WO2012079800A1 - Procédé et agencement pour caractériser un blanchiment gras et une qualité de chocolat contenant des surfaces par diffraction de rayons x - Google Patents

Procédé et agencement pour caractériser un blanchiment gras et une qualité de chocolat contenant des surfaces par diffraction de rayons x Download PDF

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Publication number
WO2012079800A1
WO2012079800A1 PCT/EP2011/067510 EP2011067510W WO2012079800A1 WO 2012079800 A1 WO2012079800 A1 WO 2012079800A1 EP 2011067510 W EP2011067510 W EP 2011067510W WO 2012079800 A1 WO2012079800 A1 WO 2012079800A1
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WIPO (PCT)
Prior art keywords
ray beam
intensity pattern
characterizing
ray
pattern
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PCT/EP2011/067510
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English (en)
Inventor
Markus Weygand
Peter Laggner
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Bruker Axs Gmbh
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Publication of WO2012079800A1 publication Critical patent/WO2012079800A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/02—Food
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/201—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials by measuring small-angle scattering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions

Definitions

  • the present invention relates to a method and an arrangement for characterizing an object comprising a triacylglyceride, wherein an X-ray beam is incident at a surface of the object at a grazing incident angle. Further, the present invention relates to a method and to an
  • the object may comprise cocoa butter, cocoa or chocolate and the quality of the chocolate may be derived from the grazing incidence X-ray data.
  • the present invention relates to the quality control and analysis of chocolate and chocolate containing surfaces.
  • X-rays wherein an X-ray beam is transmitted through the object.
  • the X-ray beam is diffracted at the bulk of the object and the diffracted X-ray beam is detected using a detector.
  • the diffracted X- ray beam forms a pattern, such as a ring pattern, at the detector.
  • a size of the one or more rings comprised in the ring pattern may be indicative of an intermolecular distance of molecules contained in the object.
  • OP Optical Profiling System
  • AFM Atomic Force Microscopy
  • cocoa butter may adopt different molecular configurations or phases, such as a p(V)-phase and a p(VI)-phase which differ in the relative arrangement of the molecules, in particular in their intermolecular distance.
  • the different phases of the cocoa butter may be indicative of different qualities of the cocoa butter.
  • the quality of the cocoa butter may not be derived from X- ray measurements with sufficient accuracy.
  • a method for characterizing an object comprising fatty acids
  • carboxylic acids with an (unbranched) aliphatic tail which may be either saturated or unsaturated, comprising chains of moieties CH2 which are terminated by a carboxyl group and a glycerol ligand
  • the method comprising : directing an X-ray beam (a focused beam of electromagnetic radiation having a wavelength in between 50 nm to 1 pm, in particular in between 0.1 nm to 1 nm) to a surface (in particular a plane surface) of the object (which may be supported by an object holder, which in particular enables orienting the object to adjust the incidence angle) at a grazing incidence angle (which may be in between 0° and 3°, and which may in particular depend on a composition of the object which may define a critical incident angle at which a transmitted beam of the X-ray beam propagates parallel to the surface of the object); diffracting the X- ray beam at the object (which may involve interaction of the X-ray beam with constituents or molecules within the object, such that the
  • determining one or more derived values from the intensity pattern such as a derived value indicating an intermolecular distance of molecules comprised within the object; matching the intensity pattern and/or the derived values with the reference data; deriving a deviation of the intensity pattern from the reference data, wherein the reference data may comprise a reference intensity pattern, a reference intermolecular distance, a reference shape of the intensity pattern or the like); and characterizing (which may in particular comprise structurally
  • characterizing characterizing; characterizing with respect to quality; characterizing with respect to a structural phase; characterizing with respect to an
  • the characterization of the object may involve assigning a quality to the object.
  • a structural change of an object comprising a fatty acid, in particular comprising cocoa butter may be initiated at the surface of the object and may then affect the bulk of the object later on. Since the X-ray beam is incident at a grazing incidence angle the X-ray beam interacts predominantly only with a thin surface layer of the object (because the X-ray beam may exponentially decrease with increasing penetration depth into the object), the described and specified method is well suited to observe or measure a structural rearrangement of molecules of the object which are present at the surface of the object.
  • the method may involve analysis of a particular structural phase of the cocoa butter, in particular the p(V)-phase of the cocoa butter which may have a particular intermolecular distance at the bulk or in the volume of the object which may amount to about 64 A to 68 A, in particular to about 65 A.
  • This bulk intermolecular distance between molecules (in particular one or more types of fatty acid residues) comprised in the bulk of the object (cocoa butter) may serve as reference data.
  • the surface intermolecular distance of this p(V)-phase (at the surface of the object) may be different from the bulk
  • intermolecular distance may in particular be smaller than the bulk intermolecular distance.
  • the surface intermolecular distance may decrease more and more, when the cocoa butter approaches a phase transition from the p(V)-phase to the p(VI)-phase.
