BACKGROUND Changes in the physicochemical properties of shrimp meat treated with two‐stage heating were investigated. Currently, shrimp products in the processing process are susceptible to uneven dehydration, shrimp meat shrinkage, which results in rough and hard texture, poor chewiness, and seriously affects the edible quality as well as economic benefits. Improving the utilization value of shrimp resources, expanding its market shares, optimizing the tenderness of shrimp is the key to developing new types of fresh and ready‐to‐eat shrimp products. RESULTS The results indicated that preheating at 30 °C could not affect the quality of shrimp meat significantly (P > 0.05). As the preheating temperature increased from 40 °C to 50 °C, the hardness and shear force of shrimp meat decreased due to the exposure of protein hydrophobic groups, protein aggregation and degradation, muscle fraction broken, and weight loss increase. Further increase in preheating temperature would lead to further aggregation and gelation of proteins, causing hardness and shear force increase. Besides, the results of microstructure showed that preheating at 40 °C and 50 °C could cause the shrimp muscles to become loose. CONCLUSION This study showed that the preheating temperature ranging from 40 °C to 50 °C could effectively improve the tenderness of shrimp meat. This study might be useful for developing tenderized shrimp products in the future. © 2022 Society of Chemical Industry.

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Iron deficiency anemia (IDA) is a global health concern affecting one‐third of the world's population, particularly those dominated by plant‐based food. Fortifying staple foods with iron has been an effective strategy for preventing IDA. Pneumatophorus japonicus is an essential economic fish in China. Pneumatophorus japonicus dark meat is usually underutilized as a byproduct, though it contains bounteous nutrients, including heme iron (10.50 mg/100 g). This study aimed to investigate the iron bioavailability of P. japonicus dark meat and to evaluate its potential as an iron fortifier for whole‐wheat flour, a typical staple food, using an in vitro digestion/Caco‐2 cell culture system. Our results suggested the excellent iron bioavailability of P. japonicus dark meat in comparison with beef (a heme dietary iron reference), whole‐wheat flour (a non‐heme dietary iron reference), and FeSO4 (a conventional iron supplement). The addition of P. japonicus dark meat notably enhanced iron solubility, bioavailability, and protein digestibility of whole‐wheat flour. The flour‐dark meat mixture yielded 1.96 times the iron bioavailability compared to beef per gram. The iron bioavailability was further improved by adding vitamin C, a commonly used dietary factor, at the Vc/iron mass ratio of 2:100‐5:100. Our findings reveal the promise of P. japonicus dark meat as a significant source of bioavailable iron, providing a basis for developing fish byproducts as alternatives for iron supplementation. Practical Application This study investigated the iron bioavailability of Pneumatophorus japonicus meat using in vitro digestion/Caco‐2 cell culture system. These results could be used to improve the utilization of Pneumatophorus japonicus byproduct (dark meat) and develop the potential of the byproduct as an iron fortifier for whole‐wheat flour.