Chocolate honours

6 July 2017

For World Chocolate Day, we open a hidden stash of chocolate research to make your mouth water.

Katrina Carlino and Dr Kim-Yen Phan-Thien looking at fermented and dried cocoa beans in the food science laboratory.

Fourth-year student Katrina Carlino (left) and Dr Kim-Yen Phan-Thien (right) checking a sample of Indonesian cocoa beans in the Food Science Laboratory.

Chocolate is probably a staple food for a fourth-year research student. On average, Australians eat more than six kilograms of chocolate per capita each year.

But how discerning is our chocolate palate? This is one question that Food and Agribusiness students are raising in their final-year research projects.

Dr Kim-Yen Phan-Thien from the School of Life and Environmental Sciences and the Sydney Institute of Agriculture is supervising two projects looking into the sensory qualities and market potential of cocoa beans from different geographical origins.

“We are engaging with industry, retailers, chocolatiers and manufacturers to find out what their Australian consumers are looking for in their chocolate. We want to know what’s driving the specialty chocolate market, what consumers regard as premium products, and what the price points are,” said Dr Phan-Thien.

Consumer opinions are also being sought as part of the research.

“Our market research and focus group testing aims to determine consumer opinions and expectations about chocolate products, including their perceptions of origin and ethical labelling such as Fairtrade and Rainforest Alliance certification. We want to know if these factors are taken into consideration – do consumers know what these products are, can they tell the difference, do they look for these products, how much are they willing to pay?

“We are exploring whether there is an opportunity for farmers to supply a high specification product and secure a niche market channel, such as Australian specialty chocolate makers. Supplying to a niche market may provide a way forward for smallholder farmers to stabilise or improve their incomes, and avoid being at the whim of world price fluctuations.”

A second project, conducted by fourth-year student Katrina Carlino, is firstly getting a whiff of the aroma profiles of cocoa beans from different places of origin, including Sulawesi and Bali in Indonesia, the Solomon Islands, and Bougainville in Papua New Guinea.

“Beans from diverse regions have been produced and fermented according to different methods and traditions. Differences in microclimate, management practices, and microbial ecology all act to influence the complex microbiological and chemical reactions taking place in the beans, leading to the development of unique aromas and flavours.

“Our research will include a chemical analysis to characterise the aroma profiles of cocoa beans from different regions. We will then use some of these beans to make chocolate for further consumer testing in the Food Science Laboratory.”

We want to know if there are measurable differences between chocolates, whether consumers can discern those differences, and what their preferences are.
Dr Kim-Yen Phan-Thien
Katrina Carlino in the food science laboratory holding cocoa beans.

Katrina Carlino with the cocoa beans that will soon be made into chocolate.  

Consumers will conduct a sensory evaluation of each chocolate type.

“Qualities such as the break or snap of the chocolate, aroma, silkiness of texture, persistence of flavour, and melt in the mouth properties will be tested.

“We want to know if there are measurable differences between chocolates, whether consumers can discern those differences, and what their preferences are,” said Kim.

“Many of us can tell the difference between different brands of chocolates as each company has its own particular recipe that it attends to. Hershey’s chocolate tastes different to Cadbury’s chocolate, and Mars Bars are made slightly differently in different parts of the world to meet the demands of local consumers, but sometimes the differences are much more subtle.”

The cocoa butter or cocoa fat in chocolate has six different crystal forms, or different configurations in which they solidify. This is known as polymorphism.

“Tempering involves heating the chocolate so all the cocoa butter melts, then letting it cool down again to form a solid. The tempering temperatures are carefully chosen to promote formation of the desired crystal structure. This influences the properties that the solid chocolate will display, including how it looks and how it breaks.

“The fifth crystal phase is the most desirable phase because it gives the chocolate a nice sheen, a good snap, and that melt-in-the-mouth experience, as this crystal phase of chocolate has a melting point just below body temperature.”

Beans from different places have differing fat compositions, which leads to slight differences in melting and crystallisation. This is another factor in the unique character of cocoa beans that this research will be looking at.

The complexity of chocolate goes on. Cocoa beans have around 600 different volatile chemical compounds which include several chemical classes such as alcohols, aldehydes, diketopiperazines, esters, furans, ketones, lactones, pyrazines, pyrones, pyrroles, and quinoxalines.

And Kim says that different cocoa beans will exhibit different flavours and aromas because the concentrations and characteristics of these compounds can vary significantly.

“A consistent product is one of the most important factors for the big chocolate companies. Consumers like certain products for particular reasons and come to expect a certain taste or quality.”

So, could our chocolate ultimately be made in the chemistry lab?

“Chocolate made purely in a controlled environment might not display the qualities we love. The natural influences on cocoa are incredibly complex and not understood well enough to replicate in a laboratory situation, but there is speculation around being able to control certain conditions to maintain consistency.

“Supporting smallholder farmers is a priority and it’s evident their methods for delivering the most amazing base product for our chocolate are working.

“Our research can be fed back through the supply chain and could help smallholder cocoa farmers to determine how they might differentiate their products. For example, they might sell their top-quality beans for a higher price and these beans would be made into premium chocolates, instead of selling the entire harvest to one or two buyers at the same price.

“The research has ties to development agriculture and takes some small steps to lifting farmers out of poverty, which is a situation that is far too common in the chocolate industry.”

Will Kim’s students have any trouble finding recruits to conduct the consumer testing? Stupid question. Look out for sensory testing in September! Until then, have a happy World Chocolate Day. Savour every morsel you eat, engage your senses and celebrate the complexity of chocolate.

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