FR2531321A1 - Juice prepn. from foodstuffs e.g. fruit and vegetables - Google Patents

Abstract

Process comprises slicing the foodstuffs before pressing, to prepare a pulp consisting of individual lonitudinal strips, pref. having thickness 1.5-3mm. Slicing forms channels for the flow of juice. Juice yield in pressing is increased, e.g. by at least 20% in apples, without using pressing auxiliaries. Pref. after slicing and before pressing, the temp. of the sliced pulp is set to 29 deg. C, which is the optimum temp. for improved pressing efficiency. The pressed pulp is removed continuously from the pressing zone and worked up after the 1st pressing, so as to convert the long strips to flakes. The pulp is then pressed again, opt. repeatedly. During slicing the foodstuffs are kept at least at room temp.

Description

Process for extracting liquids from edible products such as fruits and vegetables
The present invention relates to a process for extracting liquids from edible products in solid or semi-solid form such as fruits and vegetables.
Hitherto, fruits or vegetables or a pulp made from them have been physically pressed into fixed plates or between a fixed plate and an expanding membrane to express the juice of fruits, vegetables or pulp when pulp press5 it is common to add various pressing aids, such as rice husk, the pulp so as to provide channels along which the juice can flow out of the pulp during pressing.

In accordance with the present invention there is provided a process for extracting juice from edible products in solid and semi-solid form such as fruits and vegetables, comprising the phases consisting of - cutting into slices the edible product to produce a pulp consisting of individual lamellae of elongated shape; and press the slat pulp in a pressing zone to extract the juice.

Thus, the method according to the invention comprises a cutting phase into strips, before pressing, during which the fruits or vegetables are cut into strips to produce a pulp consisting of elongated strips, preferably having a thickness of in the range of 1.5 to 3mm. The lamellar consistency of the pulp provides channels along which the juice can flow out of the pulp during pressing so that there is no need to use pressing aids to achieve extraction returns. superior juices.

Advantageously, the yield is further increased by the fact that both the edible product and the slat pulp are tempered by adjusting their temperature to an optimal level before the slicing and pressing phases respectively.

The invention will be better understood on reading the description which follows, given solely by way of example, with reference to the appended drawings, in which - FIG. 1 is a schematic representation illustrating an embodiment of a treatment installation which implements the method of the invention; and - Figure 2 is a sectional view of a grater for cutting the fruit into elongated strips.

The process of the invention is preceded by the preliminary preparation of the fruits or vegetables from which the juice is to be extracted, which consists in passing the fruits, for example, through a decanter 1 which eliminates the undesirable particles such as stones, pieces of metal, etc., to protect the rest of the installation.

This decantation can be carried out in many ways, for example by means of a hydraulic device such as that illustrated in US Patent 3,704,041. -
The fruits or vegetables are then cut by means of a grater in the form of a pulp made up of lamellae of elongated shape and a thickness preferably between 1.5 and 3 mm. This can be achieved by means of a grater such as that which is illustrated in FIG. 2. It has been found that cutting into elongated strips increases the juice extraction yield without the need to use pressing aids, such as rice husk or the like, during subsequent pressing phases.

For pressing apples, for example, without the use of pressing aids, the juice yield can be increased by at least 200. It has also been noted that cutting apples immediately after refrigeration produces more uniform strips than they are obtained by cutting the apples at room temperature and this further increases the juice yield.

The cut pulp is then pre-drained as shown in 3 and the resulting juice flows through the conduit 4 to a reservoir 5 for storing juice. During this treatment phase, centrifugal or centrifugal drainage devices can be used. The extraction of the free juice by draining makes the subsequent stages of juice extraction by pressing more efficient.

The pre-drained slat pulp is then tempered at 6 in a pulp storage container where its temperature is brought to about 29-30 C which has been found to be at optimum temperature for increasing the pressing iuiidenint. You can also add enzymes to the pulp during this processing phase. The pulp storage tank can be a double walled tank which circulates hot water in the double wall, or the tank can be fitted with heating panels.

