A bouquet of chocolate

Chocolate has been around for thousands of years. While I can’t imagine how chocolate could get much better, chocolate-makers are still experimenting with ways to make new types and flavours of chocolate to keep our tastebuds titillated. Now, a new way of processing cocoa beans has been published in Journal of Agricultural and Food Chemistry. Could our favourite food about to be improved by science?  

So how is chocolate made?

In the conventional process, cocoa beans are harvested, traditionally covered in banana leaves, and left to ferment. During this time the microbes degrade the pulp surrounding the beans, heating and acidifying them. This process is important as the biochemical changes happening to the beans reduce the bitterness and astringency, and help develop the flavours and aromas we associate with chocolate. However, this traditional mode of fermentation can be difficult to control and takes several days.

To make chocolate, the beans are roasted, dehusked (winnowed), then milled into a cocoa paste. This paste is then pressed and separated into cocoa butter, and defatted cocoa paste. The defatted cocoa paste is then pulverised into cocoa powder. All chocolate contains cocoa butter, but to make different types of chocolate, a few key ingredients are modified. Dark chocolate contains sugar and cocoa powder. Adding milk makes this into milk chocolate. Omitting cocoa powder creates white chocolate. A fourth kind of chocolate, called ruby chocolate, is made similarly to white chocolate but uses unfermented cocoa beans, which keep their pinkish hues.

So what does “moist-incubation” chocolate taste like?

But does the new method pass the taste test? A group of sensory panellists (and yes, this is a genuine job) tasted bars of chocolate made through the new moist-incubation method, traditional ferment, and also unfermented beans as a control.  The moist-incubated chocolate had higher intensities of “fruity, flowery, malty and caramel” aromas than the traditional fermented chocolate, which had higher “roasty” notes. The chocolate made from unfermented beans had a primarily “green” aroma. The moist-incubated samples were also rated highest for sweetest-tasting, while the unfermented chocolate was the most bitter and astringent.

The aroma compounds were identified using gas chromatography (GC)-olfactometry – which extracts and separates single aroma compounds – and quantified using gas chromatography–mass spectrometry (GC-MS), which measures levels of separate chemical compounds. This confirmed the presence of higher levels of malty compounds called Strecker aldehydes, and lower levels of roasty compounds called pyrazines in the moist-incubated chocolate compared to the traditionally fermented chocolate.

In a boon for sweet snackers worldwide, using this faster and better-controlled “moist-incubation” process to ferment cocoa beans, can produce high-quality chocolate with untraditional but pleasant aromas and tastes. The researchers suggest that producing chocolate naturally sweeter in flavour, means less sugar needs to be added. It’s not quite a health food yet, but we’re sure science won’t stop trying.