In a review study currently in press for Food Research International, Ngo et al. (2011) explain that proteins in marine foods contain potential functional food ingredients such as bioactive peptides, which are released during digestion, food processing or fermentation and according to Erdmann et al. 2008, cut the risk of illnesses such as cardiovascular disease.
When obtained through enzymatic hydrolysis, the authors said the literature showed that peptides possessed antioxidant, anti-hypertensive, anticoagulant and antimicrobial qualities, with these benefits already available in naturally hydrolised foods such as blue mussel or oyster sauce.
Antioxidant benefits of bioactive peptides
Ngo et al. wrote: “Several studies have indicated that peptides derived from marine fish proteins have greater antioxidant properties in different oxidative systems Jun, Park, Jung & Kim 2004).”
“However, the exact mechanism of peptides to act as antioxidants is not clearly known, but some aromatic amino acids and histidine are reported to play a vital role in the activity.”
The authors said that Shahadi et al. (1995) “clearly demonstrated” that Capelin fish protein hydrosylate reduced the formation of secondary oxidation products (including thiobarbituric acid) in the product by 17.7%-60.4%.
But Ngo et al added that the bitter taste of protein hydrolysates prevents the use of bioactive peptides as food additives – presenting a challenge for food technologists – while their bioactivity may be also be reduced by food processing methods or interaction with other ingredients (Moller et al.2008).
Chitin derivatives to treat hypertension, diabetes?
The polysaccharide chitin – prepared from shells of crabs and shrimps – also showed promise, said the authors, with chitooligosaccharide derivates (COSD) of it showing antioxidant effects (Park, Je, Kim 2003) angiotension-converting enzyme inhibition (useful in the treatment of hypertension and congestive heart failure) antimicrobial, anticancer and anti-diabetic qualities, amongst others.
Meanwhile, sulfated polysaccharides (SPs) in brown algae, carrageenan in red algae and ulvan in green algae all exhibited “various health benefits” in several cited studies, said the authors, including anti-HIV1, antioxidant and anticoagulant effects, as well as immunomodulating and anti-cancer benefits.
For instance, Kim et al. (2007) found that SPs in brown algae sargassum fulvellum was a “more potent” nitric oxide scavenger than commercial antioxidants such as BHA and alpha-tocophorol.
Ngo et al. added that phlorotannins (phenolic compounds), found in brown marine algae in particular, showed natural antioxidative effects that “can protect food products against oxidative degeneration as well as preventing and/or treating free radical-related diseases”, and also praised carotenoids from marine sources, such as astaxanthin, for their potent antioxidant effects.
Title: Marine food-derived functional ingredients as potential antioxidants in the food industry: An overview, Food Research International (2011) doi: 10.1016/j.foodres.2010.12.030 (published online ahead of print).
Authors: Dai-Hung Ngo, Isuru Wijesekara, Thanh-Sang Vo, Quang Van Ta, Se-Kwon Kim