Here’s a comprehensive overview of factors affecting essential oil yield and composition, specifically for hydrodistillation and REHD processes:
1. Plant-Related Factors
a. Species and Variety
- Different species produce different oil types, concentrations, and chemical profiles.
- Example: Agarwood vs. Sandalwood vs. Ylang-Ylang.
b. Plant Part
- Oils are concentrated in leaves, flowers, bark, seeds, or wood.
- Example: Citrus peel (high in limonene) vs. flower petals (high in esters).
c. Plant Age and Maturity
- Young vs. mature plants have different secondary metabolite profiles.
- For Agarwood, resin formation increases with tree maturity.
d. Harvesting Time
- Time of day / season affects essential oil content and composition.
- Example: Lavender harvested in the morning may have higher linalool content.
2. Pre-Processing Factors
a. Moisture Content
- Proper drying or fresh material usage affects extraction efficiency.
- Too wet → water dilution; too dry → loss of volatiles.
b. Particle Size / Comminution
- Smaller particles increase surface area → better oil release.
- Over-grinding can cause thermal degradation during distillation.
c. Storage Conditions
- Oxidation or microbial growth can degrade oil quality.
- Store plant material in cool, dark, dry conditions.
3. Distillation/Extraction Factors
a. Distillation Method
- Traditional HD, REHD, steam, or supercritical CO₂ extraction affects yield and chemical profile.
b. Temperature
- High temperatures → faster extraction but may degrade heat-sensitive compounds.
- REHD reduces temperature, preserving delicate aromatics.
c. Pressure
- Reduced pressure → lower boiling point → gentle extraction of thermolabile components.
d. Duration of Distillation
- Longer extraction → more oil yield but may include undesirable components.
- Fractional collection can separate early- and late-eluting compounds.
e. Steam Flow Rate / Water-to-Plant Ratio
- Affects mass transfer efficiency of volatiles into vapor phase.
4. Environmental Factors
- Soil type, nutrients, and irrigation influence plant metabolite production.
- Climate / temperature / sunlight exposure affects biosynthesis of essential oils.
- Stress factors (drought, pests, inoculation in Agarwood) can enhance secondary metabolites.
5. Microbial and Biotic Factors (for Agarwood and Induced Resins)
- Fungal inoculation or pathogen-induced stress can trigger resin formation, altering oil yield and chemical profile.
- Examples: Fusarium oxysporum or dual-action inoculants (BarIno™ blends).
6. Summary Table
| Factor Category | Examples | Effect on Yield / Composition |
|---|---|---|
| Plant Species & Variety | Agarwood vs Sandalwood | Determines oil type & chemical profile |
| Plant Part | Leaves, flowers, bark | Different concentration & compound profile |
| Maturity & Harvest Time | Age, season, time of day | Alters secondary metabolite content |
| Pre-Processing | Moisture, particle size | Influences extraction efficiency & oil quality |
| Extraction Conditions | Temp, pressure, duration, steam flow | Affects yield, volatile retention, chemical profile |
| Environmental | Soil, nutrients, climate | Modulates biosynthesis of key compounds |
| Microbial / Biotic | Fungal inoculation, stress | Induces resin or secondary metabolites |
Visual / Infographic Concept
- Title: “Factors Affecting Essential Oil Yield & Composition”
- Structure:
- Plant Factors (species, part, age)
- Pre-Processing (moisture, size)
- Extraction (temperature, pressure, duration)
- Environmental & Biotic (soil, climate, inoculation)
- Use icons for plant, sun, water, steam, flask, microbes.
- Optional: Color-coded arrows showing positive/negative impact on yield and quality.
I can create a professional infographic summarizing all these factors for your training course or lab manual, showing how each category influences essential oil yield and composition.
Do you want me to make that next?