HK1179119B - Method for preserving fresh cut lemon - Google Patents

Description

Preservation method of fresh-cut lemons

The object of the present invention is a method for preserving fresh cut lemons cut into slices, pieces or chunks in cans or plastics at room temperature while maintaining all of their natural organoleptic properties. The aim is achieved with a filled food that maintains the lemon character for a minimum of 4 months to 2 years.

Background

Currently, lemon cut into pieces and slices are preserved by different methods. The most common of them is freezing, where fresh lemons are cut into pieces or slices at temperatures below 0 degrees and preserved in plastic at refrigeration temperatures between 2 and 5 degrees for a maximum shelf life of 1 month.

Attempts have been made to store fresh-cut lemons in plastic and glass packages at room temperature, resulting in storage at a temperature of 20 degrees for 2 to 2.5 months. The technical problem underlying the present invention is therefore to preserve fresh cut lemons at room temperature, whatever the packaging, with a minimum of preservation of organoleptic properties for 6 months or more.

Disclosure of Invention

In order to solve the technical problem described, namely the preservation of fresh-cut lemons, the object of the present invention comprises at least the following steps: (a) adding a covering liquid to the container containing the cut lemon portions, said liquid combining lemon juice, lime juice, ascorbic acid, citric acid, salt and sodium metabisulphite; (b) degassing the cover liquid; and (c) vacuum packaging by adding nitrogen or water vapor atmosphere.

Optionally, after the degassing and packaging, there may be a step of additionally treating the fresh-cut lemons introduced into the covering liquid at a high pressure of at least 300 to 600 MPa.

Thanks to the process thus described, it is achieved to keep a slice, a segment or a half-moon of fresh lemon at room temperature for a minimum of 4 months and at refrigerated temperatures for up to 2 years.

Throughout the description and claims the word "comprise" and variations of the word "comprise" and "comprises" is not intended to exclude other technical features, additives, components or steps. Additional objects, advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The following examples and figures are provided by way of illustration and are not intended to limit the present invention. Moreover, the present invention covers all possible combinations of the specific and preferred embodiments described herein.

Detailed Description

In a particular embodiment of the invention, the method for preserving fresh-cut lemons comprises at least the following steps:

(a) adding a covering liquid consisting essentially of lemon juice, lime juice, ascorbic acid, citric acid, salt and sodium metabisulphite to a container containing cut lemon portions;

(b) degassing the covering liquid by applying a vacuum or by displacing oxygen with an inert gas; and

(c) and (7) vacuum packaging.

More specifically, the covering liquid contains: 65% to 75% lemon juice; 25% to 35% lime juice; 5% to 0.1% ascorbic acid; 5% to 0.1% citric acid; 5% to 0.1% NaCl; and finally sodium metabisulfite in the range of 1g/1 to 0.7 g/1.

Embodiment of the covering liquid:

in a practical embodiment of the invention, the covering liquid consists of 65% lemon juice (6.25% lemon concentrate), 30% lime juice (6.35% lime concentrate), 2% ascorbic acid (antioxidant E-300), 1% citric acid (acidulant and antioxidant E-330), 1% salt (NaCl) and from 1g/1 to 0.7g/1 of sodium metabisulphite (preservative E-223). A covering liquid with this composition has the following characteristics:

a density of 1.0430g/l,

-pH 2.12，

9.25 Brix, and

-a viscosity below 25 cp.

Since one of the factors responsible for the non-enzymatic oxidation of ascorbic acid is the presence of oxygen, it is important to avoid the presence of oxygen for the preservation of fresh-cut lemon. During the preparation of the product, the concentration of oxygen dissolved in the covering liquid is removed or reduced by one of the following methods:

(i) by replacing oxygen with an inert gas, in a practical example, by replacing oxygen with helium (E-339), which is a noble gas and an inert gas, i.e. it does not react, and whose use has been approved as a food additive (according to RD 1422002), and wherein said replacement is performed once the covering liquid is formulated, i.e. by injecting pressurized helium which forms a plurality of microbubbles that replace dissolved oxygen.

(ii) Removing oxygen by applying a vacuum, wherein a degasser consisting of a reservoir, a vacuum pump and a compressor has been used for applying a vacuum to the covering liquid, the reservoir also acting as a dispenser; and wherein the cover liquid is subjected to a given pressure until the oxygen content in the cover liquid is below 2 mg/l.

Finally, once the oxygen present in the covering liquid in which the fresh lemon portions are bathed has been removed, the vacuum packaging is continued by adding a nitrogen or water vapour atmosphere.

Claims (8)

1. A method for preserving fresh-cut lemons, characterized in that it comprises at least the following steps: (a) adding a covering liquid to the container containing the cut lemon portions, said liquid combining lemon juice, lime juice, ascorbic acid, citric acid, salt and sodium metabisulphite; (b) degassing the cover liquid; and (c) vacuum packaging.

2. Method according to claim 1, characterized in that said covering liquid more particularly comprises: 65% to 75% lemon juice; 25% to 35% lime juice; 5% to 0.1% ascorbic acid; 5% to 0.1% citric acid; 5% to 0.1% NaCl; and finally sodium metabisulfite in the range of 1g/l to 0.7g/l, wherein the sum of the contents of the ingredients is 100%.

3. Method according to claim 2, characterized in that the covering liquid consists of 65% lemon juice, 30% lime juice, 2% ascorbic acid, 1% citric acid, 1% NaCl and 1 to 0.7g/l sodium metabisulphite, the sum of the contents of the individual components amounting to 100%.

4. Method according to claim 1, characterized in that said degassing of said covering liquid is carried out by a method selected from the group consisting of: (i) degassing by replacing oxygen with an inert gas; and (ii) removing the atmosphere by applying a vacuum.

5. Method according to claim 4, characterized in that said degassing by replacing oxygen with an inert gas is carried out by injecting pressurized helium which forms a plurality of microbubbles replacing dissolved oxygen once said covering liquid is formulated.

6. Method according to claim 4, characterized in that in the removal of oxygen by applying a vacuum, a degasser consisting of a reservoir, a vacuum pump and a compressor has been used for applying a vacuum to the covering liquid, the reservoir also acting as a dispenser; and wherein the cover liquid is subjected to a given pressure until the oxygen content in the cover liquid is below 2 mg/l.

7. Method according to claim 1, characterized in that the vacuum packing is performed after the addition of an atmosphere selected from nitrogen or water vapour.

8. The process according to claim 1, characterized in that after said degassing and packaging there is the step of additional treatment of the fresh cut lemons introduced into the covering liquid at high pressure, wherein said high pressure is comprised between 300 and 600 MPa.