Judul: Optimation of Unsaturation Level Increase of Crude Palm Oil with Desaturase by Using Continuous Systems
Abstrak: Desaturase is the catalyst for the formation of the double bond carbon chains either monounsaturated fatty acids (MUFA) or polyunsaturated fatty acid (PUFA). Desaturase producing fungi can be used to increase the unsaturation of crude palm oil (CPO). In the present study the fungi used was Rhizopus oryzae, because it is edible. The purpose of this study was to test the ability of Rhizopus oryzae in producing desaturase, extending enzyme-substrarate contact time, and increasing unsaturation of crude palm oil using bioreactor system model of spiral hose with height variation. First, the fungi were cultured in liquid media with supplements containing certain salts and CPO using Erlenmeyer. After incubation, the culture supernatant was separated from the biomass (liquid fermentation). Liquid fermentation was transferred into a bioreactor system model of continuous spiral hose with height variations (50 cm, 100 cm, 150 cm, 200 cm and 250 cm). Palm oil was pumped from the bottom of the column using a peristaltic pump. CPO was then characterized by determining the iodine number, saponification number, acid number and fatty acid composition both before and after the bioconversion. The results showed that Rhizopus oryzae fermentation liquid was able to increase the unsaturation CPO and multiple unsaturated fatty acid content. On studied conditions, the maximum unsaturation increase occurred at a height of 200 cm with iodine value change of 17.091 g I2/100g CPO with the contact time for 35 minutes. This indicated that the longer the contact time, the higher the unsaturation of CPO. Iodine number could also decrease due to the oxidation of the C = C double bond, that was indicated from the results of iodine number at a height of 250 cm with iodine value change of 15.886 g I2/100g CPO for contact time of 47 minutes. At the optimum conditions, the saponification number was 183.489 g KOH/g CPO and acid number was 9.36 g KOH/g CPO with levels of free fatty acids (% FFA) of 0.936%. Fatty acid composition of palm oil after optimum bioconversion conditions showed increase in oleic acid, and linoleic acid.
Keyword: polyunsaturated fatty acid, liquid fermentation, desaturase enzymes, Rhizopus oryzae, and continuous systems

Judul: Kendali Proses Deasidifikasi dalam Pemurnian Minyak Sawit Merah Skala Pilot Plant
Abstrak: Deacidification is one of the steps of palm oil refining process which is carried out using alkali solution such as NaOH (sodium hydroxide). Carotenoids in palm oil is affected by the process of deacidification that has to be controlled to minimize the destruction of carotenoids during processing. The objective of this research was to improve deacidification process in pilot plant scale so that the process can produce low level free fatty acids (FFA) and higher carotene recovery in high yield neutralized red palm oil (NRPO). Characterization of physical and chemical properties of crude palm oil (CPO) such as moisture content, FFA, carotene content, saponification number, iodine value, peroxide value, and color were determined before processing. Excess NaOH was found in the trial of deacidification in the pilot plant scale and it gave 17.5% excess NaOH. The degumming was done before deacidification process. The optimization of temperature and time for deacidification process were using central composite design (CCD). Response surface method (RSM) was used to observe the influence of treatments on reduction of FFA, carotene recovery, and yield of NRPO. The result showed that the optimum condition of deacidification process was at 61 ± 2oC in 26 minutes, and strength of NaOH 16oBe with 17.5% excess of NaOH. In this optimum condition, the process could achieve reduction level of free fatty acid was about 96.35%, recovery of carotene was 87.30%, and yield was 90.16%.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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