Effect of combustion method on the yield, specific gravity, and color of oleoresin of Dipterocarpus grandiflorus

Oleoresin is a non-timber forest product of Dipterocarpus spp. tree from Dipterocarps family that can be yield from tapping process. Some countries, such as Thailand, and Laos, the combustion method was conducted in the tapping hole to increase oleoresin yield. However, in East Kalimantan, the combustion method in tapping holes has never been carried out, and results are still unknown. This study aimed to determine the effect of the combustion method in Dipterocarpus grandiflorus tapping hole on volume, specific gravity and color changes of oleoresin yielded. The research was carried out in aforest area with particular purposes Labanan, Berau, East Kalimantan by making burning and non-burning tapping holes in two groups of different diameters of D. grandiflorus trees. The volume of oleoresin yielded for two weeks was collected in a plastic bottle and then measured. Specific gravity testing was conducted using the pycnometer method and the color properties of oleoresin by computer vision analysis method. The present study showed that a tree diameter of 50 cm contained more oleoresin yield than a tree diameter of 40 cm, both in combusted and non-combusted tapping holes. The combustion method showed a decreased on volume of oleoresin up to 39.03%, but the specific gravity increased to 0.96-0.97. Meanwhile, the combusted method produced more darker oleoresin, namely L* 11.75, a* 3 and b* 7.75. However, this recent study provided that the best method to obtained oleoresin is non-combusted tapping holes.