Functional Properties of Sugar- Caramelisation and Crystalisation

Hey everyone! today I baked chocolate chip cookies and I also made almond chocolate covered brittle and they were delicious!. From these two recipes we will be discovering the concept of Caramelisation, Crystalisation and Dextrinisation and explore about their chemical changes.

For the almond chocolate covered recipe we will be exploring the chemical changes of Caramelisation and Crystalisation.

The first recipe I am showing you today is the almond chocolate covered brittle.
For the almond chocolate covered brittle, the equipment's and recipes that are needed such as:
- 1/3 cup of water
- 225g butter, cut into cubes
- 1 cup of sugar
- 1/4 tsp salt
- 3/4 cup of salted roasted almonds, coarsely chopped (you can use raw or roasted almonds)
- 100g of semi-sweet or dark chocolate melts
- Pinch of bicarbonate soda

For the Method:
1. Prepare a slice tin by lining it with baking paper. Prepare a separate square of baking paper and place on your benchtop.
2. Put the water in a medium pot and arrange the butter chunks in a single layer on the bottom. Heat on extremely low heat until the butter melts (should take 10-15 minutes). Do not stir.
3. Increase the heat on medium-low and bring the butter to a rolling boil.
4. Add the sugar and salt, stirring to combine. Stop stirring and insert a candy thermometer. Turn your heat down to medium. Cook, undisturbed, until the caramel reaches 126 degrees, or begins turning amber coloured, whichever come first (this will differ depending on your saucepan, but should take around 10-15 minutes to start turning colour). At this point, don't take your eyes off of the saucepan as you'll risk burning the caramel.
5. Wait until caramel reaches 149 degrees (it should be the colour of peanut butter) and immediately pour all but approx., 1/4 cup of the caramel into the prepared slice tin. Use a wooden spoon to spread it into a thin layer. Then sprinkle the chocolate chips evenly into a chin chocolate coating.
6. Let it sit in freezer for 30 minutes, or until the toffee has cooled and the chocolate has solidified. Break into chunks.
7. In the meantime, add a pinch of bicarb soda to the remaining caramel and pour immediately onto your separate sheet of baking paper. Record the difference in appearance, texture  and colour between the two types of caramel.

Now for the observations, I noticed that when the bicarbonate soda was added in, the mixtures colour turned into sorta like a honeycomb colour. It gave the mixture more volume and colour, it also gave it texture.

The chemical change that occurred in the process of melting sugar is caramelisation . When the sugar is melting, a chemical reaction happens in which monosaccharides and disaccharides turn brown with the application of heat. Then the sugar molecules change from their natural colour to a caramel- brown colour.

a) The one with the greatest volume was the honeycomb, it has bicarbonate soda

b) The one with the lightest texture was the honeycomb, it also has bicarbonate soda.

c) The one with the darkest colour was the toffee, it has no added bicarbonate soda.

d) The one with the most lustrous (shiny) surface was the toffee, it also has no added bicarbonate soda.

The effects on adding bicarbonate soda on the sugar are that it turned the sugar into a honeycomb colour and gave it a lighter texture and more volume. When the bicarbonate soda was added in, the sugar started bubbling, almost like it was being aerated. It is because bicarbonate soda produces strong alkaline and gives the baked recipe a bitter, "soapy" taste and a yellow colour.

There are two methods of creating caramel, one involves adding sugar and one doesn't. For the sugar and water method, it is important to not constantly stir it. Stirring cooking sugar with the wet method can cause it to crystalise, it is because the heat is disturbed which can lead to crystallization. For the dry sugar method, it is important to frequently mix the sugar to prevent it from overheating and to avoid burning.

For the chocolate chip cookies

The equipment's that are needed are:

-120g unsalted butter - Electric scales

-100g brown sugar - Electric mixer

-70g castor sugar

-1 teaspoon of vanilla essence

-230g Self Raising Flour

-120g of dark chocolate

-1 egg

For the Method:

1. Preheat oven to 180 degrees. Line a baking tray with non-stick baking paper.
2. In a large bowl, cream butter, brown sugar and caster sugar with an electric mixer.
3. Beat in egg and vanilla
4. Transfer to a large bowl. Sift the flour. Add the choc bits. Use a wooden spoon to mix until well combined.
5. Roll teaspoons of mixture into a ball. Place on lined baking tray 3cm apart. Press down with the back to fork. Bake in oven for 12 minutes or until golden. Set aside on trays for 5 minutes to cool before transferring to a wire rack to cool completely.

Dextrinisation is the process in which starch breaks down into dextrins. Toasting bread is one of the common examples. It is responsible for turning the bread brown during toasting. It is the browning of starch due to dry heat. It is also responsible for the brown crust on baked breads, pastries and baked vegetables, baked breakfast cereals and brown gravies. Dextrins are also used as a sweetening agent and to give the product colour.

The physical appearance of the cookie dough mixture before putting it in the oven was wet and oily and the colour is a lot more pale/white compared to when its baked. It was a lot more dense and the consistency was sticky and soft. After placing it in the oven, the cookie dough triples its volume and  the colour of the mixture darkens and becomes more brown. Also, the suface hardens. It is because when you put the raw cookie mixture into the oven, a series of chemical reactions occur, such as Dextrinisation.

There are three types of heat when it comes to cooking, they are Conduction, Convection and Radiation. Baking and roasting are the most common forms of Convection cooking. The heating elements within the oven; heats up the air and that comes contact with food. Radiation is also a type of heat when it comes to the oven cooking method. The light from the oven transfers heat of pure energy through waves. Technically, everything has thermal radiation, so every cooking method has a form of radiation.

By using the oven cooking method, heat is transferred through air. If the mixture is cooked for an extra 30 minutes, they would overcook and turn black in colour and the taste would be unpleasant. The whole cookie would be pretty much burnt. It is because the longer the heat is applied, the dextrin breaks down into maltose which then breaks own into glucose molecules, then we are left with an excess amount glucose.

Starch -->        Dextrin -->        Maltose -->        Glucose
                    (disaccharide)  (monosaccharide) (polysaccharide)

Dextrinisation, Caramelisation and  Crystallisation are three types of chemical reactions. To compare the three processes, lets start off with the comparisons between caramelisation and crystallisation. They both involve sugars most commonly being fructose or fructose, whilst dextrinisation involves starches. Caramelisation and dextrinization involves the process of colouring such as "browning", but crystallisation doesn't. All three processes have different ways of being useful in food preparation. Caramelisation is used for many things, it can be used for sweet and savoury. For sweet, it can be used to caramelise sugar and create toffee, and for savoury it can be used to caramelise onion or even carrots or other vegetables, If bicarbonate soda is added in the caramelise sugar, it will produce another a product called honeycomb. For Dextrinisation ,it is used to change the colour of food such as browning toast, but to also add texture and flavour like the crust of bread. Lastly, Crystallisation changes the texture of food, it can be used in many different ways, depending on what form of texture you would prefer. It can used for confectionary like caramel or toffee or fudge etc.

That is the end of my blog, I hope you learned a lot today!

Thanks, Kae! :)