Chapter 9 Processing -Induced Hazard-Acrylmide by Dr. Tang在线视频

Chapter 9 Hazards – acrylamide by Tang

Hello, Ladies and Gentlemen. Welcome to our lecture again Science-based Food Safety supervision. In this lecture, I am going to talk about hazards from processing. We have hazards from nature materials, from the plant borne materials, and also animal borne materials. During the processing or food chain there may have hazards contaminated from the food chain. So today I would like to talk the possible hazards during the processing or storage. This lecture will cover three things. What would be the hazards during the food processing? We will just give a few examples? Why do those hazards take place and how to prevent it?

This slide shows the bread. The bread on the surface, you may see the mold outside of the bread. So this is already the food we can eat, but it is a mold over there. So the mold, of course has the benefit one and harmful one. But if you see this one, you cannot eat it. So the question is what is happened? Why is happened?

This is the food which is called hamburger. I think many people love it. So the hamburger you see there are several layers. The top layer and the bottom layer actually are bread. Inside there are kinds of beef and also vegetable and tomatoes and also other things. So how about those popular foods? Are there any hazards inside during preparation of these top popular foods?

This slide shows the production line for the snack food. Snack food takes many steps and also many machines. So each machine actually each step we called unit operation. In this unit operation, we input something and take out something. So when input something there may be some kind of hazards contaminated inside. So this is an example of unit operation. And you can see and there are energy, labour, human, material input. There are also products out, and also waste come out, but are there any hazards to contaminate the next step? So during the process, actually there is input and output as I told you in the previous lectures, our process is not in the vacuum environment. It is in a natural environment. The natural environment has hazards. But here in the process, we input energy or input substances or materials. Are these kinds of materials reacted each other? We are not sure.

Now I give an example to see if there is a hazard just during the processing to take place. This example is called acrylamide. Acrylamide is a hazard not in our food. I think it is 10 years ago, we know that this is in the plastic industry. But since 2001 there are scientists discovered that the acrylamide was determined in the French chips. Since then it’s a very hot topic.

Why did this acrylamide attract scientists? Because it is harm toxic to nervous system. It is harm to reproductive system and also it is mutagenic and carcinogenic. And the toxicity based on LD₅₀ is 150-180 mg/kg, this is belonging to medium toxic. We have methods to determinate that. We use modern methods, GC-MS, the LC-MS determinate it. So use this method, we found out this one in some kinds of food.

This is example here. This shows you the chips. The chips are very attractive, in particular for kids. But all chips come from potato. The potato does not contain acrylamide at all. But now when you eat final products, the chips and the chips contained acrylamide.

How is this acrylamide formed? This slide shows you this mechanism of acrylamide formation. You see some substrates. Tow substrates here, one is reduced sugar which is called glucose. Not only the potato contained this one, also sweet potato contained this one. And other substrate is called asparagine. This is amino acid. We have 22 amino acid. Only this acid present in the potato. So the asparagines reacted with glucose which is the reduced sugar under the conditions. What are the conditions here? Number 1 is dry food. That means less water. Other one is 180℃.This is high temperature. During the fry, this temperature, under this condition, acrylamide is formed. So here there are three conditions, one is reduced sugar, another one is asparagine and the third one is under 180℃. So the chips, the potato chips are produced by this condition. So that is why the potato chips contain acrylamide.

So here is the results, we use modern methods to determine the different products. As you see here, the potato chips contain highest content of acrylamide. However, if this is the boiled one, the boiled potato chips, the potato mince there is no any acrylamide inside. So this indicates that there is no high temperature, the acrylamide is not formed. And also indicates that this hazard is not brought by the raw materials, it is formed during the production or during the processing. So now we know the acrylamide is really formed during the processes, in particularly for the French fry, or potato chips.

So now how to prevent it. What are the strategies?

Can I ask you to discuss it? So what is the method to do that? So number 1, may be you see do not eat it, not eating. So is this a good method? I do not think so. You just stop people to eat. Actually the kids even I love it with good flavor and very good colour. This is the first one.

And the second method may be no frying. No frying just liked the boiled and boiled potato means. Actually I tried when I studied in Ireland, in Canada, and in Thailand. But actually I do not like it at all. Because this is no any flavor. So I do not think it is a good method either.

So the third method would be no potato, do not use potato, or use sweet potato instead. I also did this trial when I studied in Thailand. I did one year of this and it was successful. But unfortunately, the quality is not as good as potato chips, in particularly the crispness. The sweet potato chips are harder. And the other thing is colour, the colour is dark. So this also is not a good method.

The fourth method would be asparagus. So can we find out less asparagus in the potato? I think this would be possible. So this is called breeding. The traditional breeding method we can screen some potatoes which is less asparagus less in the potato.

And another method would be we can use different fry methods. Now we use fry in the open air condition. Can we use vacuum fry? Therefore we use lower temperature. If we can use lower temperature and the amount of acrylamide would be reduced. There are some kinds of research on it. This is true reduced. But unfortunately, there is still acrylamide inside the chips, not totally reduced.

And the final one is additives to inhibit it. We can use additives to do that. Also in our Department, we have professors to do this. So those methods, strategies, we can think about it and also it is for you to think.

So these is example again, this show you highest one in the asparagine in the different potato chips species. This table also shows different species contains different asparagine content.

And we have three books in our library and talked about this issue. In the middle one this is a monograph specialized in acrylamide. So that means it is a very hot topic. If you are interested more in detail. Please refer to these books. So this is an example today I used acrylamide to show the hazard could be from the process.

So I have question here for you to think further for the acrylamide. So much for today.

Thank you very much. See you next time.