Preparation Of Cyclodextrin Based Metal-organic Frameworks And Its Encapsulation Of Menthol And Controlled Release

Menthol,one of the main components of peppermint essential oil,is widely used in peppermint-scented candies because of its characteristic smell,refreshing feeling,and low cost.Menthol has high volatility,and it always releases too fast during production and storage process,which seriously affects the taste quality of food,so that its application in food is limited.In the present study,three kinds of metal-organic framework based on different cyclodextrins(CD-MOFs)were prepared for menthol encapsulation.Relationships between their crystal structures and menthol content were studied and determined the most suitable encapsulation material.The retention rate and release behavior of CD-MOF-menthol inclusion complexes(ICs)under different temperature and relative humidity conditions were studied.Based on these results,some theoretical guidance for fragrance-holding chewing gum and other fragranceholding mint products development was provided.Using potassium ions and ?-,?-or ?-CD as raw materials for CD-MOFs preparation,that is ?-CD-MOF,?-CD-MOF and ?-CD-MOF.Detailed comparisons between their structural characteristics and properties were studied.These materials were used for menthol encapsulation through a mix-heated method under high pressure.Fourier transform infrared spectra showed ICs were formed between CD-MOF and menthol.The best material for menthol encapsulation was ?-CD-MOF,the menthol content and encapsulation efficiency of which were21.76% and 22.54%,respectively.According to influenced factors on menthol encapsulation,the optimal encapsulation conditions were determined as follows: temperature of 90 ?,?-CDMOF to menthol mass ratio of 1:1 and reaction time of 60 min through mixed-grinding method.The encapsulation efficiency and efficiency were up to 27.14% and 30.58%,respectively.The thermogravimetric analysis and composite stability test showed that the optimize ?-CD-MOFmenthol has good stability.Studies on storage tests showed that menthol loss increased with the increase of temperature or relative humidity.Compared with ?-CD-menthol,?-CD-MOFmenthol exhibits excellent heat resistance but poor moisture resistance.After continuous heated-treatment at 75 ? for 1 h,the retention rate was 13.1%(w/w).Treated at 25 ? and relative humidity of 75.5% for 35 days,the retention rate was 10.4%(w/w).In order to evaluate the sustained release effect of menthol IC in actual production,oral simulation experiment and chewing gum release experiment were carried out on pure menthol and ?-CD-menthol and ?-CD-MOF-menthol.The mechanism of the gradual release of menthol was revealed(non-specific binding and site preference.)and the release rate follows the order of "pure menthol > ?-CD-menthol > ?-CD-MOF-menthol".?-CD-MOF could stably adsorb menthol aromatic molecules and significantly slow down the release rate of menthol,which provided a theoretical basis for the application of ?-CD-MOF aromatic compounds in production practice.