Study on the preparation of kelp polyphenols and the effect of kelp polyphenols on the fresh-keeping of peneaus vannmei

In order to prepare kelp polyphenols which have anti-bacterial activity,Laminaria japonica aresch was treated with the combination extraction of ultrasonic and microwave. The optimal conditions of the extraction of kelp polyphenols were determined by orthogonal experiment.Meanwhile,the effects of kelp polyphenols on penaeus vannmei during storage at -1.2℃ were initially evaluated. The results indicated that optimal extraction conditions of kelp polyphenols from Laminaria japonica Aresch were the ratio of sample weight to the solvent volume 1∶7,85% ethanol,the temperature 70℃,the extraction times 2,the extraction time 4h,and the yield of kelp polyphenols was 0.4050%. 0.2g/L kelp polyphenols demonstrated good effects of fresh-keeping on penaeus vannmei. It could more effectively retard pH value than control,decrease the total bacteria counts(TBC) and TVB-N during storage,and extend its shelf life 48h compared with the reference group(-1.2±0.2℃).