Roast Your Own Perfection

In three minutes, you will learn how to perfect your cup of coffee – just the way you like it.

To do this, we have to talk about chemistry!

Seven years ago, German food chemists researched how the bitterness of coffee changes depending on how long you roast the beans.

They confirmed what Trugo and Macrae found in 1984: the more you roast coffee beans, the more bitter the coffee tastes because organic compounds called chlorogenic acids are degrading.

 

Structure of one chlorogenic acid: 5-O-caffeoylquinic acid.

Wikimedia Commons: Ed. https://commons.wikimedia.org/wiki/File:Neochlorogenic_acid.svg

Then, what makes this 2010 study different?

Well, these German scientists used evolved technology.

In 1984, those researchers used High Pressure Liquid Chromatography (HPLC), a technique that separates the components of coffee in a solvent. In 2010, however, the German researchers used the evolved form of HPLC: HPLC-MS/MS and HPLC UV/Vis. The combination of HPLC with mass spectrometry (MS, another analytical technique) enabled these researchers to figure out how much there is of each compound as you increase the roasting temperature.

An HPLC-MS Diagram. 

Wikimedia Commons: Daniel Norena-Caro. https://en.wikipedia.org/wiki/File:Liquid_chromatography_tandem_Mass_spectrometry_diagram.png

With this advanced tool, they tracked the concentration of three classes of compounds:

  • Caffeoylquinic acids (CQAs), a chlorogenic acid, gives the non-bitter taste;
  • Monocaffeoyl quinides (MCQs), also a chlorogenic acid, gives a pleasant bitter taste;
  • And oligomers (Os), a newly discovered class of compounds in coffee, gives a harsh bitter taste

And found that as roasting temperature increases from 190°C to the maximum 280°C, the concentration of CQAs decrease exponentially, MCQs increase then decrease, and Os increase exponentially. So, the presence of each compound is different at different roasting temperatures.

With this knowledge, you can personalize the bitter taste of your coffee.

For example, if you prefer a pleasant tasting brew, set your oven at 235°C and roast your coffee beans for less than 20 minutes. Watch as your beans change from green to brown and crack twice.

Then make your coffee as usual: grind the beans in a filter, then pour hot water through.

(By the way, why should you roast your coffee beans? It’s easy and tastes much better!)

And so for YOU who’s a keen coffee-drinker, I also note that water percolation or “pouring hot water through” the coffee beans makes a difference in how much of these compounds there are in the end as well! Not that much of a difference, but if you really want that perfect brew, look into this study in the Journal of Agricultural and Food Chemistry.

As for me, I don’t like bitterness anyway; so I’ll just stick to water.

-Ivy Wu

What Exactly are Natural Flavours?

If you look at the product label of blueberry yogurt, you may notice “natural flavours” listed in the ingredients, but what is it? The flavour did not come from crushing up the fruit. It’s not that simple. Chemical compounds that give blueberry its flavour are extracted in a laboratory, enhanced, and added to the yogurt. This might surprise some of you but yes, natural flavours contain chemicals. The truth is, everything around us is made up of chemicals.

Yogurt (Source: By Takeaway (Own work))

The positive connotation associated with “natural” has misled many consumers. The food industry tells us what we want to hear and keeps the rest a secret, and it’s working. A study published by Consumer Reports found that people prefer to buy food labelled as natural.

On Merriam-Webster, “natural” is defined as “existing in nature and not made or caused by people” and “not having any extra substances or chemicals added”. This is not the case in the food industry, which is why many people are misled. Aside from the flavouring, natural flavours contain emulsifiers, solvents, and preservatives that do not need to be disclosed on the product label. The term “natural flavours” listed on the food label could contain up to 100 added ingredients.

According to the FDA’s Code of Federal Regulations, natural flavours are derived from a natural source such as, plants, animals, fungi and microorganisms. But are the flavours still “natural” after being processed in a laboratory? Many techniques to extract flavours from a natural source have been studied. In enzymatic extraction, enzymes like lipases, esterases, nucleases or glycosidases break down the flavouring component from larger molecules. In solvent extraction, acetone, alcohol or propylene glycol are used to extract the flavouring chemical. The flavour is labelled as “natural” even when a synthetic solvent, like propylene glycol (safe in small quantities but toxic in large doses) is used because the flavour came from a natural source.