Significantly high juice yields can be obtained from apples, for example, brought to a temperature of about 290 ° C. At this temperature, the comparative juice yield of a tempered apple pulp compared to an apple pulp at a temperature of 100 ° C. is approximately 623 liters per tonne and approximately 584 liters per height respectively.

The tempered pulp is then distributed, in a predetermined volume, to a first pressing stage 8a. A suitable press includes an intermittently moved conveyor belt which carries a preset thickness of pulp from the volumetric feeder 7a.

For apple pressing, the "cake" thus founded has a thickness of between 25 and 76mm. The strip ensures the positioning of a pulp cake in a pressing zone between a pair of pressing plates, for example. They can consist of a pair of rigid plates set in motion by a hydraulic system, or one of them can consist of an expandable membrane such as that which is disclosed in the article entitled 1, Automatic Pneumatic Press "( automatic pneumatic press) published in the journal "Vines and Wines;" December 1960. In this first pressing stage, the plates move together and press the pulp cake for about one minute under a pressure between 14062 and 28124 kg / m2 The expressed juice flows through the conduit 9a to the reservoir 5. The elongated pulp strips form conduits to allow the juice to flow out of the cake.

After releasing the pressure, the conveyor belt of the pressing stage moves the pressed cake from the pressing zone j-llsqç a stage of brasuaue 10a. The band rejects the pressed cake in a first mixer - the scoop which breaks the pressed cake between rotating pallets and crumbles the strips of elongated pulp. This mixing opens up new channels between strips for drainage and exposes new surfaces. for the pressure applied in the next pressing stage. -
The cake thus brewed and kneaded feeds a second feed hopper 7b which feeds a predetermined volume of pulp-to constitute another cake with a thickness of between 25 and 76 mm on the belt with intermittent movement of a second pressing stage 8b "The cake is pressed there in the pressing zone under a pressure of approximately 35,155 to 49,217 kg / m2. The expressed juice flows through the conduit 9b to the reservoir 5.

Following the second pressing stage, the conveyor belt rejects the pressed cake in a second stirrer-kneader 10b in which the cake is again broken and the strips of pulp crumbled. The mixture produced in the second stirrer 10b feeds a third feed hopper 7c which provides a predetermined volume of pulp on the conveyor belt of a third pressing stage 8c in the form of a pulp cake with a thickness between 25 and 76mm. The pulp cake is pressed under a pressure greater than or equal to 49217 kg / m2 in the pressing zone of the third pressing stage and the expressed juice flows through line 9c to the tank 5.

The conveyor belt of the third pressing stage then rejects the pressed cake on a cake cake conveyor 1-1 for disposal.

An embodiment of an apparatus for making tabs which can be used in the context of the invention is illustrated in FIG. 2. It comprises a housing 15 inside of which is mounted a rotary cutting disc 16 carried on a shaft 17 mounted on bearings.

Fruits, such as apples 18, are fed by gravity from the hopper 19 to the cutting disc 16 and are cut into tongues in the form of tongues 20 of elongated shape and of suitable size as described above. As a variant, the cutting disc 16 can remain stationary, while the hopper 19 comprises suitable blades or blades driven in rotation to move the fruit along the cutting disc 16.

Claims (5)

Claims 1. Method for extracting juice from solid and semi-solid edible products, such as fruits and vegetables, in which the product is pressed to express the juice, characterized in that, before the pressing phase, the edible product is cut into strips to provide a pulp made up of individual, elongated strips. 2. Method according to claim 7, characterized in that the temperature of the tab pulp is brought to approximately 290C after the cutting phase into strips and before the pressing phase. 3. Method according to either of claims 1 and 2, characterized in that the pressed pulp is then removed from the pressing zone, in that it is then brewed near its first pressing so as to crumble the elongated tabs and in that the pulp is then pressed again. 4. Method according to any one of claims pr dentes, characterized in that the edible product is cut into tongues of elongated shape having a thickness of 1.5- and 3mm. 5. Method according to any one of the piecedent claims, characterized in that the edible product is at a temperature lower than the ambient temperature during the cutting phase in strips.