## 3 Results and Discussion
### Texture Analysis  
The results of measuring the three distinguishing features of texture of dried pork snacks are shown in Table 2. The penetration method, used together with the effect of squeezing meat products, shows that the lowest strength, evidenced by the highest destruction force (i.e., cracks registered during penetration), was present in the sample that was preprocessed with the use of papain and NaCl. Moreover, a lower value on the curve slope also indicates the lower strength of preprocessed samples. The mean values acquired for modified samples were significantly different from the ones that were not exposed to pre-processing. Preprocessing resulted in lower mean values of the distinguishing mechanical features (except for the number of peaks), which indicates that the meat products acquired were of higher, more desirable tenderness (crispness).  
Analysis of the distinguishing features of meat products' texture using the instrumental method for the first variant showed a positive link with the conducted sensory analysis that yielded the highest tenderness value [35]. It can be assumed that not exposing the raw meat to preprocessing would yield unsatisfactory results for consumers, who would not enjoy these less tender meat snacks.  
The instrumental analysis of the texture of enzymatically pretreated meat products was in line with the sensory evaluation of the texture as shown in the first part of the paper [35]. The pretreatment of meat muscle contributed to a reduction in hardness of over 25% with a simultaneous increase in the crispness of the final product.  
The irregular peaks observed in the force curves of the roasted samples, for example, characteristic of a crispy product, reflected multiple fracture events, and could be a result of a non-homogeneous morphology and microstructural elements, such as water or oil phase distribution, causing the anisotropy of the structure. However, the particular importance of these elements in the perception of crispiness is still unknown [61].  
Enzymatic methods are applied with an increasing frequency to control the technological properties of food raw meat. They are used to obtain hydrolysates with specific properties through enzymatic proteolysis of proteins or modification of their amino acid composition in the plastic reaction. One of the groups of proteases are cysteine proteases, with the best-known example being the plant enzyme papain [62]. It functions in a neutral environment and is used for meat tenderization. Figure 2 shows average curves acquired during a pork puffing mechanical properties study. The positive impact of enzymatic meat tenderization on lowering the mechanical strength of the samples analyzed can be observed.  
Myofibrillar proteins (actin and myosin), intramuscular connective tissue, and perimysium played major roles in the mechanical resistance of muscle fiber [63]. Connective tissue and longitudinal muscle fiber contracted during the heat-induced denaturation of proteins, resulting in water leaking out of cells. This caused a change in hardness and in the force required for biting [64]. A similar effect can be seen in the case of studies in which microwave-vacuum drying of pork muscle slices was used.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Type of Sample** & **Hardness [N]** & **Slope [N/s]** & **Work of Compression [Nxs]** \\ \hline Unmodified pork & 133.53 \({}^{\mathrm{a}}\)\(\pm\) 12.43 & 4.60 \({}^{\mathrm{a}}\)\(\pm\) 0.51 & 1788.51 \({}^{\mathrm{a}}\)\(\pm\) 214.67 \\ Modified pork & 108.40 \({}^{\mathrm{b}}\)\(\pm\) 9.64 & 3.80 \({}^{\mathrm{b}}\)\(\pm\) 0.41 & 1632.95 \({}^{\mathrm{a}}\)\(\pm\) 207.91 \\ \hline \hline \end{tabular}  
Means in the same column with different letters as superscripts indicate that there is a significant difference at \(\alpha\) = 0.05 (n = 15) (sample description: see Table 1).  
\end{table}
Table 2: Mean values of distinguishing features of puffed pork snacks texture.