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ePaper created 2017-03-14, 10:25:37 | version 1.49.03
protein (soluble) protein (insoluble) omega-3-fatty acids / EPA fucoxanthin lutein 100 600 content of proportional biomass in g kg–1 400 300 500 200 10 15 5 40 value of proportional biomass in € kg–1 30 20 35 25 m u t u n r o c i r t . P 0 0 1 2 2 3 VALUABLE SUBSTANCES FROM MICROALGAE FOR FOOD APPLICATIONS F e li x D e r we nskus , U lr ike S chmi d -St a i g e r Microalgae – integrated use for food and feed Based on CO2 and sunlight, microalgae can produce a large number of substances that are of interest for the food and feed sector as well as for cosmetic companies (Fig. 4). In addition to unsaturated omega-3 fatty acids such as eicosa- pentaenoic acid (EPA; C20:5 n-3), photosynthesis-associated pigments, for example fucoxanthin or lutein and phytosterols, make a signii cant contribution to the value added from algal biomass. Many ingredients have health-promoting properties that can be benei cial in human nutrition. The wide range of ingredients and the varying composition of different microalgae species necessitates selective processing of the biomass. The primary objective is to effectively extract high-quality ingredients and simultaneously preserve the processing technique is essentially determined by the chemi- cal character and market specii cation, such as the required degree of product purity. Further requirements are avoiding, as far as possible, an energy-intensive drying step as well as ensuring gentle extraction that both maintains the functional- ity and permits the extraction of further cell components. Selective extraction and scale-up of the procedures A procedure known as pressurized liquid extraction (PLE) plays a key role; this process allows wet biomass to be extracted using appropriate organic solvents. For this purpose, extrac- tion properties of the selected solvents were examined under pressure with various conditions (e.g. extraction temperature) at Fraunhofer IGB (Fig. 1). In follow-up to optimization of the extraction parameters that has already been carried out at technical, functional, nutritional and physiological properties of these products. Within the framework of the Baden- Württemberg Bioeconomy Research Program, the “Microal- laboratory scale, a scale-up of this PLE procedure to pilot scale is currently being carried out in collaboration with afi liated partners at Hohenheim University. gae – Integrated Use for Food and Feed” research association is seeking to utilize the different fractions as completely as possible through coupled or cascade use, in order to develop sustainable processes for bioeconomy. Processing of algae ingredients Three microalgae strains (Phaeodactylum tricornutum, Chlorel- la vulgaris and Nannochloropsis oceanica) were selected based on their fundamental differences in size, cell wall assembly and ingredients. A combination of successive extraction processes was used to fractionate both mid- and high-priced ingredients such as EPA and carotenoids as well as the princi- pal fractions that consist of proteins and nonpolar triglycerides sequentially obtained from the microalgal biomass. The 5 0 Extraction with supercritical l uids (SCF) represents an alterna- tive. Cosolvents such as ethanol can be added to the primarily nonpolar supercritical l uids (e.g. carbon dioxide) in order to increase polarity. The different extraction behavior with and without a cosolvent is also specii cally utilized for the separa- tion step (cascade extraction) of nonpolar triglycerides and polar lipids such as eicosapentaenoic acid or carotenoids (e.g. fucoxanthin). Fraunhofer CBP offers an opportunity to move this procedure up to pilot scale.