Study On Extraction And Purification Of Flavonoids From Helianthus Annuus And Preservation Effect Of Compound Preservative On Chilled Pork

Abelmoschus manihot as one of the plants rich in flavonoids,it has always been the focus of research by the majority of scholars.However,the research on flavonoids as preservative is relatively few.Therefore,it is of great significance to develop the preservative of flavonoids of C.chinensis.In this paper,the dry powder of Abelmoschus manihot was used as raw material to extract flavonoids by alcohol extraction method.The extraction conditions were optimized by response surface development,and then the preservation effect of chilled pork was studied by making compound fresh-keeping liquid with chitosan.The main research contents are as follows:(1)The response surface method was used to optimize the alcohol extraction conditions of the flavonoids in Abelmoschus maniula.The extraction time was 2 h,the ratio of material to liquid was 1:20,and the temperature was 60? through single factor experiments.Based on the above conditions,a combination design was carried out.The selected independent variables were extraction time,material-to-liquid ratio and temperature,and the selected response value was the extraction rate of flavonoids.The three-factor three-level response variable analysis was carried out to obtain the optimal conditions.The temperature was 61?,the ratio of material to liquid was 1:23,and the extraction time was 2.3 h.The measured extraction rate of flavonoids was 7.01%.(2)LS-300B macroporous resin was used to purify the extract,and the content of flavonoids reached 25%after purification.Qualitatively analysis by high performance liquid chromatography(HPLC)revealed the flavonoids in the alcohol extract of C.anemone,among which flavonols and isoflavones were the most abundant,and the antioxidant index of the purified flavonoids was determined.At the concentration of 1 mg/mL,the total reducing power was 0.296,the scavenging rates of superoxide anion radical,hydroxyl radical and DPPH radical were 70%,and 76%,indicating that flavonoids of C.aureus had good antioxidant effect.(3)Through single factor experiment,select the most suitable preservative liquid preparation ratio,and select four groups of blank group,flavonoid group,chitosan group,and composite group to explore the preservation effect of cold fresh pork.The composite group has the best The fresh-keeping effect of the fish is pH 6.21 at 10 days,the juice loss rate is 1.5%,the TVB-N is 14 mg/100g,it is still fresh meat,the total number of colonies is 3 lg CFU/g,and the sensory evaluation is the best.In summary,the composite preservation liquid of chitosan and flavonoids of Abelmoschus manihot has a good fresh-keeping effect,which provides a data basis for subsequent development and also provides a theoretical basis for the further utilization of Abelmoschus manihot.