2.1.Sample collection and preparation All raw materials were purchased from the local market, Dhaka, Bangladesh. In the laboratory, raw materials were weighed according to the formulation and packed with polyethylene bag until use.
2.2.Chemical and reagents Sugar, Macogel, CMC, Compound stabilizer, citric acid, sodium benzoate, potassium sorbet, and permitted artificial litchi flavor and litchi concentrate etc. were used in this study.
2.3. Preparation of artificial litchi flavored drinks The sucrose is added to the purified water at 2:3 ratios in a syrup preparation tank and heated (70-80oC) until dissolved completely, then strained and sufficient purified water added to make the desired weight or volume. Blending for 60 minutes and maintain the final brix at 60°. During cooking, syrup mixed with water, fresh Litchi concentrate and blending for few minutes and add Sodium benzoate then add Citric Acid, Ascorbic acid, Potassium Sorbet, Macogel, CMC, Compound stabilizer. Mixing the ingredients at steam pressure 0.5-1.5 kg/cm² and temperature (80-85) °C. After 30-35 minutes later check the brix if get as per required then add color and flavor. Then filtered by SS net and transfer to the reserved tank. After cooking the mixture send to the filling machine through pipe line. And it’s falls into the poly propylene cup by filling valve. During filling, temperature (40-45) 0C is maintained. After filling the product sealed at 200-2200C. Then it pasteurized at 85oC for 15 minutes. End of the pasteurization, the product pass through the cooling tank and cooling at temperature (38°C) using normal water for 4 to 5 min. After cooling operation, the product become wet and drying by air blower for 4 to 5 minutes. Finally, dried product fill into suitable package.
2.4.Determination of pH The pH of artificial litchi flavored drink was measured by a pH meter (Hanna Instruments, HI 8417, Italy) calibrated using buffers of pH 7.0 and 4.0. Then the pH of the samples was recorded.
2.5. Determination of Acidity/Titratable Acidity Acidity of artificial litchi flavored drinks was determined according to the method reported with few modifications. 5 ml of sample was diluted to 95 ml of de-ionized-distilled water. 10 mL diluted sample was taken in conical flask. After that, 2-3 drops of phenolphthalein indicator were added to the flask. Then the solution was titrated against 0.1N NaOH solution until the end point is reached. The acid content of the sample was calculated based on the volume of 0.1 N NaOH used for neutralizing the acid content in the sample and multiplying by a correction factor of 0.064 to estimate titratable acidity as percentage of citric acid. The titratable acidity was calculated using the following equation:
% Acidity = ml NaOH × 0.1N NaOH × 0.064 / Volume of Sample x 100
2.6.Determination of Total Soluble Solid (TSS) The TSS ( oBrix) of the artificial litchi flavored drink were determined by using a handheld refractometer (Model: HT119-ATC).
2.7.Sensory Evaluation Sensory characteristics of artificial litchi flavored drink sample was carried out on 28 days of storage. Semi-trained fifteen-panel members were selected from the university community. Randomly, the samples were presented to the panel members. Artificial litchi drink samples were evaluated organoleptically for color, flavor, taste and overall acceptability, according to the hedonic scale of nine points (9-like extremely to 1- dislike extremely) as reported.
2.8.Statistical Analysis Data were analyzed statistically using the statistical software R (windows version 2.13.1). All results were measured in triplicate for each sample. Results were expressed as mean values with standard deviation (±SD). DMRT (Duncan Multiple Range Test) was performed to evaluate the significance of the difference between mean values at the level of 5%.