Thermal Analysis of Food
On Demand Webinar

Thermal Analysis of Food

On Demand Webinar

"Thermal Analysis of Food" details the main thermoanalytical techniques used to characterize food

Thermal Analysis of Food
Thermal Analysis of Food

Food, usually of plant or animal origin and containing important nutrients, is usually modified and made fit for consumption. Thermal analysis allows the of study physical and chemical effects related to temperature changes that occur during the normal food processing cycle, such as boiling, freezing, and drying. A better understanding of these processes is vital in the food industry.

In this Webinar, we will show how thermal analysis is used to analyze food and will present some typical examples of samples measured by DSC, TGA, TMA, or DMA.

45:10 min
English

The Webinar covers the following topics:

  • Introduction
  • Basic properties of food
  • Typical questions
  • Thermal analysis
  • Industries and applications
  • Instrumentation and applications
    - Differential Scanning Calorimetry (DSC)
    - Thermogravimetry (TGA)
    - Thermomechanical Analysis (TMA)
    - Dynamic Mechanical Analysis (DMA)
  • Summary

In the webinar titled "Thermal Analysis of Food", we describe a number of interesting application examples that demonstrate the use of thermal analysis techniques in fields such as food processing, food storage conditions, and food quality in various segments of the food industry.

A highly regulated industry

Food products are directly linked to public health issues. As a consequence, various international or national regulations and laws exist which provide methods for checking the quality of food products.

Thermal analysis is nowadays an important technique for characterizing different materials in many fields of the food industry.

 

Thermal analysis of food

The most important effects that can be analyzed by DSC are the melting point, melting range and melting behavior. DSC is used to determine the heat of fusion, purity, polymorphism, glass transition, and oxidation stability.

The main applications of TGA have to do with evaporation, desorption and vaporization behavior, thermal stability, kinetics of decomposition, and compositional analysis.

TOA is used to study the melting point, melting range, and polymorphism using visual observation and recording images and videos.

TMA is normally used to study the expansion or shrinkage of materials and the glass transition.

DMA is the most sensitive method for characterizing glass transition of materials.

Thermal Analysis of Food

Slide 1: Thermal Analysis in the Food Industry

 

Ladies and Gentlemen,

Welcome to the METTLER TOLEDO webinar on Thermal Analysis in the Food Industry.

The role of food is nowadays more important than just providing essential body nutrients and nourishment - it is a pathway to good health. This change has opened up new fields in food science and food technology as well as in the analytical testing of foods and foodstuffs.

During this webinar, I would like to describe a number of interesting application examples that demonstrate the use of thermal analysis techniques in fields such as food processing, food storage conditions, and food quality in various segments of the food industry.

 

Slide 2: Contents

The slide lists the topics I would like to cover.

First, I want to mention regulatory guidelines and standards used in the food industry, and discuss the most important effects or properties that can be investigated by thermal analysis techniques.

The techniques include:

- Differential Scanning Calorimetry, or DSC;

- Thermo-Optical Analysis, or TOA including Hot-stage microscopy and DSC-Microscopy,

- Thermogravimetric Analysis, or TGA;

- Thermomechanical Analysis, or TMA;

- Dynamic Mechanical Analysis, or DMA; and

- Dropping point instruments.

 

I will then present a number of application examples that illustrate how thermal analysis can be used to investigate the physical behavior of products in the food industry.

 

Finally, I will summarize the different thermal analysis techniques and their application fields and list a number of useful references for further information and reading.

 

Slide 3: Introduction (1)                                                                                                      

In general, good quality food should have a pleasant appearance, taste, aroma, and texture.

 

Let’s take chocolate as an example - everybody likes to eat chocolate, but what if the chocolate loses its texture before you eat it?

The chocolate manufacturer will be faced with questions such as:

- What ingredients are needed to guarantee the desired quality?

- How can the desired texture of the chocolate be maintained?

- How can the quality of the end product be checked?

 

The slide displays the DSC heating curves of samples of the same chocolate measured after the samples had been cooled under different cooling conditions:

The top curve is the heating curve of the chocolate as received.

