Progressive Freeze-concentration of Aroma Components of Peach Fruits

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 peach fruits by progressive freeze-concentration. Condensated water containing the aroma components of peach fruits 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 11.6 times (volume to volume) by the progressive freeze-concentration, the major aroma components of peach fruits (γ-decanolactone, (E)-2-hexen-1-ol, 1-hexanol, (Z)-3-hexenyl acetate and so on) were concentrated almost to the theoretical limit, about 8-12 times. The aroma components that were incorporated in the ice phase were less than 0.5％, even in the worst cases ((E)-2-hexen-1-ol). In summary, the aroma components of peach fruits were very effectively concentrated to a high degree with good yields by progressive freeze-concentration.