Penelitian ini bertujuan untuk menentukan pengaruh penambahan gula dengan konsentrasi yang bervariasi terhadap stabilitas warna ekstrak antosianin buah rukem yang terpapar cahaya lampu fluoresens berdasarkan kinetika degradasi warnanya dan menentukan konsentrasi gula yang optimal untuk meningkatkan stabilitas warna ekstrak antosianin buah rukem. Variasi konsentrasi gula yang digunakan adalah 20, 40, dan 60% (b/v). Uji stabilitas warna dilakukan terhadap ekstrak antosianin buah rukem yang disinari selama 10 jam dengan intensitas cahaya 3580, 4655 lux, dan 8544 lux. Metode yang digunakan yaitu pemodelan kinetika degradasi, dimana nilai konstanta laju degradasi (k) dan nilai waktu paruh (t1/2) dihitung berdasarkan orde reaksi yang sesuai. Degradasi antosianin mengikuti orde reaksi 0. Hasil penelitian menunjukkan bahwa penambahan gula 20% mampu meningkatkan stabilitas warna ekstrak antosianin buah rukem dibandingkan dengan kontrol (tanpa penambahan gula), terlihat dari meningkatnya waktu paruh dari 54,82 jam menjadi 61,35 jam. Namun, pada penambahan gula 40 dan 60% dapat menurunkan stabilitas warnanya dengan menurunnya waktu paruh dari 42,52 jam menjadi 31,66 jam pada intensitas 3580 lux. Kecenderungan kenaikan dan penurunan waktu paruh yang sama juga terjadi pada intensitas cahaya 4655 lux dan 8544 lux. Kesimpulannya, penambahan gula mempengaruhi stabilitas warna ekstrak antosianin buah rukem yaitu dapat meningkatkan dan menurunkan stabilitasnya.Effect of Various Concentration Sugar Addition on the Color Stability of Rukem Fruit Anthocyanin Extract (Flacourtia rukam Zoll. & Mor.)This study is aimed to determine the effect of sugar addition with varying concentrations to the color stability of anthocyanin extract of rukem fruit exposed to fluorescent lamp lights based on color degradation kinetics and determining the optimal sugar concentration to improve color stability of anthocyanin extract of rukem fruit. Variations of sugar concentration were 20, 40, and 60% (w/v). The color stability test was performed on the anthocyanin extract of rukem fruit which was irradiated for 10 hours with the light intensity of 3580, 4655, and 8544 lux. The degradation kinetics modeling was used as method, where the value of the degradation rate constant (k) and half-life value (t1/2) were calculated according to the appropriate reaction order. Degradation of anthocyanin was analyzed using zero order reaction. The results showed that sugar addition at 20% could increase the stability of rukem fruit anthocyanin extract compared to control (without sugar addition), that was reflected by increase of half-life from 54.82 to 61.35 hours. However, addition of 40 and 60% sugar decreased the color stability with the half-life decline from 42.52 to 31.66 hours. The similar half-life increase and decrease also occured at the intensity of light 4655 and 8544 lux. As conclusion, sugar addition might increase and decrease of the color stability in the extract rukem fruit.