DE3928299A1 - Vacuum packaging of fruit for storage - conditions during packaging stage are chosen such that vacuum is created in package through fruit respiration during storage - Google Patents

Abstract

A process for packaging and storage of fruit and vegetables under a sealed cover e.g. polyethylene film is described. The packaging acts as a vacuum package both during storage and for selling to purchasers. Vacuum is created by the natural respiration of the fruit within the sealed package. The dry air necessary for the continuous ripening process is calculated so that after a given storage time and a specified temp. during packaging a vacuum occurs as the temp. is lowered. The ratio of CO2 gas given off to O2 gas taken in by the contents of the package is less than one.

Description

The invention relates to a method for the marketable and the manufacture of vacuum packaging intended for the end user of stock fruits (fruits and vegetables), which in the Stage of harvest has not yet fully reached maturity and for the further ripening process (crumbling process, residual acid conversion) need cool, dry air (atmospheric oxygen O₂).

The production of this packaging is very simple using standard equipment while complying with the specified boundary conditions feasible anywhere and enables storage of fruit for up to 9 months (depending on the variety) without any special effort.

The method was tested in winter 88/89 with the fruit types Bell Apple, Gold Parmaene, James Grive, Gloster 69, Jonathan and Idared in maturity stage 1 = green, 2 = green-yellow and 3 = yellow-green, medium size.

After harvesting, reading and possibly cleaning the fruits (stored fruits) these are packed in boxes in a cool, dry room with constant Temperature (approx. 12-13 ° C) and low humidity (relative humidity approx. 40-50%). Here they stay for a certain time (Dwell time for apples e.g. approx. 2-3 weeks) to dry external moisture and the assumption of room temperature too to reach. This is important so that in the case of further cooling in the welded Condition is not passed through the dew point and condensation is created in the vacuum packaging.

After that, the fruits are in the desired sales unit e.g. B. 6 apples) in a commercially available film made of polyethylene welded in and up to the intended consumption finally stored.

The size of the bag and the amount of atmospheric oxygen trapped inside is for the desired state of maturity (residual acid or short state) important. Are z. B. bell apples welded so that the bag the fruits are loosely spanned, so after a storage time of approx. 9 months left a little residual acid. To convert the total acid, the bag volume should be increased by approx. 10%.

The sealed fruits are now in a dry storage room stored slowly over a period of 6-8 weeks to 6-7 ° C is cooled. This can be done in a dry, unheated concrete cellar Be earth that in the winter months this temperature is natural Way achieved.

As is known from the literature (bibliography can be sent on request), the storage of fruit during the shorting process carbon dioxide (CO₂), water (H₂O) and one certain amount of heat released. The more carbon (C) from glucose sugar (C₆H₁₂O₆) and of the organic acids is present, the more more oxygen (O₂) is needed to add carbon dioxide or water form. The lower the temperature (lowest storage temperature for Apples + 4 ° C), the slower this conversion process takes place. This metabolic process is regulated by the enzyme apparatus, the is specific to each variety and also its usability depends on the environmental conditions.

During the slow cooling phase, the one in the tightly welded one Air oxygen present (21%) due to fruit breathing (Crumbling process, conversion of the acid) consumed and it arises a vacuum. The film firmly covers the wrapped fruits and gives them the strength of a compact block. Is the oxygen consumed, the ripening process (and fruit breathing) becomes strong slowed down.

The so-called breathing coefficient is important for the process of fruit breathing. If a fruit is accurate within a certain period as much oxygen (O₂) in vol .-% as carbon dioxide (CO₂) forms, the breathing coefficient is 1. In the case of stored fruit, the coefficient ranges between 0.8 and 1.5 (Literature of the ratio Vol .-% CO₂ / O₂).

If the fruit absorbs more oxygen than how it releases carbon dioxide, this reduces the volume in an airtight container Polyethylene bags continuously until the oxygen is almost (approx. 1-3%) is used up. In this way, over a period of approx. Generated a vacuum pack for 3-6 weeks, the subject of this invention is. The dry air remaining in the shrunk film can despite the drop in temperature from 13 to 6 ° C Keep moisture so that it does not lead to a passage of the Dew point comes, but only to a (desired) high relative Humidity of approx. 90%. However, the storage temperature should not be below 6 ° C, otherwise there is a risk of water in the pack forms.

