Gracilaria Lemaneiformis Oligosaccharides And Its Compound Preservative Treatment Of Prawn And Bean Sprouts

Penaeus vannamei(prawns)is one of the most important aquatic products in China,and it was deeply loved by people because of its high nutrition and delicious flavor.The sensory quality and commercial value of products was affected by phenol oxidase which could lead to melanosis during the processing and storage.Bean sproutsare was reasonable in price accoding to its nutration and it tests delicious.But it is abundant in moisture,which makes bean sproutsare vulnerable,breathing intensively,easily browning and could be infected by microbial easily,leading to staling and corrupting.In result,bean sprouts is short in shelf-life.So,how to keep fresh of Penaeus vannamei and Bean sprouts is an urgent problem.Gracilaria lemaneiformis is the forth-largest farming algae in the world and the raw materials of the agar preparation.Develop functional products of Gracilaria lemaneiformis can improve its added value,and promote the development of Gracilaria lemaneiformis aquaculture industry.Therefore,in the present study Gracilaria lemaneiformis oligosaccharide was developed and applied as preservatives in Penaeus vannamei and Bean sprouts.The results were gotten as follows:Penaeus vannammei is treated by Gracilaria lemaneiformis oligosaccha solution with 0.01% of 4-Hexylresorcinol,and the un-treated prawns was used as the contral.After the treatments,prawns were stored at 4 °C.In order to study the effects of Gracilaria lemaneiformis oligosaccharide on the shelf-life extension,the sensory changes,TVB-N,the total count of bacteria colonies and K value were regularly evaluated.Results indicated that the Gracilaria lemaneiformis oligosaccharide has a good preservation effect.The shelf-life of the control group was 3~4 days,but that in the experiment groups were prolonged to 6~7 days.Through orthogonal experiment,an efficient complex preservative with Gracilaria lemaneiformis oligosaccharide,4-Hexylresorcinoland(4-HR)tea polyphenols was developed.According to the results of orthogonal experiment L9(33),the optimal proportion of preservative is 1.0% of Gracilaria lemaneiformis oligosaccharide,0.2% of tea polyphenols and 0.01% of 4-HR,and the effect of this complex preservative was verified.Results showed that the complex preservative has a good preservation effect.Shelf-life of Penaeus vannammei treated by the complex preservative could prolong to 8 days,4 days longer than that of the contral group.In the present study,L9(33)orthogonal test was designed to investigate the preservation effects of Gracilaria lemaneiformis oligosaccharide,phyticacid and tea polyphenols on Bean sprouts.According to the results of orthogonal experiment,the optimum composition was determined to be 0.125% of Gracilaria lemaneiformis oligosaccharide,0.1% of phytic acid and 0.1% of tea polyphenols.By measuring the protein,nitrate,vitamin in normal temperature storage to validate the best experiment group,at the end of 5 d storage,preservation group compared with the control group,the protein content was 39.3 μg/g higher,the vitamin C content was 14.1 μg/g higher,the nitrate content was 415.1 mg/g lower,it mens that the experiment group with the complex preservative could delay the decrease of protein,slow down the loss vitamin C,eliminate the nitrate accumulation in the bean sprouts.In the present study,a complex preservative based on Gracilaria lemaneiformis oligosaccharide was developed,to keep freash of Penaeus vannaammei and Bean sprouts.Solved the problem of the spoilage of Penaeus vannaammei and Bean sprouts in the storage and transportation of deterioration,and their shelf-life is extended.At the meantime,realize the high value utilization of Gracilaria lemaneiformis oligosaccharide.