title: Influence of organic solvents on the structural and thermal characteristics of silk protein from the web ofOrthaga exvinaceaHampson (Lepidoptera:Pyralidae).
abstract: The silk protein from the web ofOrthaga exvinaceawas isolated, purified, and casted into films. This film was treated separately with methanol, acetone, ethyl acetate, and isopropyl alcohol in 50 % concentration for about 30 min. The treated films were thus dried in a desiccator and subjected to FTIR and TG-DTA analysis. The structural studies revealed that the organic solvents induce conformatory changes in the protein film, especially the most sensitive amide I (1650 cm-1) band. This band had shifted to lower wavenumber (1633-1636 cm-1). Furthermore, the conformatory characteristics associated with amide I band also changed from random coil to β-sheet. Generally, β-sheet contributes strength to the protein film. