Browsing by Author "Purnomo, Eko Hari"

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    Effect of Tocopherols, Tocotrienols, β-Carotene, and Chlorophyll on the Photo-oxidative Stability of Red Palm Oil
    (2016-09-29) Ayu, Dewi Fortuna; Andarwulan, Nuri; Hariyadi, Purwiyatno; Purnomo, Eko Hari
    Effect of tocols, β-carotene, and chlorophyll on photo-oxidative stability of red palm oil (RPO) were studied. Model systems of triacylglycerols+tocols, triacylglycerols+β-carotene, triacylglycerols +tocols+β-carotene, and triacylglycerols+tocols+β-carotene+chlorophyll were exposed to fluorescent light at intensities of 5,000, 10,000, and 15,000 lux for 7 h at 30±2oC. Changes in concentrations of tocopherols, tocotrienols, β-carotene, chlorophyll, and peroxide values were evaluated every hour. Light intensity accelerated degradation of tocols in the triacylglycerols+tocols system and β-carotene in the triacylglycerols+β-carotene system. Gamma-tocotrienol showed the highest degradation rate and β-carotene was the most sensitive compound to changes in light intensity, indicated by the lowest light intensity coefficient (zi) value. The presence of tocols and β-carotene together showed protective effects for the photo-oxidative stability of RPO. The presence of chlorophyll increased the rate of photo-oxidation at high light intensities. Interactions between tocols and β-carotene contributed to the photo-oxidative stability of RPO.
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    Karakterisasi Sifat Fisiko Kimia Minyak Kelapa
    (2015-08-01) Mursalin; Hariyadi, Purwiyatno; Purnomo, Eko Hari; Andarwulan, Nuri; Fardiaz, Dedi
    Coconut oil (refined bleached deodorized coconut oil/RBDCNO) was studied for their physicochemical properties. The main analysis were fatty acid composition, triacylglycerol (TAG) composition, solid fat content (SFC), water content, free fatty acids content and slip melting point (SMP). Coconut oil is dominant with lauric (C12:O), miristic (C14:0) and caprilic (C8:0) acid which composed the main trilaurin (LaLaLa), caprodilaurin (CaLaLa) and dilauromiristin (LaLaM) TAG. The content of lauric, miristic and caprilic acid in coconut oil are 51.73; 15.57 and 10.61%, respectively; while LaLaLa, CaLaLa and LaLaM TAG are 20.43; 16.23 and 15.38%, respectively. Coconut oil contains medium chain trigliserides (MCT) of 53.71%, trisaturated (St3) of 82.54%, disaturated (St2U) of 14:24%, monosaturated (StU2) of 3:22% and the proportion of high/low-melting TAG (S/L) by 49.25%. Coconut oil has a high SFC at low temperatures and a sharp decline to a temperature of 25 °C and then constant up to a temperature of about 30 ºC. Coconut oil’s SFC with about 32% was measured in temperature interval 21-22 °C, indicating that coconut oil has a good spreadibility at ambient temperature for countries that have 4 seasons. At temperature of 27 °C, coconut oil’s SFC was 3.53%, this means that at the temperatures, coconut oil slip melting point (SMP) has been exceeded. Coconut oil has SMP ranged between 24.5-26.2 °C, the water content of 0.021% and a free fatty acid content of 0.018%.
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    KINETIKA FOTODEGRADASI KLOROFIL, TOKOFEROL, DAN KAROTENOID DALAM MINYAK SAWIT MERAH
    (2016-09-29) Ayu, Dewi Fortuna; Andarwulan, Nuri; Hariyadi, Purwiyatno; Purnomo, Eko Hari
    Penelitian ini bertujuan untuk mengkaji laju fotodegradasi klorofil, tokoferol, dan karoten dalam minyak sawit merah (MSM) selama penyimpanan dalam kondisi terpapar cahaya fluoresen pada intensitas 5000, 10000, dan 15000 lux. Fotodegradasi dikaji dengan mengukur perubahan kadar klorofil, tokoferol, dan karoten MSM pada botol transparan yang disimpan dalam kotak inkubator (31,60±0,69 oC) dengan intensitas cahaya dipertahankan konstan. Sebagai pembanding, MSM murni dalam botol gelap dan transparan disimpan pada suhu (31,46±1,04 °C) dan pencahayaan normal laboratorium (476,25-484,89 lux). Hasil penelitian menunjukkan bahwa klorofil mengalami fotodegradasi mengikuti model reaksi ordo pertama dalam dua periode; yaitu periode fotodegradasi cepat selama penyimpanan 6 jam pertama dengan nilai konstanta laju (k) 3,81x10-2, 4,45x10-2, 5,64x10-2 hari-1, diikuti periode fotodegradasi lambat pada penyimpanan yang lebih lama dengan nilai k 1,41x10-2, 3,01x10-2, 4,59x10-2 hari-1 masing-masing pada intensitas cahaya 5000, 10000, dan 15000 lux. Fotodegradasi tokoferol dan karoten juga mengikuti model reaksi ordo pertama. Fotodegradasi tokoferol berlangsung dengan laju paling tinggi (nilai k 9,10x10-2, 12,02x10-2, 17,33x10-2 hari-1), sedangkan fotodegradasi karoten berlangsung dengan laju paling rendah (nilai k 0,80x10-2, 1,40x10-2, 1, 98x10-2 hari-1) masing-masing pada perlakuan intensitas cahaya 5000, 10000, dan 15000 lux. Konstanta intensitas cahaya (zi) sebagai indikator ketergantungan nilai k terhadap perubahan intensitas cahaya untuk klorofil, tokoferol, karoten berturut-turut adalah 20000, 33333, dan 25000 lux. Hal ini mengindikasikan bahwa laju degradasi klorofil paling sensitif terhadap perubahan intensitas cahaya.