What is Denaturation?
Denaturation is the physical changes in protein when it is exposed to abnormal conditions in the environment.
Mechanical agitation, heat, acid, high salt concentration and alcohol can cause proteins to denature.
(Denaturation can only occur in protein foods)
When proteins are denatured, what happens is that the protein bonds are broken down and the natural state of the protein structures are unraveled and becomes a single strand of amino acids.
For example, you put a piece of steak onto a hot frypan. The moment the steak comes in contact with the hot surface, the proteins start to vigorously vibrate from the extreme heat exposed to it and the whole structure of the proteins start to unfold.
Then you may think "wouldn't the whole steak collapse into little pieces?" Well what happens next is that the individual strand of protein align themselves and start to stick together forming an aggregate. This means that instead of falling apart, it stays in one piece.
Denaturation is often accompanied with coagulation.
What is Coagulation?
Coagulation is a vital chemical process in which proteins in a liquid state is changed to a solid state and it can only occur
after the substance has gone through denaturation.
However, coagulation can only occur in the presence of heat.
When a protein substance is going through coagulation, the strands of protein or amino acids start to vibrate from the applied heat and therefore making the strands move around and tangle with the rest of the protein strands, resulting in clumps of protein.
A linking example is steak.
When steak first touches a hot surface like a heated frypan, the proteins are denatured.
However, as the heat applied to the steak prolongs, it starts to coagulate and result in a thoroughly cooked piece of meat.
after the substance has gone through denaturation.
However, coagulation can only occur in the presence of heat.
When a protein substance is going through coagulation, the strands of protein or amino acids start to vibrate from the applied heat and therefore making the strands move around and tangle with the rest of the protein strands, resulting in clumps of protein.
A linking example is steak.
When steak first touches a hot surface like a heated frypan, the proteins are denatured.
However, as the heat applied to the steak prolongs, it starts to coagulate and result in a thoroughly cooked piece of meat.
Types of food which include denaturation and coagulation:
- Cake
- Boiled, poached or cooked eggs
- Steak
- Cooked fish
Why is Denaturation and Coagulation important?
Denaturation and coagulation has an important role to simplify the complex protein structures, in order for us to consume the food with easier digestion which is very healthy for our body, and helps keep harmful bacterias from infecting our body.
This is because raw meat has millions and millions of bacteria growing on the surface it. However, as you cook the meat thoroughly, the heat will kill any sort of hazardous bacteria and therefore makes the consumption of steak less risky and easier to enjoy!
This is because raw meat has millions and millions of bacteria growing on the surface it. However, as you cook the meat thoroughly, the heat will kill any sort of hazardous bacteria and therefore makes the consumption of steak less risky and easier to enjoy!
Physical Changes
Physical changes in denaturation and coagulation:
- The food substance become a solid state and have a tougher surface after these two processes.
- The color of food substance will change after application of denaturation and coagulation.
Chemical Changes
- The heated strands of proteins are unravelled from their structure and protein bonds are broken down.
- The prolonged heat causes protein strands to vibrate and tangle with each other.
Denaturation and Coagulation Recipes
- Home-style Beef Burger
- beef stir fry
A reminder...
Just a reminder before you start, please be aware of the significance of hygiene in this meal.
Wash your hands with soap before you have contact with your beef mince and use different knives and chopping boards for the vegetables and mince as cross contamination will occur and you and your family may become very ill.
After contact with the beef mixture, always wash your hands again before you handle the rest of the ingredients.
Also, use different tongs when placing your beef patties on the frypan and taking it out when its cooked as cross contamination of the bacteria from the raw mince will infect the cooked ones.
Please follow these advices, as it is guaranteed that this will keep you and the rest of your family safe from harmful bacteria, leaving you healthy and happy.
Wash your hands with soap before you have contact with your beef mince and use different knives and chopping boards for the vegetables and mince as cross contamination will occur and you and your family may become very ill.
After contact with the beef mixture, always wash your hands again before you handle the rest of the ingredients.
Also, use different tongs when placing your beef patties on the frypan and taking it out when its cooked as cross contamination of the bacteria from the raw mince will infect the cooked ones.
Please follow these advices, as it is guaranteed that this will keep you and the rest of your family safe from harmful bacteria, leaving you healthy and happy.
Home-style Beef Burger
Serves for 4 people
Ingredients:
Equipments:
Serves for 4 people
Ingredients:
- 600g beef mince
- 1 onion, finely chopped
- 1tsp crushed garlic
- 1 tsp of dried Oregano and Dijon mustard each.
- 1 egg, beaten
- 1/2 cup (35g) fresh breadcrumbs
- 1/3 cup (25g) grated Parmesan
- 2 tomatoes, sliced
- 4 burger buns (or bread rolls), split, toasted
- Butter lettuce leaves
- Aioli (recipe in emulsification)
Equipments:
- Frypan (electric frypan is optional)
- Big mixing bowl
- smal bowls
- knife
- chopping board
- Tongs
- Spatula
- Enamel plate ( for beef patties)
Method:
- Preheat your frypan to a medium-high heat . (Electric frypan- Temp on the dial would be 6 or 160)
- Combine mince, garlic, onion, Oregano, Dijon, egg, breadcrumbs and Parmesan in a big bowl.
- Then season your mixture with a little bit of salt and pepper and thoroughly mix with damp hands (to prevent the mixture from sticking on your hands) and form 4 meat patties. The patties should be at least 1cm thick.
- Place your raw patties on an enamel tray to prepare for cooking and set another enamal plate to place the cooked patties.
- add the meat to the pan (no oil required) and cook for about 5 minutes on each side until the patties are cooked through.
- Place your cooked beef patties on a clean enamel plate.
- Prepare your burger buns and place your beef patty, lettuce, tomato and aioli sauce inside and finish your burger with one of your piece of bread on top.
- Place the burgers on plates and enjoy your homemade beef burger!
Beef Stir Fry
Serves for 2 people
Ingredients:
- 250g Lean beef cut into strips
- 1 small onion, diced
- 1 garlic clove, crushed
- 2 Tsp of barbecue sauce
- 1/4 cup oyster sauce
- Approximately 2 cups of sliced vegetables (small piece of bokchoy, 1 carrot, 1/2 stick celery)
- 100g of vermicelli
- Arrowroot sauce (recipe in gelatinisation)
Equipments:
- Frypan
- Large bowl
- Cook's knife
- Garlic crusher
- Peeler
- Wooden spoon
- Small metal plate
- Spoon and fork
- Serving plates
- glass bowl
Method:
- Place the beef, onion, garlic, barbecue sauce and oyster sauce in a large mixing bowl and mix well.
- Then spray the frypan and heat the oil on high.
- Add the vegatbles to the pan and stir-fry for 2-3 minutes. Remove from the pan and place on metal plate.
- Cook the meat mixture in batches until the meat is cooked.
- Add the cooked vegetables back into the pan and mix well to cook until the sauce boils.
- Slowly add the arrowroot sauce to the pan while stirring.
- Continue stirring the mixture until the sauce thickens.
- Once it has thickened and cooked enough, turn the frypan off and place the lid on to keep the heat in.
- To prepare for the vermicelli, place it in a glass bowl and cover with boiling water for a few minutes until it is soft.
- Drain the noodles with a strainer and pile the vermicelli evenly onto each serving plate and serve even amounts of the stir-fry mixture on top.
- Prepare your spoon and fork and enjoy the taste of a traditional Asian dish.
Remember when softening the vermicelli, do not leave it in the water for too long, or else the vermicelli will dissolve and you will lose the shape and texture of your noodles.