Abstrak
Kappaphycus alvarezii is one of the main sources of carrageenan with high economic value. The process of producing sea salt from this seaweed generates residue (waste) that has not been optimally utilized. This study aimed to identify the properties of carragenan derived from the by-product (residue) of K.alvarezii seaweed salt production collected is Sebatik Island utilizing potassium hydroxide (KOH) solvent, and to compare it with carragenan extracted from whole seaweed. The investigated parameters and encompassed yield, moisture conten, sulfate conten, ash content, and viscosity. The result showed that the moisture content of the salt residue was 21.68%, which was lower than that of the whole seaweed (28.60%). The carraginan derived from salt residue contained 8.33% water, 1.34% sulfate, and 32.33% ash and had q viscosity of 20.00 cPs. All parameters, except sulfate concentration, mer the Indonesian National Standard (SNI 8391-1:2017). The relatively high viscosity indicated that carragenan derived from salt residue still has potential applications, particularly in non-food industries. Therefore, sea salt production residue from K. alvarezii can be utilized as an alternative raw material in the production of economically valuable carrageenan.