Study On The Change Law Of Volatile Flavor Compounds In Processing And Storage Of Rapeseed Oil

Through the study of the changes of volatile flavors during the processing and storage of rapeseed oil,it provides a theoretical basis for the rational use of rapeseed to produce concentrated rapeseed oil.This topic used electronic nose combined with gas chromatography-mass spectrometry to study different varieties(Sichuan Shuanggao(A),Sichuan low-sulfur glucosinolate(B),Anhui low-sulfur glucosinolate(C),Nanjing double-low rapeseed(D)),Different oil extraction methods(cold press,hot press,leaching,fried seeds combined with leaching),different dry temperature,same fried seed moisture,same drying temperature,different moisture content,different oven simulation of fried seed time,different microwave frying time and storage of vegetables The effect of the volatile flavor of seed oil is as follows:(1)A,B,C,D rapeseed oil volatile flavors were identified 32,34,29,21,respectively,mainly composed of glucosinolate degradation products,heterocyclic substances,oxidative volatiles,and content The difference is obvious.The substances common to the four rapeseed oils are provided by methyl cyanide,cyclopropiacetonitrile,5-capronitrile,carbon disulfide,methyl mercaptan,propadiene,propyne,2,6-dimethylpyrazine and the like.A includes 13 kinds of peculiar substances,among which 3-butenyl isothiocyanate,2-butenenitrile,methacrylonitrile and propylene alcohol account for a relatively high proportion;B includes 17 kinds of peculiar substances,among which nitrogen pyridazine accounts for The highest;C,D include 9 kinds of specific substances,respectively,cyclobutyl methoxide,1-(2-chlorophenyl)-2-isopropylamino-ethanol accounted for the highest proportion.Through the analysis of flavor substances and sensory scores,the rapeseed varieties significantly affected the flavor of rapeseed oil.The local double-high rapeseed oil in Sichuan has the best flavor.(2)It has been found through several different oil extraction methods that the types of sulphur glycosides,heterocyclics,aldehydes and ketones are increasing in the hot-squeeze compared with other oil-extracting methods,while the types of hydrocarbons are decreasing.After the crushed seeds were pressed(compared to the unsqueezed seeds),the hydrocarbon content showed a decreasing trend;the ketones,aldehydes,glucosinolates and heterocyclics showed an increasing trend.Through sensory analysis,it was found that the oil extraction method had a significant effect on the flavor of rapeseed oil,and the rapeseed-squeezed rapeseed oil had more flavor substances and better flavor.(3)The content of alcohols,ketones and heterocyclics in the same fried seeds at different drying temperatures increased first and then decreased.The content of aldehydes and glucosinolates increased,and the content of hydrocarbons decreased.Through flavor analysis and sensory analysis,high temperature drying has a significant effect on the flavor of rapeseed oil.The contents of alcohols,ketones,glucosins and heterocyclics showed fluctuations in the same drying temperature.The content of esters and hydrocarbons increased first and then decreased.The content of aldehydes decreased first and then increased.There are 46 kinds of substances unique to 7.75%-17% of fried seeds,including 8,12,12,10,4 kinds,respectively,3-mercapto-1,2,4-triazole,2-methyl-2-Nitropropane,dextrorotene,3-methoxypyrid ine,ethyl lactate accounted for the highest proportion.Sensory analysis showed that the moisture content of the fried seeds was 7.75%.(4)The content of glucosinolates,heterocyclics,aldehydes and ketones increased in different ovens during simulated frying time;the content of alcohols and acids increased first and then decreased;the content of hydrocarbons decreased.The content of alcohols and ketones fluctuated in different microwave frying time.The content of aldehydes and heterocyclics showed an increasing trend;the content of glucosinolates showed a decreasing trend.The unique substances in different ovens simulated 0min-30 min include 89 species,including 11,12,19,22,25,respectively,with 3,3-dimethylhexane,n-valeronitrile,1-vinylimidazole,2,4-Dimethylthiazole,2-ethyl-5-methylpyrazine accounted for the most.There are 52 kinds of substances unique to different microwave fried seeds for 1min-5min,including 16,13,4,9,10 kinds,respectively,vinyl butyrate,ethyl n-hexanoate,2,3,5-trimethylpyrazine Acetyl alcohol and tropone are the most abundant.Sensory analysis found that the oven simulated the best 30-minute flavor of fried seeds.(5)Electronic nose analysis found that the leaching method,cold pressing,oven simulation of fried seeds for 10 min and oven simulation of fried seeds for 15 min flavor and other treatments have different flavors,while microwave fried seeds for 1min and fried seeds combined with leaching have similar flavors.Sex;while other treatments have similar flavors.(6)The volatile flavor of rapeseed oil during storage period showed that the content of aldehydes,ketones,hydrocarbons,alcohols,glucosinolates and heterocyclics fluctuated;the content of esters increased first and then decreased.The unique substances stored in 0d-30 d include 69 species,including 4,9,11,14,17,14 species,respectively,2,3,5-trimethylpyrazine,pyridone,phenylacetaldehyde-ethylene glycol The acetal,p-cresol acetate,3-furfural,and 2,3-diphenyl-2,3-butanediol accounted for the highest proportion.The electronic nose analysis found that the overall flavor of rapeseed oil stored at 0d and stored for 6d was similar,and the other samples showed a change in flavor with the storage time.