Soy protein-inulin complex coacervation for beverage ingredient encapsulation
A low-cost, enzyme-crosslinked microencapsulation technology using soy protein isolate and inulin complex coacervation to protect beverage ingredients (anthocyanins, Vitamin E, caramel color). Tunable for hydrophilic and lipophilic actives with long-term pH and thermal stability.
Overview
This technology uses complex coacervation between soy protein isolate (SPI) and inulin, crosslinked with transglutaminase, to produce microcapsules that protect sensitive beverage ingredients. Complex coacervation is a simple, low-cost liquid-liquid phase separation process between oppositely charged polymers. By adjusting polymer concentrations, the hydrophilic/lipophilic balance can be tuned to encapsulate either water-soluble or oil-soluble actives. The approach targets long-term stability (over three months) for ingredients commonly used in beverages, including anthocyanins, Vitamin E, and caramel color.
Technical specifications
Process workflow:
- Mix SPI solution with the food encapsulant
- Coacervate with inulin at pH below 6.5
- Add transglutaminase enzyme for crosslinking and allow overnight decantation
- Sieve and wash to collect uniform microcapsules
Key features and benefits:
- SPI provides high water solubility, fat absorption, water-holding capacity, and emulsification
- Inulin increases hydrophilicity and prevents oil droplet collision and coalescence
- Enzyme crosslinking delivers high pH and thermal stability
- Tunable polymer ratios allow encapsulation of both hydrophilic/water-soluble and hydrophobic/oil-soluble ingredients
- Controlled release of diverse actives over a broad temperature range
- Simple, low-cost, high-efficiency process suitable for scale-up
Encapsulation performance targets:
- Uniform microcapsule size distribution
- High encapsulation efficiency and loading
- pH and heat stability suitable for beverage and gastrointestinal conditions
- Reproducible controlled release validated in triplicate studies
Technology readiness level
The underlying coacervation and Pickering emulsion expertise has been demonstrated through prior published work, including a modified-inulin system for sustained ibuprofen release in acidic conditions and tunable Pickering emulsions for water-soluble actives and spores. The proposed work focuses on optimizing the SPI-inulin-transglutaminase process specifically for beverage ingredients, generating non-crosslinked reference microcapsules, and validating process yield, morphology, stability, encapsulation efficiency, and controlled release performance. The technology is advancing from laboratory proof-of-concept toward formulation optimization and pilot-relevant validation, with potential pathways to scale-up and commercialization through the university's technology transfer office.
About North Carolina State University
North Carolina State University is a large, comprehensive public land‑grant research university in Raleigh. Its on‑campus research and technology park co‑locates corporate R&D groups, government partners, and faculty labs, enabling shared facilities, prototyping, and agile contracting. Located in North Carolina’s Research Triangle, partners tap a dense regional ecosystem while engaging through a statewide extension network and a mature co‑op program that deliver field deployment and workforce pipelines. Multiple pilot and demonstration facilities support scale‑up and validation toward pre‑commercial readiness. Research is supported by competitive funding from major federal agencies, including NSF, USDA, DOE, and DOD, and a dedicated technology transfer office with clear IP pathways helps accelerate commercialization.
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