[go: up one dir, main page]

WO1994015475A1 - Procede permettant de prolonger la duree de conservation de feuilles de salade fraiches pre-coupees - Google Patents

Procede permettant de prolonger la duree de conservation de feuilles de salade fraiches pre-coupees Download PDF

Info

Publication number
WO1994015475A1
WO1994015475A1 PCT/CA1994/000036 CA9400036W WO9415475A1 WO 1994015475 A1 WO1994015475 A1 WO 1994015475A1 CA 9400036 W CA9400036 W CA 9400036W WO 9415475 A1 WO9415475 A1 WO 9415475A1
Authority
WO
WIPO (PCT)
Prior art keywords
leaves
cut
drying
cut leaves
temperature
Prior art date
Application number
PCT/CA1994/000036
Other languages
English (en)
Inventor
Chiu Hui Wu
William Duncan Powrie
Original Assignee
The University Of British Columbia
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The University Of British Columbia filed Critical The University Of British Columbia
Priority to AU58774/94A priority Critical patent/AU5877494A/en
Publication of WO1994015475A1 publication Critical patent/WO1994015475A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVATION OF FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES; CHEMICAL RIPENING OF FRUIT OR VEGETABLES
    • A23B7/00—Preservation of fruit or vegetables; Chemical ripening of fruit or vegetables
    • A23B7/14—Preserving or ripening with chemicals not covered by group A23B7/08 or A23B7/10
    • A23B7/144—Preserving or ripening with chemicals not covered by group A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor
    • A23B7/148—Preserving or ripening with chemicals not covered by group A23B7/08 or A23B7/10 in the form of gases, e.g. fumigation; Compositions or apparatus therefor in a controlled atmosphere, e.g. partial vacuum, comprising only CO2, N2, O2 or H2O

