Stability of Stevioside and Glucosyl-Stevioside under Acidic Conditions and its Degradation Products

The stability of stevioside and mono- and di-glucosyl-stevioside(produced via Leuconostoccitreum SK24.002 alternansucrase acceptor reaction), and the possible formation of the steviol at elevated temperature and different pH levels was assessed, covering a typical pH range that simulated both relevant and extreme beverage storage conditions. Acid solutions mixed with stevioside or mono- and di-glucosyl- stevioside after 24, 48, and 72 h of storage time at 50 and 80C were analysed. Under mild conditions (at a pH range of 2–6.5 over 72 h and 50C) stevioside and mono- and di-glucosyl-stevioside showed good stability. Degradation of up to 55% was observed at pH 3 and 80C after 72 h, and stevioside was less stable than mono-glucosyl-stevioside. Complete degradation was observed at pH 2 and 80C after 72 h. Stevioside and mono- and di-glucosyl-stevioside and their degradation products were analysed by high-performance liquid chromatography with a diode array detector (DAD-HPLC) on an NH2 analytical column, and the identity of the degradation products was confirmed by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) in negative mode. Practical Application: Utilizing transglucosylated stevioside products as natural sweeteners or sweetness enhancers, impose to understand physicochemical profiles of transglucosylated stevioside products in various systems of interest, here we studied the stability of a steviosid and transglucosylated stevioside products at elevated temperature and different pH levels covering a typical pH range that emulated both relevant and extreme beverage storage conditions.