Myth or Fact? #16 – Skin on heated milk is dangerous
I was a young boy when my mother told me something that would haunt me for years. Before going to bed I loved to drink a glass of warm milk. Usually my mother prepared the milk for me but one day I wanted to do it on my own. I was 10 and had no idea how to cook (shame on me).
So what happened was that the milk cooked too long and a weird skin appeared on the top. Not knowing what happened I asked my mother and she told me to remove the skin since it’s bad and dangerous to me.
Years later I understand what happened back then. Do you? Is it true or false? A myth or fact? We will find out my friends!
What is milk?
Milk serves as the primary nourishment for infant mammals. It is an emulsion (colloidal dispersion) which consists of proteins, vitamins, carbohydrates, milk-fat and water (~87%). The greatest part of proteins in milk takes casein with almost 80%, the other 20% are referred to as whey proteins.
Further more we have some important carbohydrates such as glucose and lactose.
Did you ever wonder why a raw egg turns into a fried egg when heated? Or better say: why it turns from almost liquid into kinda solid? Let me tell you!
They solution lies within the proteins
Proteins are big molecules (polypeptides) which consists many amino acids. I personally love proteins! Big muscles and stuff...Okay, just kidding! But I really love proteins because they are so wonderfully build!
We have four different layers of structure for the proteins.
Fig.1 (from top) Primary, secondary, tertiary and quaternary protein structure Source
The first layer is the sequence of amino acids. They basically build a chain of amino acids. The so called primary structure.
The secondary structure of proteins are either alpha helix or the pleated sheet pattern (note that there are few other pattern we will not include here). The hydrogen bonding of the peptide backbone cause the above described pattern.
The tertiary protein structure is three-dimensional folding of the amio acid chain. This means that if you have a long chain of different secondary pattern, due to sidechain interactions they will put into a tertiary structured protein.
The last structure is the quaternary protein structure which consists of more than one amino acid chain.
As you can see proteins are very well structured and organized. What a pity that heat destroys this structure!
Denaturation
As described above our proteins have a complex structure. Heat is one of the main reasons why proteins denature. What happens is that the proteins losses its second and third structure. Imagine the heat as energy that let the molecule swing. The hotter it gets the more they move until they lose their structure. However the energy is not great enough to break the covalent bonds. This is the reason why proteins still keep their primary structure. Biologically the protein loses its function.
The below pictures depicts what happens with a protein when it denatures.
Fig.2 1. Protein in quaternary structure 2. Heat is applied 3. Protein in primary structure Source
So the skin on my milk is denatured proteins? Right! You can still drink your milk and it wont harm you. Everything is totally fine.
By the way: the skin appears because the denaturated proteins build threads that move upwards.
Tim
I find it funny. I would be more concerned if the milk would not have a 'skin' after heating it up. Great post @timsaid I hope more people read this!
lol! Now that would be definitely a concern.
Thanks!
Read and gained some knowledge, thanks tim
Myth or Fact #16 2.0
Is it dangerous? MYTH
Is it *eww*? FACT
LOL! Excellent article again, from here on end, I'm following your work. Thanks a bunch for sharing such knowledge with us, it empowers us all. Namaste :)
Namaste Eric! Great to have your feedback
This is awesome! I always wondered what the heck was going on when I made hot chocolate, Not enough to actually do any work to figure it out but since you put it in front of me... thanks!
In order to prevent the emergence of the skin on the milk just stir it :) Thanks for the kind words!
Am I losing out on anything by just scraping it off before I put in the mix? I'm kind of a weirdo and find it interesting to see it attach to the spoon.
Yeah I'm a flat out weirdo.
This is exactly why I usually stir milk 1-2 times during the process of heating it. Never thought it was bad, just nasty.
Some proteins 💪
Thanks for that I now understand why people eat raw eggs, very informative 👍🏻
The skin will not hurt you (well, no less than any other over-cooked food). However, as it cools, it is possible that the skin later becomes a "barrier" and collects mould, whilst the fluid remains edible. This could be a reason why it was seen as unsafe. However, baked rice pudding (ugh!), with its skin, has never been seen as such a health hazzard as far as I am aware.
