Thermal Analysis of Foods

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Foods usually have complex compositions and are subjected to many changes in temperature during production, transport, storage and processing. Pasteurization, sterilization, cooking and freezing are only some examples of such processes. Along with the factors of time and water content, temperature changes can have a decisive impact on the quality of foods.

Many substances are metastable and undergo phase changes during storage. Chemical reactions such as hydrolysis or oxidation can change color, appearance, or texture, or can even cause foods to become inedible. A good understanding of the effect of temperature changes on the physical and chemical properties of foods is therefore important for manufacturers in order to be able to optimize processing conditions and improve product quality.

Various Thermal Analysis methods, primarily Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG) but also Dynamic-Mechanical Analysis (DMA), yield meaningful results for the evaluation of foods and their raw ingredients. NETZSCH-Gerätebau GmbH, a renowned manufacturer of instruments for Thermal Analysis and for the determination of thermophysical properties, provides equipment for all of the techniques needed for a comprehensive characterization.

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For example, the specific heat (cp) indicates the amount of heat energy which must be supplied to or removed from a unit quantity of substance in order to change its temperature by one degree centigrade. This makes the specific heat to an extremely important parameter in the drafting of cooling, freezing, or heating procedures.
Some biological materials, as well as some spray-dried, ground or frozen substances, are amorphous; in other words, thermodynamically they are in a state of non-equilibrium.

This is characterized by a so-called glass transition, the temperature position of which is a function of several factors including the water content. Associated temperature-dependent phase changes can thereby cause powders to become sticky, affect the crispness of breakfast cereals or cause gelled starches to crystallize.

Sourced and published by Henry Sapiecha 18th October 2009

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Apatite

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A mineral for hungry people? Apatite is a phosphate mineral with the composition Ca5[PO4]3(OH,F,Cl). It has been used extensively as a phosphorus fertilizer and is still mined for that purpose today. The mineral called “asparagus stone” is a appropriately a type of green apatite. Ironically, apatite is the mineral that makes up the teeth in all vertebrate animals as well as their bones.

The gem material makes a great faceted stone.

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Thanks to ‘Sparkly’ Sally Ewen for suggesting this molecule and to Sean and to Kay Dekker for some info about it.

Apatite - click for 3D structure

Sourced and published by Henry Sapiecha 18th October 2009

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Angelic Acid

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Angelic acid isn’t very angelic at all – it’s a defence substance for certain beetles. It gets its name from the Swedish plant Garden Angelica (Archangelica officinalis) from whose roots it was first obtained in the 1840s. Its proper name is (Z)-2-methyl-2-butenoic acid. The other isomer (E) goes by the equally silly name of tiglic acid (from the plant Croton tiglium, the source of croton oil) and is also a beetle defence substance.

Thanks to Andrew Walden for suggesting these molecules and to Florian Raab and Bo Ohlson for providing some of the information about them.

Angelic acid - click for 3D structure
Tiglic acid - click for 3D structure

Sourced and published by Henry Sapiecha 18th October 2009

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SILKWORM INTERESTING FACT

More than 5,000 years ago, the Chinese discovered how
to make silk from silkworm cocoons. For about 3,000 years,
the Chinese kept this discoverya secret.
Because poor people could not afford real silk,
they tried to make other cloth look silky.
Women would beat on cotton with sticks to
soften the fibres.
Then they rubbed it against a big stone to make it shiny.
The shiny cotton was called "chintz."
Because chintz was a cheaper copy of silk, calling something
"chintzy" means it is cheap and not of good quality.

Silkworm Information

Phylum, Arthropoda; Class, Insecta; Order, Lepidoptera
Identifying Features Appearance (Morphology)

  • Larvae are worm-like with a short anal horn.
  • Three distinct body parts: head, thorax, abdomen
  • Adult has four wings covered with scales

Adult Males and Females
Adult moths have creamy white wings with brownish patterns across the front wings. The body is very hairy and the wingspan is about 50 mm. Adult females are larger and less active than males. Male moths actively crawl around looking for females. They will copulate for several hours.

