A Research On The Pepper Postharvest Physiology And The Coating Preservation

In this paper,the research of the fresh pepper postharvest physiology under the condition of the low temperature(9℃±1℃),normal temperature(20℃±5℃) and sand storage(20℃±5℃) is carried at first.And by regular determination of the indices of its red fruit rate,rot rate and weight loss rate,respiratory intensity,pectin,vitamin,enzyme activity etc.and observation of the change law of them during storage and preservation.The results showed that:the red fruit rate,the rot rate,and the weight loss rate showed a raise tendency;the respiratory intensity had a descending trend,and has no respiratory climacteric;the content of vitamin C,pectin,chlorophyll, total sugar had a descending trend;the water-soluble pectin increased,while the insoluble pectin, and the insoluble pectin hydrolyzed the water-soluble pectin gradually,so that the fruit softened gradually;the PG and PE enzyme activity first had a raise tendency,and then decreased gradually, which has a correlation with the change of the water-soluble pectin and the insoluble pectin;the POD and CAT enzyme activity had a descending tendency.In general,low temperature processing is better than the sand storage and the normal temperature processing.In the experiment researches on film-forming properties and coating adopting the single factor film and orthogonal compound film experiment were carried,and 2 groups of optimal formula compound fresh-keeping films were selected,that is chitosan1.5%,konjac flour 0.15%, modified SiO₂0.0035%and sodium alginate 2.0%,konjac flour 0.15%,CMC0.70%;2 groups of compound fresh-keeping film which structure changed were obtained through infrared analysis, that is chitosan 1.5%,konjac flour 0.15%,modified SiO₂ 0.0040%and sodium alginate 1.5%, konjac flour 0.2%,CMC0.70%.The best fresh-keeping film formula was screened through general-purpose rotation unitized design,the best compound fresh-keeping indices formula is sodium alginate 2.0%,konjac flour 0.15%,CMC0.70%,CaCl₂0.1%s,1-MCP 0.0018%.the verification of coating experiment showed that the fresh pepper treated with coating after normal storage for 35 days,the good fruit rate is 85.4%,the weight loss rate is 11.50%.Coating had marked inhibitory effect on respiratory intensity and the loss of nutriment,which can lower the PG and PE enzyme activity,and has function of slowing down on the original pectin hydrolysis rate, which can improve the POD and CAT enzyme activity obviously delayed senility and delayed the pepper's senility.There was no obvious difference between the temperature preservation and coating preservation except green keeping and pickled-keeping.Compared with the temperature preservation,the coating preservation is of low cost,simple equipment and easy operation.