  • the phase p(VI)-phase may indicate a lower quality of the cocoa butter or chocolate than the p(V)-phase.
  • the comparing the intensity pattern with the reference data comprises determining a deviation (in particular a difference in value, a difference in shape) of the detected intensity pattern from the reference data (which may be a reference intensity pattern or any derived values), wherein the characterizing is based on the deviation.
  • the detecting the intensity pattern of the diffracted X-ray beam comprises detecting an intensity ring pattern (characterized by enhanced intensity of diffracted X-radiation at a cone around a direction corresponding to the direction of the main reflection angle of the X-ray beam, wherein the cone-shaped enhanced intensity of the X-radiation may impinge onto the detector to form circular or oval ring(s)), and wherein the comparing the intensity pattern with the reference data comprises comparing the detected intensity pattern with a reference pattern (such as a pattern derived computationally from a molecular model or measured for example at the bulk of the object, in particular using transmission X-ray diffraction technology).
  • a reference pattern such as a pattern derived computationally from a molecular model or measured for example at the bulk of the object, in particular using transmission X-ray diffraction technology.
  • image processing may be applied to compare a two-dimensional detected intensity pattern with a two-dimensional reference pattern.
  • correlation methods may be employed.
  • Image processing may in particular involve detecting or deriving a transformation which may optimally transform the detected intensity pattern to the reference pattern.
  • the transformation may in particular comprise stretching and/or scaling and/or normalizing the detected intensity pattern.
  • transformation may in particular be parametrized and the parameter may indicate a degree of the deviation and/or may indicate a quality measure.
  • the intensity ring pattern is further analyzed to determine a width (in particular a radial extent) of a ring (extending in a circumferential direction perpendicular to the radial direction) in the intensity ring pattern, wherein the characterizing the object is further based on the width of the ring.
  • the width of the ring may indicate a coherence of molecules (in particular fatty acids) comprised in the surface layer of the object.
  • the width may indicate a degree of order in the particular structural phase of the object, in particular cocoa butter.
  • the larger the width of the ring the lower the order of the molecules in the particular structural phase may be.
  • a lower order may indicate an ongoing phase transition from a high quality phase to a low quality phase of the cocoa butter.
  • the method for characterizing the object further comprises determining an anisotropy of the intensity ring pattern (which may involve detection of changing intensity when propagating in the circumferential direction) for deriving an orientation of a fatty acid chain comprised in the object relative to the surface of the object, wherein the characterizing the object is further based on the anisotropy of the intensity ring pattern.
  • a degree of the anisotropy may be associated with the quality of the object.
  • the anisotropy may change upon a transition of the cocoa butter from the high quality phase to the low quality phase. Thus, an ongoing phase transition may be detected before the phase transition is completed within the bulk of the object.
  • the method further comprises associating a first intermolecular distance (such as the surface intermolecular distance at the surface of the p(V)-phase) with a first portion of the detected intensity pattern (the first portion may comprise one or more rings corresponding to one or more diffraction orders of the diffracted X-ray beam), wherein the comparing the intensity pattern with the reference data comprises comparing the first intermolecular distance with a reference intermolecular distance (which may be for example the bulk intermolecular distance of the p(V)-phase, i.e. the high quality phase of the cocoa butter or which may be a literature value).
  • a reference intermolecular distance which may be for example the bulk intermolecular distance of the p(V)-phase, i.e. the high quality phase of the cocoa butter or which may be a literature value.
  • the method further comprises associating a second intermolecular distance (such as for example the surface intermolecular distance of the p(VI)-phase of the cocoa butter) with a second portion of the detected intensity pattern (the second portion may comprise one or more rings corresponding to one or more diffraction orders), wherein the characterizing the object is further based on a total intensity of the second portion of the detected intensity pattern (an integral of the intensity value or a sum of the intensity values belonging to the second portion of the detected intensity pattern) and/or a total intensity (a sum or an integral of the intensity values belonging to the first portion) of the first portion of the detected intensity pattern.
  • a second intermolecular distance such as for example the surface intermolecular distance of the p(VI)-phase of the cocoa butter
  • the second intermolecular distance may correspond to the intermolecular distance of the p(VI)-phase which may in particular be in between 42 A and 46 A, in particular about 44 A.
  • the first portion of the detected intensity pattern may result from a portion of molecules ordered or structured according to the high quality phase
  • the second portion of the detected intensity pattern may result from another portion of molecules structured according to the low quality phase.
  • a relative ratio of molecules (in particular fatty acids) belonging to the high quality phase or belonging to the low quality phase may be determined, which may be indicative of a quality of the object, in particular the cocoa butter or chocolate.
  • the reference data are derived from a predetermined molecular model of the object (such as obtained from literature data or/and molecular modelling).
  • the reference data may comprise particular features of the molecular model, such as the intermolecular spacing or distance of molecules contained within the object.
  • the molecular model may comprise information regarding an interdigitated arrangement of molecules comprised within the object.
