Based On ~1H-NMR And GC-MS Metabolomics Approach To Understanding The Processing Effects On The Chemical In Black Carrots

Food processing affects the chemical composition,the nutritional and sensory attributes of food,and has potential health problems.However,the present detection method of chemical composition changes in processed foods is relatively simple,and there is no overall understanding the chemical composition changes during the processing steps.The metabolomics is to study all small molecule metabolites in organisms,which can systematically,comprehensively and continuously analyze the law of material changes affecting quality changes during processing.Among them,NMR metabolomics technology has the advantages of simple processing,non-destructive and short analysis time in characterizing the chemical composition of complex mixtures.And GC-MS metabolomics technology can measure volatile components with high sensitivity and perfect comparison of reference materials.Based on ~1H-NMR and GC-MS metabolic analysis methods,the more complete information on complex samples can be obtained.In this paper,black carrots rich in nutrients were studied:(1)Based on the ~1H-NMR and GC-MS metabolomics research methods,the chemical composition changes of black carrots in different freeze-thaw treatment methods were studied.(2)Based on ~1H-NMR and GC-MS metabolomics,the chemical composition differences of black carrot juice after different sterilization methods were compared.The main differential components were obtained and the quality of black carrot juice after different sterilization treatments were evaluated.Firstly,based on ~1H-NMR and GC-MS techniques combined with multivariate statistical analysis,the changes of chemical composition in the different freeze-thaw treatment of black carrots were studied.In the ~1H-NMR spectrum,32 chemical components were identified,and51 chemical components were identified in the GC-MS total ion chromatogram.By comparing the differential chemical constituents of black carrot extracts with different freeze-thaw cycles after fresh and blanching,including changes in glucose,fructose,sucrose,anthocyanins,sterols,fatty acids.The main change trend of volatile differential metabolites is the decrease of terpenes and the increase of aldehydes and alkanes.After freezing and thawing,the terpinolene in fresh samples decreased from 23.08%to 14.06%to 12.40%,while in the blanching samples,it decreased from 24.06%to 17.39%to 15.27%,and the reduction became slow.And(E)-?-bisabolene in fresh samples was reduced from 19.21%to 8.69%to 5.16%,(E)-?-bisabolene in blanching samples did not decrease after freeze-thaw reduction(from12.89%to 12.80%to 12.78%),there is a similar trend in other terpenes.It was found that the freezing and thawing of black carrots after blanching is more conducive to the retention of nutrients and volatile substances.It provided a useful data reference for the processing and storage of black carrots.Secondly,based on ~1H-NMR and GC-MS metabolic techniques combined with multivariate statistical analysis,the chemical constituents in black carrot juice treated by different sterilization methods(US sterilization,US+H sterilization and heat sterilization:60°C,80°C,90°C)were studied.Differential metabolites including glucose,fructose,sucrose,malic acid,alanine,anthocyanins,sterols,fatty acids,phospholipids,lutein and terpenes were identified.Among them,the anthocyanin content of important chemical components increased by 10.64%and 6.82%in US+H and US sterilization,respectively.And decreased by 46.34%,28.29%,and 52.20%in thermal sterilization.The fatty acid content decreased by 43.27%,34.52%,12.49%,26.48%,and 24.65%,respectively.The experimental results showed that the black carrot juice after ultrasonic sterilization was more conducive to the retention of nutrients and volatile substances.This investigation provides important analysis data for the selection of sterilization methods for black carrot juice.