Nutritional Composition of Different Varieties of Apple Purees Sweetened with Green and White Stevia Powder

The aim of this study was to analyze the chemical composition of apple purees of four different apple varieties: ‘Golden Delicious’, ‘Idared’, ‘Jonagold’ and ‘Cripps Pink’, in the fresh state (FP) and after thermal treatment by process of pasteurization with added green (PG) or white stevia powder (PW) derived from the leaves of the stevia plant. Also, to determine whether there is a significant influence of sweetening with stevia on the change of analyzed nutritional parameters of apple purees based on the results. Significant increase of dry matter content in PG and PW samples of apple purees was determined for approximately 10%, and also for total soluble solid content for 1%. High increase of natural invert content, for approximately five times higher, and some lower increase of total invert content of analyzed purees was determined in PG and PW samples in comparison with the FP samples. Total acid content and pH value did not show any significant change during the process of pasteurization and sweetening with stevia. The pasteurization significantly influenced the slight vitamin C reduction as well as the high reduction of total phenols in PG and PW samples. Based on the obtained results it can be concluded that the thermal processing by pasteurization significantly affects the degradation of high antioxidant activity compounds. Adding a green and white stevia powder significantly influenced the alterations of some nutritional components analyzed in apple purees: the dry matter content, soluble solids, and natural invert content (sugar glucose). It is important to emphasize, that the main effect of green and white stevia powder was the increase of natural invert content i.e. content of glucose and fructose, thereby increasing the sweetness of product, without increasing the content of “harmful” sugars e.g. sucrose.