  • the method further comprises transmitting the X-ray beam (in particular the same X-ray beam which has been used for the grazing incident measurement) through the object (which may for this purpose be supported by another object holder which enables transmission of the X-ray beam through the object, which may for example have a thickness in between 0.5 mm and 5 mm, in particular around 2 mm); diffracting the X-ray beam at the object; detecting a reference intensity pattern (in particular using a two-dimensional detector, a one-dimensional detector or a point detector with
  • the goniometer of the diffracted X-ray beam; and deriving the reference data (such as the bulk intermolecular distance, the ring-shape or the like, as set forth above) from the reference intensity pattern.
  • the reference data such as the bulk intermolecular distance, the ring-shape or the like, as set forth above
  • the bulk intermolecular distance of the high quality phase may depend on the exact composition and constitution of the object (for example may also depend on a production method of the object).
  • the X-ray beam which is used for directing the X-ray beam to the surface of the object at the grazing incidence and which is used also for transmitting the X-ray beam through the object is generated by a same X-ray source.
  • the arrangement for performing the method may be made simpler and may be manufactured at reduced costs.
  • the transmission measurement and the grazing incidence measurement may be performed using a same arrangement.
  • a same detector such as a two-dimensional detector, a one-dimensional, or a point detector
  • an arrangement for performing the method is simplified and reduced in costs.
  • the transmission diffraction experiment and the grazing incidence experiment may be performed (subsequently) using a substantially same arrangement.
  • the grazing incidence measurement is performed with a varying incidence angle.
  • a first intensity pattern may be acquired when the X-ray beam is directed onto the surface at a first incidence angle and a second intensity pattern may be acquired when the X-ray beam is directed onto the surface at a second incidence angle which is different from the first incidence angle.
  • varying the incidence angle may enable to derive information (in particular regarding a structural arrangement) of the object from different depths of the object (i.e. different thicknesses of surface layers).
  • the structural arrangement of the molecules comprised in the object may be probed at different depths of the object or different thicknesses of the surface layer of the object.
  • the object in particular the cocoa butter, may be characterized with respect to its quality with a higher precision.
  • the characterizing the object further comprises determining a structural configuration of the object based on the detected intensity pattern.
  • the structural configuration may for example comprise assignment of one or more structural phases to the object.
  • the quality of the object may be correlated with the structural configuration of the object.
  • the characterizing the object further comprises determining a structural phase transition (such as a phase transition from the p(V)-phase to the p(VI)-phase of the cocoa butter) of the object based on the detected intensity pattern.
  • a phase transition may be predicted from a reduction of the surface
  • the characterizing the object further comprises predicting a structural phase transition at a bulk of the object based on the detected intensity pattern.
  • the structural phase transition at the bulk of the object may be predicted exclusively based on the intensity pattern or intensity patterns acquired during the grazing incidence measurement or measurements, in particular before the phase transition at the bulk of the object is actually completed.
  • it is enabled to apply countermeasures such that the object may be maintained at the high quality phase before the bulk of the object transforms into the low quality phase.
  • the predicting of the structural phase transition comprises determining that the first intermolecular distance is lower than the reference intermolecular distance at least by a
  • a reduction of the intermolecular distance at the surface compared to the bulk intermolecular distance of the p(V)-phase may indicate that the molecules comprised within the object at the surface of the object approach each other towards a phase or arrangement of the p(VI)-phase.
  • a phase transition of the high quality phase to the low quality phase may be initiated at the surface of the object and may propagate into the bulk of the object.
  • the characterizing the object further comprises relating (or associating) the detected intensity pattern to quality data indicative of a quality of the object.
  • the quality of the object may for example relate to a visual appearance of the object, a taste of the object, a mechanical property of the object, a physico-chemical property of the object, a surface appearance of the object and so on.
  • the quality of the object may be related to a fat bloom of the cocoa butter.
  • the fat bloom may in particular occur at the surface of the cocoa butter or the chocolate and may involve a deterioration of the surface and a change of colour and/or glossiness of the surface.
  • grey or white patches may occur at the surface of the chocolate and the smoothness of the surface may decrease.
  • the object prior to the detecting the intensity pattern (i.e. prior to performing the grazing incidence measurement) the object is subjected to a predetermined temperature for a predetermined time interval and/or the object is subjected to a predetermined humidity for another predetermined time interval.
  • a predetermined temperature for a predetermined time interval and/or the object is subjected to a predetermined humidity for another predetermined time interval.
  • an effect of subjecting the object to different conditions may be derived.
  • maintenance conditions or storing conditions which do not negatively affect the quality of the object may be
  • the quality of the object may be appropriately maintained.
  • the object comprises at least one of stearic acid, palmitic acid, decanoic acid, cocoa butter, and cocoa or any combination of these fatty acids.
  • characterizing an object may (individually or in any combination) as well be applied, used for, employed or provided for an arrangement for characterizing an object.
