FORMULASI MIKROEMULSI EKSTRAK FULI UNTUK MENGHAMBAT FOTOOKSIDASI VITAMIN C DALAM SISTEM AQUEOUS

HASBULLAH, Prof. Dr. Ir. Sri Raharjo, M.Sc.

2011 | Tesis | S2 Ilmu dan Teknologi Pangan

Tujuan penelitian ini adalah untuk mendapatkan formula mikroemulsi ekstrak fuli yang stabil dan efektif menghambat fotooksidasi vitamin C dalam sistem aqueous. Ekstrak fuli diperoleh melalui proses ekstraksi menggunakan pelarut organik. Total phenolic content (TPC) dan kandungan β-karoten dari ekstrak fuli diukur. Aktivitas antioksidasi ekstrak fuli ditentukan dengan metode DPPH dan metode linoleat. Mikroemulsi o/w sebagai sistem pembawa (delivery system) bagi ekstrak fuli disiapkan dengan menggunakan virgin coconut oil (VCO), aquades dan kombinasi 3 surfaktan nonionik. Formula mikroemulsi yang diperoleh, diuji stabilitasnya terhadap penyimpanan suhu ruang selama 8 minggu pada kondisi terang dan gelap, sentrifugasi 4000 rpm selama 15 menit dan pemanasan oven pada suhu 105oC selama 5 jam. Mikroemulsi ekstrak fuli disiapkan dengan menambahkan ekstrak fuli 500 dan 750 ppm ke dalam mikroemulsi o/w dan diuji stabilitasnya terhadap penyimpanan suhu ruang 4 minggu pada kondisi terang dan gelap, sentrifugasi 4000 rpm selama 15 menit dan pemanasan oven pada suhu 105oC selama 5 jam baik dengan dan tanpa pengenceran 1:9 menggunakan buffer sitrat pH 3.1. Efek antifotooksidasi mikroemulsi ekstrak fuli ditentukan berdasarkan laju kehilangan vitamin C dalam dua macam sistem aqueous, yaitu sistem model minuman dan sari buah apel yang masing-masing ditambahkan 20 ppm eritrosin sebagai sensitiser dan 100 ppm vitamin C. Laju fotooksidasi vitamin C ditentukan dengan mengamati kadar vitamin C dalam sistem pada jam ke-0, 2, 4, 6 dan 8. Hasil yang diperoleh menunjukkan bahwa penambahan mikroemulsi ekstrak fuli mampu mengurangi laju kehilangan vitamin C pada kedua sistem aqueous yang berarti bahwa mikroemulsi ekstrak fuli mampu menghambat fotooksidasi vitamin C dalam sistem aqueous.

The objective of this research was to obtain stable microemulsion formula containing mace extract which effectivelly inhibits the photooxidation of vitamin C in aqueous system. Mace extract was obtained from extraction process by using organic solvent. Total phenolic content (TPC) and β-carotene content of the mace extract was measured. Antioxidative activitiy of mace extract was determined by DPPH and linoleic method. Microemulsion o/w acts as delivery system for mace extract was prepared by using virgin coconut oil (VCO), aquadest and combination of three nonionic surfactants. The stability of the obtained microemulsion formula was tested against room temperature storage for 8 weeks under light exposure and dark condition, centrifugation 4000 rpm for 15 minutes, the heating in oven at 105oC for 5 hours. Microemulsion containing mace extract prepared by adding mace extract as much as 500 ppm and 750 ppm to the o/w microemulsion and its stability was tested against room temprature storage for 4 weeks under light exposure and dark condition, centrifugation 4000 g for 15 hours and heating in oven at 105oC for 5 hours both with or without dilution 1:9 with citrate buffer pH 3.1. Antiphotooxidative effect of microemulsion containing mace extract was determined based on the rate of vitamin C degradation in two types of aqueous systems: beverage model system and apple juice in which each added with 20 ppm of erytrosine as sesitizer and 100 ppm of vitamin C. The rate of vitamin C photooxidation was determined by observing the amount of vitamin C in the system at the starting time, following by 2, 4, 6 and 8 hours after that. The result shows that the added microemulsion containing mace extract decreased the rate of vitamin C degradation in both aqueous systems which mean microemulsion containing mace extract inhibited photooxidation of vitamin C in aqueous system.

Kata Kunci : fuli, mikroemulsi, fotooksidasi