Preparation Of Licorice Total Flavonoids Microcapsules And Application In The Preservation Of Chilled Beef

Licorice(Dlycyrrhiza uralensis Fisch.),also known as Guolao,sweet grass,sweet root seed,is a leguminous licorice plant and one of the homologous plants of medicine and food.Licorice is rich in flavonoids.Modern pharmacological studies have shown that total flavonoids of licorice have anti-inflammatory,antibacterial,antioxidant and other biological activities.However,flavonoids are unstable to oxygen,temperature,light,etc.,resulting in low utilization of flavonoids;in addition,the special odor of flavonoids limits their application in the food field.In this project,licorice is used as raw material to study its microencapsulation and its practical application effect by extracting total flavonoids of licorice.The main research contents and results are as follows:1.Using licorice as raw material,the heating and reflux method was used for extraction,and the influence of three factors,ethanol concentration,extraction time and solid-liquid ratio on the content of total flavonoids in licorice,was investigated.On this basis,three factors and three levels were designed by Box-Behnken.The experimental scheme was established,and the mathematical model was established through the regression analysis of variance,and the optimal extraction process conditions were determined as follows: ethanol concentration of76%,extraction time of 2.4h,and solid-liquid ratio of 1:26(g/m L).The flavonoid content was5.42±0.06%.2.Using bio-embedding technology,using yeast cells as wall material and total flavonoids of licorice as core material,the effects of core-to-wall ratio,embedding time and embedding temperature on the microencapsulation of total flavonoids of licorice were investigated by single factor test.On this basis,the response surface methodology was used to optimize the microencapsulation process,and the optimal microencapsulation process conditions were determined as follows: core-to-wall ratio 4.3:1(g/g),embedding time 7.2 h,embedding temperature 42.50 ° C.Under this condition,the encapsulation rate can reach 77.68±0.34%,and the total flavonoid content in the microcapsules is 52.69 mg/g.The total flavonoids and microcapsules of licorice have better stability than flavonoid powder in the form of microcapsules under high temperature,ultraviolet light and long-term storage conditions,so the flavonoid microcapsules have a good protective effect on the stability of the active ingredients of flavonoids.3.By applying the total flavonoid extract of licorice,the yeast microcapsule solution of flavonoids,and the chitosan solution to the preservation of chilled meat,through the juice loss rate,total number of colonies,volatile base nitrogen,high iron myoglobin and fuzzy mathematics Sensory evaluation of these six indicators compared the preservation effect of different preservatives on chilled meat.Compared with the blank group,different freshkeeping liquids had certain fresh-keeping effects on chilled meat.The total flavonoids group of licorice can prolong the shelf life of chilled meat by 2 days,and the fresh-keeping effect is not as good as that of the microcapsule group and the chitosan group(p<0.05).4 days,and the preservation time is the same as that of the chitosan group(p>0.05).Therefore,licorice total flavonoids microcapsules can protect the quality of chilled meat.