Selection of Optimum Process, Solvent and Drying Method for Extraction of Antioxidants

Satu uji kaji telah dijalankan untuk pemilihan proses optimum, pelarut, dan teknik pengeringan bagi pengekstrakan antioksidan daripada buah Morinda citrifolia. Pengekstrakan telah dijalankan dengan soxhlet, ultrasonik dan tekanan tinggi hidrostatik yang diubahsuai pada 100 bar dan 50°C dengan 15 gram serbuk Morinda dalam 200 ml pelarut. Pelarut yang telah digunakan ialah air, etanol, dan etil asetat. Hasil penurasan kemudiannya dikeringkan melalui vakum dan pengering semburan. Aktiviti antioksidan atau peratusan ekstrak perencatan ditentukan dengan radikal Di-Phenyl picryl hydrazyl. Hasil ekstrak juga telah ditentukan dalam kajian ini. Pengoptimuman telah dilakukan dengan menggunakan kaedah gerak balas permukaan. Hasil kajian ini menunjukkan bahawa, aktiviti antioksidan atau peratusan perencatan DPPH radikel bebas yang paling tinggi dipamerkan daripada ekstrak yang diperolehi dari proses HHPE dengan etil asetat sebagai pelarut yang dikeringkan melalui vakum. Daripada kajian ini juga, hasil ekstrak yang tertinggi diperolehi melalui proses HHPE pada 100 bar dan 50°C, di mana etil asetat digunakan sebagai pelarut dengan teknik pengeringan vakum. Di samping itu, didapati juga bahawa keadaan pengekstrakan dan pelarut secara langsungnya memberi kesan kepada pengekstrakan antioksidan daripada buah Morinda citrifolia jika dibandingkan dengan teknik pengeringan. Kata kunci: Aktiviti antioksidan, radikel DPPH, pengekstrakan tekanan tinggi, Morinda citrifolia, pengekstrakan ultrasonik, pengekstrakan soxhlet An experimental study was performed for optimum process, solvent and drying method for the extraction of antioxidants from Morinda citrifolia fruit. Extractions were performed by soxhlet, ultrasonic and modified version of high hydrostatic pressure extraction at 100 bar and 50°C with 15 grams of powdered morinda in 200 ml of solvent. Water, ethanol and ethyl acetate were used as solvents. The filtrate was dried by vacuum and spray dryers. The antioxidant activity or inhibiton percentage of the extracts was determined by Di-Phenyl picryl hydrazyl radical scavenging method. The yield was also determined. Optimization was performed using response surface methodology. It was found that the highest antioxidant activity or inhibition percentage of DPPH free radicals was exhibited by the extract obtained from HHPE process with ethyl acetate as solvent and vacuum dried. It was also found that the highest yield was obtained from HHPE process at 100 bar and 50°C with ethanol as solvent and vacuum dried. It was noted that the nature of the process and the solvent used significantly contributed to the extraction of antioxidants from Morinda citrifolia fruit when compared with the drying methods. Key words: Antioxidant activity, DPPH radical scavenging method, high hydrostatic pressure extraction, Morinda citrifolia, ultrasonic extraction, soxhlet extraction