Nuclei carrying entrapped air are the most likely starting points for eye formation

Eye nuclei with structural elements, such as hay particles with capillary structures, have been hypothesised to be a prerequisite for eye formation in cheese. Such eye nuclei act as microscopic air bubbles in capillaries that are trapped in the cheese matrix, into which the CO 2 diffuses to initialise the eye formation process. To verify this hypothesis, this experimental study evaluated the impact of synthetic hollow fibres and tube pieces with standardised capillary properties instead of hay particles. The results clearly showed that both synthetic hollow fibres and tube pieces with capillary cavities were highly effective in the process of eye formation and were found in cross-sectional microscopic images related to the cheese eyes. The control cheeses without any fibres or tube pieces tended to have a very low number of eyes and therefore showed cracks because the formed CO 2 was not able to diffuse into non-existent eye nuclei.