Optimasi pH dan Waktu Ekstraksi dengan Teknik Microwave terhadap Total Fenolik, Total Flavonoid, dan Kapasitas Antioksidan Tanaman Krokot

Abstract

Tanaman krokot (Portulaca grandiflora Hook.) memiliki potensi sebagai antioksidan karena memiliki kandungan metabolit sekunder antara lain fenolik dan flavonoid. Faktor-faktor yang mempengaruhi hasil ekstraksi antara lain waktu ekstraksi dan pH. Penelitan ini bertujuan menentukan pH dan waktu ekstraksi optimum untuk mengekstrak metabolit sekunder krokot berdasarkan kadar total fenolik, flavonoid, dan kapasitas antioksidan menggunakan response surface methodology. Sampel diekstraksi dengan metode microwave assisted extraction. Data hasil optimasi menunjukkan total fenolik tertinggi saat waktu ekstraksi 3,53 menit dan pH 6 sebesar 3,25 mg GAE/g DW. Total flavonoid tertinggi pada waktu ekstraksi 5 menit dan kombinasi pH 4,20 sebesar 13,85 mg GAE/g DW. Kapasitas antioksidan DPPH tertinggi saat waktu ekstraksi 5 menit dan pH 2,50 sebesar 1,18 µmol TE/g DW sedangkan FRAP saat waktu ekstraksi 3,66 menit dengan pH 2 sebesar 25,70 µmol TE/g DW. Solusi optimasi yang didapatkan pada waktu ekstraksi 4,69 menit dan pH 6 dengan desirability sebesar 0,58.

The purslane plant (Portulaca grandiflora Hook.) has potential as an antioxidant because it contains secondary metabolites, including phenolics and flavonoids. Factors that influence result of extraction is extraction time and pH. This research aimed to determine the best pH value and extraction time to extract secondary metabolites of purslane based on total phenolic, flavonoid and antioxidant capacity levels using response surface methodology. Samples were extracted using the microwave assisted extraction method. Optimization data shows that the highest value of phenolic content when the extraction time was 3,53 minutes and pH 6, that is 3,25 mg GAE/g DW. The highest value of flavonoid content was at extraction time of 5 minutes and a combination of pH 4,20 that is 13,85 mg GAE/g DW. The highest value of antioxidant capacity of DPPH when the extraction time was 5 minutes and pH 2,50 was 1,18 µmol TE/g DW, while FRAP when the extraction time was 3,66 minutes with pH 2 was 25,70 µmol TE/g DW. The optimization solution obtained was an extraction time of 4,69 minutes and a pH of 6 with a desirability of 0,58.