The three curves below this were obtained from samples that had been cooled at different cooling rates.

The curves show melting peaks at different temperatures due to polymorphism. However, only one of the polymorphs is the desired form.

In this particular example, the key points are melting behavior and polymorphism.

 

Later on in the seminar, I will describe other thermal analysis techniques such as thermo-optical methods that help to answer such questions.

 

Slide 4: Introduction (2)                                                                       Regulations and standards

Food products are directly linked to public health issues. As a consequence, various international or national regulations and laws exist which provide methods for checking the quality of food products.

In this slide, I would like to draw your attention to regulations, laws and standard norms applicable to the food industry. In general, the industry follows the Good Manufacturing practices (GMP) and regulations set by the United States Food and Drug Administration (FDA) and the International Organization for Standardization (ISO22000).

 

Thermal analysis is nowadays an important technique for characterizing different materials in many fields of the food industry.

 

Slide 5: Thermal analysis

The ICTAC definition of thermal analysis is:

“A group of techniques in which a physical property of a substance is measured as a function of temperature whilst the substance is subjected to a controlled temperature program”.

The schematic diagram on the right shows a simple linear temperature program.

 

The lower half of the slide illustrates typical events that occur when the sample is heated. For example, initially melting, in which the sample changes from the solid to the liquid state. If the sample is exposed to air or oxygen, it will start to oxidize and finally decompose. We use thermal analysis techniques to investigate these effects.

 

Slide 6: Thermal Analysis                                                                                   Techniques

The slide presents the six most important thermal analysis techniques used to characterize foods and foodstuffs, namely:

 

Differential Scanning Calorimetry, or DSC is the most widely used thermal analysis technique. The picture shows a DSC sensor with a crucible containing a sample colored red, and a reference crucible.

 

Thermogravimetric Analysis, or TGA. Here we see part of the TGA ultra-micro balance with its automatic internal ring weights.

 

Thermomechanical Analysis, or TMA. The image shows the sample area with a sample colored red and the quartz probe and sensor.

 

Dynamic Mechanical Analysis or DMA. Here we see one of the several different sample-clamping assemblies.

 

Thermo-optical Analysis or TOA monitors optical properties as a function of temperature using a microscope or a video camera.

 

And finally, the Dropping Point instrument, which determines the dropping or softening properties of a given material.

 

I will explain these techniques in more detail in the following slides and describe some application examples.

 

Slide 7: Industries and applications                                                  Food analysis

This slide lists application examples that demonstrate the analytical power and versatility of thermal analysis techniques used for checking quality and for developing new products in various segments of the food industry.

For example, in the milk and dairy industry where dry milk powder is the main ingredient of many products, TGA and DSC techniques can be used to determine thermal stability, moisture content, protein denaturation, melting and crystallization.

 

In the bakery industry, bread and related products can be investigated by DSC, TGA, and TMA techniques to determine the gelatinization of starch, thermal stability, and expansion and swelling properties.

 

The confectionery and oil industry is mainly concerned with edible fats and oils. Here DSC, TGA, and the Thermal Values techniques provide important information on thermal and oxidative stability, moisture content and the dropping point.

 

Slide 8: Differential Scanning Calorimetry

Let’s now begin with DSC. This technique allows us to determine the energy absorbed or released by a sample as it is heated or cooled.

 

The standard METTLER TOLEDO DSC 1 instrument measures from minus one hundred and fifty degrees Celsius to plus seven hundred degrees at heating rates of up to three hundred Kelvin per minute. Samples are normally measured in small crucibles made of aluminum, alumina or other materials using sample amounts of one to ten milligrams.

The schematic curve on the left shows a typical DSC measurement curve with a number of typical effects that can be observed depending on the sample studied. Exothermic effects point upward and endothermic effects downward. The curve is plotted as heat flow in milli-watts versus temperature. The different effects are numbered next to the curve and explained in the table below, namely:

One, the initial deflection or start-up transient of the DSC;

Two, the baseline where no thermal effects occur;

Three, a glass transition with enthalpy relaxation;

Four, cold crystallization;

Five, melting of the crystalline fraction; and finally

Six, oxidative exothermic decomposition.

