Optimasi Ekstraksi Senyawa Polifenol Antioksidan Kulit Pisang Kepok (Musa paradisiaca) Menggunakan Metode MAE dan Response Surface Methodology

Abstract

Kulit pisang kepok merupakan limbah agroindustri kaya senyawa fenolik dan flavonoid dengan aktivitas antioksidan tinggi, melebihi kandungan pada buahnya, namun pemanfaatannya masih terbatas. Metode konvensional seperti maserasi memiliki efisiensi rendah dan durasi ekstraksi lama, sedangkan Microwave Assisted Extraction (MAE) menawarkan waktu lebih singkat dan yield lebih besar. Penelitian ini bertujuan menentukan kondisi ekstraksi optimum MAE, membandingkan potensi kulit pisang matang dan mentah, serta mengevaluasi efektivitas MAE, maserasi, dan fermentasi (Aspergillus oryzae). Optimasi MAE dilakukan menggunakan Response Surface Methodology desain Box-Behnken pada tiga faktor: konsentrasi etanol (50 sampai 96%), daya microwave (100 sampai 500 W), dan waktu ekstraksi (3 sampai 7 menit), menghasilkan 17 kombinasi perlakuan yang dianalisis dengan Design-Expert 13.0. Respon yang diukur meliputi kadar fenolik total (TPC), flavonoid total (TFC), DPPH, dan CUPRAC. Model kuadratik signifikan (R² 0,88 sampai 0,99). Kondisi optimum diperoleh pada konsentrasi etanol 71,275%, daya microwave 500 W, waktu 7 menit (desirability = 0,954), dengan verifikasi laboratorium sesuai prediksi (%RSE < 5%, p > 0,05). Kadar air simplisia kulit matang dan mentah berturut-turut 7,51% dan 2,44%, memenuhi standar Farmakope Herbal Indonesia. MAE konsisten unggul dibandingkan maserasi dan fermentasi. Kulit pisang matang dengan MAE menghasilkan nilai tertinggi: TPC 43,09±2,62 mg GAE/g, TFC 1,97±0,14 mg QE/g, DPPH 77,08±0,49 µmol TE/g, CUPRAC 545,52±6,70 µmol TE/g. Metode maserasi dan fermentasi menunjukkan pola sebaliknya, kulit mentah cenderung menghasilkan kadar fenolik lebih tinggi. Pengaruh kematangan bersifat spesifik dan berinteraksi dengan metode ekstraksi. Pendekatan RSM desain Box-Behnken terbukti efektif mengoptimasi kondisi ekstraksi MAE. Kombinasi kulit pisang matang dengan metode MAE merupakan kondisi paling optimal, berpotensi dikembangkan sebagai sumber antioksidan alami dari limbah agroindustri pisang.

Kepok banana peel is an agro-industrial waste rich in phenolic and flavonoid compounds with high antioxidant activity, exceeding that of the fruit itself, yet its utilization remains limited. Conventional methods such as maceration show low efficiency and long extraction duration, while Microwave-Assisted Extraction (MAE) offers shorter extraction time and higher yield. This study aimed to determine the optimum MAE conditions, compare the potential of ripe and unripe banana peel, and evaluate the effectiveness of MAE, maceration, and fermentation (Aspergillus oryzae). MAE optimization was conducted using Response Surface Methodology with a Box-Behnken design involving three factors: ethanol concentration (50–96%), microwave power (100–500 W), and extraction time (3–7 minutes), yielding 17 treatment combinations analyzed using Design-Expert 13.0. Measured responses included total phenolic content (TPC), total flavonoid content (TFC), DPPH, and CUPRAC. The quadratic model was significant (R² 0.88–0.99). Optimum conditions were obtained at 71.275% ethanol, 500 W microwave power, and 7 minutes extraction time (desirability = 0.954), with laboratory verification consistent with predictions (%RSE < 5%, p > 0.05). Moisture content of ripe and unripe simplicia was 7.51% and 2.44%, respectively, meeting the Indonesian Herbal Pharmacopoeia standard. MAE consistently outperformed maceration and fermentation. Ripe banana peel extracted via MAE yielded the highest values: TPC 43.09±2.62 mg GAE/g, TFC 1.97±0.14 mg QE/g, DPPH 77.08±0.49 µmol TE/g, CUPRAC 545.52±6.70 µmol TE/g. Maceration and fermentation showed an opposite pattern, with unripe peel producing higher phenolic content. The effect of ripeness was specific and interacted with the extraction method. The RSM approach with Box-Behnken design proved effective for optimizing MAE conditions. The combination of ripe kepok banana peel with MAE represents the most optimal condition, with potential development as a natural antioxidant source from banana agro-industrial waste.