Of crystallising chocolate and fussy vegans

Around 80 specialists from the fields of neutron and food research gathered in Garching during the week of 15–18 June for the eighth edition of the ‘Neutrons & Food’ conference. The focus was on fostering dialogue between the two disciplines, as the organisers from the Forschungszentrum Jülich emphasise.

Applied food science: The conference participants visited the Freising campus of the Technical University of Munich and had a look inside the university’s brewery. © Iris Köhler, Forschungszentrum Jülich

Applied food science: The conference participants visited the Freising campus of the Technical University of Munich and had a look inside the university’s brewery. © Iris Köhler, Forschungszentrum Jülich

There is a tempting smell of freshly baked pretzels in the Garching Community Centre. During the conference break, however, most of the overly soft dough pieces are left on the tray. Prof. Dr Peter Fischer emphasises in his keynote speech that food must appeal to all the senses: “The texture of the products is the main reason why over 90 per cent of customers in supermarkets do not choose plant-based meat alternatives,” says the professor from ETH Zurich.

Vegan products analysed by neutrons

Not only must the soya cutlet look and taste like a real one made from chicken, but it must also feel like one in a veggie’s mouth. And it is precisely this texture of the soya and pea protein products that Dr Tong Guan , as part of Fischer’s team, has investigated using X-rays and neutrons during the manufacturing process, in order to find out how the fibrous structure forms at a molecular level. The research team even simulated the act of chewing directly using machinery and then expressed it mathematically.

Why ice cups melt in your mouth

Aside from meat alternatives, another talk by Prof. Dr Thomas Vilgis was all about that evergreen favourite among foods: chocolate. In an interview, he reveals himself to be a fan of ice cups. “We used to get them at the cinema all the time,” enthuses the professor from the Max Planck Institute for Polymer Research in Mainz. Why does this sweet treat melt so delicately on the tongue? And why does old chocolate simply refuse to melt and get stuck between your teeth? Thomas Vilgis has discovered the answer using scattering methods: “With ice cups, it’s a clever mixture of coconut oil and chocolate. The coconut oil lowers the chocolate’s melting point.” Of course, Thomas Vilgis produced the perfect ice cups in the lab, with 30% cocoa butter and 70% coconut oil: “They were even better than the ones at the cinema.”

Prof. Dr Thomas Vilgis, pictured here in conversation during the coffee break, has conducted research into the crystallisation of chocolate. © Iris Köhler, Forschungszentrum Jülich

Prof. Dr Thomas Vilgis, pictured here in conversation during the coffee break, has conducted research into the crystallisation of chocolate. © Iris Köhler, Forschungszentrum Jülich

Older chocolate’s melting point is too high

The ideal melting point for chocolate is 33°C. Old or poorly made chocolate often has a higher melting point of 36°C, which means it simply won’t melt in the mouth. According to Vilgis, cocoa butter from beans harvested closer to the equator needs to be heated to a higher temperature, as the higher proportion of unsaturated fatty acids in this cocoa results in a higher melting point.

An insider’s tip for chocolatiers

Thanks to his measurements, Vilgis also has an insider’s tip for chocolatiers: “Instead of just heating the chocolate to 50°C, you need to heat it up to 90°C to preserve its typical structure.” As the chocolate is heated, crystals form which act as nuclei, thereby ensuring the lower melting point in the set chocolate.

The food industry in a state of change

With so many fascinating presentations – covering topics such as 3D printing of food, the analysis of Gouda and espresso using neutrons, and a training day introducing neutron and food technologies – the organising team led by Dr Theresia Heiden Hecht and Dr Olaf Holderer were delighted. “The food industry is undergoing radical change and is highly technologised. That is precisely why collaboration between the various disciplines – with neutron researchers on the one hand and food technologists on the other – is so important,” says Theresia Heiden Hecht.

And over a glass of beer at the conference dinner in Weihenstephan, the researchers were able to practise ‘applied food science’, as Prof. Stephan Förster from the Forschungszentrum Jülich had suggested at the opening of the conference.