Method for extracting oils from sauces while simultaneously determining fat content, peroxide value, and acid value

A method for extracting oil from a sauce and simultaneously determining fat content, peroxide value, and acid value, comprising the following steps:

• (1) adding water in an amount that is 0.5 to 3 times the weight of the sauce, stirring at 500 to 2000 rpm for 2 to 5 minutes to disperse uniformly and obtain a suspension, wherein the sauce is an oil-rich emulsified encapsulated sauce;
• (2) while stirring at 500 to 1000 rpm, adding edible salt amounting to 2-5% of the mass of the suspension and stirring until completely dissolved;
• (3) adding 95% ethanol (by volume) in an amount that is 1 to 3 times the weight of the sauce in step (1), stirring at 500 to 1000 rpm for 2 to 5 minutes to mix and disperse evenly;
• (4) conducting three extractions sequentially:
• first extraction:
• adding petroleum ether in an amount that is 1 to 3 times the weight of the sauce in step (1), stirring at 500 to 1000 rpm for 2 to 5 minutes to mix and disperse uniformly, and letting the suspension stand for 10 to 15 minutes to form three distinct layers from top to bottom:
• a petroleum ether oil phase layer, an emulsified sauce layer, and an aqueous phase layer, using a pipette to extract the upper petroleum ether oil phase layer, leaving the emulsified sauce layer and aqueous phase layer mixture;
• second extraction:
• adding petroleum ether in an amount that is 1 to 1.5 times the weight of the sauce in step (1) to the emulsified sauce layer and aqueous phase layer remaining from the first extraction, stirring at 300 to 700 rpm for 2 to 5 minutes to mix and disperse uniformly, and letting the suspension stand for 5 to 10 minutes to form three distinct layers from top to bottom:
• a petroleum ether oil phase layer, an emulsified sauce layer, and an aqueous phase layer, using a pipette to extract the upper petroleum ether oil phase layer, leaving the emulsified sauce layer and aqueous phase layer mixture;
• third extraction:
• adding petroleum ether in an amount that is 0.5 to 1.0 times the weight of the sauce in step (1) to the emulsified sauce layer and aqueous phase layer remaining from the second extraction, stirring at 300 to 700 rpm for 2 to 5 minutes to mix and disperse uniformly, and letting the suspension stand for 5 to 10 minutes to form three distinct layers from top to bottom:
• a petroleum ether oil phase layer, an emulsified sauce layer, and an aqueous phase layer, using a pipette to extract the upper petroleum ether oil phase layer, combining the petroleum ether oil phase layers obtained from the first, second, and third extractions to obtain petroleum ether oil mixture;
• (5) filtering the petroleum ether oil mixture obtained in step (4) through an anhydrous sodium sulfate funnel, collecting it into a recovery bottle, then rinsing a filter paper and funnel with 5-20 mL of blank petroleum ether, and obtaining and collecting a dehydrated petroleum ether oil mixture;
• (6) performing rotary evaporation on the dehydrated petroleum ether oil mixture obtained in step (5) at a temperature of 25-40° C. and a vacuum degree of 0.04 to 0.09 MPa, using a condenser at −5 to −20° C. to recover the petroleum ether until no petroleum ether drips from the condenser and the oil has no petroleum ether odor, continuing rotary evaporation for an additional 5-10 minutes to further reduce solvent residue, obtaining the oil in the recovery bottle;
• (7) wiping an outer surface of the recovery bottle multiple times, then blowing with nitrogen gas at a pressure of 0.01-0.2 MPa for 5-30 minutes to further reduce solvent residue in the oil, and reducing the oil to room temperature under nitrogen protection to minimize the oxidation of the oil;
• and
• (8) testing the fat content, peroxide value, and acid value of the oil after the nitrogen blowing in step (7).