The study was undertaken in December 2006, by Dr Edna Pessis and Oleg Feigenberg, of the department for post-picking agricultural produce research (storage) at the Volcani Institute, and MTEX’s Eli Oliel. Its purpose was three-fold. Firstly, it looked to examine the effect of various types of carton (octagonal and standard) on avocado quality after shipment by sea to storage facilities in Barendrecht, the Netherlands. Secondly, it examined the effectiveness of using a new container from Hamburg Sud and AFAM+ technology. And thirdly, the experiment intended to analyse the effect of ethylene absorbents in marine shipping containers.
The Ettinger avocados were picked on December 1-2, 2006, and the unwaxed fruit was packed on December 3-4, 2006, at Mehadrin’s packhouse in Ashkelon and placed into storage at 5°C until December 7-8, when they were loaded for shipment.
Three types of Hamburg Süd containers were used in the experiment: a) a standard container; b) a container holding two ethylene absorbents manufactured by Spanish firm Bioconservation; and c) a container incorporating AFAM+ technology. The consignment included six pallets of Ettinger (size 14), of which three pallets contained standard cartons and three pallets contained octagonal cartons; and two pallets of Ettinger avocado size 12 (one pallet containing standard cartons and one containing octagonal cartons).
Three thermometers were inserted into each pallet: in the bottom row, in row 13 (mid-pallet) and row 26 (top row). In addition, a thermo couple was placed in the middle of each pallet. All experimental pallets were tested for weight loss. While loading, temperature of avocado pallets was measured using thermo couple. The pallets containing standard and octagonal cartons were loaded in pairs, in a mid-location in the experiment containers. Pallets containing size 12 avocados were loaded to a container holding an ethylene absorbent located mid-container.
The containers arrived at Mehadrin warehouses (Olympic Fruits) in Barendrecht on December 21, 2006. Ethylene levels in the containers were measured upon opening the containers. The container without ethylene absorbent measured 0.4ppm, the container with ethylene absorbent measured 0.2ppm and the container using AFAM+ technology measured 0.1ppm.
On unloading, the pallets were again evaluated for weight loss and after temperature measures, the avocado pallets were unloaded, thermometers removed and samples taken for testing at removal from chilling at shelf life. All samples were taken from rows two and 25, from a total of 12 cartons in each pallet and a total of 24 cartons from each container.
All samples were divided into three shelf-life temperature conditions: 14°C in the corridor of Olympic Fruit’s building, 20°C at MTEX offices, and 22°C at the hotel, in order to obtain a complete picture of fruit shelf life, and due to the fear of missing the maturity process during Christmas.
During storage, the various quality and ripening indices were measured, including: firmness by manual touch, general appearance, colour, damage and decay. A pentrometer was used to measure fruit firmness in a destructive process.
Thermo couples were used to measure fruit temperature subsequent to removal from chilled storage in Ashkelon and arrival of containers in Barendrecht. No significant temperature differences were found when comparing octagonal and standard cartons on size 14 pallets in all three experimental containers. In contrast, the temperature in size 12 standard cartons was higher by 0.5°C compared to the octagonal cartons. No differences were recorded in temperatures or humidity on avocado pallets in both carton types. Temperatures were stable throughout the entire storage process, and in all locations on the pallets.
The research team says: “In the weight loss test, we observed that the octagonal carton showed slightly reduced weight loss. Apparently, these cartons were better ventilated, and had lowered respiration, which affected weight loss. In all the other tests, no significant differences were found between the cartons, which indicates that octagonal cartons are also suitable for packing and transport of avocados.”
When it came to the use of AFAM+ technology, Hamburg Süd did not make available any data on oxygen and carbon dioxide levels upon opening the new container. “However,” say researchers, “based on the ethylene levels, the new container clearly had a level of carbon dioxide between five per cent and 10 per cent. “After unloading the containers in Holland, avocado fruit firmness was measured using a digital Lutron electronic scale, manufactured in Taiwan. The firmest fruit was in containers with AFAM+ and ethylene absorbents. In standard containers, fruit was softer upon arrival in Holland, consistent with the ethylene levels in the containers during transport.
