Characterization of Nutritional, Mineral, Heavy Metal, Phytochemical, and Antioxidant Profiles of Eucheuma spinosum from Gerupuk Waters, Central Lombok

Abstract

Eucheuma spinosum is a promising marine resource for food, hydrocolloid, and bioactive compound applications, although its nutritional and safety characteristics may vary with geographical origin. This study characterized E. spinosum from Gerupuk Waters, Central Lombok, focusing on raw material quality, nutritional composition, mineral and heavy metal contents, phytochemical profile, and antioxidant activity. Samples were dried and extracted using ultrasound-assisted extraction (UAE) with methanol. Analyses included organoleptic assessment, clean anhydrous weed (CAW), proximate composition, mineral analysis by ICP-OES, heavy metal analysis by ICP-MS, qualitative phytochemical screening, and DPPH radical-scavenging activity. The raw material complied with SNI 2690:2023, with an organoleptic score of 8 and CAW content of 50.20%, while the methanolic extract yield was 1.36%. The seaweed was characterized by high ash (35.88%), carbohydrate (32.01%), and crude fiber (15.41%) contents, with potassium as the predominant mineral (18,221.22 mg/100 g). Hg, Cd, and Pb concentrations were within SNI limits; however, total arsenic reached 7.12 mg/kg, exceeding the applicable maximum limit. Phytochemical screening revealed the presence of alkaloids, flavonoids, phenolics, saponins, and steroids, while the methanolic extract showed strong DPPH radical-scavenging activity (IC₅₀ = 70.81 ppm). Overall, E. spinosum from Gerupuk Waters exhibited favorable raw material quality and considerable nutritional and antioxidant potential. However, the elevated total arsenic content represents an important food-safety concern, and arsenic speciation and further toxicological assessment are required before its suitability for direct food or functional-food applications can be established.