Definitions

  • the present invention relates to improving the shelf life of precut produce fo a salad. More particularly the present invention relates to a process for extendin the shelf life of fresh pre-cut salad leaves by air drying prior to modified atmospher packaging and storage under cool conditions.
  • U.S.Patent 3,795,749 issued March 5, 1974 to Cummin et al discloses that heads of lettuce can be stored for prolonged periods by packaging each head in gas permeable polyvinyl chloride film having an 0 2 permeability of at least 2,000 cc/100 sq.in./24 hr/1 atm. and a C0 2 permeability of at least 10,000 cc/100 sq.in./24 hr/1 atm.
  • U.S.Patent 3,849,581 issued November 19, 1974 to Kubu teaches that the shelf life of shredded lettuce can be extended to about 3 weeks by treating the shredded lettuce with an antioxidant such as sodium bisulphite in solution, buffered to a pH of about 5 to 6.5, subjecting the drained treated shredded lettuce to spin or centrifuging to remove surface water to the extent of about 6 to 10 per cent of the original weight of the wet, treated, shredded lettuce and then packaging in air-tight bags.
  • an antioxidant such as sodium bisulphite in solution
  • U.S.Patent 3,987,208 issued October 19, 1976 to Rahman et al teaches cut lettuce leaves can be stored for about 4 weeks with a minimum loss of overall quality by treating with a dilute aqueous solution of sodium meta-bisulphite, citric acid, ascorbic acid and potassium sorbate, draining, centrifugation at about 1,200 rpm for about 1 minute to remove a substantial amount of surface solution and placing the leaves in bags made up of vinylidene chloride-vinyl acetate or polymer film with a 0 2 permeability of 9-13 cc/100 sq.in./24 hr/1 atm/21° C.
  • U.S.Patent 4,001,443 issued January 4, 1977 to Dave describes a package and method for packaging and storing cut leafy vegetables to prolong the shelf life by subjecting the cut leaves to 70-150 ppm chlorine solution buffered at pH level about 5 to 7, and at a temperature about 7.5° C to 15.6° C; removing of adhered moisture by basket centrifugation; packaging the of cut leaves in packages having high gas barrier properties; partial evacuation of air from package to the extent of package wall collapse to the leaves; and storage of packages at a temperature of about 1.7° C to about 7.2° C.
  • the invention details the construction of a multi-layer laminate which consists of a first perforated film of propylene homopolymer or copolymer, a second film having a bonding layer of ethylene vinyl acetyl copolymer and an outer heat sealable layer.
  • U.S.Patent 5,097,755 issued March 24, 1992 to Hill teaches the method and apparatus for processing produce by treating the produce with sprayed chlorinated water, slicing and washing the produce, followed by dewatering eg. by vibration, and an air flow drying to remove substantially all water from the surfaces of the cut produce by, for example, air knife drying and fluidized bed drying prior to packaging.
  • the present invention relates to a method of extending the shelf life of pre-cut salad leaves comprising
  • said salad leaves will be lettuce leaves.
  • said aqueous washing liquid will comprise an aqueous solution of a suitable disinfecting chemical.
  • said aqueous washing liquid will comprise acidic chlorinated water.
  • removing said surface water will comprise centrifugation of said washed cut leaves.
  • said evaporative drying will comprise air drying and more preferably said air drying will be under drying conditions including controlled temperature, time and drying air moisture content so that said washed cut leaves during drying do not have a temperature higher than 25° C.
  • said air drying will include a fluidized bed drying. It is also preferred to lower the temperature of said cut leaves prior to packaging to 0-5° C within about 45 minutes of completion of said air drying, more preferably within of 30 minutes of completion of said air drying.
  • said cut leaves will be package with an input modified atmosphere gas mixture contained in a gaseous atmosphere containing 3 - 12% 0 2 ; 5 - 10% C0 2 ; the remainder of the atmosphere being an inert gas.
  • said containing in a gaseous atmosphere will comprise modified atmosphere packaging (MAP) of said tissue moisture-reduced cut leaves in an atmosphere which under equilibrium conditions will contain 1 to 3% 0 2 (preferably
  • Figure 1 is a block diagram illustrating the steps in the process of the present invention.
  • the fresh salad leaves (or other vegetables if they are to be included in the stored salad) are introduced into the process system as indicated by the arrow 10 and are preferably subjected to a unit operation i.e. sorting as indicated at 12.
  • the rejected material is discarded from the process as indicated at 14 and the selected material is passed on as indicated at 16 into a pre-cutting stage 18.
  • the salad leaves are cut using conventional cutting equipment and known techniques to reduce the leaves to the desired size without significantly damaging the leaves by bruising. As is well known, this is normally accomplished by using relatively sharp cutting edges or knives to slice the leaves.
  • the cut leaves pass as indicated by the line 20 into a treatment stage 22 i.e. a washing stage wherein the cut leaves are washed with a suitable aqueous liquid.
  • the liquid will be water but preferably will be water containing a suitable disinfecting agent such as hypochlorite; i.e. the conventionally acidic chlorinated water preferably will be used to inactivate microorganisms.
  • the washed cut leaves pass as indicated by arrow 24 into the surface water removal station 26 wherein the washing liquid is removed from the surface of the cut leaves in the conventional manner.
  • a centrifuge is used to spin the washed cut leaves for the removal of the major portion of the surface water.
  • Other techniques such as high-speed air treatment may also be used to remove substantially all of the surface water.
  • the cut leaves pass as indicated by the arrow 28 into an evaporative drying stage 30 which will normally be air drying controlled to remove a selected amount of tissue moisture. Care must be taken in the drying of the cut leaves to insure that they are not subjected to excessive High temperatures as this will cause quality deterioration. Generally such drying is accomplished by using a low humidity air at a relatively low temperature probably not above 30° C to insure that the leaves themselves do not attain a surface temperature above 25° C for any significant length of time.
