STUDY ON MOTHLY CHANGES CARRAGEENAN YIELD AND QUALITY FROM THE RED ALGA BETAPHYCUS GELATINUS

Abstract

The red alga Betaphycus gelatinus is a species of seaweed with high value, favored by the market, exploited naturally and facing extinction due to overexploitation. The seaweed was collected monthly during the harvesting period according to folk experience (March - May) in Ninh Thuan, Vietnam to evaluate the change in carrageenan yield and quality (3,6-anhydrogalactose content, sulfate content and carrageenan type), thereby giving an appropriate harvest time for this seaweed. The content of naturally extracted carrageenan gradually increased from 68.4 to 73.1%, the content of 3,6-anhydrogalactose ranged from 22.9 to 24.8%, the content of sulfate gradually increased from 18 to 20.6% in March, April, and May 2021. The obtained results suggest that the harvest period from March to May 2021 is the period when the seaweeds mature and achieve the highest carrageenan content and quality. The results of absorption bands from infrared spectroscopy show that the carrageenan sample naturally extracted from Hong Van seaweed harvested in Ninh Thuan province, Vietnam is a mixture of kappa- and beta-carrageenan.