| Tangerine peel Orange peel has extremely high medicinal value.The main biologically active components are flavonoids and volatile oil;the polymethoxylated flavones(PMFS)contained in flavonoids have strong biological activity and good market application value.Nobiletin(Nob),a flavonoid extracted from tangerine peel,has a very unique structure and a large fat solubility,resulting in low bioavailability in the organism,which reduces the medicinal or edible value of tangerine peel and affects its potential as a functional food or health food.First,the flavonoids was extracted from Pericarpium Citri Reticulatae(PCR)using ultrasonic extraction technique,and the antioxidant activities of them were tested by1,1-diphenyl-2-picrylhydrazyl(DPPH)assay and2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid(ABTS)assay.Then,this study selected the nobiletin as the research material,designed the nanoemulsion prepared by three different emulsifiers,various physical and chemical properties of the emulsion were studied.In vitro digestion experiments were conducted to explore the effects of three nanoemulsions on the bioavailability of nobiletin.Experimental results show that the best process conditions were 60% ethanol mass fraction,ultrasonic time 36 min,and material-liquid ratio 1:25(g/m L).Under theserequirements,the forecasted value of flavonoid extraction rate is 24.99 mg/g.The DPPH free radical scavenging ability of tangerine flavones increases with increasing mass concentration.In the range of 300-500 μg/m L,the DPPH free radical scavenging ability of tannin flavone after ethyl acetate extraction and AB-8 resin purification increased by 71.80%and 85.91%,respectively.According to the values of IC50 and AEAC values,the antioxidant capacity of flavonoids from different peels can be judged as follows: AB-8 resin purification> ethyl acetate extraction >> before purification.The anti-ABTS free radical scavenging ability of tangerine flavone increased with its mass concentration,and the magnitude of the enhancement was stronger than the DPPH scavenging ability under the same sample concentration.In the range of 50 ~ 250 μg/m L,the ABTS free radical scavenging ability of tannin flavone after ethyl acetate extraction and AB-8 resin purification increased by 76.79%and 90.67%,respectively.According to the IC50 and AEAC values,the antioxidant capacity of the three groups of flavonoids can be judged as: AB-8 resin purification> ethyl acetate extraction >> before purification,the above is consistent with the conclusions obtained by the DPPH method.Then,The preparation method of the emulsion was as follows: oil phases were prepared by dispersing 100 mg nobiletin into the rapeseed oil(40g)followed by Ultrasonic at room temperature.Aqueous phases were prepared by adding the emulsifier(6g)into first-order water(154g).Coarse emulsions were formed by mixing oil phase(40g)and aqueous phase(160g),and then blending them for 10 min at ambient temperature using a high-speed mixer homogenizer,Coarse emulsions were then passed through a high-pressure homogenizer for six passes at 100 Mpa to form an oil-in-water nanoemulsion.Through the detection of the particle size and ζ-potential,the particle size is less than 200 nm,which indicates that the emulsion is indeed the nobiletin nanoemulsion.After the successful preparation of the nobiletin nanoemulsion,in order to study its bioavailability,each nanoemulsion was passed through a three-step in vitro digestion model that simulates mouth,gastric and small intestine digestion.The results show that the nanoemulsions prepared by Tween 20 have the best bioaccessibility after in vitro digestion simulation,followed by Sodium stearyl lactate(SSL),and the worst is Ethyl Lauroyl Arginate Hydrochloride(LAE). |
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