 

Slide 9: Differential Scanning Calorimetry (DSC)

DSC is used to study thermal behavior such as melting, and chemical reactions. Most of these processes are related to enthalpy changes initiated by increasing or decreasing temperature.

Another useful, more specialized DSC technique is high-pressure DSC, or HPDSC for short. The METTLER TOLEDO HP DSC 1 can analyze samples under inert or reactive gases at pressures of up to ten megapascals. This suppresses undesired vaporization of samples or enables the stability of samples to be studied under increased oxygen pressures.

The table summarizes the effects which can be used to characterize foodstuffs. The main applications have to do with melting behavior and polymorphism. DSC measurements also provide information about the enthalpy of protein denaturation and changes in heat capacity.

The picture on the right of the slide shows a view of an open DSC furnace with sample and reference crucibles. The standard crucibles are made of aluminum.

 

Slide 10: Application 1: DSC                                              Denaturation of egg white proteins

The first example is taken from the field of food processing and deals with the denaturation of proteins in hen egg white.

DSC detects denaturation as an endothermic effect, usually in the range of forty to one hundred degrees Celsius.

The diagram displays the DSC heating curve of a sample of egg white. Dried egg white contains about 93% protein and 6% carbohydrate. Overall egg white consists of more than forty different proteins.

The egg white was separated and stirred for two minutes. About 33 milligram of sample was weighed into a hermetically sealed 40-microliter standard aluminum crucible and heated from 30 to 110 degrees Celsius at a heating rate of 10 Kelvin per minute. The reference crucible contained about the same amount of water.

The DSC curve shows two main endothermic peaks at 70 and 87 degrees. The first peak relates to the denaturation of the conalbumin fraction, which makes up about 13.8% of the total protein. The second peak corresponds to the denaturation of the ovalbumin fraction, which makes up 65 percent of the total protein.

 

The typical denaturation peaks and their enthalpies allow us to identify and quantify protein fractions.

 

Slide 11: Application 2: DSC                                                              Liquid fraction of palm oil

Palm oil is semi-solid at room temperature and contains several saturated oils as well as mono- and poly-unsaturated oils. It can be fractioned into two phases, namely Palm stearin and Palm olein.

Samples of the palm oil and the two fractions each weighing about 20 milligrams were first cooled to minus 40 degrees Celsius and then heated from minus 40 to plus 80 degrees at 10 kelvin per minute using hermetically sealed standard aluminum crucibles.

The DSC heating curves of the three samples are displayed on the left side of the diagram. Their melting behavior is clearly different - for example, Palm stearin exhibits peaks at much higher temperatures than Palm olein.

The data from the melting curves can be used to calculate the liquid fraction as a function of temperature. This is done by evaluating partial integrals of the melting peaks using the Conversion software program. The results are shown on the right of the slide.

For correct results: the specific enthalpy of fusion of all fractions in joules per gram should be the same. This is the reason why we have used the highest enthalpy value of 85 joules per gram of Palm stearin as the so-called literature value to calculate the conversion curves for the three samples.

This yielded values of 95% for Palm olein, 80% for Palm oil, and 52% for Palm stearin for the liquid fraction at room temperature. The evaluation allows us to easily differentiate the samples.

We see that DSC is an excellent method for characterizing and distinguishing between edible fats like palm oils, and gives us valuable information about the liquid fraction at room temperature.

 

Slide 12: Application 3: DSC                                              Crystallization of vegetable oils

DSC is widely used in food processing to investigate the crystallization behavior of fats and oils. The diagram displays DSC cooling curves of four different oil samples, namely Olive oil, Palm oil, Soybean oil and Rape seed oil.

For the analysis, about twenty-five milligrams of each sample was weighed into hermetically sealed standard aluminum crucibles. The samples were then cooled from fifty degrees Celsius to minus one hundred degrees at a cooling rate of ten kelvin per minute.

