<![CDATA[                                   ABSTRACT  This study aimed to study the effect of substitution of purple sweet potato flour on antioxidant level, fiber content, and organoleptic properties of donuts. This study used a completely randomized design (CRD) with 5 treatments, namely D0 (100%: 0%), D1 (80%: 20%), D2 (60%: 40%), D3 (40%: 60%), D4 (20%: 80%). Data analysis in this study was obtained from the results of organoleptic assessment. Data were analyzed using analysis of variance (ANOVA) and if it significantly affected the observation variables, then continued with the DMRT (Duncan Multiple Range Test) test at 95% confidence level. The results of substitution of purple sweet potato flour showed a very significant effect (p<0.05) on organoleptic color, aroma, taste, texture. Analysis of antioxidants in treatment D0 (238.53 µg/mL), D1 (168.34 µg/mL), D2 (124.28 µg/mL), D3 (98.82 µg/mL) and D4 (47.22 µg/mL) The results of analysis of crude fiber in treatment D0 (0.46%), D1 (1.16%), D2 (1.52), D3 (1.98%) and D4 (2.25%). So it can be concluded that addition of sweet potato flour increased the antioxidant content and crude fiber of donuts.                                                                            Keywords: purple sweet potato, purple sweet potato flour, donuts, antioxidants, crude fiber                                                                                                                                    ABSTRAK                                                                                     Penelitian ini bertujuan untuk mempelajari pengaruh substitusi tepung ubi jalar ungu terhadap kapasitas antioksidan, kadar serat dan kualitas organoleptik kue donat. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan 5 perlakuan, yaitu perbandingan tepung terigu dan ubi jalar D0 (100%: 0%), D1 (80%: 20%), D2 (60%: 40%), D3 (40%: 60%), D4 (20%: 80%). Analisis data dalam penelitian ini diperoleh dari hasil penilaian organoleptik. Data dianalisis dengan menggunakan analisis ragam (Analysis of Varian) dan apabila berpengaruh nyata terhadap variabel pengamatan, maka dilanjutkan dengan uji (Duncan Multiple Range Test) DMRT pada taraf kepercayaan 95%. Hasil substitusi tepung ubi jalar ungu menunjukkan pengaruh yang sangat nyata (p<0,05) pada uji organoleptik warna, aroma, rasa, tekstur. Kapasitas antioksidan yang dinyatakan dengan IC50 pada setiap sampel adalah D0 (238.53µg/mL), D1 (168.34 µg/mL), D2 (124.28 µg/mL), D3(98.82 µg/mL) dan D4(47.22 µg/mL). Hasil analisis serat kasar pada perlakuan D0 (0.46%), D1 (1.16%), D2 (1.52), D3 (1.98%) dan D4 (2.25%).Jadi dapat disimpulkan bahwa semakin tinggi tingkat penambahan tepung ubi jalar ungu akan meningkatkan kandungan antioksidan dan serat kasar kue donat.               Kata kunci: Ubi jalar ungu, tepung ubi jalar ungu, kue donat, antioksidan, serat kasar]]>
