Effect Of The Extraction Technology,Component Identification And Fresh-keeping Effect Of Polyphenols From Rye Grain

Rye?Secale cereale L.?is an annual herb of Gramineae.It is widely planted in cold regions of north China,Europe and North America.Rye is rich in natural active ingredients such as alkyl resorcinol,phenolic acid,lignin and benzooxazine.Studies have shown that plant polyphenols have many physiological functions such as scavenging free radicals,anti-aging,anti-oxidation and inhibiting microorganisms.In order to make full research and development of rye resources,this paper extracted and separated polyphenolic antioxidants from rye seeds.The anti-oxidation and anti-bacteria components were identified by spectroscopy and mass spectrometry?HPLC-MS?.And rye will be added to spiced beef as a preservative.The research content and results are as follows:1.Two different extraction processes,ultrasonic extraction and supercritical CO₂ extraction,were used to optimize the extraction process by single factor,orthogonal design and response surface methodology.The results showed that the optimum technological parameters of ultrasonic extraction of polyphenols from rye seeds were as follows: ethanol concentration was 60%,solid-liquid ratio was 1:28.4 g/m L,ultrasonic time was 37.3 min,temperature was 70?,and the yield of polyphenols from rye seeds was 3.73 mg/g.The optimum conditions of supercritical CO₂ extraction of polyphenols from rye seeds were as follows:entrainer was 95% ethanol,material-liquid ratio was 1:4 g/m L,extraction pressure was 5230 psi,and extraction pressure was 5230 psi.The extraction time was 2.07 h and the extraction temperature was55.65?.The yield of rye polyphenols was 0.20 mg/g.It was found that the effect of ultrasonic extraction of rye polyphenols was better than that of supercritical CO₂ extraction.2.Through the purification and detection of polyphenol extract from rye grain,four compounds were deduced: matairesinol,tricosylresorcinol,pentacosenylresorcinol and sitosteryl-18:1.Two of them are alkyl resorcinol,one is lignin,one is phytosterol,and the relative content of alkyl resorcinol is the highest.3.By adding different concentrations of Rye polyphenol extract into five groups of spiced beef samples: negative control group without any preservative,positive control group with 0.02% butyl hydroxyanisole?BHA?,control group with 0.02%,0.06%,0.10% Rye polyphenol,and regular p H,total bacterial colonies,thiobarbituric acid reactive substance?TBARS?of each group of spiced beef samples.TBARS and TVB-N were tested to study the fresh-keeping effect of rye polyphenols on spiced beef.The results showed that BHA and Rye grain polyphenols could significantly inhibit the rapid propagation ofmicroorganisms in spiced beef during storage,significantly inhibit the oxidation of protein and lipid in spiced beef,and delay the deterioration of spiced beef.The highest concentration of 0.10% Rye grain polyphenols had better antioxidant effect on spiced beef and could be used as natural freshness preservative.