Appropriate shelling process parameters of Antarctic krill at initial stage of fishing

Abstract: The Antarctic krill is a marine organism with a large number. It has great value of development and utilization. As a new protein resource, Antarctic krill will get more and more attention since the offshore fishery resources are dwindling. Although the Antarctic krill has a high value of nutrition, it is hard to process because of its high fluorine content and strong enzyme activity. The krill has to be processed within 2 h on the ship after fishing in order to maintain its quality. Shelling is one of the effective methods to improve the quality of krill product. In previous studies peeling method was researched in order to get integral meat of Antarctic krill. Parameters such as body length and body weight of Antarctic krill that was just caught up were also measured. And we know that the peeling process conditions got from the response surface for Antarctic krill had a certain value in use and the method could be used on the ship. So the shelling prototype was developed and tested on the ship. In order to verify the krill shelling equipment and improve the production process, the research focused on the impacts of feeding rate, storage time and pre-cooling on shelling yield and residual rate, which would provide the bases for the practical production. The production process was considered carefully. Feeding speed was controlled by manpower in order to put the krill into a trough evenly. Then the krill would be pumped to the shelling machine after evenly mixing with water. The shrimp was put on the gauze for 2 min to filter the water after shelling, and then residual shells in shrimp were removed by manpower. The last processes were weighing, packaging and frozen. Test equipment unit was designed as 8 groups of rollers with reciprocating rotation. Yield was one of the most important indices for the evaluation of equipment ability, and residual rate was the other. The product quality of shrimp meat needed to be judged by sensory evaluation. The sensory evaluation team was made up of 5 seafarers who had a lot of experience of krill production on board. The comprehensive point was based on the integrity of shrimp, shell residue, plumpness and cleanliness. The results showed that the yield was about 24% and the residual rate was about 5%, and the shelling equipment was reliable. The yield of shelling from fresh Antarctic krill reduced slowly with the increasing of the feeding speed. It was relatively stable when the feeding speed was under 50 kg/h. And the residual rate was on the rise with the increasing of the feeding speed. When the feeding speed was higher than 60 kg/h, the residual rate of shrimp shell increased significantly. The krill with the storage time of less than 120 min could be used for production. Freshness is the most important factor in the quality of shrimp meat. Pre-cooling is an effective way to maintain shrimp quality. Frozen shrimp is not recommended to be used because the yield of shrimp meat will become lower significantly.