Studies On Preservative Theory And Technology Of Green Asparagus Treated By Photosynthesis And MAP

Asparagus is a kind of the Liliaceae and asparagus genus.The edible part of asparagus is the tender stem,which is abundant of medicinal and nutritious component. Fresh asparagus has high water content and active respiration rate,which can cause blooming metabolism.Thus post-harvest freshness will be declined rapidly,increasing the degree of lignification,the head rotten quickly,quality reduced greatly.These factors arenot better for its storage and transport,more importantly,which restricts the export of fresh asparagus and the expansion of the domestic market.Preserving green asparagus is significant for improving market competitiveness,reducing cost and raising effectiveness.The effects of different temperature on fresh-keeping of green asparagus during storage were investigated.The results showed that 0℃was the most appropriate temperature for the storage of the green asparagus,the rot rate of green asparagus was 0% and commodity rate was 95.4%after 15 d at 0℃.The effects of different packaging model(modified atmosphere box,polystyrene foam box and PE film) on the related indicators of green asparagus during storage were studied. The results showed that the fresh-keeping effects was as follows:modified atmosphere box＞polystyrene foam box＞PE film,and the rot rate of green asparagus was less than 1%, commodity rate was more than 94.7%after 42 d.The research of low-light irradiation preservation at 6℃storage environment after 17d indicated that the content of green asparagus's Vc and chlorophyll of green asparagus's stem treated with low light irradiance improved 3.5%and 6.8%than that without low-light irradiation.Low-light irradiance decreases green asparagus's increasing speed of gross fiber and as well as the content decreasing speed of soluble solids.The effect of biological preservative agents on the qulities of green asparagus was also investigated.The storage effect showed that MA box-type packaging associated biological preservative agents(the longer storage period:56 d)＞polystyrene foam box associated biological preservative agents(the better storage period:42 d)＞mechanical refrigeration(CK).Combined with the analysis of post-harvest nutritional and sensory quality,the effectiveness of the stem during storage were investigated in detail in the paper which revealed the box-type MA technology on the basis of modified atmosphere box and the technical model of MA box-type packaging associated biological preservative agents and mechanical refrigeration for green asparagus.The treatment of the technical model can inhibit respiratory intensity and ethylene production,delay the degradation of nutritional components(vitamin C and chlorophyll),decrease the increasing speed of gross fiber content and rot rate,improve commodity rate and keep better effect of storage.It is the best technical model and a rare event and extends the storage period to 56 day.The commodity rate of green asparagus treated with MA box associated biological preservative agents was 83.4%after 56 d.Moreover,the treatment of low light irradiance at 6℃increases the preserving rate of the content of vitamin C and chlorophyll obviously.The best storage conditions of green asparagus were that 0.5℃,85%～95%relative humidity,14.9%of the oxygen content,6.5%of the carbon dioxide content,400μL/L of the preservative concentration.