Perubahan Antosianin dan Aktivitas Antioksidan Tepung Uwi Ungu selama Penyimpanan

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 cm3 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.Antocyanin and Antioxidant Activity Purple Yam Flour Changes During StorageAbstractThe purple yam (Dioscorea alata L) is a food that has the potential as a source of natural antioxidants, because of the anthocyanin and phenolic component. The objective of this research is to know the change of purple yam flour component during storage at different room storage. In this study, the purple yam flour was stored in the space size 60x60x60 cm3, with lamp 150 lux (LT) and without lamp (KLT). Room relative humidity (RH) was recorded. Purple yam flour was stored for 25 days. Analysis of the moisture content, anthocyanin concentration, phenolic concentration, antioxidant activity (% RSA ) was done in every 5 days. The data were statistically analized by ANOVA method, if there were significant difference were followed by Duncan Multiple Range Test at 5% confidence level. The results showed that KL provided stabil relative himidity (65%) and TKL provided much less stabil relative himidity (77–85%). Stored purple yam at KL room increased water content, decreased anthocyanin, phenolic compounds and antioxidant activity (% RSA). These changes generated lower value than that of in storage of TKL room. Storage purple yam flour on 10 days increased water content, decreased anthocyanin and phenolic levels, and antioxidant activity, significantly. Purple yam flour components after 10 days storage at KL room provided composition as follows: moisture content of 15.5%, anthocyanin content of 56.24 mg/100g db, phenolic compounds EGA of 104.2 mg/100 g bk and antioxidant activity of 75.42%. As conclusion, KL provided better storage of purple yam than TKL