“During the entire shelf-life period, avocado fruit transported in AFAM+ containers was firmer than the fruit from the other two containers; fruit from the container with ethylene absorbents was firmer than the fruit transported in the standard containers. The exact same situation is evident in tests for browning, decay and chlorosis. Avocado from AFAM+ containers suffered less from these three issues than fruit from the other containers. Avocados from containers holding ethylene absorbents were in a better state compared to avocados transported in standard containers.”
Based on its study, the research team came to the following 10 conclusions:
• The condition of all Ettinger avocados packed in octagonal cartons located in the middle section of all three experimental containers was superior.
• Use of Hamburg Süd AFAM+ containers for marine transport reduced ethylene levels in the containers, and produced firmer avocado fruit with less decay at shelf life. In contrast, discoloration in skin was increased.
• Use of ethylene absorbents with avocados during sea shipments reduced ethylene levels in containers from 0.4ppm to 0.2ppm, and produced firmer fruit.
• Use of ethylene absorbents is essential to prevent accelerated softening due to ethylene that causes decomposition of chlorophyll, softening and discoloration, especially with end-of-season avocado.
• The larger the fruit (size 12), the more rapidly it softens and suffers from discoloration, decay and loss of chlorophyll from skin, compared to smaller fruit (size 14).
• In standard containers, there is a clear benefit to octagonal cartons compared to standard cartons. Fruit in octagonal cartons suffered less from browning, skin discoloration and loss of skin chlorophyll (chlorisis). The reason is that octagonal cartons are apparently better ventilated and prevent accumulation of ethylene, which is the major cause of fruit defects and chlorophyll decomposition.
• In the other containers, octagonal cartons showed no benefit because ethylene levels in these containers were lower. In these containers, ethylene levels were lowered by an external factor such as ethylene absorbents or a carbon dioxide-rich atmosphere.
• In containers with ethylene absorbents, fruit (both sizes) in octagonal cartons suffered from a lower rate of decay than fruit in standard cartons. It is possible that the ventilation in octagonal cartons was superior and prevented ethylene from accelerating the decay process.
• In containers with ethylene absorbents, fruit from octagonal cartons (size 14) suffered from a higher rate of skin discoloration. In contrast, larger fruit (size 12) suffered from less discoloration in octagonal cartons after seven days at a temperature of 22°C. It is possible that size 12 avocado pallets containing octagonal cartons were placed in a better location in the container in terms of ventilation.
• The new octagonal containers meet all the requirements and standards for avocado storage (carton strength, crush resistance, good air passage in the pallet core).
The study is good news for MTEX, which is already using the octagonal cartons for avocados, citrus and grapes and has put great faith in the stronger cartons and what they appear to offer in terms of better air circulations during both storage and transit. Work carried out by designer Menashe Rogotner and manufacturer IMA (see box) has changed the direction airflow from horizontal to vertical, and this too has had a positive effect on results.
And the stacking process has also been monitored and improved, with care at all times to ensure that the strength of the cartons, and therefore their ability to protect the fruit, is not compromised.
REMODELLED WITH PURPOSE
The octagon tray has MAF8-registered patent in Israel, Europe, the US and South Africa. Its design is registered as a protected mark in Israel and the rest of the world.
The unique tray was developed by Menashe Rogotner, a consultant representing Israeli fruit exporters through box manufacturer Itzur Mutzarei Ariza (IMA 1990). Although already successfully integrated in the fresh produce supply chain, the boxes have been modified in the last 12 months to enhance their suitability to the fruit market.
“We have produced a tray with better qualities than the current model. We have improved and added airflow between the trays and inside the pallet. We now have a tray that is significantly stronger than the former model. Its innovative shape is the result of a new structure that is far more appealing to our customers,” says Rogotner, pictured.
“Box compression tests produced excellent results. The new shape is more attractive and, while the layout is the same, the side-to-side and vertical air tunnel created by the trimmed corners has definitely been a success and allows the air to reach all of the fruit in each tray.
“The new design of the tray provides solutions for constraints that were difficult to overcome in the past, and what’s more, the improvement in performance has come at no extra cost.”
The cartons were initially designed for citrus, but were also adapted for the avocado sector. The distinct airflow characteristics of the cartons “makes the fruit more durable during the sea journey to Europe,” says Rogotner.
No comments yet