  • an arrangement for characterizing an object comprising a fatty acid comprising a X-ray source for generating X-ray radiation; X-ray optics for focussing the X-ray radiation to a X-ray beam and directing the X-ray beam to a surface of the object at a grazing incidence angle; a detector for detecting an intensity pattern of the X-ray beam diffracted at the object and emanating from the surface; a processor adapted to compare the intensity pattern with reference data and to characterize the object based on the comparison.
  • An embodiment of the invention provides a laboratory X-ray system and a method for analyzing the surface structure with Grazing Incidence Small Angle X-Ray Scattering (GISAXS) and Small Angle X-Ray
  • SAXS Scattering
  • the chocolate surface presents the visible finish to the consumer of chocolate products. Under non ideal conditions the surface may degrade and expose a grey/whitish color and change its morphology. This is believed to be caused by transitions in the cacao butter crystal - that determines largely the properties of the chocolate - to more stable polymorphic crystalline phases.
  • the invention enables a novel quality control for chocolate surfaces and chocolate coatings on the supramolecular scale. This may be achieved by a method of contrasting bulk information from the SAXS data against surface properties obtained from the GISAXS data.
  • the properties of chocolate are determined by the cacao butter that consists mainly of three mono-unsaturated triglycerides and crystallizes in six different polymorphic forms.
  • Chocolate with cacao butter in a particular phase state, the ⁇ ( ⁇ ) phase state, does possess the most convenient melting point, best haptics like snapping properties and visual appeal for the consumers of chocolate products.
  • Fat bloom is a undesirable, uncontrolled re-crystallization of the cacao butter which manifests itself in its mild form as a global dulling of the chocolate surface and in its extreme form with the emergence of pronounced white patches at the surface. Fat bloom is a consequence of inadequate processing or non ideal storing conditions especially too high temperatures of chocolate. Maybe the cause of fat bloom is attributed to phase transitions from the ⁇ ( ⁇ ) to the ⁇ ( ⁇ / ⁇ ) phase of the cacao butter or to a growth of existing ⁇ ( ⁇ ) crystals.
  • Fig. 1A schematically illustrates an arrangement for characterizing an object by performing a grazing incidence X-ray measuring experiment according to an embodiment
  • Fig. IB schematically illustrates a measurement process according to an embodiment
  • Fig. 2 schematically illustrates an arrangement for performing a transmission diffraction experiment according to an embodiment
  • Fig. 3A illustrates a reference intensity pattern obtained by performing small angle X-ray scattering (SAXS) according to an embodiment
  • Fig. 3B illustrates an intensity pattern obtained by performing grazing incidence small angle X-ray scattering (GISAXS) according to an embodiment
  • Fig. 4A illustrates a reference intensity pattern obtained by performing small angle X-ray scattering (SAXS) according to an embodiment
  • Fig. 4B illustrates an intensity pattern obtained by performing grazing incidence small angle X-ray scattering (GISAXS) according to an embodiment
  • Fig. 5 illustrates a diagram with a penetration depth in dependence of an incidence angle.
  • An embodiment of the invention uses both transmission SAXS and grazing incidence GISAXS measurements of a chocolate sample for example a shard from a chocolate bar.
  • the transmission SAXS uses both transmission SAXS and grazing incidence GISAXS measurements of a chocolate sample for example a shard from a chocolate bar.
  • GISAXS measurements probe the structural features of the bulk and provide reference data for the crystalline properties of the cacao butter phase and composition at the surface.
  • the GISAXS measurements probe the surface of the chocolate sample and provide complementary data with specific information from the surface ( Figures 1A and I B below give an outline of the GISAXS geometry).
  • the crystalline properties from the bulk phase have been found to be disturbed at the interface and hence those differences in the crystalline structure are conveniently to be addressed by our method. Since the fat bloom is mainly a surface phenomenon the grazing incidence (GISAXS) approach is highly relevant for the problem and provides genuine new information over the transmission X-ray (SAXS) data on the supramolecular details of the chocolate in the interface.
  • SAXS transmission X-ray
  • Fig. 1A illustrates an arrangement 100 for performing grazing incidence small angle X-ray scattering (GISAXS) according to an embodiment.
  • the arrangement 100 comprises an X-rays source 103 for generating a primary X-ray beam 105 which propagates along an axis 107.
  • the X-ray beam 105 may for example be generated by bombarding a copper cathode with electrons, whereupon an X-ray beam of the K a line of copper is generated.
  • the X-ray beam 105 traverses a focusing optics 109 and subsequently a collimation system 111 to appropriately shape and focus the beam and to direct the X-ray beam 105 to the surface 113 of an object 115.
  • the object is supported by a sample holder 117 which allows adjustment of the orientation of the surface 113 relative to the incident X-ray beam 105 as indicated by the double arrow 119.
  • the surface 113 is adjusted such that an angle between the incident beam 105 and the surface 113 of the sample amounts to ⁇ ,.
