Vegetable oils are typically extracted with hexane; however, health and environmental concerns over its use have prompted the search for alternative solvents. Mustard oil was extracted with isopropyl alcohol (IPA) to produce an IPA‐oil miscella suitable for industrial applications. Single‐stage extraction resulted in 87.6 % oil yield at a 10:1 (v/w) IPA/flour ratio. Multiple‐stage extraction resulted in higher extraction efficiency with lower IPA use. Four‐stage cross‐current extraction at an IPA/flour ratio of 2:1 (v/w) per stage resulted in 93.7 % oil yield. At 45 °C, a 91.5 % oil yield was achieved with three‐stage extraction using a 2:1 (v/w) IPA/flour ratio. Any changes to the pH of the mixture resulted in reduced oil yield. Water also reduced the extraction efficiency. The azeotropic IPA solution containing 13 % water extracted ~40 % less oil than did dry IPA in both single and multiple‐stage extractions. Some polar compounds were also extracted, including sugars; however, protein extraction was negligible. The protein left in the extracted meal was not degraded or lost during the extraction. The results suggest that IPA is an excellent solvent for mustard oil, but water content exceeding 5 % in the solvent adversely affects the oil extraction and reuse of the IPA.

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Using an isopropyl alcohol (IPA):flour [volume:weight (ml:g)] ratio of 1.5:1 per stage of extraction resulted in an oil yield of 86.3%. The combined miscella (IPA + oil), which contained 90.6 wt% IPA, 9.8 wt% oil, and 2.1 wt% water, was used as a feedstock for biodiesel production by transesterification. Transesterification of the IPA/oil miscella dehydrated using adsorption on 4Å molecular sieves with 1.2 wt% (based on oil) potassium hydroxide for 2 h at 72 °C converted only 29% of the feed to esters. The addition of methanol (MeOH) resulted in an ester yield of 87%, consisting of 79% methyl ester and 7% isopropyl ester when starting with an IPA:oil:MeOH molar ratio of 146:1:30. By increasing the KOH catalyst to 3 wt%, the ester yield increased to 94%. To increase the ester yield, the miscella was pretreated with sulfuric acid. This resulted in a reduction of the IPA content, the removal of other impurities such as phospholipids, and reduction of the water mass fraction to less than 1%. When IPA was used as a cosolvent with methanol in the transesterification process, a very high ester conversion (>99%) was achieved. The biodiesel produced was compliant with ASTM standards, showing that IPA can be used as a solvent for oil extraction from yellow mustard flour.

The Chilean granado bean (Phaseolus vulgaris L.) contains nutritionally valuable proteins, and there was indication that the proteins can help in the prevention of diabetes. To further explore tis potential purified samples of the bean proteins is required. A membrane-based process was developed for the isolation of proteins from granado beans, adapted from methods reported earlier for mustard protein processing. The optimised process consists of alkaline protein extraction from granado bean flour at pH 10, ultrafiltration at concentration factor 4 and diafiltration with diavolume 4 followed by isoelectric protein precipitation at pH 4. The process starting with granado beans containing 28% protein, recovered 60.1% of the protein as precipitated protein isolate (PPI) and 7.2% as acid soluble protein isolates (SPI). The losses in the process system were approximately 26% of mass and 18.8% of nitrogen due to removal of non-protein nitrogen and small molecular weight components, likely carbohydrates. The protein contents of the PPI and SPI were˜92 % and˜62% on a moisture-free basis; the protein content of the SPI produced is considerably lower than typical isolates. This may be due to the co-recovery of high molecular weight carbohydrates. The water absorption capacity and nitrogen solubility index, of the PPI and SPI were measured and compared to other oilseed isolates. The PPI showed high water absorption (<400%). SPI dissolved completely-a nitrogen solubility index of 100%, while PPI had low nitrogen solubility near its isoelectric point. Both isolates had traits desirable for easy incorporation into food products.