Opinion: Tackling preservation challenges in avocados

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Opinion: Tackling preservation challenges in avocados

By OctoFrost Group marketing coordinator Carmen Popescu

carmen-popescuThe fast-paced world of today, as well as different social and economic dynamics, are opening new opportunities to food processors all over the world while making competition between suppliers harder than ever.

There are new emerging markets where consumers are become more aware of their possibilities, and they are prepared to pay for excellent quality and for exotic products that normally don’t exist in their own countries. 

We can see an upward trend of supply for exotic and organic products, but the tricky part is that handling the demand for good quality products is not always so easy. There is a high dependency on seasons, good harvests and a good perservation of food products.

The avocado is one of these items that has witnessed high demand due to its many health benefits and nutritious values, but it has proven to be quite a difficult product to process and to preserve because of its highly perishable nature.

On the market, fresh avocados with imperfections and odd-sized fruits are usually rejected. In addition, the fruits selected require special handling because they can turn bad so quickly. Their high oil content readily becomes rancid and they also have a very active oxidative browning system.

Therefore, the development of new avocado products and of improved methods of preservation are of interest to avocado growers. Even though the avocado originates in Central America and southern Mexico, it is now one of those star products grown in many countries of the world.

The avocado can be botanically classified into three races:

1. West Indian (WI) - tropical with large variably shaped fruit and lower oil content.
2. Mexican (MX) - semitropical with smaller elongated, thin-skinned fruit and higher oil content.
3. Guatemalan (G) - subtropical with mostly round, thick-skinned fruit and intermediate oil content.

Many of the commercial cultivars that we find on the market today are hybrids of these three races. There is great variability in fruit traits and one of the most distinct differences between cultivars is the peel color when they ripe. The peel of some cultivars changes from green to black or purple with increasing maturity or ripening.  

The majority of the cultivars are considered to be primarily G-MX hybrids and the most common and highly appreciated avocado on the market is the Hass variety.

Hass avocado trees produce fruit all year-round, accounting for 80% of cultivated avocados in the world. That says quite a lot about the fame and success of this cultivar. Also, the Hass avocados are more easily preserved in comparison to other avocados, which makes them of course better candidates for the market. With good-looking, better preserved avocados, the chances to sell your merchandise will increase exponentially. 

So what is the most essential aspect to keep in mind when processing avocados? The answer is time. Once the avocado is plucked from the tree it starts to ripen and here starts the challenge, as the avocados are one of the few fruits that contain significant quantities of oil, sometimes more than 30%, and little quantities of water; a perfect recipe for fast decay.

The ripening and softening of avocados can be delayed however by cooling them directly after the harvest. This is critical where long storage periods are required or where field temperatures reach above 25°C (77°F).

Therefore, forced or passive air-cooling is generally carried out as rapidly after harvest as possible and it is recommended to have the target temperature vary between 5°C (41°F) and 15°C (59°F). 

As we’ve already concluded avocados are hard to preserve by canning and any other method of preservation will cause undesirable changes in flavor, texture, or color. So what preservation methods are actually suitable for this product? Luckily, innovative freezing technologies are coming up with new solutions that help preserve the fruits for longer and make it possible to use it in various forms.

Individual Quick Freezing (IQF) technology, especially the OctoFrost IQF system is having good result when freezing avocado fruits. Avocado is a tricky product and it comes with a few notable challenges:

- Avocado has to have the right ripeness for freezing, it cannot be too overripe as otherwise the quality will get compromised.
- Too much surface water on the avocado will generate corals during freezing.
- Avocado is quite a sticky product.

Generally, a good pre-freezing treatment is needed in order to guarantee a good freezing result. Approximately 65% of an avocado is flesh and a good practice for freezing the fruit would be the following:

1. Cut the avocado in halves. 
2. Scoop out the stone and remove the flesh manually.
3. Put the fruit in a water bath in a hydro cooler.
4. Dice or slice.
5. Spray or use a bath of citric acid or lemon juice.
5. Remove surface water with a dewatering shaker or air knives.
6. Transport the product in the IQF tunnel for freezing.

Avocado is also really sensitive to mechanical impact, but the OctoFrost IQF freezer provides remarkable results due to the adjustable freezing zones and gentle bedplate movements. The OctoFrost freezing tunnel is thus one the very few types of technologies managing to preserve the natural appearance, creamy texture, color and buttery flavor of IQF avocado.

It is really interesting to see that consumers are getting more aware that frozen food can, in many cases, be a better alternative for a healthy and convenient lifestyle compared to the conventional fresh market. The avocado is prized for its high nutrient value and has become an important part of the Western diet, mine included. As many customers find its perishable nature as a great disadvantage, the IQF frozen avocado will definitely become a real hit on the modern food market and we can’t wait to witness that.


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