The Botanical Relationship: Duku, Lanzones, and Langsat
Understanding the Lansium Family
Both duku and the fruit known as lanzones belong to the same genus, Lansium, which is in the mahogany family (Meliaceae). The distinction between them is typically made at the varietal level. Lanzones is the name commonly used in the Philippines for the langsat variety, while duku represents a different, though closely related, fruit variety. Some botanists classify them all under Lansium parasiticum or Lansium domesticum, which contributes to the widespread confusion. This close botanical relationship is the reason for the common interchangeability of the names in casual conversation.
A Quick Note on Terminology
Before diving into the specific differences, it's crucial to clarify the terminology. In many regions, the name 'lanzones' is used broadly to describe any fruit from this genus, but in the Philippines, it specifically refers to the variety known as langsat in other parts of Southeast Asia. For clarity, when discussing 'lanzones' in this article, we are referring to the langsat variety unless otherwise specified.
Key Differences in Fruit Appearance and Characteristics
Comparing the Fruit's Skin and Sap
One of the most noticeable differences between the two fruits lies in their rind and the sap it contains. This is often the quickest way to identify the fruit without tasting it.
- Duku: Features a thicker, somewhat rougher skin that is yellowish-brown and often shows blemishes as it matures. Crucially, its skin does not exude the milky, sticky latex that the langsat variety is known for. This makes duku significantly easier and cleaner to peel.
- Lanzones (Langsat): Has a thinner, smoother skin that is pale yellow. When picked or peeled, the skin releases a sticky, white latex that can be difficult to wash off hands and fingers. The skin also tends to brown or blacken more quickly after harvesting.
Variations in Flavor and Texture
The taste and texture of the translucent flesh are key differentiators for the connoisseur.
- Duku: Tends to be sweeter and more aromatic, with a milder, less acidic flavor profile. The flesh is also generally thicker and less watery than lanzones, offering a satisfying bite.
- Lanzones (Langsat): Offers a more balanced sweet-tart taste that can sometimes be quite acidic, which many find refreshing. The flesh is often more juicy and watery than duku.
Seed Differences
The seeds within the fruit also provide a tell-tale sign of the variety.
- Duku: Typically has smaller, less developed, and less bitter seeds. Many duku fruits are virtually seedless or contain only a small, soft, and edible seed.
- Lanzones (Langsat): Often contains one or more seeds that are larger and notoriously bitter. Accidental biting into a seed can release a strong, unpleasant bitterness that affects the overall eating experience.
Differences in Tree and Cluster Growth
The parent trees themselves exhibit distinguishing characteristics that help identify the variety before the fruit is even harvested.
- Duku Tree: Grows with a dense, spreading, and dome-shaped canopy. It bears shorter fruit bunches with fewer, typically larger and round-shaped fruits.
- Lanzones (Langsat) Tree: Features a more slender, upright growth habit with a sparser, less dense crown. The fruit clusters are longer and hold more ovoid-shaped fruits.
Duku vs. Lanzones (Langsat) Comparison Table
| Feature | Duku | Lanzones (Langsat) |
|---|---|---|
| Appearance | Larger, rounder fruit with a thicker skin | Smaller, more ovoid fruit with a thinner skin |
| Skin & Sap | Thicker, rougher, and latex-free | Thinner, smoother skin that contains sticky latex |
| Ease of Peeling | Easy to peel and clean | Can be messy due to the sticky sap |
| Taste | Generally sweeter, more aromatic, and less acidic | Sweet and tart, often with a more pronounced acidity |
| Seeds | Smaller, less bitter seeds; often seedless | Larger, distinctly bitter seeds |
| Fruit Cluster | Shorter bunches with fewer fruits | Longer bunches with more fruits |
The Intermediate Varieties: Acknowledging Complexity
It's important to acknowledge that the distinction isn't always clear-cut. There are also intermediate varieties, sometimes called duku-langsat, that share characteristics from both types. The popular longkong variety from Thailand is a good example, known for being sweeter and often nearly seedless. Local growers and fruit sellers in Southeast Asia are often adept at differentiating these subtle variations based on their regional experience. For most casual consumers, the primary distinction can be made by the sap: a sticky rind means you're likely holding a lanzones (langsat), while a clean rind points towards duku.
Conclusion
In summary, while the names are often used interchangeably, the differences between duku and lanzones (langsat) are clear and significant. From the flavor profile and presence of sticky sap to the characteristics of the seeds and tree structure, these variations offer a distinct experience for fruit lovers. The sweeter, cleaner-peeling duku is often preferred, but the refreshing, tart taste of a sticky-sap lanzones is equally cherished in its native regions. The existence of hybrid varieties adds another layer of complexity, highlighting the rich diversity within the Lansium species. For a deeper scientific analysis of the fruit's properties, researchers and enthusiasts can explore detailed phytochemistry studies found on authoritative resources.
For further reading, the National Institutes of Health provides a comprehensive review of the fruit's properties: Lansium domesticum—A Fruit with Multi-Benefits: Traditional Uses, Phytochemicals, Nutritional Value, and Bioactivities.
