AU781514B2 - Fruit and vegetable preservative - Google Patents

Description

AUSTRALIA

Patents Act

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: /01 Divisional of 72609/00 Lodgement Date: 2 8 th August 2001 Nominated Patentee: Citrus Sensation Pty Ltd Invention Title: Fruit and Vegetable Preservative The following statement is a full description of this invention, including the best method of performing it known to the applicant.

FRUIT AND VEGETABLE PRESERVATIVE This invention relates to the preservation of minimally processed fruits and vegetables and flowers, particularly cut and peeled or juiced fruits and vegetables.

Background to the Invention Most fruits and vegetables are subject to discolouration and spoilage once they are cut and peeled. This is usually due to enzymatic and bacterial action.

Patent application WO 97/16976 discloses a method of storing cut apple pieces in which whole apples are washed in chlorinated water to inactivate microorganisms, the apples are then cored, peeled and sliced and immersed in an ascorbic acid solution having a pH of 2.2 to 2.7 and are then drained and stored in modified atmosphere containers.

Patent application W099/34683 discloses a method of treating cut fresh vegetables by dipping in a solution containing calcium ions and ascorbate or erythorbate ions.

USA patent 6054160 treats cut apples with a solution containing L-cysteine, sorbitol, and calcium chloride and then stores them in a modified atmosphere pack.

These treatments provide a shelf life of up to 2 weeks but in practice this is not •long enough.

It is an object of this invention to provide an improvement in shelf life for minimally processed fruit and vegetables.

Brief description of the invention To this end the present invention provides a process of extending the useful shelf S' life of minimally processed fruits and vegetables which includes the step of treating the fruits and vegetables with a flavonoid compound.

This invention is partly predicated on the discovery that the presence of flavonoids inhibits the enzymatic and bacterial action that leads to discolouration and spoilage. The flavonoid may be added to a solution sprayed or dipped on to the processed fruits or vegetables or added to the fruit or vegetable juice.

Flavonoids such as proanthocyanidin have been identified as antioxidants and recommended as food additives for nutriceutical use but not to prevent deterioration in minimally processed fruits and vegetables.

It is preferred that an anti oxidant such as ascorbic acid, erythorbic acid, lipoic acid including alpha lipoic acid, be present with the flavonoid compound. It is believed that these compounds act synergistically with the flavonoid compounds to inhibit oxidation of the minimally processed fruits and vegetables. Some fruits and vegetables have an adequate content of ascorbic acid and for these addition of a flavonoid is sufficient.

Throughout this specification minimally processed means the steps of processing raw, uncooked fruits, nuts and vegetables for storage and/or transport prior to eating or further processing. This includes peeling, coring, slicing and juicing.

Throughout this specification flavonoid means a polyphenol compound of the type having at least two aromatic rings which occur widely in the plant kingdom and inhibits oxidation. These compounds may also form polymeric compounds with the flavonoid repeating unit .The term flavonoid as used throughout this specification includes individual flavonoids, mixtures and plant extracts having a high flavonoid SIs content.

i° The fruits to which this invention is applicable include oranges, mandarins, grapefruit, tangerines, tangellos, pomellos, kiwi fruit, mango, pineapple, apricots, strawberries, blackberries, raspberries, mulberries, cherries, blueberries, grapes, figs, peaches, nectarines, apples, pears, nashi, plums, tamarillo, cantaloupe, guavas, lychees, rumbutans, melon, passionfruit, avocado and mangosteen. Nuts such as chestnuts may also be treated The vegetables which can be treated according to this invention include broccoli, brussel sprouts, carrot, cabbage, capsicum, chili, chocos, cauliflower, celery, lettuce, garlic, ginger, green beans, shelled peas, asparagus, corn, pumpkin, mushrooms, snow peas, zucchini.

The fruit or vegetables are sprayed or immersed in the solution containing the flavonoid and excess solution is removed from the surfaces and the products are packaged in the usal way for minimally processed fruits and vegetables.

Fruit juice can be preserved by the addition of flavonoids to the juice. Navel oranges are usually not preferred for juicing because the juice acquires a bitter taste. The addition of a flavonoid to navel orange juice inhibits the development of this bitter taste. In preparing the fruit juice the pulp is usually separated from the serum and then recombined to form the juice. The flavonoid may be added to either the pulp or the serum or both but preferably to the pulp.

