Effect of drying time-temperature history on the quality of coconut oil from the wet grated coconut | |
| Author | Joko Nugroho Wahyu Karyadi |
| Call Number | AIT Thesis no.PH-01-6 |
| Subject(s) | Coconut oil--Quality Coconut--Drying |
| Note | A thesis submitted in pa1iial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources, and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Wet grated coconut was subjected to rotary drying with surface heating temperatures of 90, 115 and 130°C. The effect of time-temperature history on the moisture removal rate and the quality of coconut oil were investigated. The drying time required for 3 kg of wet grated coconut were 170, 120 and 82.5 minutes respectively at 10 rpm to reduce moisture content from 49% to 2.5% (wet bases). It was observed that the drying periods reduced with the increased surface heating temperature. The drying was found to be a constant rate process with drying rate were 0.0062, 0.0092 and 0.0137 kg H20 removed/min. Conventional logarithmic model could not be used for modeling the moisture removal with time. Instead, a linear relationship between the moisture ratio and drying time represented the drying process satisfactorily. Also, the grated coconut drying by conduction heating in terms of the mean bulk temperature computed from time temperature history and exposure time was found to be reasonably accurate. This model could be used in over a wide range of operation conditions The mechanical extraction process resulted in oil yield of 49 ± 3.0% from the grated coconut dried at l 30°C and final moisture content of 2.5%. The highest level of FFA in coconut oil (0.27 ± 0.04%) was obtained from samples dried at 90°C up to 15% of moisture content and the lowest value of FFA was obtained from dry process (0.053 ± 0.005 %). However, the levels of FFA in all oil samples were below the critical limit. The peroxide value in oil samples from all treatments was found to be undetectable based on titration method. The highest mean absorbance of coconut oil (0.48 ± 0.46) was obtained for surface heating temperatures at 90°C and 7% of moisture content and the lowest of mean absorbance was obtained from drying at surface temperature of 90°C and 15% of moisture content. The oil samples from solvent extraction also resulted the lower in mean absorbance value in term of color. The highest moisture and volatile content of coconut oil was obtained by surface heating temperatures 115°C and 15% of MC (0.36 ± 0.44%) and the lowest moisture and volatile content was resulted by surface heating temperatures at 130°C, 2.5% of moisture content (0.09 ± 0.04%). Refractive index of coconut oil when drying at surface heating temperatures 130°C and 2.5% of moisture content was the highest (1.4527 ± 0.0001) and the lowest of refractive index resulted in coconut oil with drying at surface temperature 130°C and 7% moisture content was 1.4487 ± 0.0009. The results showed that drying wet grated coconut at high temperature at 130°C did not affect on the quality of oil. It was concluded that the wet grated coconut could be dried at 130°C to reduce drying period without any effect on the quality of coconut oil. However, the possibility advantage of using partially dried coconut for oil extraction over that of the traditional copra process needs to be studied further. |
| Year | 2001 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Postharvest and Food Process Engineering (PH) |
| Chairperson(s) | Jindal, V.K. |
| Examination Committee(s) | Athapol Noomhorm ;Rakshit, S.K. |
| Scholarship Donor(s) | DAAD |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |