**5. Conclusions**

*Innovation in the Food Sector Through the Valorization of Food and Agro-Food By-Products*

has promising applications as antioxidative, anti-inflammatory, antitumor, anti-enterovirus and hepatoprotective [132]. Despite its potential biochemical and therapeutic benefits, there are some challenges in its downstream processing including difficulty in primary extraction and purification, containing lower proportion of phycobiliprotein rather than phycocyanin and the resistance of cell membrane to disruption cause extraction of 50–60% of A-PC by conventional methods. Moreover, the main objective of pigment extraction form *spirulina* is C-PC, consequently, remaining high content of A-PC (about 40–50%) in biomass

Algae protein waste is a by-product derived from water-extraction process of microalgae, during algae essence manufacturing. The underutilized algae wastes, containing above 50% protein, have low economical value to be used as animal feed. The pepsin hydrolysate from algae protein waste exhibited antioxidative activity in preliminary experiments, indicating that algae waste might become a new protein

Furthermore, protein hydrolysates from marine sources such as algae by-products, have generally been used to produce seafood flavorings. A high flavor quality is difficult to ensure for seafood flavoring that is produced from marine animal sources because of their high susceptibility to lipid oxidation and the high cost of removing excess fat. Seaweed by-products after agar extraction are good sources of plant protein and contain taste-active amino acids, such as aspartic acid, glutamic

A seaweed protein hydrolysate using 10% bromelain for 3 h, resulted in high level of arginine, lysine, and leucine as free amino acids. These amino acids exhib-

Most microalgae contain high level of protein which discarded or damaged during biofuels production, while are good candidate for protein extraction and consequently, obtain lipid-rich product as by-product as feedstock for biofuels production. Even though proteins are major algae biomass component, usually they are undervalued compared to minor components such as omega fatty acids, pigments

For instance, Garcia-Moscoso et al. [136] extracted more than 60 wt% of nitrogen content of *Scenedesmus* sp. by subcritical water medium then the lipid-rich

Moreover, protein isolation, as valuable by-product, from defatted

*Nannochloropsis*, can be obtained after lipid extraction during biofuel production. Defatted and non-defatted *Nannochloropsis* contained 56.9% and 40.5% protein respectively. The protein yields by alkaline (pH 11 and 60 C) extraction method were 16% and 30% respectively. These isolated proteins had a high molecular

There are numerous investigations about algae protein waste and extraction of peptides or amino acids with functional properties. For instance, the antioxidative peptide of VECYGPNRPQF was isolated by pepsin from *Chlorella vulgaris*. This peptide had some bioactivity such as DNA protective effect against hydroxyl radicals, gastrointestinal enzyme-resistance, and strong antioxidant properties. Fractionation of proteins exhibited the high level of aspartic acid, glutamic acid, leucine and lysine [134]. This amino acid sequence (VECYGPNRPQF) can act as cheap and natural anticancer peptide because had antiproliferation and induced a post-G1 cell cycle arrest in AGS cells with no cytotoxicity effect in WI-38 lung

source for selection of novel antioxidative peptides [134].

acid, arginine, and lysine, in addition to a low fat content [135].

ited an umami taste and a seaweed odor [135].

or other possible valuable buy-products [136].

residue used as suitable feedstock for biofuel production.

after C-PC extraction [133].

**4.3 Proteins**

**126**

fibroblasts cells [137].

weight approximately 250 kDa [138].

This chapter indicated that seafood by-products are one of the most important sources of value added products that can play an important role in the global market due to the increasing growth of demands for health beneficiary products. Through this opportunity and based on our research background for many years, we decided to provide important information about some value-added products obtained from seafood by-products. Proteins and peptides are a major part of the seafood by-products composition that can easily provide essential amino acids and bioactive peptides with health beneficent. Fish oil is another valuable product that could be extracted from seafood by-products. This source is rich in LCPUFA and decreases the risks of chronic diseases such as cardiovascular issues, thereby directly related to our health. Marine algae are a versatile, abundant, and valuable source of many compounds that have been widely used for many industries. The presence of bioactive compounds such as sulfated polysaccharide, carotenoid, and protein makes them a suitable candidate in biomedical applications. It seems, they will play an important role in human life because of their broad applications in food, pharmaceutical, and cosmetic industries.
