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.

Sep 21
fdsc413:

Measuring acrylamide in French fries made from both cold-stored and reconditioned potatoes using high performance liquid chromatography (HPLC).  The first time our new teaching HPLC’s have been used in the wet pilot plant! Lots of acrylamide in both treatments, but still delicious…

fdsc413:

Measuring acrylamide in French fries made from both cold-stored and reconditioned potatoes using high performance liquid chromatography (HPLC).  The first time our new teaching HPLC’s have been used in the wet pilot plant! Lots of acrylamide in both treatments, but still delicious…


Sep 6
“The first thing that hits you on opening the packet is a faint but distinct whiff of tuna, an inauspicious start for a beefy sandwich. Biting down, the texture is soft and claggy, the cheesy sauce acting as a lubricant to bring the cotton wool bread firmly into contact with your dental enamel from where it refuses to budge without the aid of a fingernail. The diced beef is beefy in the way that a cheap beefburger is beefy - redolent of the artificial flame-grilled flavour favoured by certain fast food outlets and devoid of any garlic, oregano or other identifiable attempt at Italian-ness. Quite where the pasta sheet in the middle disappears to is a mystery - it’s there when you bite down, and gone by the time you swallow. Overall, the effect is of a saladless, cold, lightly pre-chewed beefburger.” The lasandwich - why?” by Rick Peters

Aug 26
fdsc413:

What’s the difference between hot break and cold break in tomato processing? The nose knows!
Processing can have a significant impact on the chemical and physical characteristics of food products.  Explore these differences with tomato sauce production!
Hot BreakProcess: Whole tomatoes are held in boiling water before milling into sauce.Outcome: Enzymes are denatured before they are able to interact with substrate leading to a more viscous, less aromatic product.
Cold BreakProcess: Tomatoes are diced and left to sit at room temperature for 15 minutes prior to heating on a stovetop and milling into sauce.Outcome: Dicing allows interaction of enzymes such as polygalacturonase and pectinmethylesterase to interact with their substrate, pectin, to create a less viscous product.  The exposure of lipoxygenase to unsaturated fatty acids allows the cleavage of fatty acids and production of aromatic compounds associated with fresh tomatoes (cis-3-hexenal, trans-2-hexenal, methyl salicylate, penten-3-one).

fdsc413:

What’s the difference between hot break and cold break in tomato processing? The nose knows!

Processing can have a significant impact on the chemical and physical characteristics of food products.  Explore these differences with tomato sauce production!

Hot Break
Process: Whole tomatoes are held in boiling water before milling into sauce.
Outcome: Enzymes are denatured before they are able to interact with substrate leading to a more viscous, less aromatic product.

Cold Break
Process: Tomatoes are diced and left to sit at room temperature for 15 minutes prior to heating on a stovetop and milling into sauce.
Outcome: Dicing allows interaction of enzymes such as polygalacturonase and pectinmethylesterase to interact with their substrate, pectin, to create a less viscous product.  The exposure of lipoxygenase to unsaturated fatty acids allows the cleavage of fatty acids and production of aromatic compounds associated with fresh tomatoes (cis-3-hexenal, trans-2-hexenal, methyl salicylate, penten-3-one).


Your Vegetable Juice is Not Vegetarian and You Shouldn’t Care

Vani Hari, the Food Babe, is concerned that V8 vegetable juice might not actually be vegetarian! She points to the “flavorings” item on the label and notes, correctly, that can mean all sorts of things, some of which can be of animal origin. In her contacts with the company she found someone who. Correctly, explained that to her – flavorings may include products of animal origin and the product is therefore not vegetarian. Later, and you can almost sense the panic in the corporate offices once they realized who they were dealing with and what they had said to her, the company issued a clarification that while flavorings can be of non-vegetable origin the ones V8 use are exclusively vegetable-based and the juice is vegetarian. Vani, unsurprisingly, sees deception here but I think it far more likely that the first contact she had made a mistake and the company rushed to correct themselves. There really aren’t many animal origin flavors you would want to put into vegetable juice and in any case having a non-vegetarian product makes no sense to the company from a branding point of view.