  • the air or evaporative drying stage 30 must produce a uniformly dried product with no surface wetness. This may be attained by air drying the surfaces of the pre-cut leaves to the extent necessary to reduce the tissue moisture by at least 2% as required for the present invention. To ensure uniform drying the air should circulate over the whole of the surfaces of the cut-leaves and not be obstructed from removing moisture from discrete areas on the cut-leaves.
  • the tissue moisture-reduced cut leaves leaving stage 30 will have a weight loss of at least 2% (i.e. weight at least 2% less than that of the surface water- free cut leaves leaving station 18). It is important that the drying step remove at least 2% of the tissue moisture but it also is important to ensure that the tissue moisture is not unduly reduced to thereby cause texture damage to the tissue moisture-reduced cut leaves. Generally it has been found that provided the tissue moisture has not been reduced by more than 12%, tissue damage to and quality deterioration of the cut leaves will be minimal.
  • tissue moisture that should be removed may differ for different types of salad leaves. Generally satisfactory results are obtained when 2 to 12% weight loss of surface water-free cut lettuce is reached; however, for iceberg and romaine lettuce, better results are obtained when 6 to 10% weight loss of the surface water-free lettuce is achieved.
  • the tissue moisture-reduced cut leaves pass as indicated by the arrow 32 to a cooling station 34 where the tissue moisture-reduced cut leaves are cooled preferably relatively quickly to a temperature in the range of 0 - 10° C preferably 0 to 5° C and more preferably 0 to 3° C.
  • This cooling operation should be completed within approximately 45 minutes, preferably less than 30 minutes after completion of the drying step 30.
  • This step may be combined with the packaging step 38.
  • the cut leaves then pass as indicated by the arrow 36 into a packaging station 38 which may take the form of a modified atmosphere packaging station 38 wherein the microatmosphere surrounding the cut leaves in the package is gassed with a specific gas mixture.
  • the modified atmosphere gas mixture applied to the cut leaves during packaging will comprise about 3 - 12% 0 2 and about 5 - 10% C0 2 .
  • the remainder being an inert gas such as nitrogen, argon, helium, or other inert gases.
  • the air can be removed from the pouch or the like in which the cut leaves are packaged by gas flushing or by gas compensated vacuum techniques.
  • Suitable packaging materials or films will be selected in the conventional manner to ensure that, under equilibrium conditions, the microatmosphere around the cut leaves in each package will contain 1 to 3% 0 2 ; 3 to 12% C0 2 ; preferably 5 to 8% C0 2 with the remainder being an inert gas.
  • MAP as opposed to controlled atmosphere storage (CA) will be used for extending the shelf life of the cut leaves.
  • CA storage may also be used to extend the shelf life of the cut lettuce.
  • the cut salad leaves are stored at a temperature in the range of 0-10° C as indicated at 40.
  • the storage temperature will be in the range of O to about 3° C.
  • the salad to be stored may include two or more different produce components that require different processing conditions prior to packaging.
  • the components may be processed separately through the initial stages of the process; for example, one of the salad components eg. carrot pieces may be introduced as indicated at 10 (line 10) and another component at 10A (or 10B or 10C etc. not shown) (lines 10A, 10B, 10C, etc.) and processed using the same steps as described above for the leaves entering at 10 with the steps for the components processed in lines 10A, 10B, 10C etc. by applying conditions specifically modified or customized the component entering that specific line 10, 10A, 10B, 10C, etc.
  • the blended salad components are then conducted as indicated by line 48 to the cooling station 34, packaging station 38 (the cooling and packaging steps 34 and 38 may be combined) and the storage station 40 where the cut leaves blended with other salad materials are stored at the appropriate temperature.
  • the shelf life of the salad leaves has been found to be 30 days and in many cases to exceed 30 days.
  • initial weight W
  • weights ⁇ -> W c , ⁇ W d and ⁇ SW p are given as a percentage (%) change in weight of the ingredient based on the weight of the ingredient leaving the immediately preceding step and indicated as + for an increase in weight and - for a decrease in weight i.e. ⁇ -> W c is a % of Wj ; ⁇ SW d is a % of W c ; and ⁇ -> W p is a percent of W d . It will be apparent that generally W d is about equal to Wj and thus «SW p provides a reasonable accurate indication of the change in tissue moisture of the leaves being processed.
  • the processing conditions degree of tissue moisture removed
  • packaging conditions were varied to determine their influence on the quality of salads over a storage period of 30 days.
  • the salads were examined for quality every 5 days.
  • the quality evaluation is subjective taking into account appearance (including color), odor, flavor and texture (i.e. examined for russet spotting, brown stain, rib and cut edge pinking and microbiological degradation of the tissue) and each sample was scored on the basis of the known 5-point Hedonic system as follows Points Condition
  • the salad in each case was packaged in a plastic film pouch of material having permeability to 0 2 of
  • the input modified atmosphere gas composition was 5% C0 2 ; 8% 0 2 and the balance N 2 .
  • Tossed salad (2 above) was subjected to the following weight changes during processing a) lettuce same as example 1.
  • b) shredded carrots: ⁇ $W p ⁇ 1% of Wj
  • the tossed salad after processing was packaged in a pouch of material having permeability to 0 2 of 4,000 ml/m 2 , over a 24 hour period, at atmospheric pressure.
  • the input modified atmosphere gas composition was 3% C0 2 ; 12% 0 2 and the balance N 2 .
  • the salad was packaged in a pouch made of material having permeability to 0 2 of 4,200 ml/m 2 , over a 24 hour period, at atmospheric pressure.
  • the input modified atmosphere gas composition was 3% C0 2 ; 15% 0 2 and the balance N 2 ⁇ quality evaluation results obtained by subjecting the salad leaves to various stages of processing (as expressed as W c , W d and W p ) and storing at the storage temperature defined above are given in Table 1 for the sample indicated as C.
  • the input modified atmosphere gas composition was 5% C0 2 ; 8% 0 2 and the balance N 2 .
  • the package size was a 2 kg box 33.5 X 29 X 12 cm. The results obtained are given in Table 3.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Zoology (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Preparation Of Fruits And Vegetables (AREA)
  • Storage Of Fruits Or Vegetables (AREA)

