Novel Oxidized and UV-Irradiated Araucaria angustifolia Pine Seed Starch for Enhanced Functional Properties

Starch is an important raw material for industrial processes. Therefore, an investigation of new sources of starch and starch modification methods is necessary. The dual oxidation effect on the properties of the native pine seed starch is investigated. Native starch is extracted from pine seeds and its proximate composition determined. The starch is then subjected to a dual oxidation process in standard NaClO or H2O2 solutions (0.2; 0.5; 0.8molL(-1)) and simultaneous exposure to ultraviolet light irradiation (UVC =254nm). Thermogravimetric (TG-DTA) curves reveal enhanced stability to thermal degradation of the dual NaClO/UV process modified starch up to 20%. Differential scanning calorimetry (DSC) shows a strong decrease in gelatinization enthalpy due to the action of the UV-rays coupled with the sodium hypochlorite (NaClO) solution. The H2O2/UV modified starch has a high final viscosity while the NaClO/UV starch pastes have a low tendency to recrystallize. Furthermore, structural analysis using an X-ray diffractometer and scanning electron microscopy (SEM) show crystallinity patterns of type A starch and that the shape of the starch granules are unaltered following the modification processes. Color parameters show a strong increase in the L* value (for whiteness) for the NaClO/UV treated samples. The modified starches demonstrate improved physicochemical properties which are suitable for several industrial applications including as stabilizers for frozen bakery products, whitening agents for paper products, and tableting agents for cosmetic and pharmaceuticals products.