A Comprehensive Investigation of Tenderization Methods: Evaluating the Efficacy of Enzymatic and Non-Enzymatic Methods in Improving the Texture of Squid Mantle — A Detailed Comparative Study

Abstract In this study, enzymatic [papain (P), bromelain (B), and A. oryzae -derived fungal protease (FP); enzyme ratios: 0.012 (v/v), 38 °C, 50 min] and non-enzymatic [control (C; saline), mineral water (95%)–lemon juice (5%) (ML) (1/2:w/v), 38 °C, 50 min)] tenderizing methods on European squid mantle ( Loligo vulgaris Lamarck, 1798) were investigated. Scanning electron microscope (SEM) imaging, water holding capacity (WHC), cooking loss (CL), total free amino acids (TFAA), total soluble protein (TSP), hydroxyproline (Hyp), and Fourier-transform infrared spectroscopy (FTIR) analyses were performed on uncooked samples. pH, water activity (aw), color, nutritional changes, amino acids (AA), total volatile basic-nitrogen (TVB-N), Warner-Bratzler shear (WBS), texture profile analysis (TPA), and sensory evaluations were performed on both uncooked and cooked samples. A significant decrease in protein content was observed in group P (12.86%) compared to untreated (U) squid (15.16%). During frying, group P absorbed more cooking oil (8.37%) than the other groups. A higher degree of hydrolysis was observed in the enzymatically tenderized groups than in non-enzymatic groups, and a shift in secondary protein structures in favor of random coils. Hydrolysis was confirmed by Hyp and AA analyses. The total AA content order was found as B < P < FP < C < ML < U. ML and FP groups have relatively higher total bitter and umami AA compositions, especially in uncooked samples. FP and ML groups had more favorable results across all analyses, especially in terms of the sensory results, nutritional values, and TPA results of cooked samples. It is concluded that both methods are very convenient regarding industrial usage.