ES2983133A1 - Reduced sugar and high fibre juices and their preparation methods - Google Patents

Abstract

The present invention relates to a method for reducing the sugar content of fruit and/or vegetable juices. Said method comprises steps of: 1) adding a fruit and/or vegetable juice; 2) adding a container containing a hydrolase-type enzyme with fructosyl-transferase activity supported on a solid support; 3) introducing the fruit juice and placing it in contact with the supported enzyme for a time; and 4) extracting from the container the resulting fruit and/or vegetable juice, the sugar content of which has been reduced by the activity of the supported enzyme. Preferably the enzyme is produced from the fungus Trichoderma reesei and the solid support is macroporous polystyrene microspheres cross-linked with divinylbenzene, in the form of a basic anionic resin. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Reduced sugar and high fibre juices and their preparation methods

Technical field of the invention

The present invention belongs to the field of biotechnology, more particularly to food technology. In particular, the present invention relates to a method of reducing the sugar content of fruit juices and increasing their fibre content.

Background of the invention

Fruit and/or vegetable juices are one of the foods with the highest vitamin and mineral content in the human diet. Their consumption is highly recommended from this point of view. In addition, fruit and/or vegetable juices are a refreshing drink as they have a pleasant taste. However, fruit and/or vegetable juices contain significant amounts of sugar (sucrose) that can negatively affect the health of people with high blood glucose levels, such as people with diabetes or prediabetes. For these people, the consumption of fruit and/or vegetable juices is not recommended due to their high sugar content.

Summary description of the invention

A first aspect of the present invention provides a method for reducing the sugar content of a fruit and/or vegetable juice comprising the steps of:

- provide a fruit and/or vegetable juice;

- provide a container containing a hydrolase type enzyme with fructosyl transferase activity supported on a solid support;

- introduce the fruit juice and put it in contact with the supported enzyme for a while; and

- extract from the container the resulting fruit and/or vegetable juice, the sugar content of which has been reduced by the activity of the supported enzyme.

The method described above makes it possible to easily obtain a fruit and/or vegetable juice with a reduced sugar content and a high fibre content, and it is possible to very easily separate the enzyme from the juice after having carried out the sugar content reduction process. The process of separating the supported enzyme from the juice can be done by a simple solid-liquid separation operation, such as filtration or centrifugation.

Fruit and/or vegetable juices with a high fiber content help facilitate intestinal transit and fibers act as probiotics, maintaining a balanced and healthy intestinal flora, which has an impact on the good health of individuals who consume dietary fiber regularly.

Preferably, the vessel is a column containing a hydrolase-type enzyme with fructosyl transferase activity supported on a solid support in the form of a fixed bed and the juice is introduced and extracted from the vessel continuously.

With this continuous method of operation, with a fixed bed of supported enzyme, it is possible to produce fruit and/or vegetable juices with reduced sugar content in large quantities, with very homogeneous properties and quality.

Preferably, the continuous method is carried out in such a way that the juice has a residence time in the column of at least one hour. This ensures a satisfactory reduction of sugars over a reasonable time and with equipment of a feasible size.

Preferably, the enzyme is produced from the fungus Trichoderma reesei. In this way, the juice obtained is considered Halal and Kosher, that is, permitted for consumption by people of Jewish and Islamic faiths.

Preferably, the fruit and/or vegetable juice is added at a concentration of 60°Brix.

Preferably, the step of introducing the fruit juice and putting it in contact with the supported enzyme for a period of time is carried out at a temperature of 40ºC.

Optionally, the method is carried out in a temperature range of 50 to 60 °C. This temperature range is the optimal temperature range for enzyme activity, without appreciable degradation.

Preferably the method comprises a step of diluting the resulting juice to a concentration of 11.2° Brix, after which it is bottled.

Preferably, the solid support consists of macroporous polystyrene microspheres cross-linked with divinylbenzene, in the form of a basic anionic resin. This is a support that allows the resulting juice to be considered Kosher and Halal. This support also has good thermal stability and good resistance to osmotic shock.

A second aspect of the invention provides a reduced sugar fruit and/or vegetable juice obtained by the method of the first aspect of the invention.

These fruit and/or vegetable juices obtained in this way not only have a reduced sugar content and a high fiber content, but are also classified as Halal and Kosher (that is, suitable for consumption by Islamic and Jewish people, respectively) because they have not been in contact with enzymes of bacterial origin or from animals not permitted in the prescribed religions.

Brief description of the drawings

Figure 1 depicts a diagram illustrating a process for producing reduced sugar juices according to an embodiment of the present invention.

Detailed description of the invention

A method for reducing the sugar content of a fruit and/or vegetable juice according to an embodiment of the present invention is described in detail below.

The process starts with a concentrated orange juice at 65° Brix, which is pumped into a tank and diluted with hot water to 60° Brix. A commercial transferase enzyme is then immobilized on a solid support. This enzyme is capable of transforming sugar into soluble fiber. The enzyme is loaded into columns and the juice is pumped at a flow rate that ensures a residence time of more than 1 hour. Once the reaction time has elapsed, the content is pumped into an intermediate tank and diluted to 11.2° Brix with water. The sugar-reduced juice is then bottled.

