Study On The Techniques Of Antisepsis And Storage Of Green Asparagus

The development of industry asparagus has been restricted by the senescence and soft-rot during the storage. So the effects of different preservations on controlling the soft-rot and heatshock-treatment on delaying the senescence were studied. The results showed that:(1)The treatment of 1.5% sodium diacetate could distinctly restrain the soft-rot.When the storage period is up to 40 days, the ratio of soft-rot is 0%, while the soft-rot ratio of controled treatment is 100%. At the same time, the treatment delays the senescence and the reducing of chlorophyll and pectin during the storage. But it could not prevent the increasing of coarse fibre.(2)The super absorbent polymer can effectively delay dewing in the package bags in a given time. But effective time could be influenced by the package method.(3) The heat treatment could control the soft-rot effectively during the storage period, delay the reducing of nutrition, and retard the senescence successively. The index is that the temperature and time should be 50±1℃and 8~10min.(4) When the concentration of ethanol solution is greater than 10%, the soft-rot could be controlled completely. But high concentration of ethanol solution causes injury to green asparagus, such as accelerating the postharvest senescence and yellowing, expecially the tip of asparagus.(5)The characteristics of POD and PAL relating to the senescence of green asparagus have been studied by spectrophotometry. The results showed that their optimum pH were 4.0 and 8.8, and the optimum temperature were 55℃and 60℃, respectively. The activity of POD reduced under the condition of PH 6 (citric acid buffer). When the temperature was below 20℃or above 60℃, the enzyme activities of POD and PAL decreased remarkably. And 1mmol/LCa2+ could inhibited the enzymatic activities of POD and PAL. The optimum substrate concentration of POD and PAL were 70μL/100mL and 0.02mol/L, and the Km value were 2.694×10-4 mol/L and 1.38×10-4mol/L, respectively.The results obtained will be useful for inhibiting the deposition of lignin in asparagus and improving the quality low temperature storage conditions.