The mechanistic effect of bromelain and papain on tenderization in jumbo squid (Dosidicus gigas) muscle

Abstract

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.

Keywords: Acetic acid (PubChem CID: 176); Adenosine 5′-triphosphate (PubChem CID: 5957); Bromelain; Carbohydrate moiety of bromelain (PubChem CID: 44263865); Carbon tetrachloride (PubChem CID: 5943); Eosin (PubChem CID: 11048); Ethylenediaminetetraacetic acid (PubChem CID: 6049); Hematoxylin (PubChem CID: 442514); Maleic acid (PubChem CID: 444266); Myofibrillar protein; Ninhydrine (PubChem CID: 10236); Papain; Paraformaldehyde (PubChem CID: 712); Squid; Tenderization; Trichloroacetic acid (PubChem CID: 6421); Trihydroxymethyl aminomethane (PubChem CID: 87073016).