In another aspect of this invention the present invention provides a preservative composition for use in preserving minimally processed fruits and vegetables which composition includes a flavonoid mixed with a food grade anti oxidant, preferably selected from one or more of ascorbic acid, erythorbic acid, lipoic acid including alpha lipoic acid and salts thereof such as sodium, potassium and calcium ascorbate. This is preferably a powder but may be a liquid concentrate that can be diluted in water, tea infusion or a fruit juice to form the dipping solution. The ratio of flavonoid to antioxidant is usually from 1:50 to 1:150 by weight. This mixture is then diluted in 30 to 50 times its weight in water or fruit juice. The flavonoid io content in the dipping solution or in juiced fruit or vegetable is preferably from 0.01wt to 0.1wt%. In addition to the flavonoid, alpha lipoic acid may also be added to the dipping solution or fruit or vegetable juice as an additional antioxidant in amounts from 0.0005 wt to 0.005wt The flavonoid may be any available compound or extract. The group takes its 15 name from the compounds flavone, flavonol, flavanone but also includes chalcones, anthocyanidins, proanthocyanidins, isoflavonoidsand polymeric forms of these compounds. Flavonoids are available as plant extracts and are an effective source for use in this invention. A preferred flavonoid source is an extract from pinus radiata or pinus pinasta [maritime pine] marketed as EnzogenolTM and 20 PyncogenolTM respectively. Enzogenol contains about 38% polymeric proanthocyanidins, 25% oligomeric proanthocyanidins and 22% monomer, dimer and trimer proanthocyanidins. Grape seed extract and grape seed oils are another favoured source. Also may be mentioned Quercitin, a flavonoid present in grapes, apples, broccoli and onions, acerola from cherries, hesperidin, rutin and 25 any plant extracts rich in flavonoids such as citrus seed extract, cranberry extract, juniper berry extract, rose hip extract.

The dipping or spraying solutions may contain other ingredients for flavour and to assist the action of the flavonoids. Acid to maintain a low pH for antibacterial effectiveness is a useful ingredient and any food grade acid such as citric acid may be used. Alternatively acidic fruit juices, such as pineapple juice, may be used. Other ingredients may include sugar, water sanitisers such as colloidal silver, or microhydrin.

Detailed description of the invention Preferred formulations and treatments for particular products will be described with reference to particular fruits and vegetables Oranges The orange is peeled, cored and the outer membrane is removed.

The dipping solution is made proportionately to the formula: Unsweetened pineapple juice 400ml Sugar 400g Grape seed oil The sugar and pineapple juice are boiled together for 3 minutes cooled and the grape seed oil is added.

The peeled and cored orange is immersed for about 3 minutes and then the excess solution is allowed to drain and the orange can be packed into a suitable display container.

15 An alternative formula may replace the grapeseed oil with about 60mg of pyncogenol T M or enzogenolTM which are pine bark extracts containing a high is :i concentration of flavonoid compounds including polymeric proanthocyanidins.

A preferred formula is Unsweetened pineapple juice 400ml boiled for 3 minutes with 400g sugar then cooled. To which is added 20ml grapeseed oil and 60mg enzogenol.

"Shelf life trials of the oranges so treated indicated that even after eight weeks the taste and flavour remained fresh.

Orange iuice Navel oranges were juiced and three samples were produced as shown in table 1 Sample Navel juice pyncogenol M enzogenol T 1 200ml 2 200ml 3 200ml The control sample 1 showed distinct bitterness after two weeks storage but the samples 2 and 3 were still tasting fresh and sweet after three weeks.

A preferred flavonoid for orange juice may be selected from citrus bioflavonoids, tangeretin, hesperidin,rutin or mixtures thereof.

In addition to the flavonoid alpha lipoic acid may also be added to the orange juice as an additional antioxidant in amounts from 0.0005 wt to 0.005wt %of the orange juice.

A preferred additive for orange juice is 30 mg alpha lipoic acid Folic acid pycnogenol or grape seed extract or a mixture.