Abstract

On prolonge la durée de conservation de feuilles de salade pré-coupées en réduisant l'humidité tissulaire de feuilles exemptes d'eau de surface, par séchage par évaporation uniforme, afin d'entraîner une perte de poids d'au moins 2 %, en emballant les feuilles ainsi séchées dans une atmosphère modifiée et en les stockant à une température comprise entre 0 et 10 °C.
PCT/CA1994/000036 1993-01-15 1994-01-12 Procede permettant de prolonger la duree de conservation de feuilles de salade fraiches pre-coupees WO1994015475A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU58774/94A AU5877494A (en) 1993-01-15 1994-01-12 Process for extending the shelf life of fresh pre-cut salad leaves

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US399893A 1993-01-15 1993-01-15
US08/003,998 1993-01-15

Publications (1)

Publication Number Publication Date
WO1994015475A1 true WO1994015475A1 (fr) 1994-07-21

Family

ID=21708624

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CA1994/000036 WO1994015475A1 (fr) 1993-01-15 1994-01-12 Procede permettant de prolonger la duree de conservation de feuilles de salade fraiches pre-coupees

Country Status (2)

Country Link
AU (1) AU5877494A (fr)
WO (1) WO1994015475A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997002758A1 (fr) * 1995-07-11 1997-01-30 Wolfe Steven K Procede de nettoyage, de conditionnement et de transport de legumes
US6451363B1 (en) * 2001-07-10 2002-09-17 The Sunblush Technologies Corporation Method and package for the preservation of whole fruits and fresh-cut salads and flowers
WO2003067998A1 (fr) * 2002-02-14 2003-08-21 University Of Georgia Research Foundation Procede de traitement d'un produit alimentaire
CN102144659A (zh) * 2011-04-22 2011-08-10 南京农业大学 一种鲜切生菜高二氧化碳气调包装保鲜方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849581A (en) * 1970-11-13 1974-11-19 Burger King Corp Extended storage life lettuce process and product
US3987208A (en) * 1976-03-25 1976-10-19 The United States Of America As Represented By The Secretary Of The Army Method of extending the storage life of cut lettuce
US4711789A (en) * 1985-10-29 1987-12-08 Dna Plant Technology Corporation Prolonging the shelf life of pre-cut fresh celery
EP0335682A1 (fr) * 1988-03-31 1989-10-04 Hercules Incorporated Emballage à atmosphère contrôlée, perméable à l'eau, fait de cellophane et d'un film microporeux
US5097755A (en) * 1989-08-17 1992-03-24 Redi-Cut Foods, Inc. Method and apparatus for processing produce

