WO1991018791A2

WO1991018791A2 - Improvements relating to the packaging of tea

Info

Publication number: WO1991018791A2
Application number: PCT/GB1991/000860
Authority: WO
Inventors: John Tugman; Peter Megson
Original assignee: Premier Brands Uk Limited
Priority date: 1990-06-01
Filing date: 1991-05-30
Publication date: 1991-12-12
Also published as: ZW6291A1; CN1057035A; WO1991018791A3; GB9012289D0

Abstract

The invention provides that on a tea estate, as soon as the tea has been processed and is ready for packaging, it is packaged as soon as possible into a bag which is hermetically sealed in order to attain the tea freshness, and in addition, the interior of the bag is conditioned in order to retain the tea freshness whilst the sealed bag is transported from the estate to the destination where the bag will be opened, by one or more of the following methods namely a) filling with an inert gas such as nitrogen, b) introducing an oxygen scavenging means, c) creating a vacuum inside the bag. The bag preferably comprises an inner bag of polyethylene laminated to metallise the polyester, which inner bag is peripherally sealed, and an outer bag of craft paper.

Description

Improvements Relating to the Packaging of Tea

This invention relates to the packaging of tea, and in particular concerns the packaging of tea at the location of tea estates.

Tea estates, where tea is grown, picked and processed, also have packaging lines so that at the appropriate time in the processing of the picked tea, the tea can be packaged into suitable containers and then shipped to various destinations throughout the world.

Conventionally, the tea is packaged in large craft paper bags suitable for transportation. When the tea reaches its final destination, it is usual to blend it with tea from other estates in order to prepare the final product which is eventually retailed to the domestic market either in the form of loose tea leaves, or in the form of tea bags.

The present invention is concerned with the packaging of the tea at the tea estates, and seeks to provide in various aspects certain features which will enhance the retention of the tea freshness so that the freshness is retained until the tea reaches its final destination.

It is known that the quality of the final tea beverage which is consumed is proportional to the extent to which the freshness of the tea is maintained. Obviously, the tea leaf is at its freshest when picked, and it is desirable that attempts should be made to maintain this freshness, ideally until the tea is finally used for the preparation of the beverage to be consumed.

As soon as the tea is picked, certain factors affect its freshness, and these factors comprise moisture, oxygen, and enzyme activity. The enzyme activity can be satisfactorily controlled, but there is considerable scope for improving the handling of the tea after picking in order to prevent or limit deterioration of the tea freshness due to moisture and oxygen presence. The moisture and oxygen attack derives from the atmosphere, and therefore if the tea can be hermetically sealed in tightly sealed packages, then freshness can be retained.

As soon as tea is picked, it passes through a number of processes prior to being packaged, and these processes include drying, crushing, fermentation, and further drying. As soon as the further drying process has been completed, it is desirable to package the tea, and the present invention is concerned with such packaging.

According to a first aspect of the invention, the tea, as soon as possible after fermentation and further drying is charged into packaging bags and the bags are sealed upon filling of same with the tea, characterised in that the atmosphere inside the bag is conditioned in order to retain tea freshness by a method including filling with an inert gas such as nitrogen, by introducing a means which will oxygen scavenge the atmosphere, or by creating a vacuum inside the bag; and where possible these conditioning steps may be used in combination.

By providing that the atmosphere is so conditioned, the freshness of the tea can be retained in the sealed bag.

In one particular embodiment, the bag into which the tea is charged is previously flushed with nitrogen or another inert gas in order to displace air therefrom. Alternatively or additionally, as the tea is charged into the bag, it may be simultaneously charged into the bag with a flow of nitrogen or other inert gas.

Upon filling of the bag with the tea and by appropriate conditioning of the environment therein as described above, the bag preferably is hermetically sealed in order to retain as much of the tea freshness as possible.

In another aspect of the invention, the bag into which the tea is charged, is constructed so as to be effectively hermetically sealable whereby there will be little or no opportunity for air to leak into the bag after sealing of same whereby the freshness of the tea is maintained until the bag is opened at the final destination and when the tea inside the bag is to be used. In this connection, the invention provides a bag which comprises an outer layer of paper, and inner layers of air impermeable material and peripherally sealed.

The inner layers preferably comprise a first layer of polyethylene defining a separate bag or sachet and spaced from a second layer of polyethylene to which is laminated one and preferably at least two layers of metallised polyester.

