Jumbo squid (Dosidicus gigas) muscle is rather hard and tough, which directly affects consumer acceptance. In this study, the tenderization effect of bromelain and papain on squid muscle during enzymolysis is examined and compared with an untreated control and water-treated sample. Squid mantle were incubated with different solutions (water, bromelain, and papain solution) for 40 min in a 30°C water bath. Then, the mantle samples were subjected to water holding capacity (WHC) analysis, texture evaluation, biochemical determination, and histological observations. The results revealed that bromelain and papain disadvantageously decrease the water holding capacity when compared to the control and water-treated samples. Furthermore, following tenderization with bromelain or papain, muscle hardness, shear force, myofibrillar protein content, and Ca²⁺ ATPase activity were all significantly decreased. Additionally, some essential amino acids were released following tenderization. When examining the myofibrillar fragmentation index (MFI), bromelain and papain were shown to cause high levels of hydrolysis in myofibrillar and sarcoplasmic proteins. Moreover, microstructural imaging indicated that the tenderization treatments disrupted myofibrils and generated a larger number of small fragments in the muscle tissues, subsequently decreasing microstructure stability and integrity. SDS-PAGE analysis confirmed that bromelain and papain have a high proteolytic activity, with some small peptides and/or short fragments detected post-tenderization. The results presented herein demonstrated that bromelain and papain improved squid muscle tenderness and can be utilized to ensure a more desirable squid product.

巨型鱿鱼（Dosidicus gigas）肌肉相当坚硬，直接影响消费者的接受度。在这项研究中，检查了菠萝蛋白酶和木瓜蛋白酶对鱿鱼肌肉在酶解过程中的嫩化作用，并将其与未处理的对照和水处理样品进行了比较。在30°C水浴中，将鱿鱼套与不同溶液（水，菠萝蛋白酶和木瓜蛋白酶溶液）孵育40分钟。然后，对地幔样品进行持水量（WHC）分析，质地评估，生化测定和组织学观察。结果表明，与对照和水处理样品相比，菠萝蛋白酶和木瓜蛋白酶不利地降低了持水量。此外，在用菠萝蛋白酶或木瓜蛋白酶嫩化后，肌肉硬度，剪切力，肌原纤维蛋白含量和Ca ²⁺ATP酶活性均显着降低。另外，嫩化后释放了一些必需氨基酸。当检查肌原纤维碎片指数（MFI）时，菠萝蛋白酶和木瓜蛋白酶显示会导致肌原纤维和肌浆蛋白的高水平水解。此外，微结构成像表明，嫩化处理破坏了肌原纤维，并在肌肉组织中产生了大量小片段，从而降低了微结构的稳定性和完整性。SDS-PAGE分析证实菠萝蛋白酶和木瓜蛋白酶具有很高的蛋白水解活性，在嫩化后检测到一些小肽和/或短片段。