WO1998047383A1 - Produit de tissu vegetal congele et son procede de preparation - Google Patents

Produit de tissu vegetal congele et son procede de preparation Download PDF

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Publication number
WO1998047383A1
WO1998047383A1 PCT/EP1998/001898 EP9801898W WO9847383A1 WO 1998047383 A1 WO1998047383 A1 WO 1998047383A1 EP 9801898 W EP9801898 W EP 9801898W WO 9847383 A1 WO9847383 A1 WO 9847383A1
Authority
WO
WIPO (PCT)
Prior art keywords
product
peas
stored
plant tissue
glass transition
Prior art date
Application number
PCT/EP1998/001898
Other languages
English (en)
Inventor
Christopher Brunsden Holt
Elliott Kirk
David George Sharp
Peter Richard Stephenson
Original Assignee
Unilever Plc
Unilever Nv
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 Unilever Plc, Unilever Nv filed Critical Unilever Plc
Priority to AU72137/98A priority Critical patent/AU7213798A/en
Publication of WO1998047383A1 publication Critical patent/WO1998047383A1/fr

Links

Classifications

    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/04—Freezing; Subsequent thawing; Cooling
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
    • A23B7/00—Preservation or chemical ripening of fruit or vegetables
    • A23B7/04—Freezing; Subsequent thawing; Cooling
    • A23B7/0441—Treatment other than blanching preparatory to freezing

Definitions

  • the invention relates to a frozen plant tissue product, such as vegetables, fruit, tea and herbs, and a process for the preparation thereof, which process does not include a step which inactivates lipoxygenase.
  • blanching results in a reduction of the nutritional and sensory quality; it reduces the vitamin content, in particular vitamin C; it also affects the cell membranes and cell walls, resulting in texture and colour alteration (eg softening) .
  • FR 2634977 discloses freezing raw cep mushrooms to -120°C and storing them at -24°C.
  • US 3600199 teaches freezing fresh root vegetables such as potatoes to a temperature in the range of -20 to -32°C, keeping them at this temperature for two days and storing them at higher temperatures of, for example, -15 or -10°C.
  • a plant tissue product which is frozen and stored at a temperature lower than or equal to its glass transition temperature, characterised in that, prior to freezing, the product is not subjected to a process which inactivates lipoxygenase.
  • Lipoxygenase is an enzyme which is known to catalyse reactions that generate off-flavours in plant tissue products. Traditionally, it is inactivated prior to freezing to prevent deleterious changes to a plant tissue product during frozen storage. The inventors were suprised to find that plant tissue products, having active lipoxygenase, had a natural 'fresh' flavour and colour after prolonged frozen storage at or below their glass transition temperature.
  • the invention also provides a process for the preparation of a frozen plant tissue product, the process comprising the steps of:
  • the frozen plant tissue product is stored for at least one week, more preferably for at least one month and most preferably for at least three months.
  • the plant tissue product is pasteurised prior to freezing.
  • Suitable pasteurising heat treatments are 60°C for 43 mins or 70°C for 2 minutes.
  • the application of ultra high pressure, high intensity light or mano-thermo-sonication are also suitable pasteurisation treatments. These treatments do not inactivate enzymes such as lipoxygenase and peroxidase, but do kill microorganisms, so that the product is microbiologically safe to eat upon thawing.
  • a blanching heat treatment is, for example, 92°C for 80 to 90 seconds; such a treatment inactivates lipoxygenase and peroxidase.
  • the plant tissue product is preferably frozen and stored at a temperature which is no lower than 10°C below its glass transition temperature, more preferably, no lower than 5°C below its glass transition temperature .
  • the present invention provides a product which is frozen and stored under controlled conditions.
  • the product may be frozen to a temperature lower than or equal to its glass transition temperature and stored at the same or a different temperature lower than or equal to its glass transition temperature.
  • the plant tissue product does not include any added preservative prior to freezing.
  • the concentration of the unfrozen media increases. Consequently, the viscosity of the unfrozen matrix between the ice crystals increases.
  • the glass transition temperature At a certain temperature, known as the glass transition temperature, the viscosity of the matrix becomes so high that molecular diffusion is greatly inhibited.
  • the glass transition temperature is different for distinct plant tissue products and is likely to vary according to variety, maturity etc.
  • the glass transition temperature (Tg) may be measured by any suitable method. Such methods are given in, for example, J Food Eng (1994) 22 . 483-494 in the article entitled “The Glass Transition in the Freezing Process” by D S Reid, Kerr and J Hisu and Zeitschrift fuer Naturforschung section C Biosciences 49 . (3-4) (1994) in the article entitled “Glassy state in plant cuticles during growth” by P Luque and A Heredia.
  • the inventors used Differential Scanning Calorimetry to measure glass transition temperatures .
  • the trace from a Differential Scanning Calorimeter of an aqueous solution shows a large peak corresponding to the heat input required to melt the ice in a sample.
  • a small step immediately prior to the large step was taken as the glass transition temperature.
  • the plant tissue product is selected from the group consisting of vegetables, fruit, leaf tea, herbs and includes, for example, peas, green beans, potato, spinach, broccoli, sweetcorn and tomatoes.
  • the plant tissue product preferably consists of only fruit and/or vegetables.
  • glass transition temperatures are as follows : Peas -38°C
  • cep mushrooms -26 to -27°C potatoes (Bintje variety) -16 to -18°C turnip -35 to -39°C
  • Blanched green beans with a glass transition temperature of -24°C were frozen in approximately 2 minutes using liquid nitrogen. They were stored at -28°C for 5 months. The beans were less firm and crisp than those in Example 1, when cooked and assessed by an informal panel.
  • the phospholipid content and free fatty acid content of a sample of hand-shelled raw (unblanched) peas was measured.
  • the peas had a glass transition temperature of -38°C.
  • Another sample of hand-shelled raw (unblanched) peas was blast frozen to around -20°C, rapidly frozen to -70°C and stored at -38°C for 6 months. Upon thawing, the phospholipid content and free fatty acid content of the peas were measured.
  • the phospholipid measured was phosphatidylcholine.
  • the fresh hand-shelled peas had a phosphatidylcholine content of 150mg/100g and a free fatty acid content of Omg/lOOg.
  • the frozen, raw hand-shelled peas had a phosphatidylcholine content of 194mg/100g and a free fatty acid content of Omg/lOOg. Comparative Example B
  • the peas stored at -20°C had a phosphatidylcholine content of 23mg/100g and a free fatty acid content of lllmg/lOOg.
  • the peas stored at -28°C had a phosphatidylcholine content of 76mg/100g and a free fatty acid content of 26mg/100g.
  • peas stored at their glass transition temperature have a phosphatidylcholine content and free fatty acid content comparable to that of fresh, raw peas.
  • phosphatidylcholine is broken down by enzymes to free fatty acids.
  • the peas therefore lose the high levels of phosphatidylcholine and the low/zero levels of free fatty acids that are usual in fresh, healthy, normally-metabolising plant tissue. This loss is detrimental to the quality of the peas.
  • the Vitamin C content of fresh, raw (unblanched) , hand- shelled peas was measured. Three samples of hand-shelled raw (unblanched) peas were frozen using liquid nitrogen. They were stored at -38°C for 3, 6 and 12 months respectively. Upon thawing, the Vitamin C content of the peas was measured.
  • the fresh peas had a Vitamin C content of 32 mg/lOOg.
  • Fresh, raw, hand-shelled peas were blanched. Their Vitamin C content was then measured. Three samples of blanched, hand- shelled peas were frozen using liquid nitrogen. They were stored at -38°C for 3, 6 and 12 months respectively. Upon thawing, the Vitamin C content of the peas was measured.
  • the unfrozen blanched peas had a Vitamin C content of 30 mg/lOOg.

