Study On The Development And Application Of Special Refrigerant For Winter Jujube In Xinjiang

Xinjiang winter jujube is famous for its crispness,sweetness,delicate flesh,delicious and richness pabulum.After picked,the winter jujube is easy to mold and rot due to its thin and juicy,leading to quite short storage and shelf life,which greatly reduced the commercial value and edible value of the winter jujube.Therefore,the post?harvest preservation of winter jujube restricted the development of the winter jujube industry.This subject takes Xinjiang's characteristic resource winter jujube as the research object,and develops two phase change cold storage agents with a single main agent for Xinjiang winter jujube,which reduced the cost of winter jujube preservation and transportation and provides technical support for the last mile of winter jujube transportation.In this paper,glycerol was used as the main energy storage agent,and sodium carboxymethyl cellulose(CMC)and sodium polyacrylate super absorbent resin were added to prepare liquid refrigerant and gel coolant,respectively.The main research contents are as follows:1.The main energy storage agent was determined by differential scanning calorimetry,to prepare the liquid refrigerant.The formula of liquid refrigerant was optimized,and the performance of liquid refrigerant was measured.The results showed that the best formula of liquid refrigerant storage is 4%glycerol(v/v),1.2% CMC(w/v,viscosity 300?800 MPa.S),0.20% potassium sorbate(w/v)and dissolved in deionized water.At these conditions,the phase change latent heat was 311.79 J/g,and the onset temperature is ?4.55?.The performance of liquid refrigerant storage was stable and had good winter?keeping effect.2.The preparetion of the gel coolant was conducted in the research.The formulation of gel coolant was optimized,and the performance of gel coolant was determined.The results showed that the best formulation of gel refrigerant was 4% glycerol(v/v),0.28% polyacrylic acid sodium super absorbent resin(w/v),0.20% potassium sorbate(w/v)and dissolved in deionized water.The latent heat of phase change was 307.91 J/g,and the onset temperature was ?3.91?.The performance of gel refrigerant was stable,which could better satisfy the long?distance transportation of winter jujube.3.The two well prepared liquid refrigerant and gel refrigerant were applied in winteren winter jujube during transportation and storage,taking a purchased cold storage agents as the positive control and the nothing?added as the blankcontrol.The suitable proportion of refrigerant was determined by simulated refrigerating application test.The decay rate,weightlessness rate,titratable acid content,respiratory intensity,and hardness of winter jujube were evaluated.The results showed that 30% of the refrigerants had better preservation effect,and when 30% gel coolants were added,the decay rate,weightlessness rate and respiratory intensity were the lowest,while the titratable acid content and hardness were highest.At this point,all the indexes were maintained in a good state.Gel cold storage agent effectively prolonged the winterness of winter jujube,and it was an efficient cold storage agent for winter jujube in Xinjiang.It provided a new idea for winter storage and preservation of winter jujube.