Study On Preservation Effect Of MAP On Cucumber

Cucumber(Cucumis sativus L.)has high water content about 95%.It is a good source of potassium,calcium,vitamin A and K.It is crisp and juicy with its special fresh flavor,which is always consumed raw.It belongs to typical perishable agricultural products,which is easy to show adverse changes of wilting,yellowing,loss of luster and dehydration with bran in short term of storage.Hence,it is of great significance to use optimal preservation techniques to reduce its weight loss rate,prolong the shelf-life,meet the need of food industry and the consumer and enhance its value.The contents of this paper were as follows:(1)At the beginning,its respiration characteristics were studied.The influence of temperature on the respiration rate of cucumber met the law of Arrhenius' equation.And the respiratory temperature coefficient was also inspected.At the same time,the change trends with storage time of O2?CO2 volume concentration,the respiration rate of cucumber and respiratory quotient were examined.(2)As CO2 could inhibit respiration,keep the green color of vegetables and maintain the hardness,the influence of the treatment with different concentration of CO2(4%?6%?8%?10%)on physiological and biochemical quality of cucumber at ambient temperature was studied.The results showed that:the treatment with 6%CO2 had optimal storage quality.It could reduce the respiration rate and the weight loss rate,maintain its hardness,slow down the loss of its soluble solid content?chlorophyll content and reductive vitamin C content.It could also inhibit the increase of cell membrane permeability and the accumulation of malondialdehyde.In addition,it was conducive to keeping the enzyme activity of protective enzymes(catalase CAT,peroxidase POD,superoxide dismutase SOD),which could decrease the speed of aging.(3)Then the preservation effects of modified atmosphere packaging(MAP)with polyethylene of different thicknesses(0.02?0.04?0.08mm)were examined.At first,modify the CO2 volume concentration to 6%by CO2 release agent.The results were that the treatment with 0.08mm thickness PE package had the favorable preservation effects with the highest score of integrated sensory evaluation.This treatment could maintain the preferably gaseous environment?retard the reduction of weight loss and the chlorophyll content?reductive vitamin C content and soluble solid content.The rise of cell membrane permeability was also delayed.The storage time could extend to 12 days or more with this treatment.