Determination and numerical modeling of sugar release based on textural properties in model gels

ABSTRACT DETERMİNATİON AND NUMERİCAL MODELİNG OF SUGAR RELEASE BASED ON TEXTURAL PROPERTİES İN MODEL GELS Serpil PEKDOĞAN GÖZTOK Department of Food Engineering PhD Thesis Supervisor: Assoc. Doc. Dr. İbrahim PALABIYIK In this thesis, model gels were prepared and three different 'hydrocolloid' components were used as stabilizers, which are gelatin (160, 200 and 250 bloom), low methoxyl (LM) pectin and modified corn (MC) starch. Hydrocolloid ratio of gels containing 30% (g/g) sucrose; different bloom gelatin 6, 8, 10 and 12%; LM pectin 1, 1.7, 2.4 and 3.1, MC starch 2.5, 5, 7.5 and 10% (g/g) were used. In order to determine the release of 90% of the sugar contained in the model gels at 25 °C, two different conditions, treatment1 (mixing only) and treatment2 (shredding with mixing process) were studied. The release times of hydrocolloids in treatment1 and 2 ranged from 45.00±0.00-517.00±0.00, 8.50±0.07-92.00±5.66 minutes, respectively. Except for the LM pectin samples, the lowest hydrocolloid concentration product had the shortest release time and the highest hydrocolloid concentration product had the longest release time in the sugar release in Environment 1 (p <0.05). It has been determined that the release in ambient2 takes less time than ambient1 and that the fracture process has an effect on the release. Texture profile analysis was performed on the model gel samples. It has been determined that the hydrocolloid concentration increase has an effect on the hardness, the products with the highest rate have the hardest value. MC starch samples had lower hardness than other samples. The relationship between hardness, K, Young's modulus values and release times was determined. The effective diffusivity values (Deff) of the release process are between 0.22x10-8 and 5.07x10-8 m2/s in treatment1, 18.47x10-8 and 1.37x10-8 m2/s in treatment2, and the mixing process has increased the Deff values. The sugar release process is modeled numerically for two different environments. A model that fits well with experimental data was developed for both different methods. Keywords: sugar release, numerical modeling, pectin, starch, gelatin