Introduction: Today, the problem that the beverage industry faces and is largely unchanged, and may be added to its complexity day by day is to provide a healthy, durable, and acceptable product. One of the main steps in this regard can be replacing the preservatives and chemical additives with their natural varieties. Since Iran is very diverse and rich in vegetation, especially in medicinal plants, due to its special geographical conditions, and on the other hand, since the medicinal plants have the known antimicrobial and antioxidant properties, they can be used as a substitute for the chemical preservatives in the beverage industry. In this regard, the possibility of production of saffron gaseous beverage has been studied in this research.
Materials and methods: Initially, in order to produce the saffron gaseous beverages, the raw materials including saffron extract (Zardband Company), Sugar (Hedieh Company), Orang Serum Agar, Kant Agar Plate, Dichloran Rose-Bengal, Sodium Benzoate, Dipotassium Oxalate, Lead Acetate, Normal Sodium Hydroxide, activated carbon, citric acid, CO2 gas, ethyl alcohol, 70% ethanol and sodium hydroxide as well as materials used in the microbial tests including Lactobacillus agar medium (MRS Agar), Orange-Serum Agar, Dichloran Rose- Bengal (all from Merck, Germany) were prepared. Next, the treatments of research including T1 (65% sugar and 0.6% saffron), T2 (65% sugar and 4% saffron), T3 (65% sugar and 2% saffron), T4 (70% sugar and0.6% saffron), T5 (70% sugar and 4% saffron), T6 (70% sugar and 2% saffron), T7 (75% sugar and 0.6% saffron), T8 (75% Sugar and 4% saffron) and T9 (75% sugar and 2% saffron) were considered. In order to prepare the treatments, the syrup tanks were prepared. Usually, for each 7-unit syrup tank which is equal to 11.659 liters, 1,750 gallons of purified water were poured into the tank. The tank mixer was then turned on and the sugar was added according to the formulation of making the desired beverage to dissolve all the crystals of sugar in the water. Since the consumed sugar had foreign objects, the prepared syrup was not clear and clean, so it was completely transparent and clear by passing the material from special filters. In order to eliminate the pathogenic microorganisms, the syrup was pasteurized. After pasteurization, the syrup was directed to the steel tanks of the extract. The capacity of the extract tank was 10 units (17032.5 liters), 6 units (10219.5) and 4 units (6813 liters). Next, the extract was added at the same time as the syrup was added to the tanks. After mixing the concentrated extract and the syrup, the mixer was turned off and the mixture was placed in the same state for 15 minutes to remove its bubbles. It is recommended that the made extract will be kept in the tank for 24-12 hours in order to achieve better maturity. The prepared extract was directed by a transfer pump to a water and extract mixer (Intermix, Flumix or Perry Mix), to mix the water entered from the refinery with the ratio of 1 to 5 for the products with the brix less than 11 or with the ratio of 1 to 5.5 for the products with the brix below 10 and form the beverage drink. To improve the work efficiency and increase the quality of extract made, the solid materials such as citric acid and sodium benzoate were added to the syrup tanks by the additive tanks to allow the filtration. After the completion of each treatment, the samples were subjected to physicochemical, microbial and sensory tests. In the same regard, in order to analyze the data of research, a factorial experiment in a completely randomized block design was used. The mean comparison was performed by Duncan's multiple range test at the probability level of 1%=α and analyzed by SPSS software, version 16.
Results and discussion: According to the results, by adding sugar and saffron extract, the amount of brix was significantly increased and it seems the sucrose to be the main reason for the increase of brix because there is a direct relationship between the concentration of sucrose and brix. Also, by adding sugar and saffron extract to the beverages produced, the pH and acidity levels decreased and increased, respectively, but they were within the standard range. On the other hand, by adding sugar and saffron extract, the density of samples did not change significantly, but the amount of dry matter increased significantly, among which the increase in the amount of dry matter can be attributed to an increase in the sugar and saffron extract in the beverage. In this regard, the ash content of treatments and total sugar content of the samples were significantly increased due to increasing the amount of saffron extract and increasing the sugar content. According to the results obtained, the amount of mesophilic bacteria increased with the addition of sugars, but it remained within the standard range. Most of the mesophilic bacteria belonged to the sample containing 70% sugar. According to the results of sensory tests, the sweetness of beverage increased by increasing the sugar content, but in the samples in which the amount of saffron increased, the amount of sweetness showed no significant difference with the first sample. Since the saffron had a bitter and astringent taste, increasing the amount of sugar made the taste desired. On the other hand, as the amount of saffron increased, the color of samples was more attractive and their flavor was more favorable. In a general conclusion and based on the results of research, it was determined that it is possible to produce saffron gaseous beverage based on its chemical and medicinal properties, which could be an appropriate substitute compared to other beverages among which the treatment containing 75 % Sugar and 2% saffron extract was introduced as the most desired treatment.