formulation of salix aegyptica hydrolat based carbonated drink and evaluation of its physicochemical and microbial changes during storage

in this study salix aegyptica hydrolat based carbonated drinks were formulated. differents ratio of salix aegyptica hydrolat (egyption willow water) mixed with carbonated water, citric acid and sugar to adjust the final drink to 10-12 brix and desirable acidity. sensory properties of the products were evaluated at a ranking test by a trained panelists for choosing the best formulation. evaluation of the product shelf life, samples were stored at different conditions during 6 months and their physicochemical and microbial properties were determined bimonthly. the product factors were evaluated in this study included: acidity, ph, total soluble solids (tss), turbidity, fungal growth and total count of aerobic and mesophilic microorganisms .the results showed that ph, acidity and tss had no considerable change, but turbidity increased during storage. turbidity of samples that stored in presence of light and ambient temperature were increased considerably. microbiological evaluations showed that total count of aerobic and mesophilic microorganisms was higher in samples that stored at ambient temperature and transparent bottles.on the basis of the results obtained from sensory evaluations at the end of storage time, it was indicated that all different stored trails were as good as the fresh sample.