Interestingly though, neither the V8 juice nor the home-made smoothies Vani promotes are truly vegetarian. Fruits and vegetables grow in fields and on trees and in gardens where insects live on them and around them. While the farmers and processors make a good effort to clean the vegetables there is a certain level  if insect eggs and body parts that inevitably remains that can be seen by a skilled microscopist.  The FDA sets standards for what is a maximum level of infestation in a product that can be sold. Tomato juice for example can contain fruit flies (drosophila) up to “10 or more fly eggs per 100 grams OR 5 or more fly eggs and 1 or more maggots per 100 grams OR 2 or more maggots per 100 grams”. Most companies work hard to keep their levels of contamination much lower than that, but the point is there is a limit and it isn’t zero.

To me, this is an eminently sensible approach. The FDA sets a limit and methods to test, then enforces that standard.  A few insect parts aren’t likely to do you any harm and the process of reducing them further would involve vastly more food waste, pesticides and wash water. The idea of having a few insect parts in your vegetables is a bit yucky but much better than the alternative.

I would contrast this pragmatic thinking with the Food Babe’s. In her world there is not risk too small, no “connection” or “link” to a disease so tenuous, that it can be ignored. There are real problems with our food system but here the Food Babe distracts attention from them by focusing on a non-issue.

Image: Fruit fly (Drosophila melanogaster, male) posted to flickr by Max Wesby under the Creative Commons License. A fruit fly is typically a couple of millimeters long.


Aug 23

Eating Insects

People have been eating bugs forever, but commonly so in warmer countries where they grow large and fat. In the typical “Western diet”, insects play no positive role - but perhaps they should. While there are some concerns with allergenicity, many insects have attractive nutritional profiles and could contribute to the human diet Insects can be readily “farmed”, sometimes using human food waste as their feed, using less energy, water and land per unit of protein than from other food animals. So how do you eat an insect?

Many countries have traditions of just cooking them and crunching them up, but people from non insect-eating cultures often have a strong disgust response to bugs. (If you are tempted to give it a go, pick one from the list of edible insects and be sure to clean/cook it appropriately. Insects carry a lot of microorganisms that could make you sick.) If the idea of eating insects is too disgusting you can grind them into animal feed and eat the animals that ate the bugs, but not eating the insects directly loses a lot of the ecological advantages of direct entomophagy. How do you feel about just eating the ground insect yourself? All the nutrition but without the legs.

Cricket flour is emerging as a commercial food ingredient. The crickets are farmed, killed, cleaned, roasted and ground to food a high protein flour that can be incorporated used to make food. Recently Chapul started marketing bars formulated with this flour. This is a huge step. It’s one thing to talk about eating bugs or to serve them to kids at some sort of science fair, but entrepreneurs who actually trying to make money from people eating insects has real potential to change the food system.

The bars are available in three flavors: Aztec (chocolate and chili), Thai (lime and ginger) and Chaco (peanut butter and ginger). The bars have quite simple formulations and cricket flour is typically the third or fourth ingredient (e.g., the Chaco bar is dates, peanuts, honey, cricket flour, cocoa powder, oats, flax seed, salt) and is 220 calories and about 15% protein. In comparison the chocolate-peanut butter PowerBar is soy protein isolate, calcium caseinate, whey protein isolate, maltitol syrup, chocolate flavored coating (sugar, fractioned palm kernel oil, cocoa, whey, nonfat milk, soy lecithin, natural flavor), oligofructose (from chicory root), fructose, water, cane invert syrup, peanut butter, partially defatted peanut flour, soy crisps (soy protein isolate, rice flour, barley malt extract, salt), peanut oil, salt, ground almonds, natural flavor, soy lecithin, butter. The PowerBar has the similar calories and is 30% protein. The added protein in the Chaco comes from the crickets while the protein in the PowerBar comes from soy and milk.

The PowerBar is packaged in an opaque foil laminate while the Chapul bars are in clear plastic that would be expected to transmit light and oxygen, possibly causing off flavors. Also products like this can have problems changing texture over the course of their shelf life and I don’t know if this is an issue with Chapul. The bars I ate tasted fine, but I don’t the shelf life Chapul expect.

I did an unscientific survey and offered the Chapul bars to some food science colleagues and my family. Most people were interested in trying insects and only one person refused the opportunity. All products were very strongly flavored, this could be an marketing feature or possibly to cover some off-taste in the cricket flour (this isn’t unusual - soy protein has a strong flavor that is often masked with other flavors). They had a chewy texture typical of a protein bar and a slight “crunch” between the teeth as you chewed that initially made you think it was the seeds in figs that, on reflection, wasn’t. The Aztec bar had a strong chili/chocolate taste that no one liked, but the other products were generally enjoyed.


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"


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