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)
  • Storage Of Fruits Or Vegetables (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Preparation Of Fruits And Vegetables (AREA)

Abstract

Produit de tissu végétal congelé et stocké à une température inférieure ou égale à sa température de transition vitreuse et non soumis, préalablement à sa congélation, à un procédé inactivant la lipoxygénase.
PCT/EP1998/001898 1997-04-21 1998-03-23 Produit de tissu vegetal congele et son procede de preparation WO1998047383A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU72137/98A AU7213798A (en) 1997-04-21 1998-03-23 Frozen plant tissue product and process for the preparation thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP97302706 1997-04-21
EP97302706.3 1997-04-21

Publications (1)

Publication Number Publication Date
WO1998047383A1 true WO1998047383A1 (fr) 1998-10-29

Family

ID=8229306

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/001898 WO1998047383A1 (fr) 1997-04-21 1998-03-23 Produit de tissu vegetal congele et son procede de preparation

Country Status (2)

Country Link
AU (1) AU7213798A (fr)
WO (1) WO1998047383A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101194645B (zh) * 2007-12-26 2011-05-04 唐明霞 果蔬的速冻冷藏方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4220672A (en) * 1969-08-25 1980-09-02 Produits Findus S.A. Preparation of deep-frozen leaf vegetables in granular form
EP0052574A1 (fr) * 1980-11-14 1982-05-26 Helmut Ruh Procédé et appareil pour la préparation d'herbes fraîches et mélanges d'herbes ainsi qu'un objet moulé à partir de ces herbes
US5206048A (en) * 1991-05-30 1993-04-27 Nong Shim Co., Ltd. Process for manufacturing potato chips
WO1998020756A1 (fr) * 1996-11-14 1998-05-22 Unilever N.V. Preparation alimentaire entierement aromatisee, transformee a l'etat vitreux

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4220672A (en) * 1969-08-25 1980-09-02 Produits Findus S.A. Preparation of deep-frozen leaf vegetables in granular form
EP0052574A1 (fr) * 1980-11-14 1982-05-26 Helmut Ruh Procédé et appareil pour la préparation d'herbes fraîches et mélanges d'herbes ainsi qu'un objet moulé à partir de ces herbes
US5206048A (en) * 1991-05-30 1993-04-27 Nong Shim Co., Ltd. Process for manufacturing potato chips
WO1998020756A1 (fr) * 1996-11-14 1998-05-22 Unilever N.V. Preparation alimentaire entierement aromatisee, transformee a l'etat vitreux

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CLAUDIA DZIUK O'DONNELL: "The Formulation Challenge - Formulating for the big freeze", PREPARED FOODS, vol. 162, no. 6, 1993, pages 55 - 56, XP002039423 *
H.D. GOFF: "Low-temperature stability and the glassy state in frozen foods", FOOD RESEARCH INTERNATIONAL, vol. 25, no. 4, 1992, CANADA, pages 317 - 325, XP002039424 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101194645B (zh) * 2007-12-26 2011-05-04 唐明霞 果蔬的速冻冷藏方法

Also Published As

Publication number Publication date
AU7213798A (en) 1998-11-13

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