Chemicals in My Food

John Coupland is a Professor of Food Science at Penn State. His research program is on the physical properties of foods, in particular fats and oils. He teaches undergraduate Food Chemistry and graduate level Food Chemistry and Food Physical Chemistry. This is about that.

Jun 23
Selfie with book

Selfie with book

Jun 16

The people say “yes”

I live in a small town with a big university in the middle of nowhere. We have one high school, which is getting old and is in bad shape and, wonderful news, is going to be refurbished and largely rebuilt.  Far more wonderful though was the way it happened – the people decided! The school board, an elected body, proposed the idea then there was a campaign – with letters in the local paper, yard signs and everything – and a referendum and the town agreed to raise their own taxes to pay for the construction.  To most Americans this must seem awfully mundane, but as a gratefully resident alien I want to applaud the best illustration of democratic government I’ve seen.

First, the people of State College were responsible for their own school. If we wanted a better building there were costs we had to pay. Second, there was real political debate focused on a real issue with reasonably known costs and benefits. Last, the proposal was for a public good. We, parents and non-parents, are going to build and pay for the school for the children of our town. In other communities the public high school would have decayed and the richer parents would have moved their children to private schools.

I’m biased. I have kids who will benefit from a great new school and I’m happy to pay the tax that goes with that. I’m proud to live in a town where ”we” can do something good for our community. However, there were people on the other side of the argument who made passionate cases against. Regardless of how it came out though, the process of a town arguing about real costs and benefits then making a decision is really special and, I think, really American.

Image courtesy of Christopher Long

Jun 5

Adulteration of Cream. Cream is often adulterated with rice powder or arrow root. The former is frequently employed for that purpose by pastry cooks, in fabricating creams and custards, for tarts, and other kinds of pastry. The latter is often used in the London dairies. Arrow-root is preferable to rice powder; for, when converted with milk into a thick mucilage by a gentle ebullition, it imparts to cream, previously diluted with milk, a consistence and apparent richness, by no means unpalatable, without materially impairing the taste of the cream.

The arrow-root powder is mixed up with a small quantity of cold skimmed milk into a perfect, smooth, uniform mixture; more milk is then added, and the whole boiled for a few minutes, to effect the solution of the arrow-root: this compound, when perfectly cold, is mixed up with the cream. From 220 to 260 grains, (or three large tea-spoonfuls) of arrow root are added to one pint of milk; and one part of this solution is mixed with three of cream. It is scarcely necessary to state that this sophistication is innocuous.

The fraud may be detected by adding to a tea-spoonful of the sophisticated cream a few drops of a solution of iodine in spirit of wine, which instantly produces with it a dark blue colour. Genuine cream acquires, by the addition of this test, a faint yellow tinge.

Excerpt From: Friedrich Christian Accum (1820). “A Treatise on Adulterations of Food, and Culinary Poisons”.

Jun 4

Claims that make you go hmmm… (1)

What I find most amazing about this product is the precision of its claims - it will (apparently) improve memory by exactly 94% and reduce fatigue by no more or less than 83%. It contains, amongst many other things, a lot of vitamin B-12, a few milligrams of NADH and a lot of caffeine. The manufacturers claim it is made with natural ingredients and safe to drink multiple times a day, but at 160 mg of caffeine (about a large cup of coffee) in each per 2 fl. oz. serving, it wouldn’t take much volume to get to a worrying dose.

Jun 3
"Corn Comes in Exciting Bubbles Now"

"Corn Comes in Exciting Bubbles Now"

May 21

Teaching to Bloom

Last semester I taught an “Introduction to Food Chemistry” course to incoming graduate students in food science.  A struggle with this course some students already have degrees in food science while others have backgrounds in engineering or microbiology and might not have taken anything beyond general organic chemistry. It is difficult to challenge one group without losing the other.  I’ve tried lots of approaches, but this year’s effort seemed most promising. I divided the class into three parts, each roughly corresponding to ascending levels of Bloom’s taxonomy.