The cooling curve of Olive oil shows the crystallization of saturated fatty acids between minus 10 and minus 35 degrees. After this, the main fraction of the olive oil consisting of the triglyceride with three oleic acid units crystallizes at minus forty five degree Celsius.

Palm oil crystallizes at higher temperatures than olive oil due to the high percentage of saturated fatty acids. Soybean oil also contains a significant fraction of both saturated and unsaturated fatty acids. These three triglyceride fractions can be seen as broad peaks in the DSC curve at different crystallization temperatures.

Finally, Rape seed oil crystallizes in a much lower temperature range because it consists mainly of unsaturated fatty acids with just 5 percent saturated acids.

 

Slide 13: Thermo-Optical techniques

Let’s now look at thermo-optical analysis or TOA.

TOA techniques are used to study optical properties of a sample as it is heated or cooled. The properties can be monitored by DSC, HPDSC or Hot-Stage systems in combination with a microscope or a video camera. The HPDSC instrument can also be connected to a chemiluminescence accessory. Some TOA systems allow calorimetric effects to be measured simultaneously while making visual observations.

The table summarizes typical applications of optical techniques for the analysis of foodstuffs. The main applications have to do with the identification of solid-solid transitions and the study of morphological changes.

The three pictures on the right show the microscopy accessory added to a standard DSC, a camera attached to an HPDSC instrument for chemiluminescence measurements, and hot-stage microscopy with the ability to quickly capture and store digital images or videos.

 

Slide 14: Application DSC Microscopy                                             Analysis of a candy

The slide shows how the microscopy accessory can provide visual information corresponding to each effect that occurs in a DSC heating or cooling run.

In this experiment, a sample of a candy consisting of three distinct layers was analyzed by DSC and microscopy. The diagram shows results obtained from the middle layer.

A sample taken from the middle layer was finely ground, inserted into a forty-microliter aluminum crucible and hermetically sealed. It was then heated from minus fifty degrees Celsius to one hundred and sixty degrees at ten kelvin per min, cooled to minus fifty degrees at five kelvin per minute, and finally heated a second time to one hundred and sixty degree at ten kelvin per minute. The first heating run displays two melting peaks at about 60 and 95 degrees, proving that the structure of the sample is largely crystalline. The second heating run shows only a glass transition at about minus 20 degrees. This indicates that the candy is in the amorphous state with no crystallization after cooling.

Images recorded using the hot-stage microscopy system confirmed these results. The first image at 50 degrees shows some large crystals surrounded by a number of smaller crystals. Some of the smaller crystals recrystallize during the heating run. The extensive black regions in third image at 85 degrees indicate that a large part of the sample has already melted. The remaining relatively large crystals melt up to about 95 degrees.

This application example illustrates how the softening, melting, and crystallization behavior of candies can be investigated by DSC combined with microscopy.

 

Slide 15: Thermogravimetric Analysis (TGA)

I now want to discuss thermogravimetric analysis, or TGA.

In this technique, the mass of a sample is continuously recorded as it is heated or cooled in a defined atmosphere. We simply put a few milligrams of the sample into a crucible, weigh the sample, heat it and continuously record the weight change.

 

The schematic curve on the left shows a typical TGA measurement curve that illustrates the different effects that can occur depending on the particular sample. Before the heating ramp begins, the TGA records the mass of the sample. At the end of the measurement, only inorganic residues and ash remain behind. The steps due to loss of mass provide valuable information about the composition of materials and the stability of substances.

 

The steps are numbered next to the curve and explained in the table. They are:

One, heating begins and volatile components vaporize;

Two, pyrolysis or decomposition of organic substances;

Three, at some point, the atmosphere is switched from nitrogen to oxygen to obtain oxidative conditions;

Four, soot or any carbon black residues burn;

Five, inorganic material that was present in the starting material is left behind as a residue.

 

METTLER TOLEDO TGA instruments simultaneously record DSC or DTA curves and so provide information about effects involving heat exchange.