100mg of citrus bioflavonoids hesperidin 50mg Rutin and 200 250mg zinc glutonate This formula is particularly effective with navel oranges. Navel orange juice after eight weeks storage had a fresh citrus smell and bright orange colour and was still pleasant tasting with no aftertaste.

Apples A dipping solution for apples is prepared by boiling 400ml of water with 20g of sugar for three minutes and allowing to cool. To the sugar solution is added of Enzogenol TM and 60ml of lemon juice or 20 mg ascorbic acid.

Granny smith apples which had been peeled nd sliced are immersed in this 20 solution for about 10 minutes while softer apples are immersed for 8 minutes. The apples are removed drained and packed for cold storage After 3 weeks the pieces are still white and crisp.

SA more complete formula for apples is prepared by using a dry mix of ascorbates and flavonoids containing 25 600mg magnesium ascorbate 25mgs of acerola 750mg calcium ascorbate 12mgs of rose hip powder [rosa canina] 600mg potassium ascorbate 25mgs bioflavonoids 37mgs hesperidin rutin 6mg maritime pine bark extract.

This powder is added to a solution of 600ml water which has been boiled for 3 minutes with 200g of sugar ,allowed to cool and mixed with 50mls of unsweetened pineapple juice.

By immersing the peeled and quartered apples in this solution for 12 minutes followed by draining and packing a shelf life of 3 weeks was achieved.

Using this formula it is possible to prolong storage of the apples by allowing the peeled and quartered apples to remain in solution or to be immersed and drained alternately for an hour repeatedly for as long as needed until the pieces are to be packed for transport.

A comparative test was carried out with apples in which group 1 were treated with a solution from which the pineapple juice and ascorbates had been omitted while group 2 were treated with the complete solution but without the addition of flavonoids.

After 17 days storage the group 1 apple slices were still normal in colour and crisp while the group 2 apple slices were rated as fairly crisp and brown in appearance.

Apple Juice Apples were juiced and three samples were r produced as in table 2 Sample Apple Juice Ascorbic acid pyncogenol enzogenol 1 200ml 2 200ml 5g 3 200ml 5g The juice of sample 1 oxidised and became brown. After 4 weeks the condi samples 2 and 3 were still fresh.

A preferred apple juice formula used per lire of fresh apple juice consists of 200ml of pure water 5g calcium ascorbate, 1mg Quercitin enzogenol or 50mg grapeseed extract.

tion of OTHER FRUITS Formulae for some other fruits are set out in table 3 The water and sugar are boiled for 3 minutes then cooled and the remaining ingredients are added.

The fruits are peeled if needed and cut to remove seeds if necessary and the prepared fruits are immersed for 3 to 8 minutes on average. Strawberries are preferably dipped quickly and packed.

Modified atmosphere packaging was used for all the packed fruit.

Table 3 FRUIT Solution Ascorbic acid Flavonoid other source Nashi 400ml water+ 15ml lemon juice 20mg enzogenol _100g sugar Honey dew 400ml water+ 10ml lemon juice 10mg enzogenol melon 100g sugar Pineapple 300ml water+ 7.5 g calcium 60mg enzogenol 10ml sanitizer 200g sugar ascorbate lemon juice Canteloupe 500ml water 250mg calcium 6gms maritime 5ml sanitizer ascorbate pine extract Strawberries 500ml water+ 5ml 5mg rosehip 5ml sanitizer fruit sugar powder +125 mgsilica __hydride Nectarines or 400ml water+ 5 g calcium 12mg maritime 5ml sanitizer Apricots 200g sugar ascorbate +45ml pine extract or +125 mgsilica lemon juice 60mg enzogenol hydride mangosteens 200ml water+ 10g 125ml grapefruit 60mg enzogenol 5ml sanitizer sugar+ 125ml juice +25ml grapeseed +125 mgsilica unsweetened oil hydride pineapple juice Durian 50ml 5 g calcium 50mg unsweetened ascorbate bioflavonoids grapeseed oil pineapple juice+ 25mg or glycerin sugar enzogenol Chestnuts 200ml water 5g calcium 90mg enzogenol green tea ascorbate Chestnuts 400ml water 60ml lemon juice 60mg enzogenol peaches 350 ml water 5g calcium 12mg maritime 5ml sanitizer +150g sugar ascorbate 40ml pine extract or +125 mg silica lemon juice 60mg enzogenol hydride Using these formulas in the process of this invention extended the usual shelf life of all these fruits to beyond 3 weeks.

