Alginates are interesting polymer, it’s biopolymer that isolated from brown algae that considered to be biocompatible, non-toxic and biodegradable. The alginate was made in gel bead consisting of dye in support matrix that have been reported to show thermochromics behavior.
The dye are consider useful for a visual indicator when it heat above its melting point. Combined with the temperature sensitivity of certain indicator would be sensitive to temperature in the range of interest and provide a visible color indicator of temperature in this range. So could be used for monitoring the temperature of packaging of chill food or a cup of instant noodle.