 

Slide 16: Thermogravimetric Analysis (TGA)

The table summarizes the main analytical applications of thermogravimetric analysis for food products.

TGA is used to investigate processes such as vaporization or decomposition. The combination of TGA with a mass spectrometer, a Fourier transform infrared spectrometer, or a gas chromatography-mass spectrometry system allows us to analyze and characterize evolved gases.

It also allows us to check thermal stability, the kinetics of reactions, and reaction stoichiometry.

The picture on the right side shows a view of the open furnace, a sample holder with two positions for the sample and reference crucibles in a TGA/DSC instrument. The standard crucibles are made of alumina.

 

Slide 17: Application 1: TGA/DSC                     Degradation of carbohydrates

The simplest way to get an overview of the water release behavior of a substance is to record a TGA curve.

The first TGA application example shows the mass-loss curve of corn starch performed to measure the moisture content, the decomposition of carbohydrate matter, and the ash residue.

About 5 milligrams of the corn starch sample was weighed into a 70-microliter alumina pan and heated from 30 to 600 degrees Celsius at 10 kelvin per minute under nitrogen.

The upper TGA curve shows three mass-loss steps. The lower first derivative or DTG curve was used to set limits for the evaluation of the overlapping steps. The mass-loss step up to two hundred degrees is due to release of moisture. The second step corresponds to the decomposition of carbohydrates, and the third step to the combustion of carbon black formed in the second step. The small residue is mineral ash.

 

Slide 18: Application 2: TGA Sorption                              Sorption behavior of milk powder

The second TGA application example displays sorption curves of milk powder measured at relative humidities of 60 and 80 percent at a constant temperature of 30 degrees Celsius.

One of the main constituents of milk powder is lactose. This is generally in the amorphous state due to processing conditions. Lactose is hygroscopic and the uptake of moisture causes the powder to become lumpy. This can lead to changes in the flavor and taste of products containing the milk powder.

In this experiment, milk powder was dried at a relative humidity of zero percent for 10 hours and afterward exposed to a relative humidity of 60 percent for 25 hours as shown by the curve in the upper part of the diagram. This cycle was repeated using the same sample. The experiment was also performed using a new sample at 80 percent relative humidity as shown by the lower curve.

The initial parts of both curves indicate that the milk powder was not completely dry even after 10 hours at zero percent relative humidity. The crystallization of the lactose in the milk powder is an irreversible process. For this reason, the peak in the sorption curve occurs only during the first exposure to moisture. The diagram also shows that the relative humidity influences crystallization behavior. At higher relative humidity, the release of water after crystallization is appreciable faster; more water was also absorbed namely 7 percent at 80 percent relative humidity and only 4 percent at 60 percent relative humidity.

Furthermore, the dry mass after crystallization at 80 percent relative humidity increases from 7.030 milligrams to 7.086 milligrams or by about 0.8 percent. This indicates that under these conditions the crystallized lactose in the milk powder is at least partially present as a hydrate.

 

TGA-sorption studies like this provide valuable information about the behavior of milk powder in humid atmospheres.

 

Slide 19: Thermomechanical Analysis (TMA)

We now move on to thermomechanical analysis, or TMA. This technique measures the dimensional changes of a sample as it is heated or cooled.

The schematic curve on the left shows a typical TMA curve of a polymer measured in the compression mode using a small sample load. The different effects are numbered next to the curve and explained in the table, namely:

One, expansion below the glass transition;

Two, the glass transition point at which the rate of expansion changes;

Three, expansion above the glass transition; the steeper slope indicates a greater rate of expansion;

Four, softening with plastic deformation.

 

Slide 20: Thermomechanical Analysis (TMA)

The table summarizes some of the more important analytical applications of thermomechanical analysis.

The main application is the determination of the coefficient of thermal expansion, or CTE, and in general any changes in sample thickness due to heating or cooling.

The technique is also excellent for determining the glass transition temperature, and for studying softening behavior especially for thin layers or coatings. Measurements of swelling in solvents are usually performed isothermally. The picture on the right shows the typical experimental setup with a ball-point probe in contact with the sample specimen resting on a flat support.

The following slide describes a specific application example.

 

Slide 21: Application 1: TMA                                              Multilayer packaging film

Packaging films often consist of several layers. This enables the composite film to satisfy requirements regarding mechanical strength, impermeability to oxygen and water, and UV-light-protection that a monolayer film alone cannot provide.

The identification of the components and the determination of the thickness of the individual layers are two important issues in the quality control of these materials.

 

The slide displays the TMA and the first derivative TMA curves of a multilayer-packaging-film. The TMA curve was measured in the penetration mode at a heating rate of 5 kelvin per minute using a force of 0.1 newtons. The thickness of the film decreases in several steps due to the softening and melting of individual layers.

Evaluation of the softening temperatures using the first derivative curve allowed us to identify the layers in the laminate as low-density polyethylene, linear-low-density polyethylene, polyamide-12, and polyamide-11.

The thickness of individual film layers was determined by integrating the area of the peaks in the first derivative curve. Alternatively, the thickness of each layer can be estimated by evaluating the steps in the TMA curve.

The double peak obtained for PE-LLD cannot be resolved. This suggests that the multilayer film contains two separate layers of PE-LLD of similar thickness.

The results demonstrate that TMA is an excellent technique for checking the quality and composition of multilayer packaging films used in the food industry. A layer with a thickness of less than 10 μm was easily detected.

 

Slide 22: Dynamic Mechanical Analysis (DMA)

Dynamic mechanical analysis is a technique that is used to measure the mechanical properties of a viscoelastic material as a function of time, temperature and frequency when the material is deformed under a periodic oscillating stress.

 

The schematic diagram on the left of the slide shows the results of a DMA measurement of a shock-cooled semi-crystalline polymer. The curves display the storage modulus, gee prime (G′), the loss modulus, gee double prime (G″),and the loss factor, tan delta as a function of temperature.

The different effects are numbered next to the curve and explained in the table. They are:

One: secondary relaxation, observed as a peak in the tan delta and the gee double prime curves; gee prime decreases slightly

Two: the glass transition, seen as a peak in the tan delta and gee double prime curves and as a decrease in the storage modulus curve;

Three: cold crystallization of the polymer. The stiffness and hence the storage modulus, gee prime (G′), increase.

Four: recrystallization accompanied by a peak in tan delta and gee double prime;

Five: melting of the crystalline fraction with a decrease in the storage and the loss moduli.

 

Slide 23: Dynamic Mechanical Analysis (DMA)

The table lists the main analytical applications of dynamic mechanical analysis.

 

In general, DMA provides information about the glass transition of amorphous components, about viscoelastic behavior, and the elastic modulus.

In addition, it also gives information on softening temperatures, the effect of moisture on the modulus, and the dynamic mechanical behavior of polymer coatings and coating materials.

The picture on the right shows a sample installed in the DMA ready for measurement in the bending mode.

 

Slide 24: Application 1: DMA                                                                             Food texture study

The texture of a food product is an important point for consumers. It includes properties such as crispiness, softness, and how the product feels in your mouth. Moisture content directly influences food texture. Different thermal analysis techniques can be used to obtain information related to texture. In this example, the texture of salty sticks, a sort of bread pastry, was investigated by DMA and TGA.

To study the influence of moisture, the salty sticks were first stored at 100 percent humidity and ambient temperature for 1 day. A stick about 65 millimeters long with a diameter of 4 millimeters was then continuously measured by DMA for 3 hours in the 3-point bending mode at 27 degrees Celsius. The results are shown in the upper left diagram. The curve of tan delta versus time shows that tan delta gradually decreases.

A sample prepared in the same way with a mass of about 18 milligrams was also measured by TGA for 3 hours at 27 degrees. The TGA curve in the lower diagram shows that the sample gradually loses moisture and dries.

