Development of heat-stable fruit fillings using gellan gum as stabilizer.

This research was designed in aim to determine the optimum percentage of gellan gum for the development of heatstable fruit fillings with a wide range of soluble solids – from 40 to 70°Brix, which maintain its sensory and textural characteristics before, during and after baking on the basis of Response Surface Methodology. The low acyl gellan gum Kelcogel F was selected to be used in heat-stable fruit filling’s development due to its excellent thermal and freeze-thaw stability. This high-viscosity hydrocolloid possesses curative properties for sufferers of hypercholesterolemia, high blood pressure, and diabetes and forms a firm gel in as little as two hours, delivering full strength in less than 5 hours. The fruit fillings’ samples with the same pH and different soluble solids content were prepared locally from fruit pulp, sugar, low acyl gellan gum Kelcogel F and citric acid. The produced fruit fillings were put through standard bakery test to evaluate their heat-stability by determining bakery index (BI) through measuring the diameter of a fruit filling’s sample before and after baking process performed under exactly fixed conditions: at a temperature of 220°C for 20 minutes. The rheological behavior of the fruit fillings prepared on the basis of gellan gum has been investigated by performing experimental measurements at the rotational rheometer Rheotest RV2. There were obtained the final equations in terms of actual factors in order to describe the influence of soluble solids and gellan gum on fruit filling's heat-stable, sensory and rheological properties. The adequacy of the regression equations was evaluated by the F-test for analysis of variance (ANOVA) using statistical package STATISTICA v.6 and has shown that the models were statistically significant.