voltage + chocolate... why?

Included in my heavy course-load this semester is a Geo-Mechanics class. Our professor brought in the book Rheological Methods in Food Process Engineering for examples of material properties and their reactions under different stress regimes. For me, things like the data table outlining various materials (Newtonian, shear-thinning, etc.) and their properties and property values was hilarious because it also listed example foods, like "fish paste". Imagining the rheological behavior of fish paste under shear stress makes Geo-Mechanics highly entertaining. I downloaded the book and began perusing for other gems. This is my favourite so far...

Why do you think one needs to zap chocolate with various voltages? Why?