Chapter 19 - Nutritional quality and bioactive properties of proteins and peptides from microalgae

Abstract

Microalgae are underutilized organisms with multifaceted bio-relevance beyond their potential as sources of sustainable biofuels. Microalgae are unique sources of bioactive compounds and proteins with nutritional, functional, and health benefits. Although the use of microalgae as food and feed dates back several centuries, strategic scientific evaluations of the nutritional value and health benefits have increasingly garnered attention in recent times, especially as sustainable, alternative sources of dietary protein. Major criteria in evaluating the nutritional value of novel food and feed sources are the protein content, amino acid profile, digestibility, protein utilization, and the protein needs of consumers. The nutritional value of microalgae is affected by biotic and abiotic factors and genomic variation between species. Using endogenous and exogenous proteases, microalgal proteins can be hydrolyzed to generate bioactive peptides with potential physiological effects in the human body, such as opioid-like, antithrombotic, immunomodulatory, and antihypertensive activities. One major challenge faced when using whole microalgae as a dietary protein source is poor digestibility, which is mostly due to the rigid and recalcitrant nature of many microalgal cell walls. This challenge can be circumvented with chemical, mechanical, and enzymatic pretreatments of microalgal biomass prior to protein extraction or food/feed product development. This chapter discusses the nutritional value and health benefits of microalgae proteins and peptides as well as the current challenges and future direction in protein assessment methods.