Postharvest of Chilean Cherries: Observed and Admired by the Global Industry

Postharvest of Chilean Cherries: Observed and Admired by the Global Industry

The primary destination for Chilean cherries is China, which means that the fruit must endure a long journey, in the best possible condition. Considering that cherries are one of the most delicate fruit species after being harvested, it is a remarkable feat that they can withstand a journey of 30 to 40 days to reach their destination.

This aspect has caught the attention of the global cherry industry, even among those who do not face the challenge of shipping the fruit for such a long duration. The postharvest handling of Chilean cherries is observed and admired by many.

Smartcherry spoke with Héctor García, General Manager and Co-founder of Diagnofrut Laboratories, who discussed various aspects of cherry postharvest.

You mentioned that 60% to 70% of postharvest quality is established during preharvest. What do you mean by that?

Sometimes it can be as much as 80%. We need to build the fruit, in this case, cherries, to be of high quality, and that process begins during preharvest. Otherwise, during postharvest, we cannot rectify certain issues that might arise from the orchard, such as nutritional imbalances, high pathogen levels, wounds, and other factors that I can’t improve during packing. In the packing stage, I can only extend the fruit’s shelf life, as the fruit is already harvested and gradually deteriorating. My goal is to maximize its remaining life and freshness. To achieve that, I need to put significant effort into preharvest activities, such as maintaining proper levels of calcium, moderate nitrogen, low pathogen levels, and a successful harvest without causing wounds. Markets demand large calibers, but excessive use of growth regulators should be avoided, as they can weaken the fruit.

Should the preharvest and postharvest teams communicate more actively?

Exactly, the preharvest and postharvest teams should collaborate, communicate openly, and address each other’s limitations. Having worked extensively in exporting, particularly in postharvest, I noticed that fruit quality could be compromised during this stage. So, I started looking at preharvest to identify critical points that were not being adequately addressed.

From all over the world, people are closely interested in Chilean postharvest practices. A cherry that can last 35 to 40 days to reach China, especially in challenging seasons like the past two. Now there’s a new destination on producers’, exporters’, and ASOEX’s radar: India, which would add a couple of extra days.

How do you perceive this scenario considering the postharvest of cherries?

It’s complex and challenging to address, as they’re not accustomed to this kind of fruit coming from such a long distance. The fruit already has a limited shelf life and will have considerably advanced by the time it reaches India. Yet, another process begins there: making it to the end consumer. That requires comprehensive studies that we haven’t conducted yet—studying how to get there, how the fruit arrived at the port, the time taken, and the temperature fluctuations experienced.

New Zealanders, who are advanced in this area, did something similar for their kiwis and realized that addressing such a market was quite complex due to temperature fluctuations; the fruit was exposed to temperatures as high as 40 degrees upon arrival. This could cause significant issues in Chile, potentially necessitating different packaging approaches or even opening bags. It’s something we need to carefully consider; success isn’t guaranteed.

Nonetheless, it must be tackled. We need to enter the market, observe, take the time to mature our ideas, and eventually come up with a product or identify the limitations of such a product. Ultimately, we need to structure how it will be sold. Despite the demand for this product, we must sit down and discuss all critical points to successfully commercialize it.

Regina Under the Microscope

Recently, we’ve observed the browning of Regina cherries during postharvest. You’re working on an interesting project to study the genes and reasons behind this phenomenon. Could you provide more information about that?

Firstly, I’d like to thank everyone involved in the project: the Chilean Cherry Committee, various exporters, Avium, the University of Chile, the University of Las Americas. We collaborated with agrochemical companies that provided funding for the project.

The project aims to decipher the genes involved in this accelerated browning process. We’ve noticed this issue in other varieties as well, even in Bing cherries. The significant challenge is that Regina cherries seem to lose a lot of their organoleptic quality—qualities related to consumption—and that’s where the problem arises. While one might think that all varieties would eventually experience browning, Regina cherries experience this more rapidly, and there’s also a decline in flavor. This quality attribute is lost.

What did we do? We monitored the variety in various regions, anticipating the browning event. At each stage, we extracted RNA, and we’re currently in the process of analyzing it. We applied a technique called RNA-Seq, which examines gene expression at that moment, essentially providing a snapshot of which genes are upregulated or downregulated. This helps us understand the proteins and mechanisms driving the accelerated process or causing different cases. We observed fruit that showed minimal browning and others that had 10% browning at harvest.

While you don’t have definitive results yet, could the orchard’s agronomic management play a role?

This is where the link to agrochemicals comes in. We explored whether any products could slow down the process, but the results weren’t very promising. Nevertheless, there are some ideas. At the same time, understanding which genes are involved in initiating or accelerating the process can provide insights into how to address the issue. This presents a significant technological challenge, but it’s possible to discover the triggering process and potentially block it. Other factors might be related to nutrition; for example, calcium levels could affect the genes responsible for cell walls. If these genes are more active, the fruit is firmer, and as it ripens, their activity decreases, resulting in reduced firmness—this is a common process in all fruits. So, we might need to consider these physiological effects as part of the response. Every piece of information will help: applying more calcium, determining appropriate methods and timing, and so on. It’s like building a puzzle, incorporating various variables that might influence the process.

Undoubtedly, it will be a significant contribution to the industry…

We’ve published several papers and held meetings. We also need to share this information with producers so they can understand how their fruit behaves. We have another major project with FIA (Chilean agricultural innovation fund) that focuses on viruses. So, we’re engaged in various activities related to cherries.

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