Abstract:
Rice bran wax is a byproduct of rice bran oil refining process in Sri Lanka, which is also used as a
feed of cattle and as a raw material for candle production although it has many nutrients for
known health benefits. Present study used two treatments for purification of crude rice bran
wax. First treatment was a two steps process. The First step of it was the removal of residual oil
from crude wax with hexane. After that it was subjected to further defatting with Isopropyl
Alcohol which yielded a light-yellow color powder. AOAC method 965.33, AOAC method 920.157
and SLS 313 methods were adopted for the analysis of peroxide value, melting point, Free Fatty
Acid (FFA) and acid values respectively. The results are as follows; melting point of the sample is
78 0C, moisture content 1.25 ± 0.00 %, FFA content 4.9981 ± 0.00 %, acid value 7.8702 ± 0.00 ml
NaOH/g and peroxide value 17.036 ± 0.00 mEq/Kg. The second step of the treatment followed
by bleaching with 10% sodium borohydride in IPA which yielded a light-yellow dry powder with
melting point of 80 0C, moisture 1.02 ± 0.00%, FFA 0.7664 ± 0.00 %, acid value 1.0852 ± 0.00mL
NaOH/g, peroxide value 13.6034 ± 0.00 mEq/Kg. The Second treatment was a single step
process where crude rice bran wax refluxed with 99% ethanol which yielded a light-yellow color
powder with a melting point of 79 0C, moisture 1.56 ± 0.00%, FFA 0.8123 ± 0.00 %, acid value
1.1502 ± 0.00 mL NaOH/g, peroxide value 13.65 ± 0.00 mEq/Kg. Fourier Transform Infrared
Spectroscopy analysis of refined rice bran waxes from both treatment procedures indicated that
those samples contained following functional groups such as; aliphatic primary amine, esters, α
and β unsaturated esters, alcohol group, alkane group and aldehyde group. There is no any
significant difference between the two refined samples obtained from the two treatments with
regards to peroxide value, FFA, melting point and acid value, except moisture. Finally, it can be
concluded that the second method is comparatively cost effective and easy method to refine the
rice bran wax for further utilizing processes such as developing edible fruit and vegetable
coating waxes.
