Total Fenolik dan Kapasitas Antioksidan Hasil Optimasi Ekstrak Krokot (Portulaca grandiflora Hook.) dengan Two Level-half Factorial Design

Abstract

Krokot (Portulaca grandiflora Hook.) adalah salah satu tumbuhan liar yang telah dilaporkan memiliki kapasitas antioksidan. Ekstraksi krokot memainkan peran penting dalam perolehan kapasitas antioksidan yang tinggi. Penelitian bertujuan mengevaluasi faktor-faktor ekstraksi tumbuhan krokot yang memiliki kontribusi signifikan terhadap kandungan fenolik total dan kapasitas antioksidan. Kandungan fenolik total dalam penelitian ini dianalisis menggunakan metode Folin-Ciocalteu, sementara itu kapasitas antioksidan dianalisis menggunakan metode 2,2-diphenyl-1-picrylhydrazy (DPPH) dan ferric reducing antioxidant power (FRAP). Faktor pH berperan paling signifikan terhadap nilai fenolik total sebesar 10.35%, sedangkan faktor rasio padatan-cairan berperan paling signifikan terhadap kapasitas antioksidan DPPH (97.73%) dan FRAP (37.02%). Kandunngan fenolik total tertinggi terdapat pada perlakuan 16 (45.72 ± 0.18 mg gallic acid equivalent (GAE)/g fresh weight (fw)). Kapasitas antioksidan DPPH tertinggi terdapat pada perlakuan 16 (16.59 ± 0.12 µmol trolox equivalent (TE)/g fw). Sementara itu, kapasitas antioksidan FRAP tertinggi terdapat pada perlakuan 16 (148.11 ± 11.82 µmol TE/g fw). Hasil optimasi menunjukan kondisi ekstraksi yang direkomendasikan sebagai solusi kombinasi perlakuan optimum yaitu pH 2; suhu 30°C; waktu 300 menit; konsentrasi etanol 80%; rasio cairan-padatan sebesar 100:1 mL/g dengan nilai desirability 0.999. Verifikasi solusi optimasi dilakukan secara triplo dan dievaluasi berdasarkan Residual Standar Error (%) dengan kandungan fenolik total, kapasitas antioksidan DPPH, dan kapasitas antioksidan FRAP yang didapatkan berturut-turut yaitu 3.77%, -2.06%, dan -4.39%. Two level-half factorial design mampu mengoptimalkan proses ekstraksi krokot dengan respon kadar total fenolik dan kapasitas antioksidan. Penelitian ini menyimpulkan bahwa kandungan fenolik total dan kapasitas antioksidan (DPPH dan FRAP) tumbuhan krokot sangat dipengaruhi oleh faktor pH dan rasio padatan-cairan.

Purslane (Portulaca grandiflora Hook.) is one of the wild plants that has been reported to have antioxidant capacity. Purslane extraction plays an important role in obtaining high antioxidant capacity. The study aimed to evaluate the factors of purslane plant extraction that have a significant contribution to the total phenolic content and antioxidant capacity. The total phenolic content in this study was analyzed using the Folin-Ciocalteu method, while the antioxidant capacity was analyzed using the 2,2-diphenyl-1-picrylhydrazy (DPPH) and ferric reducing antioxidant power (FRAP) methods. The pH factor plays the most significant role in the total phenolic value of 10.35%, while the solid-liquid ratio factor plays the most significant role in the antioxidant capacity of DPPH (97.73%) and FRAP (37.02%). The highest total phenolic content was found in treatment 16 (45.72 ± 0.18 mg GAE/g fw). The highest DPPH antioxidant capacity was found in treatment 16 (16.59 ± 0.12 µmol TE/g fw). Meanwhile, the highest FRAP antioxidant capacity was found in treatment 16 (148.11 ± 11.82 µmol TE/g fw). The optimization results showed that the extraction conditions recommended as the optimum treatment combination solution were pH 2; temperature 30°C; time 300 minutes; etanol concentration 80%; liquid-solid ratio of 100:1 mL/g with a desirability value of 0.999. Verification of the optimization solution was carried out in triplicate and evaluated based on the Residual Standard Error (%) with total phenolic content, DPPH antioxidant capacity, and FRAP antioxidant capacity obtained respectively, namely 3.77%, -2.06%, and -4.39%. Two level-half factorial Design was able to optimize the purslane extraction process with the response of total phenolic content and antioxidant capacity. This study concluded that the total phenolic content and antioxidant capacity (DPPH and FRAP) of purslane plants were greatly influenced by pH and solid-liquid ratio factors.