Abstract
Because it does not involve heating, “freeze-concentration” is one of the most suitable methods for concentrating thermally unstable materials, for instance, aroma components. We, therefore, tried to prepare a concentrate of the aroma components of the La France pear by progressive freeze-concentration. Condensated water containing the aroma components of La France pear was obtained by vacuum distillation of fresh juice using a rotary evaporator, and was further concentrated by progressive freeze-concentration. When the distillation-condensate was concentrated 11.5 times (volume to volume) by the progressive freeze-concentration, the major aroma components of La France pear (butyl acetate, hexyl acetate and so on) were concentrated almost to the theoretical limit, about 10-11 times. The aroma components that were incorporated in the ice phase were less than 3%, even in the worst cases (approximately 2.4% and 2.8% for 1-butanol and 1-butanol, respectively). In summary, the aroma components of La France pear were very effectively concentrated to a high degree with good yields by progressive freeze-concentration.
