Effects Of Drying Methods And Packaging Materials On The Quality Of Eucommia Ulmoides Leaves

Eucommia ulmoides Oliver is a plant of the genus Eucommia in the family Eucommiaceae.The traditional medicinal Eucommia ulmoides is Eucommia bark,which has anti-tumor,anti-oxidation,blood pressure lowering and other effects.Eucommia ulmoides leaves(EUL)and Eucommia bark have similar chemical components and pharmacological effects.EUL are listed in the “Medicine and Food Homologous”catalogue and become an important raw material for the industrial development of Eucommia ulmoides.With the implementation of the “National Eucommia Industry Development Plan(2016-2030)”,Eucommia and its related industries have been widely valued.At present,the drying of EUL in the production of enterprises mostly adopts traditional drying methods,these methods have low drying efficiency,and the quality of EUL is poor after drying.The materials for packing EUL are mostly woven bags or even no packaging.Outdated drying methods and packaging materials lead to the decline of EUL quality and affect the development of its subsequent products.In order to explore the drying method of new EUL,find suitable packaging materials,and clarify the effects of various drying methods and packaging materials on the quality of EUL,eight drying methods were used to dry EUL,and the appearance quality,drying kinetics,chemical composition and antioxidant activity of the dried EUL were measured.Then,four kinds of EUL extract-chitosan composite films were prepared and their physical properties and chemical structures were characterized.Finally,the prepared composite film and the other five materials were packaged with the dried EUL,and the appearance quality,moisture content,chemical composition content and antioxidant activity of the packaged EUL were measured within 180 days of storage.The results of the study are as follows:1.Four single drying methods and four combined methods were used to dry EUL.The appearance quality,chemical composition and antioxidant activity of EUL after drying were measured,and the drying kinetics and energy consumption of different methods were analyzed.The results show that the infrared vacuum and microwave vacuum drying methods shortened the time by 97.94% and 97.98% respectively compared with the shade drying method.Compared with vacuum drying,the energy consumption is reduced by51.14% and 58.08%,respectively.The quality of the dried Eucommia leaves is similar.Compared with infrared drying EUL,the contents of total polyphenols,flavonoids and chlorogenic acid in vacuum drying EUL increased by 22.09%,26.33% and 18.05%,respectively.Compared with microwave drying EUL,the contents of total polyphenols,total flavonoids and chlorogenic acid in microwave vacuum drying EUL increased by13.75%,37.95% and 8.78%,respectively.The combined drying methods of infrared vacuum and microwave vacuum combine the advantages of a single drying method and are worthy of promotion and application.2.Four kinds of composite films were fabricated using EUL extract and chitosan as raw materials,and their physical properties and structures were characterized.The results show that the addition of EUL extract-chitosan will deepen the color of the chitosan film,but the moisture content,crystallization characteristics and thermal stability of the film will not change significantly.When the addition amount of EUL extract-chitosan reaches 5.0wt%,the thickness and tensile strength of the composite film are higher than those of pure chitosan film,and the elongation at break does not decrease significantly,which has application prospects.3.The EUL were packed in woven bags,polyethylene(PE)plastic bags,vacuum packaging bags,and homemade EUL extract-chitosan composite film.The appearance color,moisture content,microstructure,total flavonoids and total polyphenols,and antioxidant activity of EUL were determined within 180 days to evaluate the effect of different packaging materials on the quality of EUL.The results show that the appearance quality,total polyphenol and total flavonoid contents and antioxidant activity of EUL packed with nylon ropes and woven bags decreased significantly.The content of total polyphenols and total flavonoids in EUL tied with ropes decreased by 7.22% and 7.34%,respectively.The appearance quality,total polyphenol and total flavonoid content,and antioxidant activity of EUL packed in PE plastic bags and composite films were similar.There is no significant change in EUL packed in vacuum bags and woven bags lined with plastic bags compared with those dried before storage.The EUL packaged in composite film can reach a quality similar to that of PE plastic bags,and it has the potential to replace PE plastic bags.In conclusion,drying methods and packaging materials significantly affect the quality of EUL.The quality of EUL dried by microwave vacuum and infrared vacuum drying method is close to that of EUL dried by vacuum drying method,and the energy consumption is significantly reduced,which is a better drying method of EUL.Woven bags lined with plastic bags have lower packaging costs and can better protect the quality of EUL during storage.EUL extract-chitosan composite film material exhibits similar protective effect to plastic bags,and it is necessary to further reduce costs and improve performance.This study provides a reference for the industrial drying processing and packaging of EUL,and it is helpful for the industrialization development of EUL.