Judul: Pemanfaatan Pati Kelapa Sawit Sebagai Bahan Baku Dekstrin
Abstrak: The oil palm trunks become waste from the rejuvenation of the oil palm plantation. The extraction of the oil palm trunk yielded 4,7% of starch. The starch was extracted and characterized its physical and chemical properties and compared it to the commercial starches (sago and tapioca). The extracted starch was modified to be dextrin by enzymatic and acid hydrolysis. The oil palm starch contained lipid (0,37%), ash (0,68%), fiber (1,78%) which were higher than that of sago and tapioca. However, the amylosa content (28,67%) of the oil palm starch was lower. The gelatinization temperature of oil palm starch (770C) was similar with that of sago, but was higher than of tapioca. The whiteness degree of starch (83,02%) and the paste clarity (15,4%T) of the oil palm starch were lower than sago and tapioca. The α-amilase susceptibility of oil palm starch was lower than that tapioca and sago; however, the susceptibility of the oil palm starch on acid was almost similar with sago and tapioca. The dextrin quality of the oil palm starch, either from enzymatic or acid hydrolysis was lower than the tapioca; however, it was almost similar with the sago based on ash content, viscosity an solubility in cold water.
Keyword: 

Judul: Hidrolisis Pati Palma Menggunakan Pullulanase dan β-Amilase
Abstrak: Palm trees are unexplored carbohydrate sources that wiidely spread in Indonesia. Palm starches are still under utilized since lacked information about their pysico-chemical properties. Hydrolysis of these starches are the right application without concerning their characteristics. This research investigated the starches from five types of palm trees, namely Metroxylon sago (commersial sago), Metroxylon sp. (sagu rumbia), Arenga pinnata, Arenga microcarpa (sagu baruk), and Caryota mitis; and the hydrolysis of palm starches by using degrading enzymes, i.e. pullulanase and β- amylase. The result showed that palm starches are normal starch which contain17-21% of amylose or 83-79% of amylopectin which differed in branch-chain lengths, and caused typical products from each type of palm. Pullulanase as debranching enzymes, cleaveged the starch to produce DP 13.9- 20.8 of Short-Chains Amylose (SCA). The starch contained 22.2-38.8% of β-limit dextrins as the residue of β-amylolysis. Simultaneous hydrolysis by using β-amylase and pullulanase mainly produced maltose for all starch with DP of 1.7-2.9.
Keyword: 

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.
Keyword: