Effects Of Fertilizer Application And Freeze-drying On The Quality Of Xiangqingcai

Non-heading Chinese cabbage(Brassica rapa ssp.chinensis)is one of the most important vegetable in China with a long cultivation history and abundant resources.Xiangqingcai,is a local variety in Wujiang area,Suzhou has a unique aroma and soft waxy taste,and very popular among the local people.In this paper,Xiangqingcai was used to studied the cultivation technology and the effect of different fertilizer ratio on its quality and yield.The freeze-dried experiment was carried out to analyze the effect of different freeze-drying time on the quality of the Xiangqingcai.The research provides basics for the realization of high quality production and subsequent processing of Xiangqingcai.The main results are as follows:1.Xiangqingcai is a local characteristic variety,since its planting area is limitted,it needs more standard cultivation techniques.The paper provides the high efficient cultivation techniques including crop arrangement,variety selection and cultivation techniques.In view of the deficiency in production,especially the degeneration of seed quality,the good seed quality can be maintained through self-crossing and hybridization.2.The effects of different combined application of organic and inorganic fertilizers on the quality and yield of Xiangqingcai were studied.The highest plant height was 25.3cm when the conventional fertilization was used,that is the early application of compound fertilizer,including inorganic fertilizer 25kg/667m2 and organic fertilizer 300kg/667m2,and urea fertilizer 10kg/667m2 was additional used later.The largest plant expansion was 75.9cm when the compound fertilizer,including inorganic fertilizer 25kg/667m2 and organic fertilizer 600kg/667m2 was used.The effect of different fertilizer combinations on the number of leaves was not significant.When inorganic fertilizer 25kg/667m2 and organic fertilizer 900kg/667m2 were fertilized,the yield of Xiangqingcai was the largest.However,the cost of using organic fertilizer is too high,and the yield of conventional fertilization is also significantly higher than that of blank processing.In different fertilizer combinations,the maximum soluble protein was 3004.55ug/ml,25.86%higher than single application of compound fertilizer 25kg/667m2,and the highest content of vitamin C in leaves was 22.12%higher.The combination of organic and inorganic fertilizers significantly improved the quality and yield of Xiangqingcai.3.Different freezing time and drying time were studied on the freezing of Xiangqingcai.When the materials were pre frozen for 1.5h and dried for 24h,the chlorophyll a,chlorophyll b and total chlorophyll of materials were the highest in all treatments.Xanthophyll and total carotene were also the highest in this treatment.It can be seen that in the experiment,when pre frozen for 1.5h and dried for 24h,the pigments level of the material can be well preserved and the freeze-drying quality can be maintained.Rehydration experiments were carried out on six kinds of lyophilized materials.It was found that the rehydration ratio of the materials pretreated for 2h and 24h was the highest when rehydrated for 1.5h.It was found that the rehydration ratio of the materials pretreated for 2h freezing and 24h drying was the highest when rehydrated for 1.5h.When the pre freezing time was 2h,the rehydration ratio was generally higher.