Study On Preparation Process Of Strong Fragrant Sunflower Seed Oil And Formation Mechanism Of The Flavor Substances

Sunflower is one of the important oil crops in China,and its seeds are not only high in oil content but also rich in nutrition.strong fragrant sunflower seed oil is prepared by pressing after high temperature treatment,Its aroma enhancement effect is achieved by the Maillard reaction during the treatment process.Enterprises have found that when shelling at the same frequency in the processing of sunflower seed products,incomplete hulling or fragmentation of seeds of different grain sizes can occur,but this phenomenon can be avoided by grading and then frequency division shelling,and the graded sunflower seed kernels are better for producing strong fragrant sunflower seed oil.Although there is still a lack of research on the differences in the composition of sunflower seed kernels after grading.The research on strong fragrant sunflower seed oil mainly focuses on process optimization and analysis of flavor substances,and there is a lack of research on the correlation between flavor substances and amino acids and reducing sugars.Therefore,in this article,the composition of sunflower seed kernels with different particle sizes was analyzed.On this basis,appropriate sunflower seed kernels were selected to study the preparation process of strong fragrant sunflower seed oil,and then its optimal preparation conditions were explored.Combined with sensory evaluation and gas chromatography-olfactometry-mass spectrometry,the correlation between key flavor substances and amino acids and reducing sugars was studied.The details are as follows:1.Study on the composition of sunflower seed with different particle sizesThe composition differences of sunflower seed kernels with different particle sizes from the same variety were analyzed and compared.The following results were obtained: the oil content and the relative content of linoleic acid decreased with the increase of particle size;The content of crude protein and amino acid increased with the increase of particle size;The content of sugar decreased with the increase of particle size;The content of total chlorogenic acid decreased with the increase of particle size;The total starch content decreased with the increase of particle size;The content of resistant starch increased first and then decreased with the increase of particle size;The total cellulose content increased first and then decreased with the particle size;The content of hemicellulose decreased with the increase of particle size.The difference in constituent content of sunflower seed kernels with different particle sizes from the same variety may be related to metabolic differences during the growth and development of sunflower seeds,so the mechanism of the difference in constituent content needs to be further analyzed to elucidate its metabolic pathway and flow direction.2.Study on the preparation process optimization and physical chemistry Index of strong fragrant sunflower seed oilUsing sensory evaluation results as the scoring standard,the single factor and orthogonal test were used to optimize the roasting and enzymatic preparation processes of strong fragrant sunflower seed oil.The results showed that the optimal conditions for the roasting process of strong fragrant sunflower seed oil were as follows: roasting temperature 150℃,roasting time 30 min,and water content 3.5%.Under these conditions,strong fragrant sunflower seed oil has a strong roasted flavor and nutty flavor,with moderate oil flavor.The optimum conditions of the enzymatic process were as follows: reaction temperature 120℃,reaction time 30 min,ratio of enzymatic hydrolysate 2:1,and ratio of liquid to oil 1:3.Under these conditions,sunflower seed oil has an aromatic flavor,with moderate roasting flavor and nutty flavor.The acid value,iodine value,peroxide value,BaP content and fatty acid composition of the strong fragrant sunflower seed oil prepared under the two optimal preparation conditions all met the national standards.At the same time,tocopherols and sterols are effectively retained.3.Study on the key flavor substances affecting the flavor of strong fragrant sunflower seed oil and their formation reasonsAccording to the optimal preparation process for strong fragrant sunflower seed oil,the microstructure of sunflower seed kernels and the changes in amino acid and reducing sugar contents during the reaction process were studied.The amino acid-reducing sugar simulated Maillard reaction system was established to preliminarily analyze the correlation between the key volatile substances affecting the sense of strong fragrant sunflower seed oil and their substrates.The results revealed that the roasting process makes the content of proteins and sugars in the system increased,thereby effective in enhancing the Maillard reaction.Analysis of volatile substances in the system,infer Arginine,histidine,and glutamic acid were the main amino acid substrates of Maillard reaction in the preparation process,while fructose,glucose,galactose,and xylose were the main reducing sugar substrates.Also,combined with the literature,it is speculated that the main characteristic flavor substances that form nutty,roasted,oily and fruity flavors.Further speculation that the main characteristic flavor substances forming fruit flavor were pinene and calamenene.Among them,the main substrates for the formation of2,5-dimethylpyrazine were arginine and fructose,the main substrates for the formation of(E,E)-2,4-decadienal were glutamic acid and xylose,and the main substrates for the formation of lilac were glutamic acid and galactose.This study examined the selection of raw materials,process optimization,quality of strong fragrant sunflower seed oil and detection of flavor substances,which provided a theoretical basis for the further study of the production of strong fragrant sunflower seed oil and the formation of flavor substances.