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3849581A (en) * 1970-11-13 1974-11-19 Burger King Corp Extended storage life lettuce process and product
US3987208A (en) * 1976-03-25 1976-10-19 The United States Of America As Represented By The Secretary Of The Army Method of extending the storage life of cut lettuce
US4711789A (en) * 1985-10-29 1987-12-08 Dna Plant Technology Corporation Prolonging the shelf life of pre-cut fresh celery
EP0335682A1 (fr) * 1988-03-31 1989-10-04 Hercules Incorporated Emballage à atmosphère contrôlée, perméable à l'eau, fait de cellophane et d'un film microporeux
US5097755A (en) * 1989-08-17 1992-03-24 Redi-Cut Foods, Inc. Method and apparatus for processing produce

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
A. BALLANTYNE ET AL.: "Modified atmosphere packaging of shredded lettuce", INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY, vol. 23, 1988, pages 267 - 274 *
H. R. BOLIN ET AL.: "effect of preparation and storage parameters on quality retention of salad-cut lettuce", JOURNAL OF FOOD SCIENCE, vol. 56, no. 1, 1991, pages 60-62 67 *
H.R. ROLIN ET AL.: "factors affecting the storage stability of shredded lettuce", JOURNAL OF FOOD SCIENCE, vol. 42, no. 4, July 1977 (1977-07-01), pages 1319 - 1321 *
T. R. KRAHN ET AL.: "Inproving the keeping quality of cut head lettuce", ACTA HORTICULTURAE, vol. 62, 1977, pages 79 - 93 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997002758A1 (fr) * 1995-07-11 1997-01-30 Wolfe Steven K Procede de nettoyage, de conditionnement et de transport de legumes
US6451363B1 (en) * 2001-07-10 2002-09-17 The Sunblush Technologies Corporation Method and package for the preservation of whole fruits and fresh-cut salads and flowers
WO2003067998A1 (fr) * 2002-02-14 2003-08-21 University Of Georgia Research Foundation Procede de traitement d'un produit alimentaire
CN102144659A (zh) * 2011-04-22 2011-08-10 南京农业大学 一种鲜切生菜高二氧化碳气调包装保鲜方法

Also Published As

Publication number Publication date
AU5877494A (en) 1994-08-15

Similar Documents

Publication Publication Date Title
CA1307698C (fr) Prolongation de la duree de conservation du celeri frais pre-coupe
US4943440A (en) Controlled atmosphere cut vegetable produce package and method
US4883674A (en) Controlled atmosphere cut fruit package and method
Bolin et al. Factors affecting the storage stability of shredded lettuce
EP0289777B1 (fr) Conservation de morceaux de fruit frais coupé et segmenté
Ahvenainen New approaches in improving the shelf life of minimally processed fruit and vegetables
Kader et al. Modified atmosphere packaging of fruits and vegetables
US6190710B1 (en) Plastic packaging material
Bolin et al. Effect of preparation procedures and storage parameters on quality retention of salad‐cut lettuce
US4001443A (en) Package and method for packaging and storing cut leafy vegetables
Mangaraj et al. Modified atmosphere packaging of fruits and vegetables for extending shelf-life-A review
US3987208A (en) Method of extending the storage life of cut lettuce
JPH07501452A (ja) 葉菜の貯蔵性を延長する処理方法
US4957761A (en) Potato preservation method
US5110609A (en) Intermediate moisture vegetables
US5226972A (en) Methods and means for cleaning and cooling produce
Cantwell et al. Fresh-cut fruits and vegetables: aspects of physiology, preparation and handling that affect quality
US5616354A (en) Method for processing fresh strawberries for extended shelf life
US20030091705A1 (en) Process for the preservation of fresh quality attributes of peeled, whole and peeled, cut kiwifruit
US20250151739A1 (en) Preserving miracle fruit berries
WO1994015475A1 (fr) Procede permettant de prolonger la duree de conservation de feuilles de salade fraiches pre-coupees
Abugoukh et al. Effect of polyethylene film lining and potassium permanganate on quality and shelf-life of banana fruits
Cantwell et al. Postharvest technology of horticultural crops: Fresh-cut and processed horticultural products
US5700506A (en) Method for prolonging the shelf life of fresh tomato pieces
EP0221489B1 (fr) Augmentation de la durée de conservation de légumes frais du genre racine

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU CA JP

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA