Oil Production from Yarrowia lipolytica Po1g Using Rice Bran Hydrolysate

The purpose of this study was to produce microbial oil from Yarrowia lipolytica Po1g grown in defatted rice bran hydrolysate. After removing oil from rice bran by Soxhlet extraction, the bran is subjected to acid hydrolysis with various sulfuric acid concentrations (1–4% v/v), reaction times (1–8 h), and reaction temperatures (60–120°C). The optimal conditions for maximum total sugar production from the hydrolysate were found to be 3% sulfuric acid at 90°C for 6 h. Glucose was the predominant sugar (43.20 ± 0.28 g/L) followed by xylose (4.93 ± 0.03 g/L) and arabinose (2.09 ± 0.01 g/L). The hydrolysate was subsequently detoxified by neutralization to reduce the amount of inhibitors such as 5-hydroxymethylfurfural (HMF) and furfural to increase its potential as a medium for culturing Y. lipolytica Po1g. Dry cell mass and lipid content of Y. lipolytica Po1g grown in detoxified defatted rice bran hydrolysate (DRBH) under optimum conditions were 10.75 g/L and 48.02%, respectively

Extraction, identification and quantitative HPLC analysis of flavonoids from sarang semut (Myrmecodia pendan)

The objective of this study was to extract and determine total contents of phenolic and flavonoid compounds as well as to identify and quantify some flavonoids from sarang semut (Myrmecodia pendan). Water bath extraction at 55 °C was employed for extracting flavonoids from sarang semut. The effects of parameters such as extraction time, composition of solvent mixture and solvent to sample ratio on extraction were investigated. From (33) factorial design the optimum extracting parameters were determined as follows: extraction time, 4 h; ethanol/water composition, 80%; and solvent to sample ratio, 50 ml/g. Under these optimal conditions, a yield of 13.82% was obtained. The free radical scavenging activity (antioxidant activity) of the extract was evaluated using DPPH radical and it was found that the IC50 occurred at 96.21 ± 9.03 μg/ml of extract. The total phenol and flavonoid contents were determined using designed methods and found to be 330.61 ± 2.13 mg GAE/g and 63.28 ± 1.75 mg QE/g of dry extract, respectively. The extract obtained under optimum conditions was analyzed by HPLC and five flavonoid compounds were identified and quantified; they are kaempferol (13.767 mg/g), luteoline (0.005 mg/g), rutine (0.003 mg/g), quercetin (0.030 mg/g) and apigenin (4.700 mg/g) of dry extract

Release of phenolic acids from defatted rice bran by subcritical water treatment

Oil production from rice bran, an undervalued by-product of rice milling, produces defatted rice bran (DRB) as a waste material. Although it is considered a less valuable product, DRB still contains useful substances such as phenolic compounds with antioxidant, UV-B-protecting and anti-tumour activities. In this study the phenolic acids in DRB were extracted with subcritical water at temperatures of 125, 150, 175 and 200 °C. Analysis of total phenolics using Folin-Ciocalteu reagent showed about 2-20 g gallic acid equivalent kg(-1) bran in the extracts. High-performance liquid chromatography analysis showed low contents of phenolic acids (about 0.4-2 g kg(-1) bran). Ferulic, p-coumaric, gallic and caffeic acids were the major phenolic acids identified in the extracts. Thermal analysis of the phenolic acids was also done. The thermogravimetric curves showed that p-coumaric, caffeic and ferulic acids started to decompose at about 170 °C, while gallic acid did not start to decompose until about 200 °C. Subcritical water can be used to hydrolyse rice bran and release phenolic compounds, but the high temperatures used in the extraction can also cause the decomposition of phenolic acids