The fruits treated with these formulae can also be used in fruit salads. The apple formula can be used with salads containing two or more of nashi, guava, watermelon, honey dew melon, kiwifruit and starfruit and peaches.

Vegetables A wide variety of minimally processed vegetables can be treated according to this invention the apple formula may be used or one of the formulae shown in table 4.

The solution is boiled for 3 minutes and then the other ingredients are added.

Immersion of the peeled and/or cut vegetables is for 3 to 8 minutes as required and then drained prior to packaging.

Table 4 formula Solution Ascorbic acid Flavonoid other source 1 200ml water+ 5g ascorbic acid 50mg grapeseed oil or enzogenol grapeseed oil 2 [celery] 200ml water 5-10 g calcium 60mg enzogenol green tea ascorbate extract 3 200ml water 50mg alpha lipoic 25mg hesperidin 5mg citric or acid tartaric acid +2mg folic cid 4 6juniper berries in 5 g calcium 500 I U d-alpha 5mg zinc 150ml water ascorbate tocopherol gluconate Formula 1 is used with carrots that have been sliced or diced Formula 3 was particularly suitable for potatoes, suedes, parsnip, broccolli, cauliflower, pumpkin, chocos, chopped beans and shelled peas.

The shelf life of vegetables treated with these solutions by immersion for 5 to o..o 10 minutes followed by drying was more than 3 weeks.

Lettuce Whole lettuce is washehed in pure water and the then 25ml of the following formula was injected into the stem of the lettuce.

folic acid 5 g calcium ascorbate 60mg of enzogenol 2.5g of barley green or spiralina chlorophyll extract.

A shelf life in excess of 21 days was achieved with this method.

a.

Cut Flowers The vegetable formula or 5g of potassium ascorbate and 20mg of enzogenol in 2 litres of water has been found to maintain the freshness of cut flowers when used as the solution in vases.

From the above it can be seen that this invention provides a unique way of using naturally occurring compounds to extend the shelf life of minimally processed vegetables. Variations and additions to the formula and process can be made without departing from the inventive concept as disclosed herein.

Claims (9)

1. A process of extending the useful shelf life of peeled and cut fruits and vegetables which includes the step of dipping, spraying or coating the cut or peeled fruits and vegetables with a an aqueous solution which contains a flavonoid derived from the seeds, fruit or bark of plants in association with a 50 to 150 times its weight of a food grade antioxidant.

2. A process as claimed in claim 1 in which the flavonoid content in the solution is from 0.01 to 0.1 by weight.

3. A process as claimed in claim 1 in which the flavonoid is selected from the group consisting of acerola, quercitin, hesperidin, rutin and flavonoid rich extracts from pine bark, grape seeds, citrus seeds,cranberries, Juniper berries and rosehips.

4. A process as claimed in claim 1 in which the solution additionally contains alpha lipoic acid.

5. A process as claimed in claim 1 in which the food grade antioxidant is selected from the group consisting of ascorbic acid, erythorbic acid, lipoic acid or salts thereof

6. A process of extending the useful shelf life of oranges wherein oranges are juiced and lipoic acid and a flavonoid derived from the seeds, fruit or bark of plants is added to the juice.

7. A process as claimed in claim 6 where the oranges are navel oranges.

8. Orange juice produced by the process of claim 6.

9. Peeled and cut fruits vegetables which have been dipped sprayed or coated with a an aqueous solution which contains a flavonoid derived from the seeds, fruit or bark of plants in association with a 50 to 150 times the weight of the flavonoid of a food grade antioxidant. 9A A fruit and vegetable preservative composition for use in the process of claim 1 which includes a flavonoid derived from the seeds, fruit or bark of plants in association with a 50 to 150 times its weight of a food grade antioxidant selected from the group consisting of ascorbic acid, erythorbic acid, lipoic acid and salts thereof. S *SS* «**oo *o o tf *O *g