Effects Of Stem-end Dipping With Preservative Solution On The Storage Qualities Of White Asparagus

The grain of asparagus immature stem is crisp and tender and it has high water content,the physiological activity of recovery is active.It is easy to change color,loss water,and fibrosis and loss nutrient.Using a plastic film bag cold storage and fresh-keeping agent spraying processing is the main storage methods at present.Because of the influence of the surface resistance,there are some problems about the rate of external substances into internal is slow,and the quantity of entrance is little,which lead to effect of preservation will be slow.It has not been reported that the way of using the larger base of asparagus cross section to absorb quickly,using exogenous substances,using the fresh-keeping agents of basal part of stem（the basal part of stem has been soaked in fresh liquid during the whole storage）in asparagus fresh.Therefore,the article combined with the nutrient solution,exogenous hormones,antibacterial agent,and researches suitable compound fresh-keeping agent for asparagus immersion preservation.The results of the study are as follows:1.Leaching experiments of nutrient.:based on the species and content nutrients that white asparagus includes,set 1/2-fold,1-fold,2-fold nutrient solution（distilled water treatment as controls）,the stem-end of asparagus was immersed separately during the storage period,determination of hardness,chromaticity,lignin content,ascorbic acid content and other preservation indicators every 2 days.Results showed that treatment of2-fold nutrient solution could effectively maintain chromaticity of white asparagus,inhibit the decline of weight loss and ascorbic acid content,and increase the activity level of phenylalanine ammonialyase（PAL）,while promote the increase of cellulose and lignin content.To some extent,treatment of 1/2-fold nutrient solution positively maintained the storage qualities of white asparagus and effectively inhibited the increase of lignin and cellulose content,though this treatment was not stronger in controlling the chromaticity than that of 2-fold nutrient solution.The experiment results show that 1-fold nutrient solution is the best in synthetically preservation under this condition.2.Leaching experiments of exogenous hormone: choose 6-BA（10,20,40 mg/L）and GA₃（50,100,200 mg/L）for exogenous hormones（distilled water treatment as controls）,the stem-end of asparagus was immersed separately during the storage period,determination of hardness,chromaticity,lignin content,ascorbic acid content and other preservation indicators every 2 days.Results showed that both 6-BA and GA₃ can effectively reduce the weightlessness rate,inhibit the increase of cellulose and lignincontent,delay the decrease of VC content.The treatment of 20 mg/L 6-BA processing effect is the best,followed by the treatment of 100 mg/L GA₃.3.Leaching experiment of application of antibacterial agents: sodium diacetate（0.5,1.0,1.5%）and sodium dehydroacetate（mass concentration 50,100,150 mg/kg）were used as bacteriostatic agents（distilled water treatment as controls）,the stem-end of asparagus was immersed separately during the storage period,determination of malondialdehyde,lignin content and the total number of colonies and other indicators every 2 days.The results show that sodium diacetate and sodium dehydroacetate can effectively inhibit the activity of POD and PAL of white asparagus and delay the weightlessness,it has obvious effect especially in maintaining chromaticity.As a whole,the effect of preservation between them is not obvious,but the antibacterial effect of sodium diacetate is better than that of sodium acetate.4.Integrated the above three single factor experimental results,selecting the nutrient solution（0.75,1,1.25 times）,6-BA（15,20,25 mg/L）,sodium acetate（0.8,1.0,1.2%）to constitute compound preservation liquid,on the tenth day of storage,determination of three indicators of VC,lignin and cellulose content.The best process conditions of comprehensive balance is as follows: 1-fold nutrient solution and 20 mg/L 6-BA and 1.0%sodium acetate three composition preservation solution,the fresh-keeping effect of white asparagus is the best.