Optimization of Enriched Diet Pastille Formulation Containing Spirulina Platensis Microalgae Using Replacement of Sucrose with Stevioside-Isomalt and Gelatin with Persian Gum by Response Surface Methodology (RSM)

In order to reduce the sugar consumption in the pastille formulation and improve its nutritional value using Spirulina platensis microalgae, the effect of sugar replacement with stevioside-isomalt, gelatin replacement with Persian gum and effect of using spirulina as a bioactive compound on the physicochemical and textural properties of pastilles were investigated. In order to optimization the production conditions of enriched diet pastille, the response surface method (RSM) in the form of a central composite design were used in 5 levels of sugar replacement with stevia-isomalt (0, 25, 50, 75, 100%), gelatin replacement with persian gum (0, 25, 50, 75,100%) and Spirulina (0, 0.25, 0.50, 0.75, 1%). The results of physicochemical, textural and sensory properties of the selected product were evaluated during 0, 15, 30, 45 and 60 days and compared with the control sample. The results showed that an increase in the percentage of sucrose replacement with stevioside-isomalt and gelatin replacement with persian gum, resulted in an increase and decrease the hardness, respectively. Density and adhesiveness decreased and increased significantly with increasing percentage of sucrose replacement with stevioside-isomalt, respectively. Among the investigated formuls, samples containing 13% sucrose replacement with stevioside-isomalt, 100% gelatin replacement with persian gum and 0.28% Spirulina; and 60% sucrose replacement with stevioside-isomalt, 100% gelatin replacement with persian gum and 0.02% Spirulina were determined as the best formulation. Comparison between treatments revealed a moisture reduction and density increment of the optimal samples (p<0.05), while the hardness of the optimal samples did not significantly change during storage time (p>0.05). Results of sensory analysis indicate that control sample had better sensory characteristics (taste, after taste, texture and overall acceptability) than the other samples. The addition of Spirulina platensis microalgae as a functional supplement can improve nutritional properties, especially protein and minerals such as iron in the product.