I didn't like the skin at all. Furthermore it can overcook the milk since the steam can't escape properly
My mom told me to just toughen up and drink the milk with the disgusting skin on top :D
I guess she did right. My mother just scared me lol
And she did the right thing. For children, there are many health benefits of consuming milk products, especially those prepared at home.
Actually no, cow milk is for cow babies not for humans. The industry has tried to make us believe that milk is good for bones, etc. but it is all false. The bioavailability of calcium in milk is very limited and actually there are concerns that it demineralise bones and one proof is that osteoporosis in more predominant on those countries with high milk consumption, like the US. Also milk is full of cows growth hormone which is far too strong for humans and can cause cancer. Furthermore milk is full of antibiotics and pus because the cows suffer from mastitis due to their excessive milk production after selected breeding or down right DNA modifications. Finally the industrial processing of milk (separation of each component and remixing plus heat treatment) denatures its proteins and destroy most vitamins. Humans should drink only human milk ideally up to 2 years old. Adults naturally lose their ability to produces lactasa which is the enzyme that processes lactose the sugar present in the milk, that's why so many people is "intolerant" to lactose, their not really intolerant, it is that adult humans are not prepared and are not meant to consume the lactose present in the milk of a mother from a different species.
"and one proof is that osteoporosis in more predominant on those countries with high milk consumption, like the US."
You mean lazy people from rich countries with poor diets. It is not proof at all. How balanced a diet is and the amount of exercise children get in their developing years, and later, is much more important.
I clearly stated, "for children".
Yes, dairy products can be unhealthy for adults. The same goes for other animal products. However, there is no doubt that animal products provide nutrition.
What a high rate of osteoporosis in countries with high consumption of milk proves is that consuming milk not only does not provide bioavailable calcium to our bones but in fact removes calcium from the bones. This is true for both adults and children.
Also the extremely potent growth homon present in cow's milk is not good for children and that has been agravated by the introduction of genetically modified growth hormon (rBGH) that is injected to cows every two weeks so they produce more milk. You can get additional information on http://www.ejnet.org/bgh/nogood.html
That's why I don 't drink cows milk and my doughter doesn't either.
I'm not vegan, I'm not against animal products, I consume them also, but not milk, processed foods or non-bio food loaded with poisons and genetically modified.
I live in Europe, so the milk here doesn't have injected hormones. Or at least I think it doesn't - it used to be banned. I remember the US complaining about it because they couldn't import their products. Maybe they do export to us now.
Even if the cows are not inyected with recombinant bobine growth hormone (rBGH) it still has "natural" BGH which is meant to make the calf to grow from 30kg to over 140kg in only 4 months. It is believed that BGH is not active in humans but this study sugest that there is a metabolic activity in humans of a fragment of BGH Metabolic Effects in Children of a 37 Amino Acid Fragment of Bovine Growth Hormone 1!. In other words, european milk cotains cows growth homones that are affecting our children, well not mine because I don't give her milk and gets all the calcium she needs from chickpeas, green leaf vegetables, brocolli and almonds.
You're not a vegan, by any chance? :)
No, I'm not, I don't think vegan is natural nor healthy for humans although I respect those that decide to go vegan as a philosophy of live. I eat meat, eggs, vegetables, seeds and fruits, unsaturated fats and everything bio and not processed to avoid pesticides, antibiotics and many other chemicals. I also try to reduce on grains and carbohidrates in general and I do intermitent fasting ;) great enery levels and brain awareness since I do it.
OK. I wasn't really being serious with that question. I would be vegetarian, If I could, but I don't like fruit and vegetables :)
(You do know that eggs are very bad for you unless you eat them almost raw?)
Yum Yum
Hello my friend
Thanks for this post and the wonderful post
I really liked what I wrote in this post
The selection of the post is so lovely
Happy day to you and always
Many talk about the benefits or harm milk! I love milk with tea :)
Here in india everyone drinks tea with milk.. Same with coffee..
I drink a lot of tea with milk. It's delicious. However I don't put any sugar into it
I also! I take honey from a spoon! Honey can not be put in hot tea! Also I like the cream from the milk most!
I am just a little frighten to eat my cold bowl or cereal now.
You can do it!