Technological advances in fermentation of Chlorella vulgaris and Arthrospira platensis biomass for production of volatile organic compounds with sensorial appeal in foods

Background: Microalgae biomass represents a promising feedstock for the sustainable production of a wide range of volatile organic compounds (VOCs) for food applications. Microalgae-derived food products may face sensory challenges, such as intense green colors due to chlorophyll or atypical odors and flavors 'fishy or grassy' that may not be well accepted by consumers. The development of fermentation processes that modify or mask these undesirable sensory attributes, or the selection of microalgae strains with more neutral sensory profiles are an interesting option to create new aroma and flavors. Scope and approach: This review discusses current research on microalgae biomass fermentation, with special attention to the microalgae Chlorella vulgaris and Arthrospira platensis and lactic acid bacteria (LAB), Bacillus spp. and yeasts (Saccharomyces cerevisiae), which represent the most common microorganisms studied in fermentation process for synthesis of VOCs with unique sensory profile. Key findings and conclusions: Fermentation of Chlorella with LAB strains demonstrated to be effective process to reduce pyrazines and aldehydes (hexanal), while esterified compounds increased. Fermentation of Arthrospira with LAB or Bacillus also reduced pyrazine (roasted nut aroma) and furans (sweet, green aroma), while an increase of ketone-acetoin associated with buttery and creamy aromatic notes was observed. Yeasts found to be responsible for alcoholic fermentation and the production of higher alcohols and esters in fermented A. platensis biomass. In sum, the fermentation of microalgae biomass is a promising biotechnological strategy to modulate or transform the VOC profile of microalgae, contributing to the reduction of their strong flavor and color features.