A thesissubmitted in partial fulfillment of the requirements for theRequirements for the degree of Master, School of Environment, Resources and Development

Thesis (M. Sc.) - Asian Institute of Technology, 2010

The aim of this study is to investigate the effect of pyrodextrins on fortification of orange juice.Pyrodextrins were developed by varying 3 important factors during pyrodextrinization; temperature (120, 140 and 160oC), amount of acid added before heating (3, 4 and 5% w/w) and reaction time (1, 2 and 3 hour). The parameters investigated in this study were indigestible fraction content, water solubility and L value (whiteness). The optimum condition of pyrodextrinizaion was selected to fortify into the orange juice.Effects of amount of modified starch added into the orange juice were studied. Physical properties (pH, total soluble solid, turbidity viscosity and color) of the orange juice fortified with different amount of pyrdextrins were compared to unfortified orange juice.The sensory evaluation was performed to determine the overall properties.It was found that the optimum condition for producing pyrodextrins was temperature of 160oC, amount of acid added of 3% and reaction time of 2 hours. At optimum condition, 26.27% indigestible fraction content, 94.67% water solubility and whiteness of 90.18of pyrodextrin was obtained.The addition of different level of pyrodextrin produced at the optimum condition did not effect to pH, total acidity of the fortified orange juice, but effected tototal soluble solid,color and viscosity of fortified orange juice. The yellowness of orange juicesupplemented with greater amount of modified starch content was lower. In contrast,whitenessand viscosity of fortified orange juice increased. Effects of adding pyrodextins into juice were supported by the results ofsensory evaluation. In this study, it was found that the acceptable concentration of pyrodextrins forfortification of orange juicewas 2%.