Extraction method and apparatus of juice and/or puree, in particular from partially or completely frozen vegetables

摘要

A rotating machine operated along an axis (3a) by a motor (3), for extraction of puree or juice from animal or vegetable food, comprises an inlet duct (1) where the animal or vegetable food (2) is loaded, for example fruit or vegetables, conveyed by a feeding screw conveyor not shown. The food pulps of the products (2) are loaded in frozen condition and enter then a shredding section comprising an armature (4) rotatable at a high speed in a stator (5) where the product is subjected to pressure pulses in quick succession by the movement of the frozen product (2) between the armature (4) and the stator (5). This way, there is a significant transformation of the mechanical energy into thermal energy that assists partial defrosting (at least 10%) of the product, obtaining a desired, temperature course of the product at least up to the end of the extraction with respect to the defrosting temperature (T*) of the product, which can be 0OC or even less. A fluid material is obtained that has the consistency of a puree even if it contains still small frozen parts. On the external wall of the stator (5) thermal power can be applied contemporaneously to the pressure pulses, in order to heat the inner surface of the stator (5) or the rotor (4), by applying vapor or by means of electric resistance.