  • Remembering. In the first part I developed a “Food Chemistry Almanac” with about 75 factual points I considered basic operational knowledge in food chemistry (e.g., what is a reducing sugar? What is an w3 oil?) I put these points in a Google doc and asked the class to fill in answers to about twenty each week, taking information from the textbooks or other sources (have a look here – feel free to edit). I was looking for simple, factual responses and the ones I felt inadequate formed material for my lecture that week. The biggest challenge with this part of the course was making students feel OK editing and correcting each other’s contributions.
  • Applying. In the second part, I gave the students problems to solve in small groups in class. These might be explaining what a couple of graphs from a paper mean, predicting what defects might result from an ingredient substitution or even explaining the reactions behind a recipe.  Each group would them present their response to the rest of the class. This task required application of the facts from the first part, but was at the same time reasonably focused. Working in groups allowed students to share their experience while diluting some of the fear of being ignorant that often goes with starting graduate school.
  • Evaluating.  In the third part, students critiqued some papers from the primary literature. This gave them a wider scope to think about how knowledge is created and evaluated in the field. Students not presenting had to fill in a one-page questionnaire on the paper including, most usefully, a thoughtful question for the presenter.

I’m not an education researcher so I don’t “know” this approach is effective. The students seemed to like it and I felt it was better than other things I’ve tried. I found the single most useful element was giving space to learning facts distinct from application of those facts.  Bloom’s taxonomy gave a structure to do that.

(Image from Wikimedia Commons)

Apr 25

Transparency and Taco Meat

The use of food additives is restricted by law, but far more tightly restricted by the marketing departments that agonize over how scary the ingredient list looks to potential consumers. Consumers, incorrectly, see a “clean label” as a sign that food is healthy and natural and food companies do their best to deliver. The additives you are left with are absolutely essential to deliver the product in the form and at the price desired.

So what to do about the ones that are left? Most companies label them to the extent required by law and when an ingredient scare pops up reformulate as quickly as possible. The Food Babe’s recent collision with Subway over azodicarbonamide is a case study.


I’m pleased to see an alternative and more mature approach taken by Taco Bell. (It feels strange to associate Taco Bell and maturity!). They have a section  on their website about the ingredients they use. You can click on and get some sort of explanation of how and importantly why it is there. Their explanations are surely simple and driven by the desire to justify the use of the ingredient but still they are explanations.


I think the food industry would do better to be far more open their ingredients and processes and Taco Bell provides a model of what that might look like. 

May 5th 2014: Well apparently The Food Babe disagrees.

May 22nd 2014: A similar effort from McDonalds

Apr 22

Apr 17

I had a fascinating evening at the launch event for “Future of Food 2050”. IFT, my professional organization, is celebrating its 75th anniversary by looking forward to what the food system will look like in 2050. What are the technologies appropriate to help us feed 9 billion people with less land and less water?  We are conducting interviews with 75 leaders and innovators across the food system and supporting Scott Hamilton Kennedy to direct a documentary movie around the question.

As part of the program Chef Cantu did a demonstration “flavor tripping”. He had formed tablets from his own locally grown miracle berries with locally grown tapioca starch. Miracle fruit blocks the sour taste receptors so taking the tablet made a lemon taste sweet. Lemon always contains a lot of sugar but normally we can’t taste it because the acid sourness is so intense. The effect is astonishing but made the glass of wine I was drinking taste strange!  

Interestingly the Chef went to huge lengths to convince us the process was “natural” and “wholesome” and involved no nasty chemicals (all while convincing a room full of strangers to eat a red pill!). The effect is remarkably similar to the sweetness enhancers Senomyx and others are developing to allow lower sugar sodas but the marketing and context is very different.

Apr 10

The aniseed taste in Ouzo (or Pernod, of Ricard or Raki or Sambuka or Arak or Pastis depending on where you’re from) is due to anethole. Anethole dissolves in the alcohol of the drink to form a clear solution but it is insoluble in water. Traditionally these drinks are served with iced water. When the drink hits the water, the alcohol is diluted and the anethole precipitates out as fine droplets of oil in water – an emulsion. Emulsions scatter light and are cloudy and the blueish tinge of the Ouzo emulsion is evidence these are small droplets are small (~ 200 nm). This sort of bottom-up spontaneous emulsification is unusual in foods; most food emulsions use a high-energy homogenizer to break up large droplets into smaller ones.

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