JP7568303B2 - How to harvest avocados without turning black - Google Patents

Description

The present invention relates to a method for harvesting avocados that does not cause the flesh to turn black.

The present invention relates to a method of harvesting avocados that does not turn black in flesh, in which avocados are harvested from avocado trees primarily in the producing area (central and western Mexico), transported to a processing plant, heated and ripened at the processing plant, packed, transported to a consumer area, and provided to consumers. More specifically, the present invention relates to a method of harvesting avocados that does not turn black in flesh, which reduces the incidence of defective products in which the flesh of the harvested avocados turns black and rots during transportation or storage, while at the same time maintaining the good taste of the harvested avocados.

Avocados are grown by grafting avocado seedlings onto a base tree, improving the soil with organic fertilizer made from natural compost, and planting them in farmland with irrigation systems that collect spring water. Avocados can be harvested more than five years after planting, making them a long-lasting product.

The average lifespan of an avocado tree is about 40 to 50 years, and the same tree blooms four times a year (approximately every three months in January, April, July, and October, although there may be some variation depending on the altitude of the cultivation area, etc.), and after flowering, the fruit (avocado) is produced at the flowering part, and about 8 to 10 months after flowering, part of the avocado's skin turns black. The average annual temperature in the mid-western part of Mexico, where avocados originate, is about 24 to 29°C, with a temperature difference between day and night of 10 to 15°C, allowing avocados to be harvested all year round.

JP2002-330625

As mentioned above, due to differences in the flowering periods of avocado trees, even on the same tree, ripe and unripe avocados will be mixed on the tree before harvesting. When harvesting, the appearance of each avocado must be carefully observed to accurately determine the internal ripeness of the avocado, and those with some of the skin that has turned black must be selected for harvest.

When harvesting avocados, it was common to use scissors to remove them so that part of the tip of the stem remained on the avocado.
In other words, the avocados that are harvested have a short stem of about 2 to 7 mm attached (to be precise, this means the calyx + stem part; hereafter this part will be referred to as the "stem").
In the past, many sources have reported that avocados with the stem attached were fresh, and consumers have preferred such avocados.

When the above-mentioned stem-attached avocados were packaged, transported, and stored, a certain percentage of the avocados (approximately 4-10%) experienced accidents in which the flesh of the ripe avocados turned pale yellow and the vascular bundles near the stem turned black and rotted, resulting in the avocados being defective.
The occurrence of these defective products was discovered when the avocado was cut with a knife or a kitchen knife just before eating. Prior to this, no signs of changes could be observed in the appearance of the skin or other parts, making it difficult to confirm the occurrence of defective products by visual inspection from the outside.

The cause of these defective products was that outside air had entered the flesh of the avocado through the stem, causing oxidation due to the oxygen contained in the air.
The black discoloration caused by oxidation of avocado flesh posed a major problem for avocado distributors and retailers, as it resulted in them selling blemished avocados to customers against their will, damaging the credibility of everyone involved in the trade.

The present invention aims to provide a method of harvesting avocados that does not cause the flesh to turn black, which solves all of the above problems and prevents the flesh of the avocado from turning black due to oxidation, thereby preventing a loss of credibility for those involved in the distribution of avocados and reducing the incidence of defective avocados.

To achieve the above object, the invention of claim 1 is a method for harvesting avocados, characterized in that when harvesting avocados, the avocados are detached from the tree so that no stems remain on the avocados.

The invention of claim 2 is a method for harvesting avocados that prevents the flesh from turning black, characterized by removing the stem that remains near the calyx of the avocado after the avocado has been removed from the tree and before packaging.

According to the avocado harvesting method of the invention according to claims 1 and 2, which prevents the flesh of the harvested avocado from turning black, the flesh of the harvested avocado is less likely to oxidize and develop black, rotten areas, which has the excellent effect of improving the quality retention of the product. By harvesting avocados with such excellent quality retention, the defective rate of the harvested avocados is reduced, which has the effect of facilitating the distribution of avocados.

