Comprehensive insights into steviol glycosides as zero-glycemic sweeteners

The plant-based steviol glycosides, comprising more than 60 compounds, serve as natural sweeteners that offer safe and health conscious alternatives to sugar in beverages, baked good, and ice cream. Stevia plants, particularly Stevia rebaudiana, produce a diverse set of steviol glycosides concentrated in the young fully expanded leaves peaked before flowering. Within the spectrum of steviol glycosides, significant sweetness is found in Stevioside, Rebaudioside A, Rebaudioside D, and Rebaudioside M. However, Stevioside and, to some extent, Rebaudioside A may exhibit a mild bitterness aftertaste. The biosynthesis involves intricate pathways and numerous genes, with UGT76G1 playing a crucial role. However, the complete understanding of downstream biosynthesis, particularly for Rebaudioside D and Rebaudioside M, remains a challenge. Indeed, steviol glycosides concentration and composition are inherently complex traits. In addition to these complexities, plant breeders must also consider other factors such as leaf area and yield in their studies and breeding efforts. Various breeding methods, including synthetic cultivars, transgressive segregation, polyploidy, mutagenesis, and genetic engineering are explored for efficacy. Additionally, research into microRNA and enzyme production studies, as well as understanding the interrelationship among steviol glycosides and morphological traits in stevia, holds promise for advancing SGs production.