Perubahan Antosianin dan Aktivitas Antioksidan Tepung Uwi Ungu selama Penyimpanan

Abstract

Uwi ungu (Dioscorea alata L) merupakan bahan pangan yang berpotensi sebagai sumber antioksidan alami, karena adanya komponen antosianin dan senyawa fenolik. Penelitian ini bertujuan mengetahui perubahan komponen tepung uwi ungu selama penyimpanan pada kondisi ruang simpan berbeda. Penyimpanan tepung uwi ungu disimpan pada ruang berukuran 60x60x60 cm 3 yang diberi perlakuan lampu 150 lux (ruang KL) dan tanpa perlakuan lampu (TKL). Kelembaban udara (RH) ruang simpan dicatat pada saat penyimpanan. Penyimpanan dilakukan selama 25 hari, setiap 5 hari dilakukan uji pada kadar air, kadar antosianin, kadar fenolik, aktivitas antioksidan (%RSA). Data yang diperoleh diuji statistik dengan ANOVA, jika ada beda nyata diuji dengan DNMRT pada tingkat kepercayaan 5%. Hasil penelitian menunjukkan bahwa RH ruang simpan kondisi KL stabil (65%) dan RH ruang simpan TKL berubah-ubah (antara 77-85%). Penyimpanan pada ruang KL dapat menyebabkan peningkatan kadar air, penurunan kadar antosianin, penurunan kadar senyawa fenolik dan aktivitas antioksidan (%RSA) yang lebih rendah dibanding penurunan pada penyimpanan ruang TKL. Penyimpanan tepung uwi ungu pada hari ke-10 menunjukkan peningkatan kadar air, penurunan kadar antosianin, kadar fenolik dan aktivitas antioksidan yang signifikan. Komponen penyusun tepung uwi setelah penyimpanan 10 hari pada kondisi KL sebagai berikut; kadar air 15,5 %, kadar antosianin 56,24 mg/100 g bk, kadar senyawa fenolik 104,2 mg EGA/100 g bk dan aktivitas antioksidan 75,42% (% RSA). Kesimpulannya, oleh karena ruang simpan KL terbukti menekan penurunan kadar air, kadar antosianin, kadar senyawa fenolik dan aktivitas antioksidan dibanding penyimpanan pada ruang TKL, maka tepung uwi ungu lebih baik disimpan dalam ruang KL.

Antioxidative Characteristics and Sensory Acceptability of Bread Substituted with Purple Yam (Dioscorea alata L.)

“…The statistical test results of anthocyanin levels showed that the baking temperature had no effect on anthocyanin levels ( p > 0.05), while the treatment of adding the purple yam flour had an effect on the anthocyanin levels of the fresh bread ( p < 0.05). A study of Tamaroh et al [ 10 ] showed that the anthocyanin level in the purple yam flour is 82.72 mg/100 g db. Another latest study by Ratnaningsih et al [ 15 ] showed that the anthocyanin content in purple yam flour is 74.3 mg/100 g. The anthocyanin value of the eight plain bread formulated with purple yam flour increased ( p < 0.05).…”

“…The total phenol content of plain bread further increased with the addition of yam flour. Studies of [ 10 ] showed the total phenol content in purple yam flour (454.67 mg GAE/100 g db). In a previous study, Hong and Koh [ 21 ] stated that the baking processing method has no effect on the total phenolic content of purple sweet potato.…”

“…The antioxidant activity of DPPH free radical scavenging in purple yam flour was 83.68% [ 23 ]. In a study by Larief et al [ 24 ] on sponge bread from wheat flour and white rice flour substituted with 30% purple yam flour showed antioxidant activity of DPPH free radical binding of 26.9%.…”

“…The purple yam flour was prepared according to the method developed by Tamaroh et al [ 10 ]. The purple yam flour was peeled, sliced, and blended for 8 min and dried in a cabinet drier (local fabricated) at 50°C for 10 h until a moisture content of 10% was achieved.…”

“…Research on the manufacture of purple sweet potato flour has been carried out, with high anthocyanin content (82.72 mg/100 g) [ 10 ]. The purple yam flour has the potential to be a substitute for fresh bread making which has the potential to be a source of antioxidants and reduce the need for imported wheat flour.…”