Novel glycoside protein sweeteners from natural sweetener conjugates for low-calorie food applications

Overview

This research presents a novel class of glycoside protein sweeteners designed as sugar substitutes for the development of low-calorie and health-conscious food products. The innovation centers on creating new sweetener compounds by directly conjugating well-known natural sweeteners, including stevioside, rebaudioside A, and mogrosides, with amino acids, the amine group of thaumatin protein, or through a succinic acid linker. These novel sweeteners offer a promising solution for the food and beverage industry, particularly for products targeting obese and diabetic consumers who require non-caloric sweetening alternatives.

Technical specifications

Synthesis approach:

• Glycosides are hydrolyzed to obtain the corresponding acid, which is then condensed with the ethyl ester of glycine or the methyl ester of L-alanine
• Coupling is achieved using EDC·HCl and the potassium salt of Oxyma (K-Oxyma) as the coupling reagent
• K-Oxyma, introduced by the research group, replaces the traditional N-hydroxylamine group with a potassium salt formulation, providing excellent solubility in water and a wide range of organic solvents
• Conjugation can also be performed through a succinic acid linker or directly with the amine group of thaumatin protein

Characterization methods:

• Spectroscopic analysis using IR, 1H NMR, 13C NMR, and elemental analysis for structural confirmation
• HPLC analysis to verify product purity

Key product properties:

• Sweetness intensity approximately 67-110 times greater than sucrose
• Clean sweetness taste with absence of bitterness compared to unmodified stevioside
• High water solubility
• Stability in acidic, neutral, and basic aqueous solutions maintained at 100°C for 2 hours
• Non-toxic up to 150 mg/kg in tested models
• Examples include glycinostevia (ST-GL) and alaninostevia methyl ester (ST-GL)

Technology readiness level

The technology has progressed beyond initial synthesis and characterization. Two stevia amino acid sweeteners, glycinostevia (ST-GL) and alaninostevia methyl ester (ST-GL), have already been successfully synthesized from natural stevioside and validated for key properties including solubility, thermal stability, sweetness intensity, sensory profile, and toxicity. The compounds have demonstrated non-toxicity up to 150 mg/kg and confirmed stability under harsh thermal and pH conditions. The technology is positioned for further development toward food application testing and eventual commercialization as a non-caloric sweetener ingredient for low-calorie and diabetic-friendly food products.