Synthesis and characteristics of a rebaudioside-A like compound as a potential non-caloric natural sweetener by Leuconostoc kimchii dextransucrase

Stevioside (ST) is currently considered as a highly-demanded natural and zero-caloric replacer of sucrose with several health-promoting properties. Nonetheless, its bitter aftertaste limits its use in the food industry. Herein, glucosyl steviosides were synthesized using primarily a food-grade lactic acid bacteria, Leuconostoc kimchii dextransucrase and conversion yield (%) was 40.3%. A glucose moiety was transferred stereo-selectively to ST by α-1,6-linkage and this is the first report about obtaining rebaudioside A (Reb-A) like glucosyl stevioside-2 (STG-2). Glucosyl steviosides revealed greatly improved stability up to 120 °C and remained stable over 32.1% and 58.12% in the pH (1.4) compared with 30.55% of ST. Moreover, the glucosylated steviosides improved the stability, reaching 95% after 30 days and Reb-A like compound (STG-2) especially exhibited higher stability in commercial beverages. Furthermore, the glucosyl steviosides showed over 1.92- and 2.24-fold decreases than that of enzymatically modified ST in the glucose generation rate test.