The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery...
-
Upload
henry-nichols -
Category
Documents
-
view
218 -
download
5
Transcript of The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery...
![Page 1: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/1.jpg)
The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a
confectionery fat
Jari Alander &Yvonne Samuelsson
Karlshamns AB, R&D
![Page 2: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/2.jpg)
Introduction
• Polymorphism and crystallisation kinetics of fats are influenced by emulsifiers– Inhibits or accelerates polymorphic
transformations– Influences nucleation and/or growth
• Few systematic studies in the presence of auxiliary food components
![Page 3: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/3.jpg)
Materials & methods
• Hydrogenated confectionery fat– C16:0 11%, C18:0 12%, C18:1 70% (c+t)
• Soybean lecithin• Sorbitan tristearate (STS)
![Page 4: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/4.jpg)
Materials & methods
• 70% fat, 30% sugar, 0-0.5% lecithin, 0-2% STS (w/w on fat+sugar), D-optimal experimental design with replicates
• Fat and sugar mixed, ground on three-roll refiner• Heated to 60°C, emulsifiers added, equilibrated
at 30°C• DSC (Mettler TA8000)• Isothermal at 21, 23 and 25°C after initial
melting at 80°C and cooling with 10°C/min
![Page 5: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/5.jpg)
Isothermal crystallisation by DSC
• Original curve with three evaluation methods
• Peak time / integral• Deconvolution• Avrami modelling of
conversion curves
![Page 6: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/6.jpg)
Results
• Peak times and crystallisation enthalpies– Evaluation of experimental design– Modelling of response surfaces
• Deconvolution of original data– Modelling of peak shape using Gaussian
peak fitting
• Kinetic modelling of conversion curves– Avrami vs extended Avrami
![Page 7: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/7.jpg)
Peak times
Peaktime at 21 C (min) Peaktime at 23 C (min)
Peaktime at 25 C (min)
Investigation: Crystallization kinetics (PLS, comp.=3)Contour Plot
Peak times are dependent on both STS and lecithin
![Page 8: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/8.jpg)
Enthalpy of crystallisation
T=21 C T= 23 C
T=25 C
Investigation: Crystallization kinetics (PLS, comp.=2)Contour Plot
The crystallisation enthalpy is mainly determined by STS concentration
![Page 9: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/9.jpg)
Conclusions / peak times
• Quadratic/interaction terms gave best modelling results
• STS at low concentrations increases crystallisation rate and decreases at high concentrations
• Lecithin has smaller influence• STS has a destructurating effect (lower
enthalpies of crystallisation)• More complex models needed for
interpretation
![Page 10: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/10.jpg)
0 600 1200 1800
0,0
0,5
1,0
1,5
2,0
N14 23 C 1 0,25
He
at f
low
(m
W)
Time (s)
0 600 1200 1800
0,0
0,5
1,0
1,5
2,0
N1 23 C 0 0
He
at f
low
(m
W)
Time (s)
0 600 1200 1800
0,0
0,5
1,0
1,5
2,0
N2 23 C 0 0,5
He
at f
low
(m
W)
Time (s)
0 600 1200 1800
0,0
0,5
1,0
1,5
2,0
N3 23 C 2 0
He
at f
low
(m
W)
Time (s)
0 600 1200 1800
0,0
0,5
1,0
1,5
2,0
N4 23C 2 0,5
He
at f
low
(m
W)
Time (s)
Lecithin
STS
Deconvolution of DSC peaks
![Page 11: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/11.jpg)
Conclusions/deconvolution
• Three peaks needed for good modelling of peak shape
• Two major crystallisation events, one slow process common in all samples
• Fractionation or selective influence on nucleation/growth events induced by emulsifiers ?
![Page 12: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/12.jpg)
Avrami vs extended Avrami equations
1110012
21
1
ntke
ntket
In original Avrami equation coefficients k2 and n2 are zero and is 100%
![Page 13: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/13.jpg)
Extended Avrami modelling of crystallisation curves
![Page 14: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/14.jpg)
Conclusions – Avrami modelling
• Traditional Avrami model does not give satisfactory fit for early or late parts for the conversion curve
• Extended Avrami model gives improved fit on entire conversion curve
• STS slows down nucleation but increases growth rate of first fraction
• Lecithin slows down both nucleation and growth
• STS overrules lecithin in combinations
![Page 15: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/15.jpg)
Mechanistic considerations
• STS contains both polar monoesters (induces nucleation) and less polar triesters (slow down nucleation and growth)
• At low concentrations, nucleation inducing effect of more polar monoesters dominate
• At high concentrations, nucleation/growth inhibiting effect of triesters dominate
• Lecithin in absence of STS slows down both nucleation and growth
![Page 16: The effect of lecithin and sorbitan tristearate on the crystallisation kinetics of a confectionery fat Jari Alander & Yvonne Samuelsson Karlshamns AB,](https://reader036.fdocuments.us/reader036/viewer/2022081516/56649e445503460f94b378c3/html5/thumbnails/16.jpg)
Summary
• The crystallisation of a hydrogenated confectionery fats was investigated by isothermal DSC in presence of sugar and emulsifiers
• Effects on nucleation/growth by emulsifiers were observed
• Polar/non-polar constituents of food emulsifiers may have different effects on the crystallisation behaviour