Immatures (different stages)
Lepidoptera are holometabolous, therefore they have three distinct morphological stages; larva, pupa and adult. After hatching from the egg, larvae go through four molts as they grow. During each molt, the old skin is cast off and a new, larger one is produced. The silk worm larval life is divided into five instars, separated by four molts. Three pair of short, jointed legs with a single claw at the tip are located on the three body segments immediately behind the head. Five pair of fleshy protuberances (prolegs) ending in a series of hooks called crockets are located posteriorly and ventrally on the abdomen and aid the larva’s clinging a climbing abilities on plants.

Natural History

Food
Silkworms natural food plant is the mulberry tree (Morus sp.).

An artificial diet has been developed to facilitate cultivation of silkworms.

If you do not have a mulberry tree available,

you must purchase the artificial diet.

Habitat
Today, the silkworm moth lives only in captivity.

Silkworms have been domesticated so that they

an no longer survive independently in nature, particularly

since they have lost the ability to fly. All wild populations are extinct,

although presumably old relatives exist in Asia.

Interesting Behaviors
Silkworms have been used by researchers to study pheromones or sexual attractant substances. The pheromones are released by female moths and the males detect the chemicals with olfactory hairs on their antennae. This allows the male to find the female for mating. The male antennae are made of many small hairs to increase the chances of picking up small amounts of the pheromones over long distances.

Collecting Live Insects

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Where to find
Silkworm eggs and artificial diet can be purchased from Carolina Biological Supply Company and Ward’s Biology. Check with other teachers and your district to see if there is a resource person in your community with eggs.

Silk Industry

History
The coveted secret of silkworm cultivation began 5000 years ago in China. Sericulture (the production of raw silk by raising silkworms) spread to Korea and later to Japan and southern Asia. During the eleventh century European traders stole several eggs and seeds of the mulberry tree and began rearing silkworms in Europe. Sericulture was introduced into the Southern United States in colonial times, but the climate was not compatible with cultivation.

Today
Today, silk is cultivated in Japan, China, Spain, France, and Italy, although artificial fibers have replaced the use of silk in much of the textile industry. The silk industry has a commercial value of $200-$500 million annually. One cocoon is made of a single thread about 914 meters long. About 3000 cocoons are needed to make a pound of silk.

To gather silk from cocoons, boil intact cocoons for five minutes in water turning them gently. Remove from the water and using a dissecting needle or similar tool, begin to pick up strands. When you find a single strand that comes off easily, wind the silk onto a pencil. Several of these strands are combined to make a thread.

Sourced and published by Henry Sapiecha 18th October 2009
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Fukiic Acid

Fuki is the Japanese word for the butterbur flower, and Fukiic acid is the hydrolysis product from this plant, Petasites japonicus. Interestingly, further oxidation of this produces the wonderfully named Fukinolic acid. (I wonder if fukanolic is anything like alcoholic…) Anyway, since the conjugate base of fukinolic acid is fukinolate, it’s probably about time we stopped!

Thanks to Anton Sherwood for info on fukiic acid, and to Andrew Reinders for suggesting fukinolate.

Fukiic acid - click for 3D structure

Sourced and published by Henry Sapiecha 13th Oct 2009

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OPTICAL MOLECULAR

IMAGING:

In vivo commercial systems

heighten appeal of molecular

imaging

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Last November, the Cleveland Clinic (Cleveland, OH) ranked an optical molecular imaging system as one of the year’s top ten medical innovations. “We believe this technology to be a game changer,” said Jennifer Hunt, the clinic’s head of surgical pathology. “When we’re talking about tumors, we’re talking about what information we can gain about that tumor to guide and direct therapy, prognosis, and diagnostics,” she said, referring to the clinic’s use of the Nuance system by Cambridge Research & Instrumentation, Inc. (CRi; Woburn, MA). “Being able to analyze multiple markers in a single cell to understand the behavior of signaling pathways will significantly aid in disease diagnosis and therapy development.”

