2 Aug 2014
12 May 2011
Longwood Gardens has lots of lakes and streams. It was sunny on Maundy Thursday, so a bit too bright for great reflections. In the shade was great, and I ended up with more than enough pictures. As I couldn’t decide on one, I made a triptych.
Copyright © 2011 cgadavies. All rights reserved.
15 Jun 2009
13 Oct 2007
It seems that the stars are aligned or something for me to continue my discussion on water and material science. Not only did Dario comment on my Water Activity post asking me to discuss the relationship between glass transitions and water activity, but in a recent Friday Sprog post on Janet’s blog, she discussed phases of matter and a commenter talked about materials that was both solid and liquid. These materials are known as amorphous materials – there seems to confusion as to whether they are solid or liquid because they can have the behavior of both phases. Amorphous materials do not have the regular, ordered pattern of crystalline solids and they typically have more structure than a liquid.
Many foods are amorphous. In fact, very few foods are true crystalline solids or true liquids. Those that are; salt, sucrose, oils; are generally pure compounds. In most foods, water is present with solutes; salts and sugars; and polymers; proteins, complex carbohydrates, and lipids. These interfere with the standard behavior of pure water.
To get you started Janet has a great post about the typical three phases of matter that you meet in high school chemistry class, namely solid, liquid and gas. In that post she represents a great phase diagram:
This is a great representation for materials such as water that have a crystalline solid, ice, and when pure easily convert into a liquid. The point of change between ice and water is the melting point if you increase the temperature or the freezing point if you decrease the temperature.
As you add solutes to water the temperature of freezing/melting changes. Freezing occurs at a lower temperature. This is one of the colligative properties and is the reason why, as long as you don’t live anywhere really cold like Minnesota, a dilute solution of salt can be used as an antifreeze, as it freezes at a lower temperature than pure water. Here is a phase diagram from Spark Notes showing both the pure solution and the solution with dissolved solutes:
This is true of whatever solute you use, so sugar would have a similar influence on the freezing temperature. Thus, food freezes at a lower temperature than pure water. If you have ever seen the Alton Brown episode on Thanksgiving the turkey guy talks about the different temperatures and definitions of fresh, hard chilled and frozen turkey. They are also given here. For instance:
Any turkey labeled “fresh” in a food store has never been cooled to a temperature lower than 26°F, which is the point that turkey meat begins to freeze.
[…]in order to be considered “frozen” a turkey must be cooled to a temperature of 0°F or below.
Obviously, hard chilled turkeys are stored between 0 and 26F.
So where does that get us?
Pure water has three phases: ice, water and steam (or solid, liquid and gas for other materials) and the phase change temperatures are influenced by the presence of solutes and polymers present in the liquid. Additionally, as a food freezes, the water typically freezes out, leaving behind a more and more concentrated solute liquid phase. This can result in an change in pH, viscosity amongst other properties. In some instances, the solute-liquid phase might never solidify. If a food is rapidly cooled to below the freezing temperature, a glass may be formed. A glass is an amorphous solid that has a disordered structure while behaving like a highly viscous solid. In some frozen foods, water will freeze to from crystalline ice and the solute-liquid phase will form a glass.
23 Jun 2007
Out on Friday night with friends going blueberry and sour cherry picking near the Conowingo Dam. On the way home we stopped on the way to walk along the Susquehanna river near Port Deposit MD, when we saw this Great Blue Heron. It was so still, I thought it was a statue at first. Herons are very cool.
3 May 2007
Encouraged by the commentators on Magical Water Part 2, I am revisiting a year old New Scientist article on the wonders of water. When I read it last April (I actually subscribe to NS, having read it for over twenty years it is hard to give it up) I was disturbed as the article seemed to concentrate a lot on Massru Emoto’s work on how emotion alters water crystal shape. His work was used in that weird movie “what the bleep!?” which left me very uncomfortable. I was also left feeling uncomfortable after reading the New Scientist article. Amongst the new age woo, there were statements by scientists, such as Dr Felix Frank who did research on the role of water in food shelf life and stability. I even had the opportunity to meet Dr Frank as I was asked to co-chair a session on the “Role of Water Functionality” at one of the Institute of Food Technologists’ annual meetings. I just have assume that Dr Frank has either joined the ranks of great scientists tripping over the great wonders of woo. The greatest member of that group being Dr Linus Pauling with his ideas about Vitamin C. Or he has been misused by New Scientist. Admittedly his comments are not too far out but it is the company that he is keeping that bothered me.
I digress. One of the reasons I didn’t get round to writing this article last April, other than day to day distractions, is that Orac chose Massru Emoto and his studies for one of his Friday Doses of Woo. All covered, I thought, by Orac. Additionally while searching for information on water and, in particular the zero point energy, I found this great site on water which is going to save me a lot of time, but also discouraged me from writing on water for a while.
