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As­so­ciate Pro­fes­sor Jian Zhao, lec­turer in Food Sci­ence and Tech­nol­ogy, School of Chem­i­cal En­gi­neer­ing, The Univer­sity of New South Wales

Australian Geographic - - The List -

How is caf­feine re­moved to cre­ate de­caf­feinated food prod­ucts?

De­caf­feina­tion meth­ods are pro­pri­etary and details are com­mer­cial se­crets, al­though they do grad­u­ally be­come known. The ear­li­est tech­niques used or­ganic sol­vents to ex­tract caf­feine from green cof­fee beans. These were then dried and roasted, which is when most of the cof­fee flavour is gen­er­ated. Sol­vent residue con­cerns led to wa­ter de­caf­feina­tion pro­cesses, ini­tially in Switzer­land and France, al­though these meth­ods were not com­mer­cialised un­til the late 1970s. The lat­est in­no­va­tion is de­caf­feina­tion by su­per­crit­i­cal car­bon diox­ide, a liq­uid form of this chem­i­cal com­pound we usu­ally know as a gas. It ex­ploits the fact that CO be­comes liq­uid un­der ex­tremely high pres­sure and ac­quires some very use­ful prop­er­ties in­clud­ing the pref­er­en­tial dis­so­lu­tion of com­pounds such as caf­feine. Su­per­crit­i­cal CO de­caf­feina­tion pro­duces cof­fee with flavour su­pe­rior to con­ven­tional meth­ods but the process is con­sid­er­ably more ex­pen­sive.

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