The laminate comprising the layers of metallised polyester and polyethylene may also comprise a separate bag inside the paper bag.

In addition to conditioning the atmosphere by using nitrogen, or as an alternative thereto, an oxygen scavenging device such as a sachet of iron filings may be dropped into the bag along with the tea. This sachet extracts oxygen from the atmosphere in the bag again providing an additional means for maintaining tea freshness.

An embodiment of the present invention will now be described. by way of example, with reference to the accompanying diagrammatic drawings, wherein:-

Fig. 1 shows a side elevation of a large bag being filled with tea; and

Fig. 2 is a sectional elevation taken on the line II - II in Fig. 1 showing a portion of the bag into which the tea is being charged.

Referring to the drawings, in Fig. 1 a large tea bag 10 having a capacity in the order of (note to Peter Megson - Please supply bag capacity) stands on a support surface 12 which may embody a vibrator in order to ensure that the tea which is being charged into the bag evenly fills same. At the top edge 14, the bag 10 in this example is shown as provided with two inlets namely a tea inlet pipe 16 and a nitrogen inlet pipe 18. Through the pipe 16 is charged the dried tea as indicated by arrow 20, and nitrogen is blown into the bag through the pipe 18 as indicated by arrow 22. The nitrogen may be supplied through the pipe 18 prior to charging tea into the bag in order to inflate the bag with nitrogen and to drive any air in the bag out through the air pipe 24. Additionally, nitrogen may be caused to flow in through the pipe 16 along with the tea as indicated by arrow 26.

As a result of this filling method, the air, and therefore the moisture and oxygen are displaced from the bag 10 creating a desirable atmosphere for retaining freshness when the bag is eventually sealed after removal of the various filling and vent pipes.

After removal of these pipes, the top edge of the bag is sealed hermetically, and in this connection the bag is constructed of a number of layers of which details are shown in Fig. 2.

Referring to Fig. 2, the bag comprises a number of layers defining separate bags comprising an inner bag 30 of polypropylene sheet ( ) , an intermediate bag 32 which is a laminate comprising an inner polypropylene layer 32A, and two metalised polyester layers 32B and 32C which are arranged with the metalised sides facing the polypropylene layer 32A, and an outer craft paper bag 34.

The respective bags are sealed in the regions 36, 38 and 40 respectively which comprise the peripheral edges of the bags and obviously the bags are sealed in similar fashion at the apertures which are left when the filling and vent pipes are removed.

The specific bag construction shown in Fig. 2 and described herein provides excellent sealing characteristics making the ingress of air virtually impossible, and the bag also has excellent strength characteristics to enable it to be resistent to the normal handling forces which it will experience in being transported from the estate to the final destination.

Various modifications may be made in the respective aspects of the invention, without departing from the scope thereof. For example other materials can be used to give different strength and/or seal characteristics when one considers the nature of the material of the bag 10, and additionally other gases than nitrogen may be capable of being used for creating the inert atmosphere inside the bag 10.

Claims

1. A method of packaging tea in bags wherein as soon as possible after fermentation and further drying on a tea estate, the tea is charged into a packaging bag, and the bag is sealed for the filling of same with tea, characterised in that the atmosphere inside the bag is conditioned in order to retain the tea freshness during transportation from the estate to the destination where the bag will be opened, by a method including any one or more of a) filling with an inert gas such as nitrogen, b) introducing a means which will oxygen scavenge the atmosphere inside the bag, or c) creating a vacuum inside the bag.

2. A method according to claim 1, wherein the tea is charged into the bag simultaneously with a flow of nitrogen.

3. A method according to claim 1 or 2, wherein the bag into which the tea is charged is previously flushed with nitrogen or another inert gas in order to displace air therefrom.

4. A method according to any of claims 1 to 3, wherein the bag comprises a heat sealable bag inside an outer paper bag, and the inner bag is heat sealed after charging with the tea.

5. A method according to claim 4, wherein the inner bag comprises a layer of polyethylene to which is laminated at least two layers of metallised polyester.

6. A method according to claim 5, wherein the bag includes third and innermost bag of polyethylene.

7. A method of packaging tea in bags substantially as herein before described.

8. A bag filled with the tea in accordance with the method of any one of the preceding claims.