The New Scientist article strongly implied that there might be something in the new age theories by using scientific studies, and talking about the quantum effects of water and the fact that water is necessary for many proteins and even DNA (gosh, the molecule of life) to function correctly. I also got discouraged because they talked about the zero-point vibration* properties of water as if this was really important and I had never heard of it before and couldn’t find anything out about it that I understood. I even asked people for help on my last magical water posts and it was confirmed that zero point energy is obviously serious woo. They even mention hydrogen bonding and the unique behavior of frozen water in hushed terms as if it was something new that no one understood.
We have known for a long time that many molecules need water as part of their structure. Known as the water of hydration, this water cannot be removed without chemical compounds losing their structure, and in the case of proteins, function.
Considering how little is known about the chemistry of water – it was disappointing to see how much space was wasted on new age theories.
I do actually believe water is amazing. See my scientific posts on water to find out how truly amazing water is without needing to add woo.
* I am sure this definition helps:
(′zir·ō ¦pöint vī′brā·shən) (statistical mechanics) The vibrational motion which molecules in a crystal lattice, or particles in any oscillator potential, retain at a temperature of absolute zero; it is quantum-mechanical in origin. Also known as residual vibration.
29 Jan 2007
In Part 1 when I introduced Essentia Water, the Ultimate Drinking Experience, I left the best bit of the label for last. Here it is:
I should really leave it here and let you think about it for a minute.
24 Jan 2007
I bought this water at Whole Foods in Chapel Hill, which was conveniently in the same mall as the knitting store, Knit a Bit. I love wandering around places like Whole Foods to see what new and wonderful food I can buy. Their produce section is typically bigger than my house. It is very inspiring for a vegetarian food scientist.
I had to buy this water because of its ‘health’ claims. As I realise the above image is too small to read, I expanded each section and added commentary.
The ultimate drinking water, cor. I must drink a lot of this. Is it like Ultimate Frisbee? The water is
purified enhanced using ionic separation. While they have nice diagrams of their purification method, it does not give details on their method of ionic separation. I assume it must be the same technique by which we obtain deionized water for the lab, which removes ions from water. Essentia then added electrolytes. Which are, aha, ions.
Well, this water contains no nutrients. Not one. Nada. Unless you consider water to be a nutrient, of course.
Electrolytes can’t be derived from sodium bicarbonate etc. as these are pure molecules. They are only derived from these molecules because in solution, any water based solution, the molecules become ionized producing Na+, HCO3– etc.
Electrolytes are important, Essentia’s website says so:
In a battery, the electrolyte fluid, creates an electrochemical pathway between one pole (+) and another (-). Electrolytes, minerals and salts do the same thing between your body’s cells in a network many billions of times more complex-and critical to maintaining normal blood pressure, restful sleep, proper cardiac rhythm, muscle strength, endocrine balance, intestinal function and more.
Essentia Water has been specifically formulated to rapidly restore intracellular fluids to their optimum state by taking advantage of the process the body naturally uses, the phenomenon of osmosis. Essentia Water has been designed to simulate intracellular fluid electrolyte concentrations. Solutions that have identical osmotic pressures are said to be isotonic solutions. For optimal and rapid replenishment of intracellular fluids and electrolytes, the replenishing fluid must be isotonic with intracellular fluids. [Their emphasis.]
So their you have it, electrolytes are a good thing. Actually, are they actually saying anything? After reading the first paragraph, I have this image of my cells having positive and negative poles with molecules lining up to the appropriate cathode or anode. I think not.
While Essentia don’t get into the details of ozonation, it is explained by the American Water Works [I must stop laughing. Waterworks is what my grandma called it when she need to pee or if I cried too much: “Switch off those waterworks, Lab Cat”] Association in this fact sheet. Unfortunately, this is the same method used by Coke to produce Dasani water in England. It caused bromate to form in the already pure and clean Thames tap water. Bromate is a potential carcinogen. Great, bottle free tap water, charge 95p per liter adding a carcinogen at no extra charge. Good thing none of those added electrolytes is bromide.
The statement about this water being bottled according the the requirements of the USEPA is a red herring. Bottled water is actually regulated by the FDA since it counts as a food. As this document shows, the EPA requires the FDA to adopt EPA’s water quality standards. This means that this water is a pure and clean as your faucet water. While searching for this information, I found this very informative document (pdf).
There is more…but that will have to wait for a second post. Too much information, not enough time.
18 Jan 2007
I mentioned in a previous post how much water we should drink but I don’t think I emphasized enough that you can have too much water. Now some one died after drinking too much water as part of a competition to win a Wii. It isn’t worth it! Orac has a couple of posts (1 & 2) and Radagast explains what goes wrong when you drink too much water.
It really is a stupid way to die!
7 Sep 2006
With the introdution of water activity, Food Scientists defined a unique and important property of food. It is also unique to Food Science as you do not meet this terminology in many other scientific disciplines. According to Chambers Dictionary of Science and Technology, water activity (Food Sci) is: (more…)