| Sea buckthorn(Hippophae L.),also known as acid thorn,belongs to the sea buckthorn family Hippophae family,is a pioneer tree for wind protection and sand fixation.Sea buckthorn fruit is rich in a large number of flavonoids,which have anti-inflammatory and bactericidal,blood lipid reduction and other pharmacological effects.It has high development and application value.However,its product structure is single,mainly sea buckthorn puree and sea buckthorn powder,and the taste is unbearable.Therefore,studying the extraction,purification and application of flavonoids in sea buckthorn can improve the theoretical basis for deep processing of sea buckthorn.In this paper,the flavonoids in sea buckthorn pomace were extracted by microwave,ultrasound and aqueous phase as raw materials,and the extraction process was optimized by response surface experiments.Then,the sea buckthorn flavonoids were purified by macroporous resin,the antioxidant activity and main components of sea buckthorn flavonoids were studied,and finally a nutritious sea buckthorn flavonoid tablet candy with sweet and sour taste was developed by using sea buckthorn flavonoid extract.The main conclusions of this study are as follows:(1)Research on the extraction process of sea buckthorn flavonoids.Univariate and response surface experiments were used to optimize the process parameters of ultrasonic extraction,microwave extraction and aqueous phase extraction of sea buckthorn flavonoids.The optimal conditions for ultrasound-assisted extraction were as follows: ethanol concentration was 60%,material-liquid ratio was 1:26,and the extraction amount of sea buckthorn flavonoids was 21.70 mg/g when the ultrasonic time was 52 min.The optimal conditions for microwave-assisted extraction were as follows: ethanol concentration of 70%,material-liquid ratio of 1:25,microwave time of 2.5 min,and extraction of sea buckthorn flavonoids of 22.13 mg/g.The optimal conditions of aqueous two-phase extraction method were as follows: ethanol mass fraction 24%,ammonium sulfate mass fraction 19%,material-liquid ratio of 3:100,ultrasonic time 45 min,and the extraction amount of sea buckthorn flavonoids was 12 mg/g.The total flavonoid extraction by microwaveassisted extraction was significantly higher than that of ultrasound-assisted extraction and aqueous two-phase extraction(P<0.05),and the extraction efficiency was the highest.(2)Purification process of sea buckthorn flavonoids and their antioxidant activity.In the experiment,four macroporous resins(D101,AB-8,X-5,NKA-9)sea buckthorn flavonoids were separated and purified,and in the static adsorption experiment,the macroporous resin AB-8 had the strongest adsorption performance,its optimal adsorption time was 5 h,the p H value was 4,and the ethanol concentration of the eluent was 80%.On this basis,the optimal separation and purification process parameters of macroporous resin AB-8 were further determined by dynamic experiments: loading concentration of 2 mg/m L,loading flow rate of 1.5 m L/min,loading volume of 70 m L,eluate flow rate of 2 m L/min,and eluate dosage of 100 m L.After lyophilization,the content of flavonoids in the product was 31.5%.Finally,the antioxidant activity of sea buckthorn flavonoids was evaluated,and the freeze-dried sea buckthorn flavonoids had strong scavenging ability against ABTS+ free radicals and DPPH free radicals,and had good total reducing power.(3)Development of sea buckthorn flavonoid tablet candy.Sea buckthorn flavonoid tablet candy was prepared by powder direct tablet pressing method with sea buckthorn fruit powder,red jujube powder powder and sea buckthorn flavonoid extract as the main raw materials,xylitol as sweetener,microcrystalline cellulose as lubricant,and magnesium stearate as binder.The formula of sea buckthorn flavonoid tablet tablets was optimized by using response surface experimental sand.The results showed that when the amount of sea buckthorn fruit powder was 38%,the amount of red jujube powder was 21%,the amount of sea buckthorn flavonoid extract was 6%,the amount of xylitol was 20%,the amount of microcrystalline cellulose was 14%,and the addition of magnesium stearate was 1%,the sensory score of sea buckthorn flavonoid tablet candy reached the highest 87.26 points.Under this formula,the tableted candy pressed by direct tableting method has a complete surface,uniform color,warm turmeric yellow,suitable taste and sweet taste,good chewiness,its hardness is 52.6 N,the crumbling brittleness is 0.57%,and the difference in sheet weight is 0.51±3.6%. |
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