Chemical Structure of Vanillin (Source)

While I agree that some natural products are better, there are also a majority that are not. Natural vanilla flavour can come from castoreum, a brown slime secreted by a beaver or from vanillin, extracted from vanilla beans. Although they taste the same, most consumers would prefer vanillin over castoreum in their vanilla ice cream. However, castoreum is hidden under the term natural flavours, so you won’t know unless you do some digging.

Health Canada and Canada Food Inspection Agency need to set stricter regulations for the food industry. It is unethical how manufactures are allowed to hide controversy ingredients under the term “natural flavours”. Consumers should be able to read a food label and know exactly what they are eating. Next time you’re buying a naturally flavoured product, you might want to think twice.

The video shown below talks more about natural flavours.

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Carmen Chu

Skin-deep tattoo woes: study confirms presence of tattoo ink nanoparticles in lymph nodes

A compelling study published last Tuesday in Nature‘s Scientific Reports has confirmed that tattoo ink nanoparticles dangerously circulate the body. In this groundbreaking study, scientists from the European Synchrotron Radiation Facility (ERSF) have demonstrated overwhelming evidence for the movement and long-term deposition of toxic elements in tattoo pigments in tissues which lead to inflammation as well as other side effects upon tattooing.

Think before you ink; experts believe there are long-term safety concerns in tattoo inks. Untitled (c) Dan Prado.  CC BY-NC-SA 2.0

Whether it be a daring drunken escapade or a meaningful memento, getting a tattoo in Western societies has long been culturally accepted and not particularly novel. Tattoos have been around for millennia, the earliest artifacts dating to 1200 BC. Due to the recent popularity of tattoos, however, some began to ponder safety concerns of this seemingly innocuous trend.

YouTube Preview Image
Concerns for tattoo ink safety are rising.

 

When it comes to the safety of tattoos, people are generally worried about the sterilization of needles, and rightly so, as infectious diseases like methicillin-resistant Staphylococcus aureus (widely known as MRSA) and HIV are known to spread through improper sanitation. However, the authors of the study believe that the chemical compounds of the inks pose an equivalent, if not greater risk for customers.

“People should be aware of the unknown risks that might come along with tattooing, rather than presuming that the colours are safe,” explains Ines Schreiver, first author of the study.

Currently, the toxicological data for individual ink ingredients are accessible, but the specific in vivo (Latin for “within the living”) interaction of tattoo compounds with cells are uncertain. So, researchers from the ERSF decided to not only to characterize the specific compounds within the dyes, but also quantify the size range of the molecules and qualify biomolecular changes in the affected tissues.

A key objective of the study was to show that organic dyes, inorganic compounds and metallic elements from tattoo particles were able to translocate from the skin to the lymph nodes in nano form, which means the particles are on the magnitude scale of 10-9 meters. Tissue samples were collected from deceased donors, and photographic evidence from comparing lysed skin and lymph nodes showed that the lymph nodes became tinged with the colour of the tattoo on the skin. Using spectroscopic techniques, the scientists were then able to identify compounds as well as quantify metal content such as Nickel and Chromium, which are linked to carcinogenicity.

Synchrotron X-ray fluorescence measurements allowed the researchers to pinpoint compounds at the micro and nano scale. Most particles detected were found at the micro scale, but the smaller particles on the nano scale had the pesky ability to migrate to the lymph nodes and induce enlargement which can lead to a myriad of other health issues.

If this finding has changed your mind about tattoos, keep an eye out for related studies. The authors of this paper will likely go ‘skin-deep’ in further research.

Frances Gu

CRISPR: A Future with Super-humans?

Researchers at Jennifer Doudna’s lab in the University of California have potentially found the cure to all forms of diseases. With the help of CRISPR and gene editing, which was only part of a dream a few decades ago has now become a reality. Research on Escherichia coli bacteria back in the 1980’s has allowed scientists to finally pin down the Cas 9 protein which enables the bacteria to survive virus attacks. When a virus attacks a bacterium, it inserts its RNA into the organism which leads to the virus using the bacteria as a factory and it eventually hijacks the entire cell. However, with E -coli and its Cas 9 protein, the RNA is recognized by the bacteria and allows it to destroy it. When a virus inserts a copy of RNA that is not recognizable by the bacteria, the Cas 9 protein is able to read the RNA and insert it into its memory where it will know which virus is attacking it.

