Study On Preparation And Flavor Of Superfine Fragrant Rapeseed Oil Based On Maillard Reaction

Rapeseed is rich in fats,proteins,polyphenols,phytic acid,glucosinolate and other compounds.In China,rapeseed oil in rapeseed is extracted by pressing to meet the needs of residents for domestic oil.Therefore,China is a big country of rapeseed production and consumption.In recent years,small squeeze superfine fragrant rapeseed oil,which is characterized by rich flavor,has accounted for one-third of rapeseed oil market share.Due to the serious protein denaturation of rapeseed cake obtained by small pressing process,the remaining beneficial substances such as polyphenols,glucosinolate and phytic acid in rapeseed cake are not only difficult to be extracted effectively and used as pharmaceutical raw materials,but also seriously affect the value of rapeseed cake as feed.Previous studies have shown that Maillard reaction products can not only give unique flavor to food,but also improve the antioxidant activity of food.Therefore,applying rapeseed cake to superfine fragrant rapeseed oil processing by maillard reaction,can both to reduce the glucosinolates in rapeseed residues and to improve the feed safety of rapeseed cake without affecting rapeseed feed value.In addition,superfine fragrant rapeseed oill with better antioxidant activity and higher sales price can be obtained,so as to improve the utilization value of rapeseed.Small press process or fry seed-pressing process is a typical aroma rapeseed oil production process,based on the extract technology of rapeseed oil flavor characteristics and research has been reported more flavor substances,used in rapeseed cake by Maillard reaction of the preparation of rapeseed oil,the reports of the flavor and flavor material study reported less.Therefore,in order to improve the utilization value of rapeseed,this paper carried out research on the preparation of rapeseed oil based on Maillard reaction,including the enzymatic hydrolysis conditions of rapeseed cake,Maillard reaction conditions and flavor substances of rapeseed oil,and obtained the following research conclusions:(1)With amino acid nitrogen content as evaluation index,the presence of alkaline protease,single factor experiment was carried out first,and then on the basis of single factor experiment using the response surface design is optimized,the regression model,and obtain the best rapeseed enzyme hydrolysis conditions were as follows: the ratio of enzyme and substrate quality 5%,hydrolysis temperature 50 ?,substrate concentration 6%,p H value 8.0,at this time of amino acid nitrogen content is(0.082±0.070)g / 100 ml,slightly higher than predicted.(2)In an integrated sensory score value as evaluation index of superfine fragrant rapeseed oil,first preliminary experiments to determine the best temperature and time,then this condition as a premise for single factor experiment,and on the basis of single factor experiment using optimization,response surface test to determine the optimal conditions for preparation of superfine fragrant rapeseed oil for the liquid cake ratio 6:8,the cake oil ratio 1:7,and the liquid sugar ratio 6:0.3,the sensory score at this time of(96.0±0.5)points,slightly higher than predicted.The basic physical and chemical indexes of the three samples prepared under the optimal conditions of response surface test were tested.The results showed that the acid value and peroxide value all met the national standard.(3)The use of electronic nose to validate the results of sensory evaluation and distinguish the differences between samples,and then using GC-MS to detect the specific flavor substances,finally using factor analysis and PCA-X analysis to sensory score over 90 points in 17 of the samples for the analysis of the volatile flavoring substances,and the characteristics of flavor substances of superfine fragrant rapeseed oil and its distribution in each sample.The results showed that the electronic nose was able to distinguish some of the samples but was not fully effective in distinguishing the differences between the 17 samples.The results of qualitative and quantitative analysis by GC-MS showed that there was little difference in the types of flavor substances among the samples,but the difference in content was great.All the17 samples contained 40 flavor compounds,including 14 aldehydes,8 heterocyclic compounds and 7 glycosides degradation products.The proportion of aldehydes is about 50%,and the content of other substances is not very high.SPSS software was used for factor analysis of 40 flavor substances,and then PCA-X analysis was carried out using SIMCA software.Combined with the results of the two analysis methods,and ultimately determine the main characteristics of a total of 10 kinds of volatile flavor substances,including 2-11 olefine aldehyde,trans-2-decyl olefine aldehyde,the trans-2,4-sebacic olefine aldehyde,2,4-(E,Z)-,sebacic olefine aldehyde,trans-2-octene aldehyde,trans-2,4-heptyl diene aldehydes,(Z)2-E-2,4-diene acrylic,vinyl-4-2,6-dimethoxy-phenol,2,3-dihydro-3,5-2-6-methyl-4H-pyran-4-ketone and 3-furan methanol;There are two kinds of secondary volatile flavor substances,which are N-methyl-2-pyrrole formaldehyde and5-methylethylpentonitrile.As a result,it can be seen that the superfine fragrant rapeseed oil features a total of 12 kinds of flavor substances,including 2-11 olefine aldehyde,trans-2-decyl olefine aldehyde,the trans-2,4-sebacic olefine aldehyde,2,4-(E,Z)-,sebacic olefine aldehyde,trans-2-octene aldehyde,trans-2,4-heptyl diene aldehydes,(Z)2-E-2,4-diene acrylic,vinyl-4-2,6-dimethoxy-phenol,2,3-dihydro-3,5-2-6-methyl-4 h-pyran-4-ketone,3-furan methanol,N-methyl-2-pyrrole formaldehyde,5-methyl sulfonium E nitrile.The results of the study on the distribution of aldehydes show that trans-2-octenal,trans-2,4-decadienal,trans-2-decenal,(E,Z)-2,4-decadienal,trans-2,4-heptanedienal and2-undecenal have small coefficient of variation,indicating that their dispersion degree among samples is small and their content is stable.This is what makes them the characteristic flavor of superfine fragrant rapeseed oil.