Composition Analysis And Comparative Evaluation Of Alkylresorcinol Homologues In Whole Wheat Flour And Wheat Flour

Whole wheat flour has rich dietary fiber,oligosaccharides,polyphenols and other active substances,and has gradually become a hot topic of consumption and research.Among these compounds,alkylresorcinol has been regarded as an important characteristic substance and specifically present in wheat bran.To further understand the composition differences of alkylresorcinols in different wheat flour types,it was necessary to to establish a fast,stable and reliable method for the determination of alkylresorcinols in wheat flour.In this study,two methods for the determination of alkylresorcinols by gas chromatography-mass spectrometry(GC-MS)and liquid chromatography-triple quadrupole tandem mass spectrometry(LC-MS/MS)were established.Subsequently,two methods were used to explore the content of alkylresorcinols in wheat flour from different regions,and and then combine cluster analysis,principal component analysis and factor analysis to comprehensively evaluate the composition of alkylresorcinol homologues.This study could provide guidance for the authenticity identification of wheat flour related products in the food industry.The main research results are as follows:1.A method for the analysis of alkylresorcinols in wheat flour by ultrasonic extraction combined with pretreatment of silanization derivatization and GC-MS detection was established.Through the optimization of the ultrasonic pretreatment conditions,the extraction process of ultrasonic treatment was conducted at 600 W in 2min,a material-to-liquid ratio of 1:40 for 2 times by ethyl acetate and the extraction efficiency was the highest.The derivatization conditions,chromatographic conditions and selective ions were subsequently optimized.The method verification results showed that the established gas chromatography-mass spectrometry-selected ion(GC-MS-SIM)method of alkylresorcinol homologues(C15:0?C23:0)has good precision and sensitivity.The linear correlation coefficients(0.001?5?g/m L)were higher than 0.99 and the detection limit is below 2.0?6.1?g/g.The relative standard deviation(RSD)range is less than 5%,and the recovery rate of standard addition is90.02%?104.84%.This method was shown to have good precision and sensitivity.2.The methods of ultrasonic extraction and solid-phase extraction purification,combined with LC-MS/MS was established to simultaneously detect 5 alkylresorcinol homologues(C15:0?C23:0).It was separated by C₁₈ chromatographic column,eluted with a mixed gradient of ammonia(0.1%)and acetonitrile,and detected by electrospray negative ion mode(ESI-)scanning and multiple reaction monitoring mode(MRM).After methodological verification,the detection limit of this method is2.0?8.4?g/g,and the correlation coefficients in the linear range(0.001?5?g/m L)are all greater than 0.98.After the wheat flour sample was purified by CLEANERT C₁₈solid phase extraction column,the recovery rate of spiked standard was89.05%?100.05%.3.GC-MS and LC-MS/MS were used to detect the content of alkylresorcinols in70 wheat flours in different regions,and the results of the two methods were found to be consistent.The total amount of alkylresorcinols in most foreign whole wheat flour was higher than domestic whole wheat flour and reached to 1535.2?g/g;C21:0content was the most abundant in all wheat flour samples,accounting for domestic whole wheat flour varieties were mainly located in the fifth cluster and clearly differed from foreign whole wheat flour.The main two components in the principal component analysis model of the total amount of diphenols explained 88%of the sample which effectively distinguishing wheat flour and whole wheat flour;basing on the PCA of homologous content.Morever,the cumulative contribution rate of the first two factors were 72.03%.The model of principal component was followed as F=0.675F₁+0.311F₂.