## 4 Conclusions  
The results presented herein are, to the best of our knowledge, the first evidence of a protein hydrolysate purified from blue whiting exhibiting antioxidant or immunomodulatory potential in a cellular model. Hydrolysate BW-SPH-A, which enhanced cellular redox status pre- and post-SGID, may have potential as an effective natural antioxidant. Hydrolysate BW-SPH-F, which increased the production of proinflammatory mediators and cytokines, also maintained its bioactivity post-SGID; therefore, it may have application as an immunostimulant with potential to improve the quality of life of immunosuppressive patients. The extraction and identification of biofunctional protein hydrolysates presents an opportunity to increase the value of low-value blue whiting through their applications as high-value functional food ingredients. Future experimentation should involve the identification and characterization of peptides responsible for the antioxidant and immunomodulatory activities exhibited by BW-SPH-A and BW-SPH-F, respectively. In vivo interventional studies should be used to assess the biofunctional activities of BWSPHs, as well as to examine the capacity of gut digestive enzymes to functionalise hydrolysates in addition to the study of potential bioactive peptide protection mechanisms, such as microencapsulation, for the fractions that lost activity during simulated gut transit.  
The following are available online at [[https://www.mdpi.com/article/10.3390/app11209762/s1](https://www.mdpi.com/article/10.3390/app11209762/s1)]([https://www.mdpi.com/article/10.3390/app11209762/s1](https://www.mdpi.com/article/10.3390/app11209762/s1)), Figure S1: The antioxidant activity of blue whiting (_Micromesitis poutassou_) soluble protein hydrolysates (BWSPH) (1.5-4 mg/mL) on 2,2-diphenyl-1-2-picryl-hydrazyl (DPPH) free radicals. Table S1: The effects of blue whiting (_Micromesitis poutassou_) soluble protein hydrolysates (BWSPH) on the viability of murine RAW264.7 cells. Table S2: The effects of simulated gastrointestinal digested (SGID) blue whiting (_Micromesitis poutassou_) soluble protein hydrolysates (BWSPH) on the viability of murine RAW264.7 cells. Table S3. Arithmetical ranks of blue whiting (_Micromesitis poutassou_) soluble protein hydrolysates (BWSPH) pre- and post-simulated gastrointestinal digestion (SGID) with respect to individual antioxidant parameters. Supplementary Table S4. Arithmetical ranks of blue whiting (_Micromesitis poutassou_) soluble protein hydrolysates (BWSPH) pre- and post-simulated gastrointestinal digestion (SGID) with respect to individual immunomodulatory parameters.  
[PERSON] and [PERSON] conceptualized the research. [PERSON] and [PERSON] provided the BWSPH samples. [PERSON] prepared the SGD digests and determined the FRAP and ORAC activity of all BWSPHs. [PERSON] determined the DPPH activity of BWSPHs and performed all cell-based assays. [PERSON] drafted the manuscript and [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON] reviewed and edited the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Department of Agriculture, Food and Marine, Ireland [grant number 17/F/260]. L.G. is funded by Science Foundation Ireland and Department of Agriculture, Food and Marine [16/RC/3835-VistaMilk].  
Data Availability Statement: Data are contained within the article or in Supplementary Data.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.