Avocado oil, especially high-quality extra virgin avocado oil, is produced using a process very similar to that of extra virgin olive oil. The core techniques involve low-temperature and physical mechanical pressing to maximize the preservation of its natural flavor, nutrients (such as monounsaturated fatty acids, vitamin E, and chlorophyll), and deep green color.

The main production processes fall into two categories: physical cold pressing and centrifugal/water extraction. Additionally, there is chemical extraction for refining the oil.

I. Main Production Processes and Comparison

1. Physical Cold Pressing

This is the most traditional and highly regarded method for producing extra virgin avocado oil, yielding the highest quality oil.

Processing Steps: 

1. Raw Material Selection and Cleaning: Select moderately ripe, fresh, and unrotten avocados (usually the Hass variety). Thoroughly clean them to remove dirt and impurities.

2. Pitting and Peeling: Mechanically remove the pit and peel, leaving only the pulp. This step is crucial because the pit and peel contribute bitterness and impurities.

3. Pulping/Pulping: Grind the pulp into a smooth, fine pulp. Grinding must be done at a low temperature to prevent oxidation and nutrient loss.

4. Gentle Stirring/Blending: Slowly stir the pulp at a controlled temperature (usually below 45-50°C) for a period of time (several tens of minutes). This process helps oil droplets release from the cell structure and aggregate.

5. Pressing: Physically press the pulp in a hydraulic press or screw press. High pressure separates the oil from solids and water.

6. Solid-Liquid Separation: The pressing produces a mixture containing:

· Oil phase (avocado oil)

· Aqueous phase (juice, water)

· Solid phase (pore, fiber)

7. Centrifugation: Send the mixture to a high-speed centrifuge. Utilizing the difference in specific gravity between oil, water, and solids, centrifugal force completely separates them, yielding pure "crude oil". 8. Filtration: The crude oil is passed through a cardboard filter or other physical filtration device to remove residual fine solid particles, making the oil clear and transparent.

9. Storage and Bottling: The filtered oil is filled into stainless steel tanks protected by inert gases such as nitrogen, and stored in a dark, low-temperature environment to prevent oxidation. Finally, it is bottled, usually in dark glass bottles for light protection.

Features:

Advantages: No chemical reagents used throughout the process; low-temperature processing maximizes the preservation of the avocado's natural aroma, grassy flavor, nutrients, and deep green color. It is a top-grade edible oil.

Disadvantages: Relatively low oil yield (typically 10-15% of the dry weight of the pulp), higher cost.

2. Centrifugal/Water Extraction Method

This is currently the more efficient and commonly used method in commercial production, also used to produce high-quality virgin oil.

Processing Steps: The first three steps (selection, pitting and peeling, pulping) are the same as the cold-pressing method.

1. Three-phase centrifugal separation: This is the core of the process. Avocado pulp is directly fed into a large three-phase horizontal centrifuge. A suitable amount of warm water is added to the centrifuge simultaneously (not to "cook" the pulp, but to aid separation). 

• Under high-speed centrifugation, the three phases are directly separated:

• Lightest oil phase (separated and collected)

• Aqueous phase (wastewater)

• Heaviest solid phase (wet pomace)

2. Subsequent steps: The separated oil phase also needs to undergo filtration, storage, and bottling, following the same steps as the cold-pressing method.

Features:

Advantages: Continuous, efficient, and highly automated process; slightly higher oil yield than pure physical pressing; produces high-quality virgin avocado oil.

Disadvantages: High equipment requirements. Improper water temperature control may affect oil quality.

3. Chemical solvent extraction method

Mainly used for secondary oil extraction from pressed pomace to produce refined avocado oil.

Processing Steps:

1. Raw Material: Dried fruit pomace, still containing approximately 10% oil, remaining after physical extraction.

2. Solvent Extraction: The pomace is soaked in food-grade organic solvents such as hexane to dissolve the remaining oil.

3. Solvent Recovery: The solvent is separated from the oil through distillation, and the recovered solvent is recycled to obtain "crude oil."

4. Refining: This crude oil contains impurities, pigments, and solvent residues, and must undergo a series of refining steps: Degumming, deacidification, decolorization, deodorization, and winterization (removing wax esters that solidify at low temperatures).

5. Finished Product: Refined avocado oil is obtained.

Characteristics:

Advantages: Highest oil yield, lowest cost, stable oil properties (colorless and odorless, high smoke point, approximately 270°C).

Disadvantages: The production process involves chemical solvents, and the refining process destroys most of the natural nutrients, flavor compounds, and pigments. The final product is a clear, pale yellow, almost odorless edible oil.

II. Processing Trends and Quality Control

Trend: The market increasingly favors high-quality virgin oil produced using physical methods. Many brands emphasize their "cold-pressed," "unrefined," and "organic" attributes.

Key Quality Control Points:

Raw Material Freshness: The shorter the time from harvesting to processing, the better.

Low Temperature Throughout:Controlling the temperature during grinding, mixing, and pressing.

Oxygen Protection:Nitrogen purging during separation, storage, and bottling.

Light Protection:Using dark containers and light-proof warehouses.

In short, the choice of production process for avocado oil directly determines the quality, flavor, and uses of the final product. Consumers can choose between aromatic virgin oil and heat-resistant refined oil based on their culinary needs and nutritional requirements.