While the first big application for in-vivo optical molecular imaging was infectious disease, oncology has been an important next step according to Caliper Life Sciences’ (Hopkinton, MA) Stephen Oldfield PhD. Indeed, Carestream Health Molecular Imaging (Rochester, NY) reports a surge of interest from oncologists just in the past couple of years. William McLaughlin, Director of Research and Advanced Applications for Carestream, says that at the American Association for Cancer Research (AACR) annual meeting two years ago, he saw significantly more interest in analytical techniques such as gel documentation and western blotting–but in 2008 noticed that more people were asking about the newer technology. Then at this year’s AACR meeting (April 18-22, Denver, CO), the majority of leads were for in vivo imaging, he said.

“The products have reached a point where they provide a lot of benefit to researchers,” McLaughlin explained, noting that in the past year or so he’s seen a shift in percentages: Previously most of Carestream’s molecular imaging customers were hard core imaging people; now, more customers are in application areas.

State-of-the-art optical molecular imaging systems enable noninvasive visualization of biological processes in vivo, enabling researchers to watch disease progression over time in the same animal. They use multiple fluorochromes to selectively target biological processes, and visualize small groups of cells (usually 50 is sufficient for research needs, though Oldfield says Caliper has followed tumors composed of just five cells–to demonstrate the technology’s capability). They enable testing at intervals to illustrate how tumors develop and respond to drugs, and their output can be co-registered with images produced by other modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) systems.

Moving up for drug discovery

For drug discovery, Oldfield says the technology has been used mainly at the end of the process, but is now being pushed much further upstream, to help determine which cell signaling pathways are affected by a drug. Previously the pathways were studied in vitro and millions of compounds were screened, he explains, but the newer approach lets researchers narrow down their work to perhaps 10 or 20 compounds, look at the pathways, learn what triggers this or that enzyme, and focus on compound optimization and drug efficacy. Oldfield says in vivo systems enable researchers to “fail faster” by getting the compounds into animals sooner so they can learn more quickly and accelerate the whole screening process. Observing disease progression in a live animal can provide all kinds of other information as well, he says.


(Courtesy Caliper Life Sciences)

Pharmaceutical companies don’t publish much (and are typically tight lipped about the technologies that help them get ahead), but Oldfield says he has just begun to see publications from the pharma labs demonstrating correlation between the upstream and downstream ends of the process.

In addition to this, in-vivo imaging is moving closer to clinical trials to enable testing of dosing levels. McLaughlin and Oldfield note that the approach has proven attractive for imaging of inflammation and for stem cell research. Explaining its use for imaging the inflammation that accompanies heart disease, McLaughlin explains that “vulnerable plaques have certain signatures of inflammation that indicate whether they are benign or active.” Oldfield points to observation of inflammation associated with asthma, arthritis, and stroke. A slideshow on Caliper’s website explains that all of the most commonly employed optical reporter labeling strategies have been used to generate light-producing stem cells; Oldfield explains that these can be seen tracking to the heart following cardiovascular damage.

The latest technology progress relates to 3D imaging for more precise pinpointing and quantification. Oldfield says Caliper has done much to improve software to enable this and make it easily accessible. And Carestream is working on a multimodal animal rotation system designed to eventually enable 3D visualization. The idea is to enable change of modalities (optical and x-ray) without moving the animal or focal plane–and register the imagery with precision. McLaughlin says the system will find the optimal angle for the optical signal and keep track of the rotation angle to enable tracking of changes over time.–Barbara G. Goode

Sourced and published by Henry Sapiecha 8th Oct 2009

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What is it?

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Terminalia catappa is a species of tropical tree that grows in Asia. It is widely believed that placing the dried leaves of this tree in your aquarium (especially with Betta fish) causes the animals better health and therefore longer life.

