Studies On Texture Of Turban Shells During Processing And Storage

Turban shells, which have delicious flavour, tender texture, many medical and nutritional functions, is one of the fond seafood in coastal area. In this paper, the Rapana venosa was chosen as the material and the following researches were carried out.Firstly, the basic composition, tissue structure and rheological properties of foot and visceral muscles of turban shells were investigated, texture profile analysis and analytic sensory evaluation was experimentized. The results were shown that the protein percent of foot and visceral muscles of turban shells were 18.62%, 17.14%. collagen percent of foot and visceral muscles were 8.4%, 1%.Fat percent were less than 1%.Myofibrils of foot muscle was thick, and the interspace of myofibrils was big; but myofibrils of visceral muscle was thin, and the interspace of myofibrils was small. The foot muscle of raw turban shell was harder than visceral muscle,while both elasticity and adhesiveness were smaller.Secondly, the basic composition, tissue structure and rheological properties of turban shells during boiling were investigated. The relativity was studied between texture profile analysis and analytic sensory evaluation. The results were shown that the interspace of myofibrils became bigger during boiling.At the same time, elastic modulus and rupture strength became smaller during boiling, and the stress-relaxation time was bigger. The rheological parameters showed positive correlation with tissue structure. Heated for 20 min was the best choice for raw turaban shells,the sample couldn't give people the best enjoy in the sensory organ if the boiling time was too long or short . The springiness and hardness of TPA significantly correlated with those of analytic sensory evaluation.The third, the shelf life of turban shells storaged in different situation were confirmed by the amount of bacteria, values of TVB-N and analytic sensory evaluation. The basic composition, tissue structure and rheological properties of turban shells during storage were investigated. The results were shown that shelf life of turban shells at 5℃was 8 days, the shelf life of turban shells storaged at controlled freezing-point was 23 days. In the storage, the interspace of myofibrils became bigger,and agglutination of myofibrils became stronger.At the same time, elastic modulus and rupture strength became smaller, and the stress-relaxation time was bigger. The rheological parameters showed positive correlation with tissue structure. Based on the above results, we can see that turban shells storaged at controlled freezing-point would be preferential.Finally, the alive time of turban shells storaged in different situation were confirmed. The basic composition, ATP and lactic acid of turban shells in different alive situation were investigated. The results were shown that alive time of turban shells at 5℃was 6 days, and alive time of turban shells storaged at ecological ice temperature was10 days. In the alive time, water was lost, the consumption of Protein in the first three days was slow, subsequently increased. The consumption of glycogen in the first three days was fast, followed by slowing. From changes in lactic acid content, we can see that turban shells under the condition of no water did anaerobic respiration, and the trend increased. Compared basic composition, ATP and lactic acid of turban shells in different alive situation, we can see that turban shells storaged at ecological ice temperature lower metabolic rate and the consumption of nutrient, would be preferential.