Effects of the powdered fruit of Rhus coriaria L. addition on quality attributes based on total polyphenols content of smoothie during storage

The effects of sumac (5, 15, and 30 g/L) addition on the quality attributes of fruit and vegetable smoothies were investigated over refrigerated storage. A slight decrease in pH was observed in the samples of the sumac-fortified drink, compared to the control smoothie (without the spice). On the third day of the study, the addition of 5, 15, and 30 g/L of sumac reduced the total number of microorganisms by 1.46, 2.07, and 2.95 log10 CFU/ml, respectively, compared to the control. The supplementation of the smoothie with 30 g/L of sumac increased the content of polyphenolic compounds on the first day of storage by 54%, compared to the control sample. This indicates that natural sumac can be used for enrichment of foodstuffs with healthy food ingredients.