Effect Of Roast Process On The Flavor And Qualities Of Sesame Oil Extracted By Water

Flavor is a key index to value sesame oil quality, and roasting process have greatinfluence on sesame oil flavor. This paper roasted sesame seed by oil bath and microwave,and extracted sesame oil by water, then discussed the relationship between roast process andsesame oil flavor and qualities.This study measured color、acid value、peroxide value and oxidation stability of sesameoil. The results were: the range of acid value of sesame oil (oil bath roast) was0.2704~1.7108(KOH)/(mg/g), range of peroxide value was0.437~1.355mmol/L, the longest inductionperiod was5.57h, the shortest period was4.06h; the range of acid value of sesame oil(microwave roast) was0.0966~0.2953(KOH)/(mg/g), range of peroxide value was0.262~1.149mmol/L, the longest induction period was13.37h, the shortest period was4.13h;the influence of oil bath and microwave roast temperature on unsaturated fatty acid in sesameoil were very significant, the influence of oil bath and microwave roast time on unsaturatedfatty acid in sesame oil were non-significant.The analysis method system of sesame oil flavor was Headspace solid phasemicroextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). HS-SPMEcondition:65μm PDMS/DVB, extraction temperature was70℃, extraction time was30minutes, thermal desorption time was5minutes. GC condition: chromatographic columnwas HP-5MS Phenyl Methyl Silox; temperature of injection port was240℃; programmableheating condition: initial temperature was35℃and kept2minutes, then rised to230℃by5℃/min and kept8minutes; carrier gas: high purity Helium, flow rate was1mL/min;samoling method was unsplit stream sampling. MS condition: ionization mode was EI, ionsource temperature was230℃, mass spectrometry interface temperature was250℃, qualityof scanning range was30~500u. This experiment detect flavors in lots of pure sesame oilsamples, and got21kinds of standard flavors in sesame oil (pyrazines, furans, pyrroles, etc),then built sesame oil flavor score model: Y=0.7163Y1+0.2463Y2+0.0374Y3, the scorerange was5.15~8.65.This study took the21kinds of standard flavors as the survey index and used PCA todiscuss the influence of roast process on standard flavors in sesame oil samples. The resultswere: among sesame oil samples extracted by water (oil bath roast), the highest flavor scorecondition was220℃35min, that was the nestest flavor score to the flavor score range of sesame oil; the lowest flavor score condition was210℃15min, that was the most discrepantflavor score to the flavor score range of sesame oil, score range was-0.87~3.85; amongsesame oil samples extracted by water (microwave roast), the highest flavor score conditionwas170℃35min, that was the nestest flavor score to the flavor score range of sesame oil;the lowest flavor score condition was155℃10min, that was the most discrepant flavorscore to the flavor score range of sesame oil, score range was-1.58~5.39.The build of flavor score model open a new way to evaluate flavor of sesame oil, andprovided basis for optimizing the process of sesame oil.