## 3 Conclusions  
Marine-collagen-based extracts have received significant attention both from the scientific community and from the industrial sector in the past 20 years as a \"blue resource\" with potential use in numerous health-related fields (food, medicine, pharmaceuticals, cosmetics, and biomaterials) [44]. This work, funded by the Horizon 2020--EcoeFISHent project, aims to valorize fishing and fish industries' side streams through the extraction of bioactives for highly valued dietary supplements and skin care products, as well as promoting their use as biodegradable and compostable biomaterials for food packaging.  
In this second part (Part II) of a larger study report, a complete characterization of the two collagenous protein types, namely gelatin and hydrolyzed gelatin peptides, was reported. The single-cascade flowchart proposed turned out to represent a promising extractive process, with good prospects in terms of industrial scalability. It should be noted that starting from non-separated side streams necessarily requires pretreatment for exploit  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Molecular weight ranges (Da) 1** & **G (relative amount \%) 1** \\ \hline
20,000+ & 40.4 \(\pm\) 1.6 \\
10,000–20,000 & 39.8 \(\pm\) 2.3 \\
5000–10,000 & 8.7 \(\pm\) 0.1 \\
0–5000 & 11.2 \(\pm\) 0.6 \\ \hline
**Molecular weight ranges (Da)** & **HGPs (relative amount \%)** \\
4000+ & 21.0 \(\pm\) 1.1 \\
2500–4000 & 15.7 \(\pm\) 0.1 \\
1000–2500 & 41.1 \(\pm\) 0.5 \\
0–1000 & 22.4 \(\pm\) 0.5 \\ \hline \hline \end{tabular} 1  
\end{table}
Table 4: Molecular weight distributions of gelatin (G) and hydrolyzed gelatin peptides (HGPs).  
ing the part richest in collagen, mainly comprising bones, from which to extract gelatin and gelatin/collagen hydrolysates. These pretreatments, especially the initial enzymatic hydrolysis, have inevitable repercussions on the quality of the gelatin that can be extracted, especially in terms of molecular weight and viscosity. However, physical properties, such as viscosity, can be released from these parameters, depending on the desired application, increasing concentration, and use of appropriate additives. Furthermore, it is important to underline that a cost-benefit analysis is crucial for the scaling up of the proposed protocol, and thus the reagents used in this research, such as the enzymatic preparation, the demineralization agent, the stabilization treatment, and so on, were chosen to be suitably scalable at the industrial scale. As far as the final drying technique was concerned, the use of a spray dryer was chosen (instead of freeze-drying) as it is more sustainable in terms of time and energy consumption. On the other hand, the cheapest oven drying technique was no longer considered, as the properties of the final products were worse.  
In conclusion, given the promising results obtained, the possible uses of G and HGPs could be investigated for different applications, such as in biomaterials as regards G, which has higher molecular weight and viscosity, and in nutraceutical and cosmetic products as regards HGPs.  
Furthermore, it is important to underline how, from this extraction process, it is possible to obtain other interesting products, some of which include Non-Collagenous Proteins (NCs), with a high extraction yield (about 15%) and whose properties will be further investigated in the future.