Sains Malaysiana 49(4)(2020): 765-774


Characterization on Phenolic Acids and Antioxidant Activity of Microalgae Chlorella sp. using Subcritical Water Extraction

(Pencirian ke atas Asid Fenol dan Aktiviti Antioksidan Mikroalga Chlorella sp. menggunakan Pengekstrakan Air Subkritikal)




1Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia


2Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia


Diserahkan: 27 Jun 2019/Diterima: 30 Disember 2019



Chlorella sp. microalgae contain phenolic compounds with good functional properties. In this study, two extraction methods, soxhlet and subcritical water extraction (SWE) were applied and compared in terms of phenolic compounds recovery from Chlorella sp. microalgae and characterization of the phenolic acid components. Phenolic acid analysis demonstrated that the main components of the Chlorella sp. extracts were ferulic, caffeic and p-coumaric acids. The comparative study indicated that SWE gave higher extraction yield compared to conventional soxhlet method. High recoveries of phenolic acids were obtained at 175 °C with 3.20, 3.05 and 3.33 mg/100 g of ferulic, p-coumaric and caffeic acid, respectively, compared to soxhlet extraction using methanol with 2.10, 2.29 and 2.37 mg/100 g of ferulic, p-coumaric and caffeic acid, respectively. This proved that subcritical water treatment could effectively be used for the release of phenolic acids from Chlorella sp. using safe and green solvent. Analysis by Fourier transform infrared spectroscopy (FTIR) was also performed to observe the effect of subcritical water on the functional groups of the extracts. The current study demonstrated that SWE provided a better way of utilising Chlorella sp. as a source of phenolic acids and natural antioxidants.


Keywords: Extraction; microalgae; phenolic; subcritical; water



Mikroalga Chlorella sp. mengandungi sebatian fenol dengan ciri pelbagai fungsi yang bagus. Dalam kajian ini, dua kaedah pengekstrakan, soxhlet dan pengekstrakan air subkritikal (SWE) telah diaplikasikan dan dibandingkan daripada segi hasil sebatian fenol daripada mikroalga Chlorella sp. serta pencirian ke atas komponen asid fenol. Analisis asid fenolik menunjukkan bahawa komponen utama bagi ekstrak Chlorella sp. adalah asid ferulik, kafeik dan ρ-kumarik. Kajian perbandingan menunjukkan SWE memberi hasil ekstrak yang lebih tinggi berbanding kaedah konvensional soxhlet. Hasil asid fenolik yang tinggi dicapai pada 175 °C dengan 3.20, 3.05 dan 3.33 mg/100 g masing-masing bagi asid ferulik, ρ-kumarik dan kafeik berbanding pengekstrakan soxhlet menggunakan metanol dengan 2.10, 2.29 dan 2.37 mg/100 g masing-masing bagi asid ferulik, ρ-kumarik dan kafeik. Ini membuktikan bahawa rawatan air subkritikal boleh digunakan secara berkesan bagi pengeluaran asid fenol daripada Chlorella sp. menggunakan pelarut yang selamat dan hijau. Analisis dengan spektroskopi transformasi Fourier inframerah (FTIR) juga dijalankan untuk melihat kesan air subkritikal ke atas kumpulan berfungsi bagi ekstrak. Kajian menunjukkan bahawa SWE adalah kaedah yang lebih baik bagi penggunaan Chlorella sp. sebagai sumber asid fenol dan antioksidan semula jadi.


Kata kunci: Air; fenol; mikroalga; pengekstrakan; subkritikal


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