Effect of acid–methanol treatment on the molecular structure and physicochemical properties of lentil (Lens culinaris Medik) starch

Effect of selected physical and chemical modifications on physicochemical, pasting, and morphological properties of underutilized starch from rice bean (Vigna umbellata)

Starch was extracted from the rice bean which is largely underutilized and modified by physical (i.e. heat moisture treatment and retrogradation) and chemical (i.e. esterification and acid alcohol modification) methods. Both, physical and chemical modifications significantly (p < 0.05) affected the physicochemical, pasting, particle size and morphological properties of rice bean starch. Both amylose content and swelling power reduced after physical and chemical modifications. Among modified starches, retrograded starch showed higher solubility (8.56%) at 90 °C. Retrogradation also resulted in higher values of water (251%) and oil absorption (106%) capacities in comparison to other modified starches. Physical modifications greatly influenced the pasting properties in comparison to chemical modifications. The particle size distribution followed the order: native starch (659.8 nm) > heat moisture treated (434.3 nm) > retrograded (355.4 nm) > esterified (218 nm) > acid alcohol treated starch (234.5 nm). The study revealed that the particle size of rice bean starch was reduced by both physical and chemical modifications. FE-Scanning electron microscopy was used to study the morphological characteristics of starches and it was observed that retrogradation had a pronounced effect on the starch granules morphology.

Development and physicochemical, thermal and mechanical properties of edible films based on pumpkin, lentil and quinoa starches

Starches isolated from pumpkin fruits, lentil and quinoa seeds were used to prepare edible films. Physicochemical, thermal and mechanical properties of films were determined and compared with potato-based starch (PS) film. It was found that botanical origin of starch has a crucial effect on the films properties. The much lower solubility and higher swelling capacity compared to PS film exhibited lentil and pumpkin starch-based films, respectively. All of the films exhibited significantly higher water vapor permeability compared to PS one. Tensile strength and elongation at break of the films varied between 8.98 and 13.85 MPa, and 3.35 to 4.44%, respectively. All of the films acted as a solid-like materials with prevalently elastic behavior and exhibited endothermic peaks in DSC measurement in the range of 249-281 °C, referred to the melting of films. This study demonstrated that starches from non-conventional sources are good alternative to conventional to develop edible films.