Search for health functional ingredients in red algae, a low-use resource × SDGs
We are conducting research on northern red algae, with a focus on the low-use red alga Dulse from Hokkaido. We have found that red algae such as dulse and other red algae, which have been removed as waste from kelp cultivation, are rich in a variety of useful biochemical components. Through these studies, we hope to contribute to the development of food sources for hunger, and to the development of functional food ingredients to improve people's health.
The United Nations has designated the decade starting in 2021 as the "Decade of Ocean Science," with the aim of contributing to the SDGs.
Red algae are one of a group of seaweeds that can be obtained in the sea near Japan, and many are marine waste. Here, we focused on the health functionality of phycobiliproteins contained in red algae in order to find an effective use of red algae. As a result, phycobiliprotein was able to confirm health functions such as an antioxidant action and a blood pressure increase inhibiting action.
Characteristics of Red Alga "Dulse"
What ‘s red alga
Red alga is a group of seaweeds that can be obtained in many areas near Japan. However, most of them are unused. Many red alga are rich in protein, especially phycobiliproteins which have pigments.
In this study, focusing on red alga proteins, we searched for its health function. The purposewas to lead to effective use of marine waste by searching for added value.
Characteristics of phycobilisome
Phycobiliprotein is a general term for light collecting proteins involved in photosynthesis. Cyanobacteria and red alga have them. In living organisms, α and β chains form hexamers, forming the complex phycobilisomes shown above. These have pigments that are the red origin of red algae. Here we searched the health functions of these proteins and pigments.
Health function of protein and peptide
Result of Antioxidant Activity
Antioxidant activity was detected only in water extracted protein. Since chromophores do not exist in heterologously expressed phycobiliproteins, it was suggested that the substance exhibiting antioxidant activity is chromophores. The antioxidant effect of isolated PE was stronger than PC because PE have more chromophores than PC. Therefore, the antioxidant effect of red algae protein is derived from the chromophore, and it is expected that the greater the number, the stronger the action.
ACE inhibitory effect of red alga proteins and peptides
Red algae proteolysates contain peptides that inhibit the activity of the blood pressure-enhancing enzyme “ACE”.
Result of Antihypertensive Activity
Antihypertensive effect was showed stronger effect in the peptides than the proteins, regardless of water extraction or heterologous expression. Based on this result, we predicted the structure of a functional peptide that most strongly inhibits ACE activity among several types of peptides produced by proteases.
Development of large-scale preparation of chromophore
Search for ACE inhibitory peptides contained in red algae protein