  • the X-ray beam 105 illuminates an area typically of about between 10 ⁇ x 10 ⁇ to 1 mm x 1 mm and the X-ray beam 105 penetrates into the sample 115 to a particular penetration depth which depends on the incidence angle a, and on material comprised within the sample 115.
  • the X-ray beam 105 interacts with molecules and materials within the sample 115 and is diffracted.
  • a portion of the diffracted beam 121 is blocked by a beam stop 123, in particular to block the beam diffracted at an angle corresponding to the incidence angle ⁇ , .
  • Another portion of the diffracted beam 121 is incident on the two-dimensional X-ray detector 125 which comprises a number of detector segments arranged adjacent to another in a two-dimensional array.
  • electrical signals are generated being indicative of intensity values at the plural detector segments.
  • the electrical signals are supplied to a collection and processing system 127 which also has a storage capability for storing the electrical signals as intensity patterns.
  • the sample holder 117 may allow horizontal and vertical tilt degree of freedom and height adjustment degree of freedom and may allow to tilt the sample holder against the incoming beam 105, wherein height adjustment of the sample holder against incoming beam is possible.
  • the sample 115 may e.g. be mounted flat on the sample holder 117, e.g. a piece of chocolate with a flat surface.
  • the data collecting and processing system 127 may comprise interfacing hardware and a computer and some storage unit.
  • the adjustable filter or beam stop 123 may be optional to protect the detector form exposure of the direct beam .
  • Fig. IB illustrate the grazing incidence experiment illustrated in Fig. 1A to clarify the incidence angle ⁇ , the scattering angle ⁇ f and the exit angle otf.
  • the incidence angle a is defined as the angle between the incident X-ray beam 105 and the surface 113 of the sample 115.
  • the exit angle a f is defined as the angle between the diffracted beam 121 and the surface 113 of the sample 115.
  • the diffraction angle ⁇ f is defined as half of the diffraction angle of the projection of the diffracted beam 121 onto the surface 113 relative to the propagation direction or axis 107 along which the original beam travels when projected onto the surface 113 of the object 115.
  • the scattered beam 121 has an angular component 2 ⁇ f against the plane of incidence and an exit angle a f against the surface.
  • the instrument for performing the GISAXS measurements ( Figure 1A) comprises an X-ray point source, a collimating optics that collects the X- ray photons from the source over a solid angle and a collimating system that cuts the beam vertically to a defined size and provides a clean signal without unwanted scattering from edges or openings.
  • the vertical direction is in the plane of incidence as defined in Figure IB.
  • the chocolate shard or piece from a chocolate bar or a slice is mounted on a sample holder that allows to position the chocolate surface against the X- ray beam under a grazing angle
  • the instrument for performing the GISAXS measurements (figure la) comprises an X-ray point source, a collimating optics that collects the X-ray photons from the source over a solid angle and a collimating system that cuts the beam vertically to a defined size and provides a clean signal without unwanted scattering from edges or openings.
  • the vertical direction is in the plane of incidence as defined in figure lb.
  • the chocolate shard or piece from a chocolate bar or a slice is mounted on a sample holder that allows to position the chocolate surface against the X-ray beam under a grazing angle a, against the incoming beam 105.
  • the value chosen for the angle a determines the penetration length of the X-rays and thus the surface sensitivity of the GISAXS method.
  • the scattered signal is received by a detecting system and the data are stored to a physical storage memory like a hard disk.
  • the detecting system may be a ID or 2D X-ray detector.
  • n l- ⁇ - ⁇ for X-rays which is a complex number if the absorption index ⁇ is considered.
  • the value of its real part is below 1 by a small amount ⁇ in the order of 10 "6 for organic materials.
  • matter is optically less dense than vacuum - or air - and an external total reflection occurs at and below the critical angle a c (where the transmitted beam gets parallel to the surface).
  • the critical angle a c is V25.
  • the main constituents of the cacao butter are stearic acid, palmitic acid and decanoic acid.
  • the electron density and absorption indices ⁇ for each fatty acid can be calculated using their chemical composition and the values of fi(0) at the energy of 8048.97 eV which are tabulated at the Center of X-ray Optics, XRCO and found on the web page http://henke.lbl.gov/optical_constants/asf.html.
  • the electron density p e for the palmitic acid (C16H3202) is 0.440 electrons A-3, for the stearic acid (C18H3602) is 0.440 electrons A-3 and for the decanoic acid (C10H20O2) is 0.436 electrons A-3 and the rounded values of their critical angles are all 0.141°.
  • the penetration depth ⁇ of the transmitted wave is
  • the macroscopic surface of the chocolate may not be ideally flat.
  • the ratio A/L must be 0.0002 or smaller, thus for example an amplitude of 1.5 ⁇ is tolerable along a 1mm repeat.
  • the scattering depth is limited by the largest exit angle from the scattered signal and thus limited to « 14 ⁇ at most.