Further research has allowed scientists to isolate this protein and use it for gene editing by using the protein to recognize faulty DNA nucleotides in the human genome. The Cas 9 protein needs to be able to bind specifically and reversible therefore the interaction is via non covalent bonds.With billions of nucleotides present in an organism this protein is highly accurate and can destroy genetic mutations such as metabolic liver disease, congenital blindness, blood disorders, Huntington’s disease and cystic fibrosis. As Jennifer Doudna has stated “We may be nearing the beginning of the end of genetic diseases”. Moreover, there is more than just curing genetic diseases, you can also go a step further and add desirable traits. Since CRISPR is very efficient in detecting the exact nucleotide sequence, you can replace it with the desired characteristics. You want a blond hair, just replace the DNA strand which codes for blond hair color, you want bigger muscles, just replace the nucleotides, you want to be taller just replace the nucleotides – you get the idea. You can be the most powerful person living with this technology – if yet reached.

The insertion of nucleotides in a genome with the help of Cas 9 protein                                                         (Attribution: ViktoriaAnselm – Own work)                                                                           (https://upload.wikimedia.org/wikipedia/commons/9/93/CRISPR-Cas9_mode_of_action.png )

Replace a strand – get super powers ?                                  Attribution: IMGUR (http://i.imgur.com/LTDKlbm.gif)

 

Researchers are still investigating the full potential of the CRISPR technology and it can lead to artificially selecting humans on birth if used at an early stage. The idea of pre-selecting humans might sound uncomfortable to a few but humans have been artificially selecting for decades from plants to humans. We currently only crop the best type of plant in order to achieve the most desirable traits. In humans , genetic disorders such as down syndrome are undesirable. 88% of people in Europe would undergo an abortion if they found out that their fetus has down syndrome. CRISPR might just amplify the amount of selecting we do, and we have to ask when is enough? I believe that CRISPR is an amazing technology in curing various genetic diseases but using it to select certain traits seems excessive. There are somethings that nature does not want changed. As research continues it is important to keep human rights in our thoughts and as Newton would say “What we know is a drop, what we don’t know is an ocean”. The ocean may be filled with gold or horror.

Garvit Bhatt

CHEM 300 Course Blog

Welcome to the CHEM 300 course blog!

Here are few things to make note of before you get started with your posts. First of all, you should read the blogging resources page under the Create menu. This will help you out a lot if you are brand new to using WordPress. On this page, you will find video tutorials about writing posts on this blog, adding media to your posts, tagging, and categorizing. You will also find a link to the rubric we’ll use to grade your blog posts.

Next, check out the blogging guidelines. Here you will find the answer to the question: “What are we supposed to blog about?” You can also check out one of last term’s blogs for some additional inspiration.

There are a few important things to keep in mind when blogging. Please do not assume that just because something is online, it is OK for you to use it. For example, unless it is explicitly stated, an image on the internet cannot just be copied, saved, and used in your own post without permission to do so. We’ve provided you with a lot more detail about properly using online content, but if you have questions, let us know.

This blog also contains a lot of resources for you. For example, still under the Create menu, you will find a  list of suggested software to use for your projects. We’ve also collected some writing and presentation resources.  Basic audio/visual equipment can be borrowed from CHEM300. Contact the course coordinator for more info.

Under the Explore menu, you will find some sample podcasts and videos, links that may be of interest or assistance, a list of groups and associations related to communicating science as well as a list of local museums and science centres. The Explore menu also contains a library resources page, which you should definitely have a look at. Finally, there is a bookshelf that lists relevant books that are on reserve for you in Woodward Library.

Let us know if you have any questions about the blog or would like to see any other resources made available. Or, if you find something that you think would be useful to the rest of the class, tell us, and we can add it to the resources. Better yet — write a post about it!

Happy blogging!

The CHEM 300 Team