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Development of supercritical CO2 extracts for flavored beer
T. Inui, D. Yonezawa and H. Abe

Different types of herbs and spices other than hops have been traditionally used for flavored beer such as Belgian style white. The distinct flavors in herbs and spices are typically derived from various terpenes. As oxygenated terpenes are easily eluted, certain terpenes, such as terpene hydrocarbons, are difficult to extract in the wort or beer and easily evaporate. Supercritical CO2 (SC-CO2) extracts were developed to provide distinct flavors to beer in a more efficient manner. Research was carried out to obtain the most appropriate temperature and pressure conditions to facilitate extraction and separation. Orange peels and coriander seeds, which contain more hydrophilic compounds, were used as starting materials. We found that a separation temperature below 20 C efficiently increased the yield of key aromatic compounds without freezing, although the separation temperatures had to be set above 40 C to prevent the water from freezing. Furthermore, the lower CO2 density obtained a higher purity of key aromatic compounds, which means it provides the resulted extracts more essential oil with lesser impurities derived from each material, although the yield of extract was low. Additionally, the ratio of terpene hydrocarbons to oxygenated terpenes increased with CO2 density, which resulted in changes in the aromatic characteristics. Finally, through a brewing trial, we find that the single unique SC-CO2 extraction technique could be the most efficient method to provide beer the distinct aromatic characteristics of herbs and spices as compared to a general beer brewing method, wherein herbs and spices are added to a wort kettle, whirlpool, or fermentation tank.

Descriptors: supercritical CO2, oxygenated terpenes, terpene hydrocarbons, orange peel, coriander seed, flavored beer

BrewingScience, 72 (September/October 2019), pp. 147-156