Alternative Names

Indian Almond leaf, Ketapang, Wild Almond, Badamier, Java Almond, Amandier de Cayenne, Tropical Almond, Myrobalan, Malabar Almond, Singapore Almond, Ketapang, Huu Kwang, Sea Almond, Kobateishi, West Indian Almond, Umbrella Tree, Amandel Huu Kwang, Kottamba

Benefits

Unsubstantiated claims of a reduced presence of fungus, boosted immune system and helping skin problems in fish are also reported.

The leaves do contain several flavonoids (like kamferol or quercetin), several tannins (such as punicalin, punicalagin or tercatin), saponines and phytosterols. Due to this chemical richness, the leaves (and also the bark) have long been used in different traditional medicines for various purposes.

It is also thought that the large leaves (7-10″ long) contain agents for prevention of cancers (although they have no demonstrated anticarcinogenic properties) and antioxidant as well as anticlastogenic characteristics.

In fishkeeping the leaves are also used to lower the ph and heavy metals of the water. It has been utilized in this way by Betta Breeders in Thailand for many years. Hobbyists across the world also use them for conditioning the betta’s water for breeding and harding of the scales.

Studies of rotting plant material (see bogwood) have shown that the organic material releases minerals as beneficial fungi and bacteria decompose it. This provides food for infusoria which in turn shrimps and fry enjoy eating as a natural diet.

Does it work?

Scientific sources of the benefits of Indian almond leaves to humans are few and far between. Certainly chemical analysis of these leaves show a high degree of variety of chemicals. We can find no similar scientific studies on the benefits of this leaf in aquariums.

Perhaps similar benefits may also be seen if you were to use standard bogwood in your aquarium. Bogwood is well known at lowering pH and reduces the toxicity of metals. Which is an aid to lowering the presence of fungus and certain species of bacteria. The organic matter is also as a food source for catfish like Plecos and is a natural food for infusoria which invertebrates like shrimp and other small fish feed off.

The tannins and other chemicals which are dissolved in the water by the decomposition of organic material is called Blackwater. There are many companies selling Amazon and African blackwater bottles. So Indian almond leaves may simply be Asia’s equivalent.

Certainly aquatic animals evolved alongside trees growing next to them. Tree leaves falling in and decomposing will have released dozens of trace minerals that the animals will have naturally absorbed. In an aquarium these chemicals will be missing so it seems sensible to assume that adding these chemicals via blackwater or bogwood will potentially restore this imbalance. The trick is to obtain the same species of plants that grow in the wild animals locale.

Failing that, other plants like Green tea, Tree spinach, Dock leaves, Cranberrys, etc. are all well known for their health benefits. Oak leaves are often used in aquariums as an alternative.

Purchasing the leaves

The leaves are not generally sold commercially in aquarium shops, though there is one product we’ve came across – Bio-Leaf by Degen Discus. eBay and AquaBid often have sellers of these items. So we recommend you look there. The leaves are not expensive.

  • The leaves should be evenly brown on both sides with no signs of fungus mould (light grey patches). Give the leaf a rinse in tap water to remove any possible lingering pesticides, etc. before you add it to an aquarium is a prudent move.
  • Keep any unused leaves in an air and watertight container away from light and heat will ensure that any unused leaves will keep for at least 4-6 months.

Indian almond leaves and Betta fish

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There appears to be word-of-mouth speculation of this leaf being used by far eastern aquarists for hundreds of years to harden the skin and increase the health of this fighting fish after bouts of fights.

Dosage

Assuming an average 6-10″ (15.2-25.4cm) long leaf, you use one quarter of this for every 4L (1.1 US G.) litres for Bettas or 1-2 leaves per 50L (13.2 US G.) for other species. Leave them in the tank for around 15 days in a filter bag or let them lie loose, they will sink after 2-3 days. Expect the water to tint slightly brown with the tannins.

  • Remove any active carbon before adding them. Afterwards carbon may be used to remove the tannins but this may impact on their benefit.
  • Sourced and published by Henry Sapiecha 5th Oct 2009
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