Judul: Kajian mutu minyak sawit kasar dan analisis karakterisrik olein serta stearin sebagai hasil fraksinasinya
Abstrak: Crude Palm Oil (CPO) is a vegetable oil obtained from oil palm fruit extraction process (Elais guinneensis) with reddish orange colour. Standards applicable in Indonesia for CPO released by the National Standardization Agency stated in the document SNI 01-2901-2006 include free fatty acids (maximum 0.5%), moisture and impurities (maximum 0.5%), iodine value (50-55 g yodium/100 g), and reddish orange. In addition to chemical characteristics, other characteristics CPO such as carotene content and DOBI are also important to know as additional data. To increase the value-added palm oil, fractionated CPO usually produces two components, namely liquid olein and stearin with solid form. This study aims to obtain quality data CPO based on SNI-01-2901-2006, carotene, DOBI, and investigate the characteristics of the olein and stearin. Analysis of five types of CPO samples show different data on each CPO character. The result showed moisture content and impurities 0.33-5.39%, free fatty acids 3.84-5.88%, iodine value 50.38-54.15 g yodium/100 g, carotene content 428.28-815.56 ppm, and DOBI 1.34-3.11. The variation can be influenced by several factors including the processing of each palm oil mill and palm fruit oil condition of maturity that will be processed into crude palm oil. Fractination process carried out by melted CPO at 50 °C. The melted CPO was cooled until 15 °C with cooling rate 5 °C/30 minutes. Then crystallization carried out at 12°C for 16 hours. Separation was done by vacuum filter to get olein and stearin. The Olein and stearin were produced from fractination were analyzed. The results showed iodine value, slip melting point, and carotene content for olein consecutive 57.75-60.02 g yodium/100 g, 18.33-24 °C, and 438-536 ppm. While for stearin iodine value 34.95-42.32 g yodium/100 g, slip melting point 50.33-52 °C, and carotene content 215-276 ppm. Olein and stearin have very different characteristics.
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Judul: Karakteristik Minyak Sawit Kasar Selama Penyimpanan dan Pengaliran
Abstrak: Crude palm oil (CPO) is one of Indonesia's main commodity. Nowadays, Indonesia is the largest CPO producer in the world. To increase the competitiveness of CPO in Indonesia, handling, storage, and transportation of CPO should be managed efficiently. The objective of this research was to obtain the basic data about the quality characteristics and rheological properties of CPO during storage and pipe flow transportation. The quality parameters of CPO that observed in this study were free fatty acids (FFA), iodine value, carotenoid content, and the deterioration of bleachability index (DOBI). The observed parameters of the rheological properties were flow behavior index (n) and consistency index (K). CPO that used in this research had 3.44% of FFA, 52.64 of iodine value, 816 ppm of carotenoid content, and 3.21 of DOBI. CPO was stored at the storage temperature of 20, 25, 30, 35, and 40 oC over 4 weeks. The results showed that during storage, FFA levels increased, while the carotenoid content and DOBI decreased. The higher storage temperature resulted in higher rate of decline in CPO quality. At each storage temperature, the longer storage resulted in decreased quality of CPO. Based on this research, the best storage temperature to maintain the quality of CPO was at 20 oC. At the room temperature, CPO was pseudoplastic (0<n<1 and K>0), but at the higher storage temperature, CPO had rheological properties that closer to Newtonian (n=1 and K>0). The analysis of rheological properties during storage showed that storage time had no effect on the rheological properties of CPO. Study on CPO flow by using circulated pipeline in isothermal conditions showed that melting temperature was the critical temperature for maintaining low viscosity to assure the flow of CPO. Flow of CPO in high temperature caused decreasing in quality of CPO significantly.
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Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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