Study On The Characterization And Application Of Nanoparticles In Shaoxing Huangjiu

Chinese rice wine(Huangjiu),beer and wine are known as the three ancient wines in the world.Huangjiu is mainly produced in Zhejiang,China,has a long history,and is a valuable asset of Chinese culture.However,at present,the development of Huangjiu still faces many challenges,such as complex and difficult to control production process and non-standard market standards.Therefore,a lot of effort has been invested.But there are still many problems to be urgently solved,such as the standardization of process flow,the optimization of bacteria in"Qu",and hazardous substance control.Nanoparticles(NPs),one kind of microstructure,widely present in food,and can accurately reflect the quality of food.The universality on nanoparticles provides new opportunities for solving the problems that exist in the development of Huangjiu.In this thesis,Shaoxing Huangjiu is picked up as a research object.Based on the prior results of protein nanoparticles(NPP)in our lab,the two kinds of dilution agents(ultrapure water and 15%(v/v)ethanol solution)and the addition of exogenous substances were utilized to explore the properties of NPs in Huangjiu.The applications of NPs in Huangjiu,including the authenticity and the bottle year were carried out.First of all,Kuaijishan Huangjiu with the three year bottle year was taken as the research object,and the existence of NPs was revealed by dynamic light scattering(DLS),Zeta-potential,fluorescence spectroscopy and other technologies.Their physical and chemical properties such as size,surface charge distributions along NPs were discussed.The results of DLS showed that the NPs in Huangjiu were solid particles with a hydraulic radius(R_h)of about 3.3 nm.Upon the dilution of two kinds of agents,the results of R_h suggest that the events of dissolution and swelling of NPs occurred simultaneously,but the patterns of this size modification depend on the polarity of the diluent agents.Zeta-potential results further verify this conclusion.On the other hand,the particle size distributions of NPs in all testing solutions follow Gaussian distribution.All the above-mentioned results indicate that:1.the spatial distribution of polymer molecules in NPs is uneven;2.the change of R_h in NPs is closely related to the type and quantity of intermolecular bonds between polymer chains;3.NPs are in quasi-equilibrium;4.all changes are controlled by the same chemical law.At the same time,combined with the fluorescence results,we found that these changes occurred rapidly at the beginning of dilution.In addition,three phases,oil phase,water phase and intermediate phase were obtained from the extraction procedure by adding n-hexane to Huangjiu.DLS test results show that the concentration of NPs in the oil phase is lower than the detection limit of this technology.In contrast,there are NPs in the aqueous phase,but their size change is different from that of the previously mentioned two kinds of dilute agents,which further validates the conclusion that the dissolution and swelling of NPs are closely related to the polarity of the dilute agent.The results of diffusing wave spectroscopy(DWS)reveal that the intermediate phase is gel,which could come from polymers in Huangjiu solutions or NPs precipitation and the following agglomeration.The results of Inductively Coupled Plasma Mass Spectrometry(ICP-MS)show that the concentration of aluminum element in the aqueous phase was lower than that of Huangjiu,which implies that aluminum element should prefer to affine to polymer chains,which could be a part of NPs.Secondly,we will further explore the differences of NPs in different brands of Huangjiu(Kuaijishan,Guyuelongshan,Tapai and Xianheng)of three bottle year.The results of DLS indicated that the R_h of Xianheng Huangjiu was the largest,ca 6.5 nm,about 3 nm differences with the other three kinds of wine.The alcohol turbidity test displays that the non-biological stability of Xianheng Huangjiu was the worst,which might also be related to R_h.It also shows that because of the small R_h in Huangjiu,the brand of Huangjiu cannot be identified by R_halone.The addition of exogenous substances led to the general reduction of NPs in four kinds of Huangjiu,but there was no significant difference between brands due to the small R_h(<10nm).This result implies that the components of NPs include various organic acids.In addition,NPs have antioxidant activity,and their free radical scavenging rate is negatively correlated with iron reduction.Finally,this study discussed the differences of NPs in five different year bottle of Huangjiu from the two brands of Kuaijishan and Guyuelongshan.The change trend of the two types of Huangjiu is basically consistent,and the DLS test results indicate that with the increase of wine age:1.The particle size of NPs in Huangjiu becomes smaller,with a variation range of about 1nm,indicating that old wine is more stable than new wine;2.NPs are generally attractive to each other.The alcohol turbidity test also shows that the non-biological stability of the old wine is higher.In addition,the maximum wavelength of the fluorescence spectrum redshifts with the aging of the wine,which suggests the microenvironment of the fluorophore becomes more hydrophilic after storage,and it may be that the polarity of polyphenols and other substances increases with the aging time.At the same time,all wines have a certain degree of antioxidant activity.The bottle year of wine is inversely proportional to the free radical scavenging rate and directly proportional to the iron ion reduction.In summary,this thesis discusses the properties of NPs in different brands of Shaoxing Huangjiu with various bottle year.These studies are expected to expand the research and application of nanoparticles in processed foods and provide a new way to solve the challenges faced by the development of Huangjiu.