Below, an embodiment of the avocado harvesting method according to the present invention that does not cause the flesh to turn black is described, but the present invention is not limited to these embodiments.

In the conventional avocado harvesting method described above, which prevents the flesh from turning black, the avocados are packaged with the stem still attached, and as time passes after packaging, there are cases where the vascular bundles in the flesh near the stem of the avocado oxidize and rot, turning black.

For the sample survey, 10,000 avocados were collected from avocado trees in Mexico and divided into two groups: 5,000 avocados with stems and the remaining 5,000 avocados without stems. Both groups of avocados were packaged in the same way using the same packaging method, and both groups of avocados were placed in refrigerated containers under the same conditions and shipped to Japan by sea over a period of approximately 17 days.
The avocados from both groups were collected from refrigerated containers that arrived in Japan and cut so that the contents could be checked eight days after customs clearance, and the incidence (waste rate) of those that had turned black due to spoilage (defective products) was investigated (the investigation was conducted separately for each of the multiple customs clearance dates during the period from January 22, 2020 to August 12, 2020).

The data on the incidence rate of defective products in this sample survey was as follows:
(Customs clearance date) 〇 Avocados with stems 〇 Avocados without stems 1/22 5.7% 1.1%
1/29 6.6% 1.2%
2/5 8.0% 1.4%
2/13 4.9% 0.9%
2/20 6.4% 1.1%
2/27 8.1% 1.0%
3/4 9.0% 1.8%
3/11 5.2% 0.9%
3/18 5.1% 0.9%
3/25 6.3% 1.1%
4/1 5.8% 0.8%
4/8 6.9% 1.1%
4/27 22.3% 3.3%
5/8 15.0% 1.8%
5/13 4.8% 0.7%
5/21 6.5% 1.0%
5/28 4.7% 0.8%
6/3 4.6% 0.8%
6/10 4.9% 0.7%
6/18 4.7% 0.7%
6/24 4.6% 0.8%
7/1 4.8% 0.7%
7/8 5.1% 0.8%
7/16 4.7% 0.7%
7/22 4.5% 0.7%
7/30 9.0% 1.3%
8/12 7.1% 1.1%

From the above data, it was found that the number of defective avocados without stems was about one-fourth to one-fifth lower than that of avocados with stems.
The reason why the rate of defective products is significantly reduced in the present invention is as follows.
The most common damage to avocados is the oxidation of the vascular bundles within the flesh, causing the flesh to turn black and rotten.
Avocados are fruits that require further ripening; as they ripen, the water content in the flesh decreases and the stem also sinks toward the flesh as it ripens. As the stem sinks, a gap appears between the stem and the flesh, and oxygen enters this gap, causing the vascular bundles in the flesh to oxidize and turn black, rotting.

In the harvesting method of the present invention, the stem is removed before the avocados are packaged, so that the gap between the stem and the flesh dries naturally in a short time, and as a result, the gap is also closed in a short time.
If an avocado has a stem attached, for a long time after it is harvested, the growing avocado will require nutrients, but because the stem has been cut off from the tree, these nutrients cannot be delivered to the avocado, resulting in the flesh of the avocado aging and rotting and discoloring. On the other hand, if the avocado does not have a stem, the avocado's growth process will stop in a short period of time, and the requirement for nutrients will also stop sooner, so the avocado will stop aging, rotting, and discoloring.

The stem of an avocado can be removed either by cutting it off when the avocado is removed from the tree, or by first removing the avocado with the stem attached from the tree and then removing the stem from the avocado before packaging.

By stopping the avocado's growth early, the flesh of the avocado will last longer, allowing you to keep the avocado ripe for longer.

The method for harvesting avocados of the present invention, which does not cause the flesh to turn black, can be used at the site where avocados are harvested.

Claims (2)

A method for harvesting avocados, characterized in that the avocados are harvested by detaching them from the tree so that no stems remain on the avocado. This method for harvesting avocados, which does not cause the flesh to turn black, is characterized in that after the avocados are removed from the tree, the stems remaining near the calyx of the avocados are cut off before packaging.