The Chemistry of Chocolate: From Bean To Bar

Chocolate is a delicious indulgence which is loved on a global scale. Its variable form means that there is a type of chocolate for everyone to enjoy from a simple bar of milk chocolate to dark, mint chocolate. Despite its large consumption many are unaware of the many processes involved in its production,with their knowledge limited to the fact that chocolate comes from cocoa seeds. These seeds are in fact processed to produce cocoa liquor, butter or solids and mixed with a sweetener such as condensed milk to produce the final chocolate product which can make you happier and more alert due to the presence of certain chemicals.

There are 8 main steps involved in the production of chocolate which lead to its final form. The first step is fermentation, which is the process by which sugars are broken down anaerobically (without oxygen present) by microorganismsCacao seeds are the main ingredient in chocolate and grow on trees. The seeds are surrounded by a pulp which is the first step to make chocolate. The pulp is made up of water, acid and sugars such as glucose. Microorganisms remove the pulp from the bean through different methods. Three microorganisms which are involved are yeast, pulp enzymes and lactic-acid-producing bacteria. The sugars in the pulp are broken down and some of the products are carbon dioxide, ethanol, lactic acid and energy. The low pH, due to the acidic compounds, results in the cell wall of the bean to break down and the separated substances can then mix.

The second step in the production of chocolate is roasting the beans. The beans are cleaned after fermentation and then roasted. This involves flavour precursors to be converted into compounds such as esters and aldehydes (organic compounds with Carbon). These are responsible for the flavour and aroma of chocolate. After roasting, winnowing occurs which is where the shells of the bean are removed by a winnowing machine. This reveals the cacao nibs which are used to form cocoa liquor. Further processes can involve the conversion of the liquor into cocoa butter or cocoa solids. Next up, is the process of blending together the liquor and different amounts of cocoa butter. Chocolate comes in many different varieties of strength and cocoa butter is added in different amounts to create these different types. Once the strength of chocolate is determined, refining occurs. This is where the sugar and cocoa is broken down

into small particles which creates a smoother finish.

The process of tempering is the sixth step involved in chocolate production and consists of varying the temperature at which chocolate is cooled. Cocoa butter contains multiple types of fatty acids which separate in liquid form. Tempering causes these fatty acids to mix together to create one solid form. There are 6 different forms of chocolate crystals (structures), also known as polymorphs, which have different melting temperatures. The one considered perfect has a 34 degree melting temperature and the chocolate is glossy, smooth, firm and melts in the mouth. After this, dutching occurs which is the chemical process of alkalizing cocoa solids to make them less bitter and acidic. Lastly, the chocolate is packaged which is done for more important reasons than just to be aesthetically pleasing. It stops the chocolate coming into contact with the heat or humidity which can result in sugar bloom and fat bloom.

So now we are aware of the multiple steps involved in chocolate production, let's take a look at some of the chemicals in chocolate, including tryptophan, phenylethylamine and anandamide, and their effect on the human body.

Tryptophan is an amino acid found in chocolate which is linked to the production of serotonin. Serotonin is a chemical that nerve cells produce to communicate in the brain and is known as the happy hormone. The increase in serotonin after consuming chocolate, due to tryptophan, can explain feelings of happiness after eating it. Phenylethylamine is a chemical which is released when we fall in love and increases the brain’s pleasure centres. It is present in small quantities in chocolate and can cause the aphrodisiac effect. Anandamide is found in small quantities in chocolate alongside the natural production in the brain. It stimulates and opens synapses in the brain which allow feel good waves to travel more readily.

Flavour precursor - breaks down or reacts with other components to produce flavour, doesn’t actually contain any flavour itself Sugar bloom - white surface on chocolate caused by the sugar absorbing moisture, dissolving and then evaporating to crystallise Fat bloom - grey coating on chocolate caused by small globules of cocoa butter forming larger ones

By Dillan Rosen