Avocado conservation: challenges and technologies in the value chain

Introduction

The Hass avocado ( Persea americana ) is a highly perishable climacteric fruit, and its ability to continue ripening after harvest presents one of the main challenges in post-harvest handling. This physiological characteristic, combined with its high metabolic activity, makes it particularly sensitive to storage, transport, and processing conditions.

From a botanical perspective, the avocado is classified as a fruit; however, its culinary versatility allows it to be incorporated into both sweet and savory dishes. In recent decades, its consumption has experienced sustained growth globally, driven by its nutritional profile and its positioning as a “superfood.”

Its high lipid content—primarily monounsaturated fatty acids such as oleic acid—makes it similar to olive oil in terms of cardiovascular health benefits, contributing to the reduction of low-density lipoproteins (LDL). It is also an important source of antioxidants, such as vitamin E, and dietary fiber, further enhancing its value as part of a balanced diet.

Production and international trade

Mexico is the world's leading producer and exporter of Hass avocados, supplying markets in North America, Europe, and Asia. Other significant producers include Chile, Peru, Colombia, Spain, South Africa, Kenya, and New Zealand, demonstrating the growing globalization of this crop.

However, exporting to distant destinations presents significant logistical challenges, particularly in maritime transport, where transit times can extend up to four weeks. During this period, the fruit, even under refrigeration (around 5°C) and in controlled atmosphere systems, continues its metabolic respiration, consuming oxygen and producing carbon dioxide and ethylene.

Ethylene, considered the ripening hormone, accelerates the fruit's internal physiological processes, generating heat and promoting senescence. In this context, inadequate management of critical variables such as temperature, gas concentration, and dry matter content can cause the fruit to reach its optimal consumption point before reaching its final destination, compromising its commercial quality.

Additionally, factors such as fat content —which in producing regions like Michoacán can vary between 12% at the beginning of the season and up to 24% at the end— increase the complexity of post-harvest handling, particularly in long-distance shipments to Asian and European markets.

Preservation of processed avocado

Avocado processing introduces new challenges, as removing the peel and pit exposes the pulp to conditions that promote spoilage. One of the main problems is enzymatic browning, resulting from the action of enzymes such as polyphenol oxidases in the presence of oxygen, which negatively affects the product's appearance.

This phenomenon is controlled through various strategies, including vacuum packaging, the use of materials with a high oxygen barrier—such as polyethylene or polypropylene—and the injection of inert gases, mainly nitrogen, which displace oxygen from the product's environment.

Furthermore, the high lipid content of avocados makes them susceptible to both enzymatic and non-enzymatic oxidation. To mitigate these effects, it is common to add acidulants that reduce the pH of the pulp from values close to 6.0–6.5 to a range of 4.5–5.0. Among the most commonly used agents are lemon juice, citric acid, and ascorbic acid.

Lowering the pH not only contributes to the physicochemical stability of the product, but also acts as an additional barrier against microbial growth, promoting food safety.

Advanced conservation technologies

Over the past two decades, the application of high hydrostatic pressure (HPP) technology has revolutionized the preservation of processed avocados. This method involves subjecting the pre-packaged product to pressures of up to 85,000 psi for short periods, typically around 180 seconds.

This treatment inactivates pathogenic microorganisms and enzymes responsible for spoilage without significantly affecting the product's sensory properties, such as flavor, color, and texture. Unlike conventional heat treatments, HPP better preserves the avocado's fresh characteristics.

However, access to these technologies can be limited for some producers due to their high implementation costs. Therefore, the rigorous application of good manufacturing practices, along with proper control of variables such as hygiene, packaging, and oxygen exposure, remains essential to ensuring product quality.

Shelf life and storage conditions

Storage conditions play a crucial role in the preservation of processed avocados. Under refrigeration, at a temperature range of 2°C to 6°C, the product can achieve a shelf life of up to 70 days, provided optimal processing and packaging conditions are maintained.

Alternatively, freezing at -20°C extends the product's stability to up to 24 months, maintaining its safety and quality for later consumption. However, this method can cause changes in texture after thawing, so its application should be evaluated based on the product's intended use.

Conclusions

The preservation of avocados, both fresh and processed, presents a multidimensional challenge involving physiological, technological, and logistical aspects. The growing global demand for this fruit requires the implementation of comprehensive strategies to maintain its quality and safety throughout the entire value chain.

The development and adoption of technologies such as high hydrostatic pressure, along with the strengthening of appropriate post-harvest handling and processing practices, will be key to ensuring the sector's competitiveness in international markets.

In this context, continuous innovation and rigorous control of critical process variables are consolidated as fundamental pillars to face current and future challenges in avocado conservation.

Eng. Jorge Alberto León Llanderal
Technical Consultant specializing in Food Technology