Penelitian ini bertujuan untuk memperoleh mikroemulsi w/o yang stabil sebagai pembawa asam askorbat dan mengetahui efektivitas mikroemulsi asam askorbat dalam menghambat proses fotooksidasi minyak ikan. Efektivitas mikroemulsi asam askorbat dibandingkan dengan antioksidan lipofil. Penelitian ini dilakukan dengan tahap-tahap sebagai berikut: pertama, melakukan verifikasi mutu minyak ikan untuk mengetahui kualitas awal minyak ikan. Tahap kedua, penentuan formula mikroemulsi w/o asam askorbat untuk memperoleh mikroemulsi w/o yang stabil menggunakan konsep HLB (hydrophilic lipophilic balance). Tahap ketiga, evaluasi stabilitas mikroemulsi asam askorbat terhadap fotooksidasi. Asam askorbat ditambahkan dalam minyak ikan pada konsentrasi 0, 50, 100, 150, 200, 250, dan 300 ppm. Semua sampel selanjutnya difotooksidasi dibawah cahaya fluorescent (4000 lux) selama 8 jam pada suhu ruang (30+1ºC). Angka peroksida (PV), angka p-anisidin (p-AnV), dan nilai total oksidasi (totoks) sampel diukur setiap 2 jam. Antioksidan lipofil TBHQ dan BHA digunakan sebagai pembanding, pada konsentrasi yang sama. Hasil penelitian menunjukkan bahwa mutu awal minyak ikan uji sesuai dengan standar IFOMA. Mikroemulsi w/o stabil terbentuk pada nilai HLB 6,5 konsentrasi minyak ikan 69% dengan kombinasi surfaktan 72,5% span 80, 15% span 20, dan 12,5% tween 20. Proporsi kombinasi minyak ikan : air dan surfaktan adalah 69% : 31%, dengan perbandingan air : surfaktan 20% : 80%. Mikroemulsi yang terbentuk transparan, jernih, stabil sentrifugasi dan stabil selama penyimpanan suhu ruang. Kelarutan maksimum asam askorbat dalam mikroemulsi w/o pada konsentrasi 2000 ppm. Konsentrasi asam askorbat 200 ppm efektif bertindak sebagai SOQ (singlet oxygen quencher) dalam minyak ikan selama pemaparan cahaya fluorescent. Kemampuan antioksidan dalam menghambat fotooksidasi minyak ikan yaitu TBHQ > BHA > mikroemulsi asam askorbat.

The aims of the study were to found a stable w/o microemulsion as ascorbic acid carriers and determine the effectiveness of ascorbic acid microemulsion in fish oils to inhibit the photooxidation process. The effectiveness of ascorbic acid microemulsion was compared with lipophilic antioxidants. This research was conducted with the following stages: first stage, verify the quality of fish oil to determine the initial quality of fish oil. The second stage, formulation of ascorbic acid microemulsion to obtain a stable microemulsion using the HLB (hydrophilic lipophilic balance) concept. The third stage, evaluate the stability of ascorbic acid microemulsion against photooxidation. The levels of ascorbic acid in fish oil were arranged on 0, 50 100, 150, 200, 250, and 300 ppm. All of these samples were subsequently subjected to photooxidation under fluorescent light exposure (4000 lux) for 8 hours at room temperature (30+1°C). The peroxide value (PV), p-anisidine value (p-AnV), and total oxidation value (totox) of samples were measured at 2 hours interval. The same level of lipophilic antioxidant TBHQ and BHA were used as comparison. The results indicated that the quality of fish oil accordance with the IFOMA standard. A stable w/o microemulsion was obtained at HLB value of 6,5 with fish oil concentration of 69%. The combination of surfactant were 72,5% span 80, 15% span 20, and 12,5% tween 20. The proportion of fish oil : water and surfactant was 69% : 31%, with the ratio of water : surfactant 20% : 80%. It formed transparent, clear, stable centrifugation and stable during storage at room temperature. The maximum solubility of ascorbic acid in w/o microemulsion was 2000 ppm. Ascorbic acid concentration at 200 ppm effectively act as SOQ (singlet oxygen quencher) in the fish oil during fluorescent light exposure. The capability of those antioxidants in preventing photooxidation of fish oil were TBHQ > BHA > ascorbic acid microemulsion.

Kata Kunci : asam askorbat, fotooksidasi, mikroemulsi w/o, minyak ikan, SOQ (singlet oxygen quencher).