| Osmanthus fragrans belongs to the genus Oleaceae,which is a traditional Chinese plant with great ornamental and industrial economic value.Osmanthus fragrans is often extracted into Osmanthus fragrans essential oil,extract or purified oil as high-grade natural fragrance raw materials,widely used in aromatherapy,daily fragrance and so on,because of its unique and charming Osmanthus fragrans fragrance.At the same time,Osmanthus fragrans has a long history of medicine and food,and occupies a space for development in the industries of medicine,food processing and health products.However,the flowering period of Osmanthus fragrans is short,the varieties are complex,the extraction rate of extracts from different processes is low,and there are great differences in aroma quality.There are also some problems,such as single application scene and low added value due to the lack of research on the biological activity of Osmanthus fragrans extract and its by-products.The main results are as follows:(1)In this paper,different extraction methods of Osmanthus fragrans were optimized and screened.Gas chromatography-mass spectrometry(GC-MS)was used to compare the composition and content of Osmanthus fragrans(O.fragrans)extracts from different producing areas(Guangxi Guilin,Zhejiang Jinhua,Jiangsu Nantong)and under technological conditions(steam distillation,supercritical fluid extraction,organic solvent extraction).The results showed that the components of Osmanthus fragrans oil varied greatly from different places and processes,and Guilin Jingui in Guangxi had a higher extraction rate among the three extraction processes.The main components are?-ionone,dihydro-?-ionone,ethyl palmitate,?-linolenic acid,d-limonene,eugenol,linalool,?-terpinene,?-terpineol,nerol and propyl decalactone.(2)Secondly,taking Guangxi Jingui(GGL)as the research object,the effects of ultrasonic time,flash time,ratio of material to liquid,extraction temperature and ultrasonic power on the extraction rate of Osmanthus fragrans oil were studied.Then,according to the main influencing factors,ultrasonic time,flash time and ratio of material to liquid,a new process,ultrasound-assisted flash extraction,was optimized by response surface method,and the extraction efficiency was increased by 80%for the first time,and the yield of Osmanthus fragrans net oil reached 3.51±0.06%(w/w).(3)At the same time,the differences of in vitro antibacterial activity,antioxidant activity,whitening activity and aroma characteristics of Osmanthus fragrans essential oil obtained by steam distillation(HDO),supercritical CO2 fluid extraction and ultrasound-assisted flash extraction of Osmanthus fragrans essential oil(UFEO)and main monomers(?-ionone,dihydro-?-ionone,carvanol,d-limonene)were also studied.The results showed that UFEO had obvious inhibitory effect on Staphylococcus aureus and Escherichia coli,especially the minimum inhibitory concentration of 7.5 mg/mL against Staphylococcus aureus.Osmanthus fragrans oils and its four potential active components extracted by other extraction processes have broad-spectrum antibacterial activity.In the antioxidant test in vitro-DPPH radical scavenging test and ABTS+free radical scavenging experiment,UFEO showed the highest scavenging activity.However,the four potentially active components performed poorly.In comparison,?-ionone(DPPH-IC50=5.70 mg/mL)and carvanol(ABTS-IC50=5.68 mg/mL)have better effects and are closely related to the molecular structure.HDO and monomer components have significant scavenging effect on hydroxyl radical.It was found for the first time that dihydro-?-ionone(IC50=1.88 mg/mL)has a good scavenging effect on OH.In addition,in the tyrosinase inhibition experiment in vitro,UFEO(IC50=8.06 mg/mL)and HDO(IC50=8.63 mg/mL)had almost the same inhibitory effect on tyrosinase activity,and both were stronger than SFEO.The results also showed that?-ionone(IC50=0.778 mg/mL)had the strongest inhibitory activity among the four monomeric species and was positively correlated with the concentration of the compound.As can be seen from the aroma radar map,the fruit aroma of the three oils is more prominent in the five aromas.The sensory score showed that,UFEO(Preference=0.6)>HDO(Preference=0.3)>SFEO(Preference=0.1).(4)In view of the fact that Osmanthus fragrans essential oil has low water solubility,low bioavailability,volatile and oxidation instability,the Osmanthus fragrans essential oil was coated with soybean protein isolate to prepare Osmanthus fragrans essential oil Pikering emulsion,and its particle size,Zeta potential and stability were investigated.At the same time,the emulsion has good antioxidant activity when the concentration of the emulsion is 32%,the DPPH·scavenging rate is 74.97%and the ABTS+·scavenging rate is 63.70%.In addition,the antibacterial activity of the emulsion against Escherichia coli is the best among the five kinds of bacteria.Based on the function of the emulsion,a good quality Osmanthus fragrans lip balm was subsequently prepared.(5)The by-product Osmanthus fragrans hydrosol produced during distillation has development value,this study provides a theoretical basis for the efficacy claim of Osmanthus fragrans hydrosol,the main components and contents were detected by GC-MS,and the antioxidant activity,in vitro whitening activity and cellular safety evaluation and whitening activity of Osmanthus fragrans hydrosol were studied.The results showed that the Osmanthus fragrans hydrosol had low toxicity and whitening activity.Therefore,it can be used in hand cream to endow more value to the by-products. |
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