Sains Malaysiana 39(5)(2010): 747–752

Kesan Pengekstrakan Terhadap Kandungan Polifenol, Aktiviti Antipengoksida dan pH Ekstrak Pegaga (Centella asiatica)

 (Effect of Extraction on Polyphenol Content, Antioxidant Activity and pH in Pegaga (Centella asiatica) Extract)

Ong Hooi Yung, Mohamad Yusof Maskat* & Wan Aida Wan Mustapha

Program Sains Makanan, Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 Bangi, Selangor D.E., Malaysia

Diserahkan: 29 Julai 2008 / Diterima: 23 Mac 2010

ABSTRAK

Kajian ini telah dijalankan untuk menentukan kesan suhu (50, 70 dan 90 ^oC) dan masa didihan (15, 30 dan 90 minit) semasa pengekstrakan pegaga serta membandingkan kesan pengekstrakan dengan kaedah haba dan tanpa haba. Parameter yang diukur adalah kandungan polifenol jumlah, aktiviti antipengoksida dan pH. Hasil menunjukkan bahawa dengan peningkatan suhu dan masa pendidihan, kandungan jumlah polifenol dan aktiviti antipengoksida meningkat secara ketara melainkan pada suhu pengekstrakan 90 ^oC untuk aktiviti antipengoksida. Kandungan jumlah polifenol dan aktiviti antipengoksida dalam sampel pegaga yang terhasil tanpa haba adalah lebih rendah berbanding sampel yang terhasil dengan melibatkan haba. pH ekstrak pegaga meningkat dengan peningkatan suhu pengekstrakan. Sebaliknya, pH ekstrak pegaga semakin menurun dengan peningkatan masa pengekstrakan.

Kata kunci: Kesan suhu; masa didihan; pegaga; pengekstrakan; tanpa haba

ABSTRACT

This study was carried out to determine the effect of temperature (50, 70 and 90 ^oC) and heating time (15, 30 and 90 minutes) during the extraction of pegaga and also to compare the effect of extraction using heat and non-heat methods. Parameters measured were total polyphenol content, antioxidant activity and pH. Results showed that with an increase in boiling temperature and time, total polyphenol content and antioxidant activity increased significantly except for extraction temperature of 90 ^oC for antioxidant activity. The total polyphenol content and antioxidant activity from samples prepared without heat treatment were significantly lower than extracts prepared using heat treatment. The pH of pegaga extract increased with increase in extraction temperature. However, pH of pegaga extract decreased with the increase in extraction time.

Keywords: Effect of temperature; extraction; heating time; non-heat; pegaga;

RUJUKAN

Abdul Hamid, A., Md. Shah, Z., Muse, R. & Mohamed, S. 2002. Characterisation of antioxidative activities of various extracts of Centella asiatica (L) Urban. Food Chemistry 77: 465-469.

Brantner, A., Males, Z., Pepeljnjak, S. & Antolic, A. 1996. Antimicrobial activity of Paliurus spina-christi mill. Journal of Ethnopharmacol. 52: 119-122.

Chen, H.M., Muramoto, K., Yamauchi, F. & Nokihara, K. 1996. Antioxidant activity of design peptides based on antioxidative peptide isolated from digest of a soybean protein. Journal of Agricultural and Food Chemistry 44: 2619-2623.

Cox, D.N., Rajasuriya, S., Soysa, P.E., Gladwin, J. & Ashworth, A. 1993. Problems encountered in the community based production of leaf concentrate as a supplement for pre-school children in Sri Lanka. International Journal of Food Science and Nutrition 44:123-132.

Goh, S.H., Chuah, G.H., Mok, J.S.L. & Soepadmo, E. 1995. Malaysian Medicinal Plants for the Treatment of Cardiovascular Diseases. Kuala Lumpur: Pelanduk.

Jaganath, I.B. & Ng, L.T. 2002. Herbs: The Green Pharmacy of Malaysia. Kuala Lumpur: Vinpress.

Jayaprakasha, G.K., Singh, R.P. & Sakariah, K.K. 2001. Antioxidant acivity of grape seed (Vitis vinifera) extracts on peroxidation models in vitro. Journal of Food Science 73: 285-290.

Jonsson, L. 1991. Thermal degradation of carotenoids and influence on their physiological functions. Dlm. Nutritional and Toxicological Consequences of Food Processing, disunting oleh M. Friedman. New York: Plenum Press.

Kan, W.S. 1986. Pharmaceutical Botany. Taiwan: National Research Institute of Chinese Medicine.

Lee, S.C., Kim, J.H., Jeong, S.M., Kim, D.R., Ha, J.U. & Nam, K.C. 2003. Effect of far-infrared radiation on the antioxidant activity of rice hulls. Journal of Agricultural and Food Chemistry 51: 4400-4403.

Madavi, D.L. & Salunkhe, D.K. 1995. Toxicological aspects of food antioxidant. Dlm. Food Antioxidants, disunting oleh Madhavi, D.L., Deshpande, S.S. & Salunkhe, D.K. New York: Marcel Dekker.

Montgomery, D.C. 1991. Design and Analysis of Experiments. 3rd Edition. Pp. 201-210. New York: John Wiley & Sons.

Oyaizu, M. 1986. Studies on products of browning reaction: Antioxidative activity of products of browning reaction prepared from glucosamine. Journal of Nutrition 44: 307-315.

Peleg, H., Naim, M., Rouseff, R.L. & Zehavi, U. 1991. Distribution of bound and free polyphenolic acids in oranges (Citrus sinesis) and grapefruits (Citrus paradise). Journal of the Science Food and Agricultural 57: 417-426.

Rice-Evans, C.A., Miller, N.J. & Paganga, G. 1997. Antioxidant properties of phenolic compounds. Trends in Plant Science 2(4): 152-159.

Rivas, A., Rodrigo, D., Martinez, A., Barbosa-Canovas, G.V. & Rodrigo, M. 2006. Effect of PEF and heat pasteurization of physical-chemical characteristics of blended orange and carrot juices. LWT-Food Science and Technology 39: 1163-1170.

Singlenton, V.L. & Rossi, J.A. 1965. Colorimetry of total phenolics with phosphomolibdic phosphotungstic acid reagent. American Journal of Enology Viticulture 16: 144-158.

Velioglu, Y.S., Mazza, G., Gao, L. & Oomah, B.D. 1998. Antioxidant activity and total phenolics in selected fruits, vegetables and grain products. Journal of Agricultural and Food Chemistry 46: 4113-4117.

Wanasundara, U.N. & Shahidi, F. 1998. Antioxidant and pro-oxidant activity of green tea extract in marine oils. Food Chemistry 63: 335-342.

Yildirim, A., Mavi, A. & Kara, A.A. 2001. Determination of antioxidant and antimicrobial activities of Rumaxs crispus L. extracts. Journal of Agricultural and Food Chemistry 49: 4083-4089.

Zainol, M.K., Abd-Hamid, A., Yusof S. & Muse, R. 2003. Antioxidative activity and total phenolic compounds of leaf, root and petiole of four accessions of Centella asiatica (L.) Urban. Food Chemistry 81: 575-581.

*Pengarang untuk surat-menyurat; email: maskatmy@yahoo.com