  • the experiments can be performed using X-ray sources with any other X-ray wavelength .
  • the analysis of the intensity distribution of the higher order diffraction rings gives access to depth dependent morphological features such as the statistical orientation of the cacao crystallites at the surface.
  • Fig. 2 schematically illustrates an arrangement for performing a small angle X-ray scattering (SAXS) measurement according to an
  • the arrangement 200 may utilize one or more components, such as an X-ray source, a focusing optics or a collimation system and/or an X-ray detector and/or a collection and processing system which are also used in the arrangement 100 for performing a grazing incidence experiment which is illustrated in Fig. 1A.
  • an X-ray source such as an X-ray source, a focusing optics or a collimation system and/or an X-ray detector and/or a collection and processing system which are also used in the arrangement 100 for performing a grazing incidence experiment which is illustrated in Fig. 1A.
  • only the sample holder 117 illustrated in Fig. A of the GISAXS-arrangement 100 may be replaced by the holder 217, as illustrated in Fig. 2.
  • the arrangement 200 for performing SAXS comprises an X-ray source 203 for generating an X-ray beam 205 which is subsequently shaped and focused using focusing optics 209 and a collimation system 211.
  • the primary X-ray beam 205 travelling along the primary direction 207 is incident at the sample 115 at an incidence angle of about 90° relative to the surface 113 of the sample 115.
  • the sample is supported by the sample holder 217 which allows appropriate adjustment of the sample 115 relative to the incident beam 205.
  • the X-ray beam 205 penetrates through the entire thickness of the sample 115 (which may be for example between 0.5 mm and 3 mm) whereupon the X-ray beam 205 interacts with molecules or materials comprised within the sample 115.
  • a portion of the diffracted beam 221 is stopped or blocked by the beam stop 223 and another portion is incident onto the detector 225
  • the processing system 227 (and also the processing system 127 illustrated in Fig . 1A) comprises a processing mechanism or program to process the intensity pattern and to derive other values from the intensity pattern, such as an intermolecular distance between molecules comprised within the sample 115. Further, the processing systems 127 and 227 comprise a storage device in which reference data are stored . The detected intensity pattern is then compared to the reference data to characterize the object 115.
  • the instrument for performing the SAXS measurements comprises a X-ray point or line source, a collimating optics that collects the X-ray photons from the source over a solid angle and focuses them in a focal point or a focal line respectively.
  • a collimating system with a defined opening cuts out part of the incoming X-ray beam from the source and provides a clean signal where unwanted scattered X-rays from openings, edges etc. are removed.
  • the sample i .e. the chocolate shard or piece, is positioned in the path of the X-ray beam that emanates from the collimating system .
  • An X-ray detector placed at the focal point receives the scattered signal from the sample and possibly part of the direct beam as well .
  • the direct beam may be shielded from the receiving detecting system by a beam stop device
  • Fig. 3A illustrates an intensity pattern as a result of a SAXS-experiment performed using the arrangement 200 illustrated in Fig. 2 and Fig. 3B illustrates an intensity pattern as a result of a GISAXS-experiment using an arrangement 100 as illustrated in Fig . 1A.
  • Fig. 3A illustrates X- ray scattering from the bulk of the object 115
  • Fig. 3B illustrates X- ray diffraction data or an intensity pattern obtained by diffraction at the surface or at a surface layer of the object 115.
  • both Figs. 3A and 3B exhibit a ring intensity pattern predominantly depicting two rings, a first ring 329 and a second, larger ring 331.
  • the two rings 329 and 331 are due to diffraction of the X-ray beam 105 and 205,
  • the first ring 329 corresponds to the first diffraction order and the second ring 331 corresponds to the second diffraction order of the diffraction process.
  • the intermolecular spacing of 65 A to 66 A may be derived by the processing system 127 or 227 by evaluating or processing the intensity patterns illustrated in Figs. 3A and 3B, respectively.
  • the bulk intermolecular spacing derived from Fig. 3A is 65,5 A
  • the surface intermolecular spacing derived from Fig. 3B is 65,9 A.
  • Fig. 3A illustrates transmission SAXS data from the "good " chocolate piece.
  • Diffraction rings of the 1st, 2nd order are displayed. They originate from the p(V) cacao crystal phase and correspond to a spacing of 65.5 A. The intensity on the rings is isotropic along the azimuthal angle.
  • Figure 3B illustrates grazing incidence (GISAXS) data from "good" chocolate piece.
  • Diffraction rings of the 1st, 2nd order are displayed in the figure and they belong to the p(V) cacao crystal phase and correspond to a spacing of 65.9 A. This spacing differs from the spacing obtained from the bulk (SAXS) measurement.
  • SAXS bulk
  • the azimuthal intensity distribution in the rings is anisotropic and peaks around the cuts with plane of incidence, thus indicating a preferential ordering of the cacao butter crystal perpendicular to the surface respectively the long crystal axis a. Also the position of the higher order reflexes are slightly disturbed .