Below, each of the stages of the method for reducing the sugar content in fruit and/or vegetable juices, represented in the flow chart in Figure 1, is described in detail.

1.- Reception of enzymes

The transferase enzyme used in the sugar reduction process is received in 20kg drums.

2.- Enzyme storage

Once received, the enzyme is stored in refrigeration until the time of use.

3.- Enzyme immobilization

The enzyme is immobilized on an industrial solid support as described in the following example.

4.- Load immobilized enzyme on columns

The immobilized enzyme is loaded onto industrial columns.

5.- Orange concentrate 65° Brix

The orange concentrate is received in tanks at 65º Brix and then stored in a tank at a temperature of 10°C.

6.- Pumping product into the tank

The orange concentrate stored at 65ºBrix is pumped to a second tank where dilution takes place.

7.- Water supply

Hot water is supplied to the dilution tank.

8.- Dilution to 60º Brix and pumping to columns

The orange concentrate is diluted to 60º Brix in the dilution tank and pumped to the columns at a flow rate that ensures a residence time equal to or greater than 1 hour.

9.- Intermediate tank

The concentrate is stored in an intermediate tank.

10.- Water supply

Water is added to the dilution tank.

11.- Dilution to 11.2° Brix

The reduced sugar orange concentrate is diluted to 11.2º Brix in the dilution tank.

12.- Pasteurization

The diluted juice is pasteurized to eliminate potential microbiological content.

13.- Bottling

The juice is bottled with reduced sugar content.

Product characterization

The product obtained has an appearance and smell characteristic of a standard orange juice. Table 1 compares the typical sugar composition of an orange juice and the sugar composition of the juice produced by the present method.

Table 1. Sugar composition of the control juice and the treated juice

Table 2. Characteristics of the treated juice

Procedure for immobilizing the enzyme on a solid support

The enzyme immobilization protocol is as follows:

1. Support conditioning: 5g of support is washed with osmosis water.

2. Activating support.

2.1. Add 70 mL of 1M NaOH to the support and allow to mix at 160 rpm for 30 minutes.

2.2. Add 70 mL of 1M HCl to the support and allow to mix at 160 rpm for 30 minutes. Filter the support and wash with immobilization buffer (50 mM sodium acetate pH 5.5).

2.3. Add 100 mL of 2% glutaraldehyde, transfer to a 250 mL glass bottle and incubate for 2 h at 65 rpm with the bottle in an upright position. Filter the support and wash with immobilization buffer (50 mM sodium acetate pH 5.5).

3. Immobilization.

3.1. The activated support, 0.1 g-1 g of enzyme preparation and 100 mL of immobilization buffer are added to the 250 mL glass bottle.

3.2. Allow to stir gently (65 rpm) in an orbital for 24 hours at room temperature. It is very important not to use magnetic stirring to perform immobilization/reaction with supports of this type. The temperature during immobilization depends on the stability of the enzyme.

4. Filtration and washing.

4.1. The immobilized derivative (enzyme support) is filtered. The liquid phase is saved to determine the immobilization yield.

4.1.1. The immobilization performance can be determined by protein quantification, or by enzymatic reaction.

4.2. The immobilized derivative is washed with 10 volumes of immobilization buffer.

Claims (9)

1. Method for reducing the sugar content of a fruit and/or vegetable juice, characterized by the following steps: - provide a fruit and/or vegetable juice; - provide a container containing a hydrolase type enzyme with fructosyl transferase activity supported on a solid support; - introducing the fruit juice into the container and bringing it into contact with the supported enzyme for a certain period of time; and - extracting from the container the resulting fruit and/or vegetable juice, the sugar content of which has been reduced by the activity of the supported enzyme. 2. Method according to claim 1, characterized in that the container is a column containing a hydrolase type enzyme with fructosyl transferase activity supported on a solid support arranged in the form of a fixed bed and the juice is introduced and extracted from the container continuously. 3. Method according to claim 2, characterized in that the juice has a residence time in the column of at least one hour. 4. Method according to any preceding claim, characterized in that the enzyme is produced from the fungus Trichoderma reesei. 5. Method according to any preceding claim, characterized in that the fruit and/or vegetable juice is supplied at a concentration of 60° Brix. 6. Method according to any preceding claim, characterized in that the step of introducing the fruit juice and bringing it into contact with the supported enzyme for a time is carried out at a temperature between 30 and 60 °C, preferably at 40 °C. 7. Method according to any preceding claim, characterized in that it comprises a step of diluting the resulting juice to a concentration of 11.2 °Brix. 8. Method according to any preceding claim, characterized in that the solid support of the enzyme is microspheres of macroporous polystyrene cross-linked with divinylbenzene, in the form of a basic anionic resin. 9. Reduced sugar fruit and/or vegetable juice characterized in that it is obtained by the method of any of claims 1 to 8.