Microscopic images of each sample were taken with a polarizing microscope (BX41, Olympus, Japan) equipped with a camera (Mikrocam II 5MP HIS, Bresser, Germany). To determine the mean ice crystal diameter of a sample, the area of at least 200 ice crystals per microscopic slide was manually analyzed using either ImagePro 9.3 (Media Cybernetics, USA) or ImageJ (National Institutes of Health (NIH), USA) software. The equivalent diameter of each ice crystal was determined by calculating the diameter of a circle with the same area. Based on the equivalent diameters of the individual crystals, the mean ice crystal equivalent diameter of the sample was calculated. Four microscopic slides were prepared for each carrageenan and the mean ice crystal diameter was derived from the mean equivalent diameters of the four slides.