There is enough carbon from sugar and in all types of stored fruit the organic acids for longer storage at low temperatures Temperatures available. It is first about 50% of that in the organic Acids existing carbon converted so that, for. B. the Bell apple no longer tastes sour after storage. Depending on the variety, the fruit's enzyme system is better or worse suitable, the metabolic processes over a longer storage period to regulate. The rule applies, the longer the growing season, the better the enzyme apparatus and the longer you can use it Store fruit. Example:

The is of particular importance for the creation of a vacuum Value of the breathing coefficient. It was found that he was at same variety varies from different locations. Whether it there is a connection between over-fertilization with artificial fertilizer (especially with potash and nitrogen) and the breathing coefficient (Value <1) could not yet be clearly determined.

Advantages of the procedure

• 1. Except an appropriate work and storage room with the specified Conditions, commercially available polyethylene foil bags, a household heat sealer and the small one No further effort is required for the energy required for welding.
• 2. If the bag is not leaking, the fruits can be effortless depending on the shelf life z. B. for fruit up to 9 months and longer be stored, even if the storage room temperature drops to approx. 12 ° C increases. The determined failure rate for the bell apple after 7 months of storage, about 4% of the stored fruit was.
• 3. The few rotting spots that can be found on individual fruits of the Vacuum pack had formed after about 3 months of storage stopped (lack of oxygen) and could see the other fruits of the Do not infect the package. A larger putrefaction can develop Do not spread beyond the contents of a pack.
• 4. No additional equipment or Energy needed. You can after outsourcing and superficial Review so delivered to retailers or end users will. The vacuum is maintained even at room temperature the goods that are not sold immediately last much longer, the losses on the distribution channel are lower.
• 5. The currently considerable CA storage effort (CA = controled atmosphere) and sorting, cleaning and packing in cardboard boxes Shrink film can be omitted. It is replaced by an environmentally friendly one Storage in polyethylene film (combustible).
• 6. The method is particularly suitable for direct marketers (smallholder family business). The fruits can also Intermediate and retail stores are stored longer without the Rotting process is accelerated.
• 7. Since there is no evaporation in the vacuum pack, the remains Get juice, the fruit smooth and fresh until the consumer the packaging sticks.
• 8. Depending on the fruit size and acidity, the amount of air can Sealing in a foil bag so that z. B. a Apple has a residual acidity even after a storage period of 7 months retains or after a certain time in the edible Wear condition passes.

Claims (5)

1. Process for packaging and storage of fruits and vegetables (Fruits) in a sealed envelope, e.g. B. made of polyethylene, which is suitable as vacuum packaging (Vacuum air pressure reduced by certain gas fractions in vol.%, e.g. B. reduced by an oxygen content O₂ of about 18-20%) both during storage and for sale to the end user (Respectability) to serve and at which the vacuum is on naturally arises from fruit breathing during storage. 2. The method according to claim 1, characterized in that the for the dry air necessary for the further ripening process when welding is dimensioned so that after a storage period of approx. 6-10 weeks and an initial temperature of approx. 13 ° C A vacuum is created which drops to 6-7 ° C due to fruit breathing is coming. The ratio of the gas emitted by the fruit e.g. B. carbon dioxide CO₂ to the absorbed gas z. B. oxygen O₂ is less than 1 (breathing coefficient <1). 3. The method according to claim 1 and 2, characterized in that by the vacuum is a stable, storable and transportable package from e.g. B. 6-10 fruits (1-1.5 kg) with which one effortlessly can handle, without the fruit bumping into each other Pressure points arise. 4. The method according to claim 1 to 3, characterized in that the products produced by the process from every fruit and vegetable producer (small farm, Gardener u. a. Direct marketers) with minimal effort packed, over a period of up to 9 months (depending on the variety) can be stored and then marketed. 5. The method according to any one of the preceding claims, characterized characterized that any putrefaction is stopped and cannot switch to the other goods and that the goods are neither stored in complex CA warehouses nor for the Sales must be washed or repacked.