by Bioconservacion July 19th, 2017 0 comments

 

It is well known that ethylene is the hormone responsible for stress processes and fruit ripening in plants, as well as the ageing of leaves and flowers, and the detachment of fruit.

One of the most typical ways of preserving cut flowers during storage and transportation is refrigeration. In this case, as the chambers or containers must be sealed, high concentrations of ethylene accumulate.

The amount of ethylene generated by a cut flower and the impact of that ethylene in the air, depends on each variety.

Damage caused by ethylene includes:

  • Abnormal shape of the flower when opening
  • Premature drop of leaves and petals
  • Loss of colour
  • Loss of shape
  • Premature drop of buds

Any of this damage seriously affects the market value of the flower, and can even result in the total loss of the product.

Our Technical Postharvest Specialists with broad experience in this field and numerous scientific publications, have recorded problems of damage by ethylene in many flower varieties, for example: carnations, gyposophilia, delphiniums, orchids, phalaenopsis, lilies, cymbidium, alstroemeria, and agapanthus.

During transport and storage, it is typical that several varieties of cut flower share the same space. If, for example, a variety of flower that emits high levels of ethylene is loaded with another that emits very little, but which is very sensitive to the gas, the effect can be catastrophic.

Some varieties of roses are sensitive to as little as 20 ppb (parts per billion) of ethylene. Bioconservacion's Postharvest Specialists have studied refrigerated warehouses of cut flowers containing up to 2 ppm of ethylene, that is, up to 150,000 times more than the concentration that can damage flowers irreversibly.

Increased risk of ethylene damage due to changes in transport practices

Traditionally, cut flowers have been transported by air, with transit times of 2 to 4 days.

The optimum way of transporting cut flowers is in an upright position in a container of water, to which chemicals may be added that inhibit the action of ethylene.

This is a very costly mode of transport, which is why cut flowers are increasingly being transported horizontally, meaning suppressant chemicals cannot be used during transport.

Additionally, to reduce transport costs, refrigerated containers are being utilised more and more, lengthening the total time of the distribution chain to two weeks. Additionally, in certain countries, part of the transportation is not refrigerated.

Technologies to eliminate ethylene damage

According to the above data, it is clear that the only sure strategy for avoiding unpleasant surprises during transport it is to guarantee that the cut flowers are not in air containing ethylene.

There are various traditional technologies that alleviate ethylene damage:

Chemicals that are applied in aqueous solution and which inhibit the biosynthesis of ethylene: AVG (Aminoethoxyvinylglycine) AOA, Aminooxyacetic acid. These cannot be used correctly when flowers are transported horizontally.

Gaseous products that inhibit the action of ethylene on flowers (1-MCP, 1-methylcyclopropane). This has no permanent effect.

Another product that inhibits the action of ethylene on flowers is STS (Silver thiosulphate). This generates heavy metal waste residues.

Removal of ethylene by chemical absorption

The most advanced technology, which is the safest and has no environmental impact, involves high-efficiency solid products that eliminate ethylene by continually absorbing it from the air, throughout the logistics chain. This keeps airborne ethylene in the containers and cold chambers at practically undetectable levels.

Cold storage chambers can be opened for daily replenishment and delivery of flowers with no problems, as the effect is not lost.

Bioconservacion solutions for protecting cut flowers from ethylene damage

Bioconservacion has a variety of proprietary technological solutions for reducing ethylene to undetectable levels, which have been validated in leading postharvest research institutions:

  • Absorbent products to remove ethylene based on Potassium Permanganate. These cylindrical pellets allow maximum efficiency with minimum power consumption.
  • Different, standardised machines at a very competitive price that force the air to circulate through chemical filters, maintaining the atmosphere completely free of ethylene, microorganisms and fungi.
  •  Small, low-cost “sachets” that, distributed throughout the load, constitute an economic and safe solution that removes ethylene and protects cut flowers.

 One of the greatest advantages of Bioconservacion absorbents, is that their effectiveness is not affected by relative humidity unlike, for example, technologies based on heavy metal catalysts.

The following chart compares the absorption of ethylene using Bioconservacion sachets with various competing products that use technologies based on heavy metals (Technology A, B and C).

Under test conditions, in 1 hour the sachet containing potassium permanganate is able to reduce the level of ethylene to undetectable concentrations.

Bioconservacion has a wide network of partners, both at the national and international levels, including technical postharvest specialists that are able to analyse each situation and recommend the best solution for eliminating ethylene.