| Hydrangea(Hydrangea macrophylla)is a plant of Hydrangea of Saxifragaceae,also known as Ziyang flower,powder ball flower and eight immortal flower,which is widely cultivated all over the world.Hydrangea has been loved by many consumers with its advantages of large color and beautiful shape,and has a good market development prospect.In recent years,Hydrangea has been used more and more in Flower Technology.However,due to the short flowering period of Hydrangea and the limitation of regional environment,the development and promotion of Hydrangea industry are seriously hindered,and the emergence of dried flowers provides a new way for the development of hydrangea industry.As a new technology,vacuum freeze-drying technology can significantly improve the ornamental value of dried flowers.High quality dried flowers can be produced by vacuum freeze-drying technology combined with color and shape protection treatment.This technology can keep the natural beautiful shape and color of flowers,which can be transported for a long distance,extended viewing period and improved viewing durability.Using vacuum freeze-drying technology that can make Hydrangea keep its unique spherical shape and beautiful colors,so as tobreak the limitation of its short flowering period and regional environment,and promote the development of its industry.At present,the production technology and technical level of dried flowers in China lags behind that of other countries,and there is no systematic and complete method for the production of dried flowers of hydrangea.In order to solve the above problems,the 'endless summer'variety of hydrangea produced in Fuzhou was used as the experimental material to carry out vacuum freeze drying,color protection agent treatment and color preservation of immortal flower organic pigment replacement solution.The experiment is mainly to control the pre freezing temperature and vacuum degree of Hydrangea in the vacuum freeze-drying process,determining the optimal combination of parameters,reducing the shrinkage rate of Hydrangea in the drying process and achieve the best shape protection effect.The hydrangea was treated with different color protection agents before drying,the formula of color protection agent with better color protection effect was determined,and the color protection scheme of hydrangea in the process of vacuum freeze drying was improved.The purpose of the experiment also is to analyze the absorbance and color difference of the existing permutation solution of immortalized flower organic pigment under light and oxygen,and to treat it with ultraviolet absorbent and antioxidant to improve the color retention effect of the permutation solution onhydrangea.The results of this study can provide technical reference for the development of dried flower industry in China,and help to expand the market prospect of hydrangea.The main results are as follows:1.Study on vacuum freeze drying of hydrangea: in the process of vacuum freeze drying of hydrangea,the shape protection effect of dried hydrangea is improved by controlling the pre-freezing temperature and vacuum.The wrinkle rate of dried hydrangea flowers under different pre-freezing temperature and vacuum degree was measured by single factor test,and the parameters with good shape protection effect under single factor were analyzed,and the best shape protection scheme of vacuum freeze drying was obtained by variance analysis of two-factor test.The results show that the average shrinkage rate of dried hydrangea increases with the increase of pre-freezing temperature and vacuum in the process of vacuum freeze drying.The analysis of variance of two-factor test showed that the flower shape of dried hydrangea could be protected to the greatest extent under the conditions of pre-freezing temperature of-45 ?,pre-freezing time of 2 h and vacuum of 300 ? bar.2.Study on color protection of hydrangea by vacuum freeze drying:the color protection effect of dried hydrangea was improved by using different color protection agents before vacuum freeze drying.The L,a and b values of each group of samples were measured by automatic color difference meter before drying,and then the samples were soaked indifferent concentrations of citric acid,magnesium chloride and konjac gum.After drying,the L1,a1,b1 values of the corresponding samples were measured again,the color difference ?E was calculated,and the color protection agent with better color protection effect was analyzed.The results show that when the concentration of magnesium chloride is0.5% and 1.0%,the color difference ?E is less than 4,and when the concentration is 1.0%,the color difference ?E reaches 3.15,which has the best color protection effect,and is the best color protection agent compared with the other two.At the same time,citric acid,magnesium chloride and konjac gum were matched with different concentrations through orthogonal experiment,and the optimal combination of dried hydrangea flower color protection scheme was 2.0% citric acid + 0.5%magnesium chloride + 0.3% konjac gum by range analysis.The color difference ?E is 2.97,which can maximize the color protection effect.3.Study on color preservation of organic pigment replacement solution of hydrangea immortal flower: to study the color-preserving effect of ultraviolet absorbers and antioxidants on the organic pigment replacement solution of hydrangea immortal flower.The organic pigment replacement solution was treated with different concentrations of ultraviolet absorbents(UV-0,UV-9,UV-531)and antioxidant 405.The absorbance curve with time,the absorbance change of the maximum absorption wavelength and the change of color difference ?E weremeasured and observed.compared with the original organic pigment replacement solution,the factors with better color retention effect were analyzed.The results show that:(1)From the aspect of photosensitivity,through the color retention test of organic pigment replacement solution with ultraviolet absorbent,it is found that the average decreasing rate of maximum absorption wavelength absorbance of three kinds of ultraviolet absorbent is slow,and the color difference ?E of 0.5% ultraviolet absorbent UV-0 is the lowest,which can have the best color preservation effect.Effectively protect the ornamental nature of hydrangea immortal flowers.(2)From the aspect of antioxidation,through the study of color preservation of organic pigment replacement solution with antioxidant405,it was found that the absorbance of the maximum absorption wavelength decreased faster than that of the original solution.Through the second verification of the color difference meter,the color difference values of adding different concentrations of antioxidant 405 are very large,and when the concentration is 0.1%,the color difference value ?E even reaches 9.40,and the color retention effect is poor,so it is not suitable to be used as a color retention agent. |
PDF Full Text Request