STABILITY OF REBAUDIOSIDE M UNDER ACIDIC CONDITIONS AND ITS DEGRADATION PRODUCTS

Current study aims to evaluate stability of Rebaudioside M, a sweet component of Stevia rebaudiana, using a typical pH (2.8, 3.2, 3.8 and 4.2) and temperature (5 °C, 20 °C, 30°C, 40 °C) for 26 weeks, range that simulated both relevant and extreme beverage storage conditions. Photostability of mock beverages at pH 3.8 was determined at 25 °C /60% relative humidity (RH) with fluorescent light exposure. Rebaudioside M (Reb M) was evaluated in mock beverage solutions by simulating formulations used in commercial soft drinks and were subjected to various temperature conditions (5 °C, 20 °C, 30 °C, 40 °C) for 26-weeks at each pH. Samples were analyzed at scheduled intervals throughout the 26 weeks for Reb M, known impurities, known degradation products, and unidentified compounds greater than or equal to 0.100% of the starting concentration of Reb M. There was minimal degradation of the Reb M when exposed to fluorescent light, and appearance did not change throughout the study. Thus, Reb M in mock beverages under relevant conditions of intended use is considered stable. Finally, Reb M sourced from 1) extraction of Stevia leaf, 2) bio-conversion of Reb A and 3) fermentation of glucose were evaluated by a trained panel for taste, aftertaste, and mouth feel qualities. Samples were evaluated at the levels of 100ppm and 300ppm, both at 4°C and at ambient temperature. Sensory evaluation revealed no significant differences in sensory profile by source, suggesting that the samples tasted similarly to each other.