Research And Application Of Antimicrobial Coatings On Preservation Of Shrimp

The object of this work was to develop a composite antimicrobial film to improve the sensory characteristic of shrimp, to restrain the microbial growth on shrimp surface and postpone the decay of shrimp, hence prolong the shelf-life of shrimp.The base film-forming material was chosen by comparing the preservation effect of three polysaccharides on the shelf-life extension of PenaeusVannamei. Then the constitution of different components and film-preparing techniques were determined by comparing characteristic of films to prepare a composite antimicrobial film. The composite antimicrobial film was used to coat whole and shelled Macrobrachium nipponense in order to testify its effect on the shelf-life extension of shrimp.Film-forming solutions based on sodium carboxymethylcellulose, chitosan and sodium alginate were used to coat ice-stored PenaeusVannamei at 4±1℃under aerobic conditions and the freshness indexes of shrimps were periodically evaluated. No favorable changes were observed in shrimps coated with sodium carboxymethylcellulose and chitosan films whereas treatments with sodium alginate film showed could effectively extend the shelf-life of shrimp by 2～3days. So sodium alginate was chosen to be the base film-forming material.A composite antimicrobial film possessing good characteristics was developed by optimizing the film-preparing techniques. The best constitution of different components was: sodium alginate 20g/L, glycerol 0.4%, kalium sorbic acid 2g/L and stearic acid 15g/L, the pH of film-forming solution should be 5.5 and the film should be stored where RH was controlled fewer than 50%.Whole and shelled were dipped in this composite antimicrobial film-forming solution. During storage time, the decaying rate of whole shrimp was effectively slowed to gained a 3.5～4 days′shelf-life extension time. At the same time, shelled shrimp showed better water-holding ability and sensory characteristics.The result of this work showed it was feasible using edible films to extend the shelf-life of shrimps and a composite antimicrobial film possessing good characteristics could be developed by optimizing film-preparing method. This composite antimicrobial film indicated assured effects in shelf-life extension of shrimps, thus providing enhanced economic benefit in shrimp-processing industry.