With the continuous improvement of people's living standards, people's demand for aquatic products is increasing while the demand for aquatic products is increasing. In order to objectively and accurately evaluate the quality of aquatic products, texture analyzers have been used more and more widely in aquatic products in recent years. Texture analysis is mainly used for texture detection of aquatic objects such as fish, shrimp and shellfish. The research content mainly focuses on the correlation analysis between texture indicators and other indicators, the evaluation of processing technology and the optimization of storage conditions.

The texture characteristics of aquatic products are clearly correlated with other indicators of the product itself. Since the softening of fish body tissue after death seriously affects the quality of fish meat, Godiksen et al [1] studied the effects of several types of cathepsins of rainbow trout on the muscle texture of fish, and several kinds of muscle fibrin under different cathepsins. The relationship between sarcoplasmic protein and fish meat hardness was established. Most of the data indicated that cathepsin D was unfavorable for maintaining fish hardness. That is to say, cathepsin D was the main factor leading to the degradation of fish fiber, which led to the softening of carp fish. LinWanling et al. [2] studied the difference in texture of pre- and post-heating of crispy grass carp and grass carp. It was found that all the texture parameters of raw grass carp were higher than that of grass carp before heating; after heating, the hardness, chewiness, recovery and elasticity of crispy grass carp The index is still higher than grass carp; the hardness, brittleness, elasticity and chewiness of the heated crispy grass fish are higher than that of the raw grass carp; while all the texture indexes of the heated grass carp are significantly reduced. Jia Yanhua et al [3] investigated the correlation between the moisture content and texture characteristics of soft-baked scallops by analyzing the texture characteristics of soft-baked scallops with different water contents. The results showed that the hardness, cohesiveness and recovery of soft-roasted scallops increased with the decrease of moisture content, and the change of hardness was the most obvious. The elasticity, adhesiveness and chewiness decreased with the decrease of moisture content, and related. Significantly, the texture and texture of the product can be evaluated using texture characteristics. Wu Yujie et al [4] used vacuum microwave dehydration method to make shrimp water into different water activity (aw) samples, determine the water adsorption isotherm of the sample at 20 ° C, and compare the aw to the shrimp after normal temperature preservation through preservation experiment. The total number of bacterial colonies in the body and the influence of texture parameters such as elasticity and hardness of the shrimp body. Studies have shown that when aw is controlled at 0.86 to 0.90, dried shrimp products stored at room temperature can be balanced in terms of taste and microbial indicators. In order to explore the factors affecting the brittleness of crispy squid, Lin et al. [5] studied the effects of water, fat content, protein composition and average muscle fiber size on the texture characteristics of the muscles of crispy squid and squid. The results showed that the muscle hardness, elasticity, chewiness and recovery of the crispy carp were 11.14%, 3.43%, 15.75% and 14.27% higher than that of the carp, respectively. These texture characteristics of the crispy squid and their muscles were low in water content and matrix protein. The high content, the short average diameter of muscle fibers and the high density of muscle fibers, the average diameter of muscle fibers and the density of muscle fibers have a greater impact on the hardness of muscles of crispy carp.

Compared with other indicators, scholars have studied more through texture analysis to improve the processing of aquatic products. Larsen et al. [6] studied several ripening methods: boiled, steamed, microwaved, hot-fried, roasted and fried to texture parameters such as hardness, adhesion, chewiness and elasticity of New Zealand salmon. Influence and conduct principal component analysis. Studies have shown that fried salmon has the highest hardness and adhesion increases at the beginning of heating, but the final heating temperature has little effect on adhesion; hot fried and fried salmon have higher elasticity; raw fish Cooked and steamed fish are poorly chewable; microwaves and grilled fish have almost the same chewability; fried fish have the best chewability. Canto et al [7] studied the texture and color parameters of the high hydrostatic pressure treated crocodile meat instrument, indicating that the 200MPa treated fish has the lowest hardness, and established a correlation between the measured value of the instrument and the sensory evaluation system. Liu Jingzhi et al [8] studied the rheological properties of conch feet and the correlation between TPA analysis and sensory evaluation under fresh and different heating conditions. The results showed that the different heat treatments on the structure and rheology of the conch foot. The characteristic parameters have a significant impact. TPA and sensory evaluation showed significant correlation in hardness, elasticity and chewiness, and also had good correlation in adhesion. This study can provide theoretical basis and scientific basis for the development of conch deep processing products and optimization of processing technology. Wang Yanbo et al [9] studied the effects of two different slaughter methods on the muscle texture and proteome of carp using the texture analyzer and two-dimensional electrophoresis. The results showed that the nitrogen-killing slaughter method significantly increased the muscle hardness, chewiness and adhesiveness of the carp after death (62.24%, 85.72% and 75.47%, respectively) compared with the direct head-killing group. The results revealed that different slaughter methods affected the protein content and metabolism of muscle in the muscle, which showed changes in texture indexes such as muscle hardness, chewiness and adhesiveness. Cao Rong et al [10] studied the TPA texture characteristics of different parts of shrimps by breeding white shrimp and sea-catching prawn, and analyzed the effects of different cooked processing methods on shrimp quality. Studies have shown that different types of shrimp (P. vannamei and hawk claw shrimp) and different parts of the same species of shrimp have different texture characteristics, in order to ensure the accuracy and comparability of the data, the test site should be fixed in the TPA. The second and third abdominal segments are suitable as the measurement sites of TPA; the sterilization process of high temperature and high pressure at 121 °C will cause a significant decrease in the hardness, elasticity and chewiness of the shrimp, and the cooked processing using boiled brine in production and processing. The way to ensure the sensory quality of the shrimp.

