Abstract Stevia rebaudiana (Bert.) Bertoni contains steviol glycosides with emphasis to rebaudioside A, which presents a stronger sweet flavor, more stability, good solubility and lower bitter residual taste, which benefits its application in foods and drinks. The objective of this study was to determine the equivalent amount of rebaudioside A necessary to promote the same degree of sweetness of sucralose in the grape- and peach-flavored soy beverages and evaluate their physicochemical characteristics and consumer acceptance. At the Natural Products Center of the State University of Maringa, the rebaudioside A was purified from the M1 Alvarez variety of Stevia plants. Through sensory analysis established that the ideal quantity of rebaudioside A to substitute sucralose in foods with peach soy and grape soy would be 3 times the quantity of sucralose. The results revealed no signifcant differences for the physicochemical and sensorial characteristics (p < 0.05) between the two formulations. The results also indicate that the rebaudioside A with high purity rate (97%) obtained from selected stevia varieties can substitute sucralose in peach soy foods and grape soy foods.

Abstract The objective of this work was to perform the ethanolic pretreatment of stevia leaves from the plant Stevia UEM-13 line and to characterize its physical-chemical properties aiming its use as a sweetener in the development of a diet cereal bar. The same formulation of the cereal bar with stevia leaves without pretreatment was elaborated for comparative purposes. The following ingredients were used in the preparation of the produtc: fine oat flakes, no sugar granola, cranberry, dehydrated apricots, water, gum acacia and stevia leaf pretreated (F1) and without treatment (F2). According to the results, the diet cereal bars presented significant amounts of crude fiber, protein and antioxidant activity. The product was microbiologically safe for human consumption, reporting lower microbiological valuesthan those foreseen by official regulation. The overall sensory evaluation indicates that the two formulations did not present statistically significant differences regarding the analyzed attributes, being the averages between “liked very much” and “moderately liked”. However, considering the group of cereal bars consumers, the formulation sweetened with pretreated leafs (F1) was found more than twice the acceptance regarding to the formulation sweetened with the leaf in natura (F2). These results demonstrate a viable option of a diet food product naturally sweetened.

ABSTRACT The aim of this study was to determine the composition and antioxidant potential of leaves of a new variety of Stevia rebaudiana (Stevia UEM-13). Stevia leaves of UEM-13 contain rebaudioside A as the main glycoside, while most wild Stevia plants contain stevioside. Furthermore can be multiplied by seed, which reduces the cost of plant culture techniques as other clonal varieties are multiplied by buds, requiring sophisticated and expensive seedling production systems. Ethanol and methanol were used in the extraction to determine the bioactive compounds. The methanolic extract was fractionated sequentially with hexane, chloroform, ethyl acetate and isobutanol, and the highest concentration of phenolic compounds and flavonoids was obtained in the ethyl acetate fraction (524.20 mg galic acid equivalent/g; 380.62 µg quercetin equivalent/g). The glycoside content varied greatly among the fractions (0.5% - 65.3%). Higher antioxidant potential was found in the methanol extract and the ethyl acetate fraction with 93.5% and 97.32%, respectively. In addition to being an excellent source for obtaining of extracts rich in glycoside, this new variety can also be used as raw material for the production of extracts or fractions with a significant amount of antioxidant activity and potential to be used as additives in food.