Black pepper (Piper nigrum) is one of the world’s most economically valuable spices. Its oleoresin contains piperine, flavonoids, monoterpenes, and sesquiterpenes known for antioxidant, anti-inflammatory, and antimicrobial activities. However, oleoresin is viscous and semi-liquid, making it difficult to handle, store, and incorporate into food products. Converting oleoresin into powder form improves stability, extends shelf life, and simplifies industrial applications.
Conventional encapsulation methods such as spray drying often use high temperatures that may degrade volatile and heat-sensitive compounds. Vacuum foam drying provides an alternative approach. The process operates under reduced pressure at relatively low temperatures (50–70°C) while mechanically generating stable foam structures. The increased surface area of the foam accelerates moisture removal without exposing bioactive compounds to excessive heat.
Five Key Processing Variables
The research team evaluated five processing variables using a fractional factorial experimental design to efficiently screen significant factors:
- Oleoresin-to-xanthan gum ratio (1:50 to 1:10)
- Tween 80 concentration (0.5–2.0%)
- Drying temperature (50–70°C)
- Mixing temperature (25–50°C)
- Drying time (3–6 hours)
Twelve experimental runs were analyzed to assess their impact on four main quality parameters: powder yield, moisture content, total piperine content, and particle size.
Wide Variation in Results
The experiments revealed substantial differences depending on process conditions:
- Powder yield: 80.13%–97.69%
- Moisture content: 7.22%–11.76%
- Total piperine: 0.49%–14.79%
- Particle diameter: 795–943 micrometers
Statistical analysis confirmed that Tween 80 concentration was the most consistent and influential factor affecting product quality.
At a concentration of 2.0%, Tween 80 significantly:
- Reduced moisture content
- Decreased particle size
- Improved piperine retention
As a non-ionic surfactant, Tween 80 lowers interfacial tension, forming smaller and more stable foam bubbles. This structure enhances moisture evaporation and creates protective layers around oleoresin droplets during drying, limiting bioactive degradation.
“The dominant influence of Tween 80 demonstrates that foam stability and emulsion protection are essential for maintaining bioactive compounds,” wrote Abdi Redha and colleagues from State Polytechnic of Pontianak.
Trade-Off Between Yield and Bioactive Content
The study also revealed a clear trade-off between powder yield and piperine concentration.
- A 1:50 oleoresin-to-xanthan gum ratio produced the highest yield (up to 97.69%) but lower piperine levels.
- A 1:10 ratio resulted in significantly higher piperine content but reduced yield.
This finding suggests that manufacturers must choose between maximizing mass recovery or maximizing bioactive concentration, depending on product goals. For high-value nutraceutical applications, higher piperine loading may outweigh yield considerations.
Additionally, the interaction between mixing temperature and drying time significantly influenced piperine stability. Optimal temperature time combinations helped preserve piperine levels up to 14.79%, the highest observed in the study.
Implications for Food and Nutraceutical Industries
The findings position vacuum foam drying as a promising low-temperature alternative for processing heat-sensitive plant extracts. Compared to conventional high-temperature drying methods, this technique:
- Better protects bioactive compounds
- Produces relatively uniform particle sizes
- Supports the development of premium nutraceutical powders
For Indonesia, a major black pepper producer, the technology could enhance the value of local agricultural commodities. High-quality oleoresin powder may serve markets in dietary supplements, functional foods, and pharmaceutical formulations.
The researchers recommend using Tween 80 at 2.0% concentration and further optimizing temperature–time conditions through Response Surface Methodology. Future studies should also evaluate long-term storage stability to ensure consistent product performance.
Author Profiles
Saniah – Researcher in food technology, State Polytechnic of Pontianak.
Y. Erning Indrastuti – Academic and researcher specializing in food processing technologies, State Polytechnic of Pontianak.
Abdi Redha, S.TP., M.Si. – Lecturer and researcher in food chemistry and bioactive compounds at the State Polytechnic of Pontianak. His research focuses on flavonoids, antioxidants, and tropical spice-based product development.
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