Aquatic products are very prone to spoilage and therefore have high requirements for their storage conditions. Many studies now tend to select better storage conditions through the texture studies of aquatic products. Ayala et al [11] studied the effects of vacuum packaging and direct refrigeration on the texture of the squid slices. The results showed that the texture parameters of vacuum treated and non-vacuum treated frozen fish fillets were significant with the prolonged storage time. Decrease, the hardness, adhesiveness and chewiness of non-vacuum-packed fish fillets vary greatly from 0d to 5th to 7d. In the later period, from 10 to 12d to 22d, these indicators change very little. Vacuum packed fish fillets The value of hardness, chewiness and adhesiveness was the highest when refrigerated for 5 to 7 days. Qiu Zefeng et al [12] used the texture analyzer TPA model to test the hardness, adhesion, elasticity, chewiness, adhesiveness and cohesiveness of the muscles of Penaeus vannamei under frozen storage conditions. Studies have shown that under the storage conditions of -18 ° C and -50 ° C, the hardness, chewiness, adhesiveness and cohesiveness of the muscle of L. vannamei showed a slow decline with the prolongation of storage period. Not obvious, but adhesion is rising. This indicates that although the frozen storage of L. vannamei can ensure its long shelf life, its mouthfeel characteristics generally decrease continuously; and the lower the temperature, the better the texture characteristics of its muscles are maintained. Wang et al. [13] tested the hardness, adhesion, elasticity, chewiness, adhesiveness, cohesiveness and recovery of frozen storage of tilapia muscles using the TPA model of the texture analyzer, indicating that at -18 °C. Under the storage conditions of -50 °C, the hardness, elasticity, chewiness, adhesiveness, cohesiveness and recovery of tilapia muscles showed different degrees of decline with the increase of storage time. Adhesion was on the rise; the change rate of texture parameters of tilapia muscle stored at -50 °C was lower than -18 °C storage conditions. It indicates that the odor characteristics of tilapia are decreasing during the frozen storage process, and the lower the storage temperature, the more favorable it is to maintain the texture characteristics of tilapia muscle. Liu Jingzhi et al [14] compared the characteristics of texture changes of conch in cold storage and ice temperature preservation, pointing out that the elastic modulus and breaking strength of refrigerated samples and ice temperature samples decreased gradually with the prolongation of storage time, while the stress relaxation time increased significantly. After reaching the shelf life (8, 23d), the decrease of elastic modulus and breaking strength gradually slowed down; while the elastic modulus of ice temperature, the decreasing trend of breaking strength and the rising trend of stress relaxation time were obviously slower than that of refrigerated samples.

references:
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[2] LIN Wanling, ZENG Qingxiao, ZHU Zhiwei. Different changes in mastication between crisp grass carp (Ctenopharyngodon idellus
C.et V) and grass carp (Ctenopharyngodon idellus) after heating: the relationship between texture and ultrastructure in muscle tissue [J]. Food Research International, 2009, 42(2): 271-278.
[3] Jia Yanhua, Yang Xianshi, Xu Zhong, et al. Effect of moisture content on texture and color of soft-baked scallops [J].
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[4] Wu Yujie, Yang Ruijin, Liu Yining. Effects of water activity on shelf life and texture of dried shrimp products[J]. Fisheries Science, 2006, 25(4): 175-178.
[5] Lin Yuling, Guan Rong, Zeng Qingxiao, et al. Factors affecting the texture characteristics of the back muscles of crispy squid [J]. Journal of South China University of Technology: Natural Science Edition, 2009, 37(4): 134-137.
[6] LARSEN D, QUEK SY, EYRES L. Evaluating instrumental colour and texture of treated New Zealand King Salmon (Oncorhynchus tshawytscha) and their relation to sensor y properties[J]. LWT - Food Science and Technology, 2011, 44( 8): 1814-1820.
[7] CANTO ACVCS, LIMA BRCC, CRUZ AG, et al. Effect of high
Hydrostatic pressure on the color and texture parameters of refrigerated Caiman (Caiman crocodilus yacare) tail meat[J]. Meat Science, 2012, 91(3): 255-260.
[8] Liu Jingzhi, Gao Wei, Xu Jiachao, et al. Changes in the texture of the foot of the conch under different heating conditions[J]. Journal of Fisheries of China, 2009, 33(3): 519-526.
[9] Wang Yanbo, Shen Xiaoqin, Li Xuepeng, et al. Effects of Different Slaughter Methods on Muscle Texture and Proteome of Carp[J]. Chinese Journal of Food Science, 2010, 10(6): 145-149.
[10] Cao Rong, Liu Qi, Yin Bangzhong, et al. Texture Analysis of TPA in Shrimp and Effects of Different Cooked Processing Methods on Its Quality[J]. FOOD RESEARCH AND DEVELOPMENT, 2010, 31(6): 1-5.
[11] AYALA MD, SANTAELLA M, MARTNEZ C, et al. Muscle tissue
s tructure and flesh texture in gilthead sea bream, Sparus aurata L., fillets preserved by refrigeration and by vacuum packaging [J]. LWT - Food Science and Technology, 2011, 44(4): 1098-1106.
[12] Qiu Zefeng, Zhang Liang, Zeng Weicai, et al. Effects of frozen storage on muscle texture characteristics of Penaeus vannamei[J]. South China Fisheries Science, 2011, 7(5): 63-67.
[13] Wang Qiaoyi, Dong Qiang, Lu Shuixian, et al. Effects of frozen storage on the texture characteristics of tilapia muscle [J].
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[14] Liu Jingzhi. Study on the texture change of conch during processing and storage [D]. Qingdao: Ocean University of China, 2009.

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