Acid and heat-stable sweet proteins for beverage applications

Overview

This research program focuses on developing acid- and heat-stable sweet proteins suitable for beverage applications. Sweet proteins such as monellin, brazzein, and thaumatin offer intense natural sweetness but are typically limited by poor stability under acidic conditions and elevated temperatures, restricting their use in many beverage formulations. By applying molecular simulations, structure-based molecular design, and protein engineering, this work aims to create engineered sweet protein variants that retain or enhance sweetness while withstanding the challenging environments found in beverage products.

The value proposition centers on enabling beverage manufacturers to use natural, high-potency sweet proteins as alternatives to conventional sweeteners, potentially reducing sugar content while maintaining desirable taste profiles. The approach is grounded in existing proof-of-concept results, including successfully produced monellin and brazzein mutants with significantly improved thermostability.

Technical specifications

Research approach:

• Molecular dynamics (MD) simulations to study thermo- and acid stability of monellin, brazzein, thaumatin, and other candidate sweet proteins including mabinlin and miraculin
• Structure-based molecular design and modification to engineer improved variants
• Analysis of intramolecular interactions including salt bridges, hydrogen bonds, hydrophobic contacts, and van der Waals forces
• Investigation of interaction mechanisms with sweet taste receptors
• Site-directed mutagenesis guided by computational predictions
• Recombinant expression in GRAS (generally recognized as safe) systems
• Validation through protein quantitation, sensory evaluation, circular dichroism spectroscopy, and cell-based sweet taste assays

Target outcomes:

• Sweet protein variants with enhanced acid and heat stability
• Maintained or increased sweetness relative to parent proteins
• Suitable solubility and functionality in acidic beverage matrices at high temperatures

Technology readiness level

The research is currently at an early-to-mid stage of development. Prior work has demonstrated the feasibility of the approach, with monellin and brazzein mutants already produced showing significantly improved thermostability while maintaining or increasing sweetness. pH-stabilized monellin mutants have also been reported by other research groups. Future validation efforts include systematic MD simulations, iterative mutant design and testing in acidic beverage conditions, and structure-activity relationship analysis to refine and optimize candidate proteins. The collaboration involves three laboratories across Northeastern University, Qilu University of Technology, and Chapman University, bringing complementary expertise in computational biology, protein engineering, and sensory science.