Development of composite biological fresh- keeping agent and preliminary research of fresh corn preservation

Fresh- keeping is required to extend the shelf life of fresh corn because of rapid dropping in quality of fresh corn after harvest.Bioactive substances were used as material to develop composite bidoyical fresh- keeping agent for fresh corn preservation. The four factors such as chitosan,pollen polysaccharide,tea polyphenols concentration,proportion of span- 80 and tween- 80 were selected and the orthogonal experimental design was used to carry out technology optimization. The optimized fresh- keeping agent was used for fresh corn preservation.The changes in moisture,hardness and sensory quality of fresh corn were analyzed. The results showed that the optimized formula of composite biological fresh- keeping agent was chitosan concentration 1.6%,pollen polysaccharide concentration 1.5%,tea polyphenols concentration 0.25%,proportion of span-80 and tween-80 1∶1.5.It was found that the pretreated fresh corn with the fresh- keeping agent maintained good fresh- eating quality during the storage period of 30 d,whereas fresh- eating quality of the control descended obviously after 5d storage and became worse in 10 d storage. The research showed that the composite fresh- keeping agent had obvious preservation effect on fresh corn.