At certain time within 30- 45 days of treated rice bran showed decrement of moisture ( Jayaraman et.al., 1994). Thus, with the range of 30 to 45 days of storage, 40 days was chosen in this studies. The result obtained from study shown in Figure 4.1 and Figure 4.2. There are two groups of comparison; stabilized and unstabilized group.
Based on the result obtained, the moisture of rice bran with different types (Bario, lowland and upland), content shows small increment from day 25 to 40. It might be due to inactivation lipase enzyme to degrade the free fatty acids in the rice bran by stabilized process. Stabilized rice bran show increment of moisture from average 1% -8.57% for bario, 1.4% -7.46% for lowland …show more content…
There similar increment of rice bran oil extracted using ethanol and methanol in both Soxhlet and soxtherm extraction method. Both of the methods show the extractability of oil of using ethanol and methanol higher than hexane. In 3,4 and 5 hours extraction of Soxhlet and soxtherm result in Figure 4.3, also indicated the 4 hours extraction time exhibit no significance different between solvent and rice bran varieties. The low extractability comparable to previous research done ranging between 18-20% (Roger et al., 1993) might due to the climate and location of the rice had been planted. As these rice types are comes from different location of planted, the factors of location and climate might influence the result of study. Figure 4.4 shows the extraction of crude rice bran oil using soxhlet extrtaction methods with modification of time. At P< 0.05. Thus, 4 hours extraction can be used in further extraction using methanol as solvents instead of 5 hours.
This condition yielded the oil extractability below 20% and the oil extractability was not very high. This might be due to the poor solubility of some portions of triglyserol in oil with an extensive disulfide bonding and aggregation (Hamada, 1997). Moreover, the triglyserols in rice bran oil are a complex mixture and could bind with other compounds in rice bran such as phytate, fiber (Hamada, 1997). 22.214.171.124 Effect of Bran Ratio