  • Figs. 4A and 4B show measurement results using another sample. Again in Fig. 4A the intensity pattern as a result of a SAXS-experiment is shown and in Fig. 4B the intensity pattern as a result of a GISAXS-experiment is shown . Again, the intensity patterns illustrated in Figs. 4A and 4B both show a first order ring 429 and a second order ring 431 of the diffraction at molecules being spaced apart by about 64.5 to 66 A. In particular, this spacing generally is indicative of the structural phase p(V) of cocoa butter. However, while the bulk intermolecular spacing as derived from Fig. 4A is 65.5 A, the surface intermolecular spacing derived from Fig.
  • FIG. 4A illustrates Transmission SAXS data from the fat bloom affected chocolate piece. Diffraction rings of the 1st, 2nd order are displayed and they belong to the p(V) cacao crystal phase and
  • Another diffraction ring 432 (also labelled as VI) appears and it corresponds to spacing of 44.1 A.
  • the reason is a partial appearance of the p(VI) phase in the cacao butter in the fat bloom affected chocolate sample.
  • the intensity on the rings is isotropic along the azimuthal angle.
  • Figure 4B illustrates grazing incidence (GISAXS) data from fat bloom affected chocolate sample.
  • Diffractions rings of the 1st, 2nd order are displayed and they belong to the p(V) cacao crystal phase and correspond to a spacing of 64.8 A. This is an about 1 A shorter spacing than the spacing found for the "good" chocolate piece. This spacing differs from the spacing obtained from the bulk (SAXS) measurement.
  • SAXS bulk
  • a diffraction ring between the 1st and 2nd diffraction ring of the p(V) cacao crystal shows up, indicating that another phase, the p(VI) phase of the cacao crystal has built up.
  • the spacing is determined as 44.1 A, exactly the same spacing that has been found for the bulk state measurements.
  • the azimuthal intensity distribution in the rings is anisotropic and peaks around the cuts with the plane of incidence, thus indicating a preferential ordering of the cacao butter crystal perpendicular to the surface respectively the long crystal axis a. Also the positions of the higher order reflexes are slightly disturbed.
  • the GISAXS data display the diffraction rings from the cacao butter crystal structure in the chocolate with some important modifications.
  • the diffraction rings are highly anisotropic with a maximal intensity around the plane of incidence and thus indicate a preferred ordering of the cacao butter crystal at the interface, namely the long crystal axis is oriented preferably perpendicular to the surface.
  • the positions of the diffraction rings originating from the ⁇ ( ⁇ ) phase are slightly shifted against the corresponding positions found in transmission SAXS reference
  • the observation of the spacial distance along the long axis a allows to monitor subtle changes in the ⁇ ( ⁇ ) phase without or before the occurrence of fat blooming, since those changes manifest subtle packing differences of the cacao crystal and provide essential supramolecular information to the detailed crystalline structure models found in the above mentioned synchrotron radiation studies by P. Peschar et al ..
  • the influence of these environment parameters on the ⁇ ( ⁇ ) phase can be readily observed in a quick measurements with a laboratory instrument, which presents a huge advantage over other techniques.
  • Another potential application would be the characterization of morphological changes of the chocolate surface which manifest itself in the anisotropic intensity distribution in the diffraction rings.
  • Figure 3A displays the transmission SAXS data from the "good" chocolate piece and figure 4A displays the transmission SAXS measurement for the fat bloom affected piece of chocolate.
  • the SAXS reference measurements recorded diffraction scattering rings for the 1st, 2nd and 5th (omitted in picture) order from the ⁇ (V) phase
  • Figure 3B displays GISAXS data from the good chocolate piece
  • figure 4B displays the GISAXS data from the chocolate piece that has been subjected to fat bloom
  • the rings labelled as 1st (329, 429), 2nd (331, 431) are the rings from the long lattice spacing in the chocolate butter crystal.
  • the spacing found for the "good/fresh" chocolate piece using the 1st ring is 65.9 A, whereas the spacing found for the blooming affected piece is 64.8 A.
  • the spacings between the maximum intensities of the higher order rings are not perfectly linearly growing and the width of the rings in the blooming affected piece is larger.
  • the intensity along the rings is asymmetric indicating a preferential orientation of the cacao butter crystals with the long axis perpendicular to the surface.
  • Fig. 5 illustrates a graph showing on an abscissa the incident angle a, and on an ordinate the penetration depth (as curve 540) into the sample 115 (perpendicular to the surface 113 of the sample 115) .
  • the lower the incidence angle a is the lower is the penetration depth.
  • Fig. 5 shows the plot of the penetration depth of the incident beam 105 in cacao butter as a function of a, .
  • this penetration length is l/2k0a c and its value is 50 A, 1 ⁇ at 0.29 ° , 10 Mm at 2.45 ° and 28 ⁇ at 6.7 ° .

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Abstract

L'invention porte sur un procédé et sur un agencement pour caractériser un objet comprenant un acide gras, lequel procédé met en œuvre : la direction d'un faisceau de rayons X (105) vers une surface (113) de l'objet (115) selon un angle d'incidence rasant (αi); la diffraction du faisceau de rayons X au niveau de l'objet; la détection d'un motif d'intensité du faisceau de rayons X diffracté émanant de la surface; la comparaison du motif d'intensité à des données de référence; et la caractérisation de l'objet sur la base de la comparaison. L'objet peut comprendre en particulier du beurre de cacao ou du chocolat.
PCT/EP2011/067510 2010-12-17 2011-10-06 Procédé et agencement pour caractériser un blanchiment gras et une qualité de chocolat contenant des surfaces par diffraction de rayons x WO2012079800A1 (fr)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050119270A1 (en) * 2000-08-04 2005-06-02 Mason R. P. Synergistic effect of amlodipine and atorvastatin on aortic endothelial cell nitric oxide release

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050119270A1 (en) * 2000-08-04 2005-06-02 Mason R. P. Synergistic effect of amlodipine and atorvastatin on aortic endothelial cell nitric oxide release

Non-Patent Citations (10)

* Cited by examiner, † Cited by third party
Title
CORALIE ALONSO ET AL: "Modifying Calf Lung Surfactant by Hexadecanol", LANGMUIR, vol. 21, no. 3, 1 February 2005 (2005-02-01), pages 1028 - 1035, XP055013659, ISSN: 0743-7463, DOI: 10.1021/la047894b *
DÉRICK ROUSSEAU ET AL: "Tailoring the Textural Attributes of Butter Fat/Canola Oil Blends via Rhizopus arrhizus Lipase-Catalyzed Interesterification. 2. Modifications of Physical Properties", JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY, vol. 46, no. 6, 1 June 1998 (1998-06-01), pages 2375 - 2381, XP055013689, ISSN: 0021-8561, DOI: 10.1021/jf970726n *
DÉRICK ROUSSEAU ET AL: "The influence of chemical interesterification on the physicochemical properties of complex fat systems. 2. Morphology and polymorphism", JOURNAL OF THE AMERICAN OIL CHEMISTS' SOCIETY, vol. 75, no. 12, 1 December 1998 (1998-12-01), pages 1833 - 1839, XP055013685, ISSN: 0003-021X, DOI: 10.1007/s11746-998-0339-6 *
G. M. CHAPMAN ET AL: "Cocoa butter and confectionery fats. Studies using programmed temperature X-ray diffraction and differential scanning calorimetry", JOURNAL OF THE AMERICAN OIL CHEMISTS' SOCIETY, vol. 48, no. 12, 1 December 1971 (1971-12-01), pages 824 - 830, XP055013686, ISSN: 0003-021X, DOI: 10.1007/BF02609292 *
J. BRICKNELL ET AL: "Relation of fat bloom in chocolate to polymorphic transition of cocoa butter", JOURNAL OF THE AMERICAN OIL CHEMISTS' SOCIETY, vol. 75, no. 11, 1 November 1998 (1998-11-01), pages 1609 - 1615, XP055013543, ISSN: 0003-021X, DOI: 10.1007/s11746-998-0101-0 *
MARKUS WEYGAND: "Transformation of cacao butter crystals and blooming", 15 June 2010 (2010-06-15), XP055013530, Retrieved from the Internet <URL:http://www.youngin.com/application/AN-2011-0007EN.pdf> [retrieved on 20111130] *
P. LAGGNER: "Beyond simple SAXS: beating ambiguousness by integration", ACTA CRYST., 2 September 2010 (2010-09-02), XP055013708, Retrieved from the Internet <URL:http://journals.iucr.org/a/issues/2010/a1/00/a46478/a46478.pdf> [retrieved on 20111201] *
R. PESCHAR, M. M. POP, D. J. A. DE RIDDER, J. B. VAN MECHELEN, R. A. J. DRIESSEN, H. SCHENK, J. PHYS. CHEM B., vol. 108, no. 40, 2004, pages 15450 - 15453
RENÉ PESCHAR ET AL: "Crystal Structures of 1,3-Distearoyl-2-oleoylglycerol and Cocoa Butter in the [beta](V) Phase Reveal the Driving Force Behind the Occurrence of Fat Bloom on Chocolate", THE JOURNAL OF PHYSICAL CHEMISTRY B, vol. 108, no. 40, 1 October 2004 (2004-10-01), pages 15450 - 15453, XP055013568, ISSN: 1520-6106, DOI: 10.1021/jp046723c *
YOSHIHITO UOZAKI: "Observation on structure in the surface region of cocoa butter, POP, SOS and POS by X-ray diffraction", ACTA CRYST., 1 January 2008 (2008-01-01), XP055013701, Retrieved from the Internet <URL:http://journals.iucr.org/a/issues/2008/a1/00/a39958/a39958.pdf> [retrieved on 20111201] *

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