The diagram on the right shows the correlation of moisture loss and tan delta. We can conclude that when the sample is sufficiently dry, it has lost about 2.8 percent moisture. At the same time, the tan delta value of about 0.058 is at a minimum. This confirms that the crispiness of the salty sticks can be restored after drying.

 

Slide 25: Thermal values                                                                    Dropping point   

Dropping-Point-Systems allow you to determine the dropping- and softening-points of oils and fats and many other materials in fully automatic operation. Standard-compliant-cups-and-measurement-methods guarantee that the results can be meaningfully compared.

 

The dropping point measurement records the temperature at which the first drop of a substance falls from a cup under defined test conditions. The softening point is the temperature at which a sample has flowed a certain distance.

 

The picture on the right shows the DP90-Dropping-Point-System with the cooling accessory, and the picture on the left the DP70, which operates from room temperature.

 

The instrument can be used in two different modes, namely to determine the dropping point, or the softening point. Visual camera observation and digital image analysis guarantee that the values obtained are reliable.

 

Slide 26: Application dropping point of edible fats and oils

Dropping point experiments are commonly used in quality control to identify and characterize edible fats and oils.

The table at the top of the slide shows the results of four different edible fats and oil samples and demonstrates the excellent reproducibility of the measurements.

The left side of the slide below the table shows the color screen of a DP70 instrument. On the right side there is a screen shot of the live video of a duplicate measurement of the canola oil sample.

 

Slide 27: Summary

The table summarizes the most important thermal properties and events that can be used to characterize food materials as well as the techniques recommended for investigating the effects. A red box means that the technique is recommended as a first choice; a blue dot indicates that the technique can also be used.

 

The most important effects that can be analyzed by DSC are the melting point, melting range and melting behavior. DSC is used to determine the heat of fusion, purity, polymorphism, glass transition, and oxidation stability.

 

The main applications of TGA have to do with evaporation, desorption and vaporization behavior, thermal stability, kinetics of decomposition, and compositional analysis.

 

TOA is used to study the melting point, melting range, and polymorphism using visual observation and recording images and videos.

 

TMA is normally used to study the expansion or shrinkage of materials and the glass transition.

 

DMA is the most sensitive method for characterizing glass transition of materials.

 

DP measurements are used for the automatic detection of dropping and softening points.

 

Slide 28: Summary

This slide presents an overview of the temperature ranges of the METTLER TOLEDO DSC, TGA, TMA, DMA, Thermo-optical analysis, and Thermal Values instruments

 

In general, DSC experiments are performed at temperatures between minus one hundred and fifty and plus seven hundred degrees Celsius. The temperature ranges may be different if special equipment or accessories are used.

 

TGA measurements normally begin at room temperature. The maximum possible temperature is sixteen hundred degrees.

 

TMA experiments can be performed between minus one hundred and fifty and plus sixteen hundred degrees Celsius.

 

DMA samples are measured in the range minus one hundred and ninety to plus six hundred degrees Celsius.

 

Thermo-Optical analysis includes hot-stage-microscopy and DSC-microscopy: Measurements can be performed in the range minus sixty to plus three hundred and seventy five degrees Celsius. DSC-Chemiluminescence is an accessory to HPDSC.

 

Thermal Values-dropping-point-measurements can be performed between minus twenty to plus four hundred degrees Celsius.

 

Slide 29: For More Information

Finally, I would like to draw your attention to information about thermal analysis applications in the food industry that you can download from the Internet.

METTLER TOLEDO publishes articles on thermal analysis and applications from different fields twice a year in UserCom, the well-known METTLER TOLEDO customer magazine. Back issues can be downloaded as PDFs from www.mt.com/usercoms as shown in the middle of the slide. A compilation of applications can be found in the “Food” and “Thermal Analysis in Practice” handbooks.

 

Slide 30: For More Information on Thermal Analysis

In addition, you can download details about webinars, application handbooks or information of a more general nature from the Internet addresses given on this slide.

 

Slide 31: Thank You

This concludes my presentation on Thermal Analysis in the Food Industry. Thank you very much for your interest and attention.

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