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

Abstract

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; 0.8 mol L−1) and simultaneous exposure to ultraviolet light irradiation (UVC λ = 254 nm). 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.

Morphological and Physicochemical Properties of Pine Seed Starch Nanoparticles

“…According to the literature, the average particle size of PS oscillates between 11 and 17 μm. [10,14] After ASP, the obtained materials also showed a monomodal distribution with particle sizes varying between 230 and 1300 nm (Figure 3), confirming the nanometric scale of the materials obtained by ASP. In the literature, starch nanoparticles obtained by ASP have a similar particle size, however, bimodal particle size distributions have been informed.…”

“…However, the reduced harvest season (between April and August) is the main factor limiting its food application. [10,11]…”

“…[2,9] The Araucaria angustifolia conifer is a pine tree widely distributed in the native forests in the southern and southeastern Brazil. [10,11] Pine seeds are harvested from April to August, and they are considered a rich source of starch which is isolated from the endosperm of this seed (Figure 1). In this way, some research studies have been carried out to isolate and characterize the physicochemical properties of pine starch (PS), being concluded that PS has comparable thermal and rheological properties that those informed in conventional starches, as well as low tendency to retrogradation when used in food formulations.…”

“…In this way, some research studies have been carried out to isolate and characterize the physicochemical properties of pine starch (PS), being concluded that PS has comparable thermal and rheological properties that those informed in conventional starches, as well as low tendency to retrogradation when used in food formulations. [10][11][12][13][14] Furthermore, the valorization of pine seeds has been considered an alternative to add value to this unconventional starch source and reduce its deforestation. [11] In recent years, the production of starch nanomaterials has been explored due to the different physicochemical properties of these nanostructures when compared with their native counterparts.…”

Evaluation of the impact of UV radiation on rheological and textural properties of food

“…The lightness values of the starches were found to be increased with NaClO/UV treatment in contrast to gelatinization enthalpy. A high viscosity value was observed for H 2 O 2 /UV‐modified starches (Hornung et al, 2019).…”