Aktivitas Antioksidan dan Komposisi Kimia Keong Matah Merah (Cerithidea obtusa) (Antioxidant Activity and Nutrient Composition of Matah Merah Snail (Cerithidea obtusa)) - Sri Purwaningsih (Marine Science Department Diponegoro University, 2012)
Beberapa komponen antioksidan dihasilkan oleh bahan pangan secara alamiah termasuk bahan dari hasil perairan. Keong Matah Merah (Cerithidea obtusa) merupakan komoditas perikanan yang biasa dikonsumsi masyarakat dan diyakini bisa digunakan sebagai obat. Tujuan penelitian ini adalah untuk menganalisis aktivitasantioksidan dan komposisi kimia dari Keong Matah Merah. Komposisi kimia Keong Matah Merah dianalisis dengan metode AOAC untuk kandungan proksimat, kandungan mineral dengan metode APHA, kandungan asam amino dengan metode AOAC . Penentuan aktivitas antioksidan dilakukan dengan metode Molyneux. Hasil penelitian menunjukkan bahwa Keong Matah Merah (Cerithidea obtusa) mempunyai kadar: air 77,5%, protein 13,8%, lemak 2,8%, dan abu 4,5%, makro mineral tertinggi natrium 283,45 mg/100 g dan terendah kalsium39,78 mg/100 g, kadar mikro mineral tertinggi selenium 39,25 mg/100 g dan terendah tembaga 0,29 mg/100 g. Kandungan asam amino esensial tertinggi isoleusin 4,82 % dan terendah arginin 0,95%, kandungan asam amino non-esensial tertinggi asam glutamat 12,08% dan terendah sistein 0,84%. Ekstrak metanol pada Keong Matah Merah mempunyai aktivitas sebagai antioksidan kuat dan mempunyai nilai IC50 58,19 ppm dengan pembanding vitamin C sebesar 3,55 ppm.Kata kunci: Keong Matah Merah, Cerithidea obtusa, gizi, antioksidanAntioxidant compounds are frequently produced by natural foods. Matah Merah Snail (Cerithidea obtusa) is one of fishery commodities which is commonly consumed by society and traditionally used for therapeutic purposes. The aim of this research was to investigate the nutrient composition and antioxidant activity of Matah Merah (C. obtusa). The nutrient compounds were analyzed using proximate contents according to AOAC method, mineral contents using APHA method, and amino acid contents using AOAC method. The results showed that Matah Merah Snail (Cerithidea obtusa) contained 77.5% of moisture, 13.8% of protein, 2.8% of fat, and 4.5% of ash. Analyses of macro- and micro-minerals revealed that the highest level of macro-minerals was sodium 283.45 mg/100 g and the lowest one was calcium 39.78 mg/100 g. The highest level of micro-minerals was selenium 39.25 mg/100 g and the lowest one was copper 0.29 mg/100 g. The highest content of essential amino acidswas isoleusin 4.82% and the lowest one was arginine 0.95%. The highest content of non-essential amino acids was glutamic acid 12.08% and the lowest one was cysteine 0.84%. Methanol extract of Matah Merah Snail (C.obtusa) displayed potential antioxidant activities with IC50 value of 58,19 ppm, with IC50 of vitamin C as positive control was 3,555 ppm.Key words: Matah Merah Snail, Cerithidea obtusa, nutrition , antioxida