chocolate and chocolate like systems, however, there is a lack of paper concerning maltodextrin addition which could stabilize incorporated water and reduce well known rheological changes. Viscoelastic and textural properties i.e. firmness values, were influenced in the same manner, which resulted in significant changes in elastic modulus and firmness by fat replacement. It can be noticed that systems prepared with maltodextrin obtained from waxy maize, which built much firmer gels [8] in comparison to potato

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maltodextrin gel, expressed larger thixotropic loop areas, higher apparent viscosity, yield stress, elastic modulus and firmness value in comparison to reduced fat systems prepare with potato maltodextrin gel.

4. Conclusion

Incorporation of waxy maize and potato maltodextrin gels in confectionery chocolate spread systems resulted in changed rheological parameters. Fat replacement could be achieved up to 15%. However, above 15% i.e. 30% and 50% fat replacement levels caused inverted phase behaviour. This product expressed rheopectic, viscous behaviour with changed sensory properties. Fifteen percent fat replacement level with both maltodextrin gels led to significant increase in hysteresis loop areas, apparent viscosity, elastic moduli and firmness value. Also, systems prepared with waxy maize maltodextrin gel expressed more significant changes in rheological and textural parameters in comparison to control sample and potato maltodextrin gel containing sample.

Acknowledgements

This work was supported by the Project III 46001, Ministry of Science and Technological Development, Republic of Serbia.

References

[1] Afoakwa EO, Patersona A, Fowler M. Factors influencing rheological and textural qualities in chocolate - a review. Trends Food Sci Tech 2007; 18: 290-298.

[2] Beckett ST. Controlling the Flow Properties of Liquid Chocolate. In: Beckett ST., editors. The Science of Chocolate 2nd Edition. Cambridge: The Royal Society of Chemistry; 2008

[3] Narine S S, Marangoni AG. Structure and mechanical properties of fat crystal networks. In: Taylor S, editors, Advances in Food and Nutrition Research vol 44, Academic Press; 2002, p. 33–145

[4] deMan JM. Relationship among chemical, physical, and textural properties of fats. In: Widlak N, editors, Physical properties of fats, oils and emulsions, Champaign: AOCS Press; 1999

[5] Hadnađev M, Dokić LJ, Dapčević Hadnađev T, Pajin B, Krstonošić V. The impact of maltodextrin-based fat mimetics on rheological and textural characteristics of edible vegetable fat. 2011; J Texture Stud; doi:10.1111/j.1745-4603.2011.00302.x

[6] Bell A, Gordon MH, Jirasubkunakorn W, Smith KW. Effect of composition on fat rheology and crystallization. Food Chem 2007; 101: 799-805.

[7] Traitler H, Windhab,EJ, Wolf B. Process for manufacturing chocolate compositions containing water. United States Patent 6165540; 2000.

[8] Hadnađev M, Dokić Lj, Pajin B, Mihić J. Rheological characterisation of maltodextrins obtained from different botanical origin starch. International Symposium ¨5th International symposium on food rheology and structure – ISFRS 2009¨ Zürich, Switzerland, 15-18 June, 2009. Proceedings p. 652-653.

Presented at ICEF11 (May 22-26, 2011 - Athens, Greece) as paper FMS766.