The effect of pH of the medium and inoculum volume variations on the enrichment of unsaturated fatty acid in rice bran oil by solid fermentation method using Aspergillus terreus

The rice milling process will produce side products, one of them is rice bran which has enormous potential both in terms of economy and health if it is further processed, but until now the use of rice bran is still very limited. Rice bran contains high oil content, which is around 10-23% consisting of 80% unsaturated fatty acids and 20% saturated fatty acids. Unsaturated fatty acids are generally obtained from fish oil, but fish oil has a high price and smells fishy. The content of unsaturated fatty acids in rice bran can be enriched by using Aspergillus terreus, because these molds can produce unsaturated fatty acid higher than other types of Aspergillus. This study examines the effect of pH of the medium variations and the volume of the mold variations on increasing unsaturated fatty acid content in fermented rice bran oil using Aspergillus terreus. The fermentation method used is solid-state fermentation with modified Bligh-Dyer extraction method and Gas Chromatography/Mass Spectrometry (GC-MS) instrument is used to determine the composition and content of unsaturated fatty acids in bran oil. The result showed that the optimum pH of the medium for increasing the unsaturated fatty acid contents in rice bran oil using Aspergillus terreus, which is at pH 5 with the initial unsaturated fatty acid content of 74.835% to 76.719%. For the optimum inoculum volume to increasing the unsaturated fatty acids contents in rice bran oil is 7 mL with the acid content of unsaturated fatty acids (linoleic acid) of 37.9% to 41.394%.