ABSTRAK Pidada merah adalah salah satu tumbuhan penyusun ekosistem mangrove dimana buahnya dapat dijadikan sebagai bahan baku makanan dan minuman seperti dodol dan sirup. Penelitian ini bertujuan untuk mempelajari proses pembuatan sirup buah pidada merah dan secara khusus bertujuan untuk mempelajari pengaruh menggunakan Rancangan Acak Lengkap Faktorial pola 4x3x3. Faktor pertama yaitu jenis penstabil (S); CMC (S1): gum arab (S2); pektin (S3); agar-agar (S4). Faktor kedua yaitu konsentrasi gula (G); 65% (G1), 70% (G2), dan 75% (G3). Analisis dilakukan terhadap buah pidada merah segar (kadar air, kadar abu, kadar lemak, kadar protein, kadar karbohidrat, vitamin C, pH, dan aktivitas antioksidan) dan sirup buah pidada merah yang meliputi uji stabilitas (organoleptik, pH, viskositas) dan uji vitamin C sirup. Formulasi sirup buah pidada merah terbaik (penstabil CMC kadar gula 70%) diperoleh dari nilai tertinggi uji organoleptik (warna, aroma, rasa) dengan metode rangking. Formulasi terbaik kemudian dianalisis total padatan terlarut (TPT) dan aktivitas antioksidan. Berdasarkan hasil analisis organoleptik jenis penstabil berpengaruh sangat nyata terhadap warna, aroma dan rasa. Konsentrasi gula (G) berpengaruh sangat nyata terhadap warna dan rasa dan interaksi antara jenis penstabil dan konsentrasi gula berpengaruh sangat nyata terhadap warna sirup buah pidada merah. Sirup yang disimpan selama 21 hari memiliki kisaran pH 4,01 – 4,66 dengan rata-rata 4,27. Viskositas sirup yang disimpan pada hari 0 sampai hari 21 memiliki penurunan viskositas sebesar 33,33%. Sirup buah pidada merah memiliki kadar vitamin C berkisar antara 9,68 – 22 mg/100 g. Total padatan terlarut sirup terbaik yaitu pada perlakuan jenis penstabil CMC dengan konsentrasi gula 70% adalah 68,09% dan aktivitas antioksidan 53,5%. Kata kunci: Pidada merah, Antioksidan, metode rangking. ABSTRACT Pidada red is one of the constituent plant mangrove ecosystem in which the fruit can be used as raw materials such as food and beverage and syrup lunkhead . This research aims to study the process of making syrup and red fruit Pidada specifically aims to study the effect of sugar concentration on the quality and type of stabilizer Pidada red fruit syrup . This study uses a completely randomized design factorial 4x3x3 pattern . The first factor is the type stabilizer ( S ) ; CMC ( S1 ) : gum arabic ( S2 ), pectin ( S3 ) ; agar ( S4 ) . The second factor is the concentration of glucose ( G ), 65 % ( G1 ) , 70 % ( G2 ) , and 75 % ( G3 ) . Analysis was performed on fresh red fruit Pidada ( moisture content , ash content , fat content , protein content , carbohydrate content , vitamin C , pH , and antioxidant activity ) and red fruit syrup Pidada which includes stability test ( organoleptic , pH , viscosity ) and the test vitamin C syrup . Red fruit syrup formulations Pidada best ( CMC stabilizer sugar 70 % ) was obtained from the highest organoleptic ( color , aroma , flavor ) with a ranking method . Best formulation was then analyzed total dissolved solids ( TPT ) and antioxidant activity . Based on the results of the organoleptic analysis of the type stabilizer very significant effect on the color , aroma and flavor . Sugar concentration ( G ) very significant effect on the color and flavor , and the interaction between the type and concentration of sugar stabilizer very significant effect on the color red Pidada fruit syrup . Syrup stored for 21 days had a pH range of 4.01 to 4.66 with an average of 4.27 . Viscosity syrup stored on day 0 to day 21 had a reduced viscosity of 33.33 % . Pidada red fruit syrup had high levels of vitamin C ranged from 9.68 to 22 mg/100 g . Total dissolved solids is best syrup in the treatment of the CMC stabilizer type sugar concentration 70 % are 68.09 % and 53.5 % antioxidant activity . Keywords : red Pidada , antioxidants , ranking methods .