Study On The Effect Of Amino Acids And Reducing Sugars On Fragrant Rapeseed Oil Prepared By Maillard Reaction

The fragrant rapeseed oil prepared by the Maillard reaction is based on the enzymatic solution prepared from rapeseed meal as the reaction source,and the reducing sugar in it reacts with amino acids to produce rapeseed oil with a unique flavor.At present,the research on fragrant rapeseed oil mainly focuses on process optimization and volatile substance analysis,lacks the study of the effect of amino acids and reducing sugars on flavor substances in the Maillard reaction,and there are fewer studies on the law of flavor change at temperature and time.Therefore,the preparation of fragrant rapeseed oil by Maillard reaction in this project uses sensory evaluation combined with gas chromatography-mass spectrometry(GC-MS)method to analyze the effect of amino acids and reducing sugars on the flavor of fragrant rapeseed oil,to explore the most important amino acids and reducing sugar types that have the most important impact on flavor,to explore the change law and the most appropriate reaction conditions for the formation of key flavor substances by reaction temperature and time,and to provide production guidance for the preparation of fragrant rapeseed oil by Maillard’s fragrance source method.Firstly,the amino acid types and contents in rapeseed meal before and after roasting were detected,proline,lysine,glutamic acid and arginine with the largest difference in content before and after the Maillard reaction were selected as the research objects,and they were added to the enzymatic solution to prepare fragrant rapeseed oil,and the influence of these four amino acids on the basic indicators,fatty acids,nutrients and harmful substances of the Maillard reaction to prepare concentrated coriander seed oil was further analyzed,and the amino acid types most critical to its flavor formation were screened out,and the sensory evaluation was combined with GC-MS.The effect of amino acids on the main flavor substances of fragrant rapeseed oil was obtained.The experimental results show that the basic indicators of fragrant rapeseed oil and the content of benzopyrene(Ba P)meet the requirements of national standards,and the content of tocopherols,polyphenols and sterols is abundant.Rapeseed oil in the lysine group had the highest content of unsaturated fatty acids(USFA)(93.16%).Lysine can effectively enhance the flavor of rapeseed oil,and its overall sensory flavor evaluation has the highest overall score(14.70 points),of which the pyrazine content is the highest(24.02 μg/g),with a strong nutty flavor/barbecue taste(4.80 points),the lowest aldehyde flavor substance content(17.77 μg/g),grass flavor(1.40 points)and oil flavor(1.10 points)are weaker.As the most critical amino acid for providing nitrogen in the Maillard reaction,lysine will have an effect on the main characteristic flavor substances such as 2-methylpyrazine,2,5-dimethylpyrazine,nonaldehyde,furfural and so on in the fragrant rapeseed oil.Secondly,through the detection of the reducing sugar content in rapeseed meal before and after roasting,glucose,fructose and maltose were selected as the research objects,and fragrant rapeseed oil was prepared by adding them to the enzymatic solution,and its basic indicators,fatty acids,nutrients and harmful substances were detected,and finally the effect of reducing sugar on flavor substances was analyzed and the key reducing sugar types were found.The results show that the basic indicators and Ba P content of fragrant rapeseed oil meet the requirements of national standards;the nutrient content is rich.The added fructose group had the highest USFA content(91.51%),and the overall sensory aroma evaluation score was the highest overall(14.60 points).Fructose can enhance the flavor of fragrant rapeseed oil,which has the highest content of pyrazine(23.28 μg/g),making it nutty/barbecued(4.70 points),aldehydes(14.82 μg/g)and isothiocyanates(0.58μg/g)have the lowest substance content,grass flavor(1.20 points)and grease flavor(1.10points)are weaker,and spicy taste is strongest(4.70 points).Fructose is a key reducing sugar that provides a carbon source in the Maillard reaction,and has a greater impact on the main characteristic flavor substances in fragrant rapeseed oil,such as hexaldehyde,2-ethyl-6-methyl-pyrazine,2-ethylpyrazine,furfuryl alcohol,and dimethyl trisulfide.Finally,the best amino acids(lysine)and reducing sugars(fructose)studied in the first two chapters were added to the enzymatic lysate,and the physicochemical indexes,micronutrients,fatty acids,hazardous substances and flavors of fragrant rapeseed oil prepared at different reaction temperatures(130.0～160.0℃)and reaction times(10～30 min)were prepared and analyzed.The results of the study are as follows: with the increase of temperature and time,the acid price and peroxide value,benzopyrene content and saturated fatty acids of concentrated coriander oil gradually increased,and the moisture content,iodine value and nutrients and unsaturated fatty acid content showed a downward trend,moreover,the effect of Maillard reaction temperature on the production of concentrated coriander oil is more significant than the reaction time.Through the sensory evaluation of flavor and the analysis of flavor substances,it was found that the concentration of pyrazines and aldehydes changed the most with the increase of temperature and time,and under the reaction conditions of 160.0°C/20 min,the sensory evaluation of fragrant rapeseed oil had the highest comprehensive score(3.86 points),the highest content of pyrazine(24.11 μg/g),the nutty flavor/barbecue flavor(4.90 points),and the lowest content of aldehyde flavor substances(14.92 μg/g),Grass flavor(1.60 points)and oil flavor(0.80 points)are weaker;furfury alcohol content is(0.74 μg/g),caramel paste taste is lighter(0.90 points);isothiocyanate content is the lowest(0.69 μg/g),giving a unique spicy taste(4.80 points),and the changes in furan,alcohol and ketones are not significant.Therefore,160.0°C/20 min can be used as the optimal reaction condition for the preparation of fragrant rapeseed oil.In summary,through the study of the effects of amino acids,reducing sugars and Maillard reaction temperature and time on fragrant rapeseed oil,lysine and fructose are the most critical amino acids and reducing sugar types that provide nitrogen and carbon sources in Maillard reactions,and the optimal Maillard reaction conditions are 160.0°C/20 min.