Resin Content Analysis

Resin Content Analysis is a critical procedure in evaluating the quality and commercial value of agarwood (Aquilaria spp.), especially for determining how much valuable aromatic resin is present in the wood. This directly impacts decisions in harvesting, processing, grading, and pricing.

What is Resin Content in Agarwood?

Resin is the dark, aromatic substance formed in response to natural infection or artificial induction in Aquilaria trees. The higher the resin content, the more valuable the wood or oil.

Objectives of Resin Content Analysis

• Quantify yield potential before oil extraction.
• Grade agarwood chips for export.
• Assess induction success (e.g., Fusarium, chemical, or physical).
• Ensure quality consistency across plantation batches.

Common Methods of Resin Content Analysis

1. Gravimetric Resin Extraction (Solvent-Based)

This is the most widely used and reliable method.

Procedure:

1. Dry and powder the agarwood sample.
2. Soak in organic solvents (e.g., ethanol, hexane, or methanol) for 24–48 hours.
3. Filter and evaporate the solvent to obtain the resin extract.
4. Weigh the residue to calculate resin content.

Formula:

Resin Content (%) = (Weight of resin / Dry weight of sample) × 100

✅ Pros:

• Accurate and reproducible
• Correlates closely with oil yield

❌ Cons:

• Time-consuming
• Requires solvents and evaporation setup

2. Solubility Index (Alcohol Solubility Test)

How it works:

• Resinous wood chips are soaked in ethanol or methanol.
• Observation: The more resin, the more sediment and color intensity in the extract.

✅ Pros:

• Quick field method
• Useful for comparative analysis

❌ Cons:

• Semi-quantitative
• Not suitable for exact resin measurement

3. UV-Vis Spectrophotometry

How it works:

• After solvent extraction, the resin is dissolved and analyzed at specific wavelengths (e.g., 280–320 nm).
• Intensity correlates with resin concentration.

✅ Pros:

• Quick, small sample size
• Good for resin fingerprinting

❌ Cons:

• Requires spectrophotometer
• Needs calibration with known standards

4. Near-Infrared (NIR) Spectroscopy (Advanced)

• Non-destructive technique for detecting resin distribution in agarwood.
• Works well for scanning large volumes or logs.

✅ Pros:

• Fast and accurate
• Portable NIR devices now available

❌ Cons:

• High initial cost
• Requires calibration for species and region

5. Microscopic and Histological Analysis

• Thin wood slices are stained and examined under a microscope.
• Resin canals and deposits can be visually quantified.

✅ Pros:

• Visual confirmation of resin structure
• Useful in research settings

❌ Cons:

• Not ideal for commercial grading

Suggested Equipment List for Resin Testing Lab

Practical Applications

• Chip Grading: Premium grades have >10% resin content.
• Induction Success: Used to compare the efficacy of inoculation methods (chemical, fungal, mechanical).
• Oil Yield Prediction: Correlates with distillation efficiency.
• Investor Reporting: Backed by lab-certified data.

Interpretation of Results (Indicative)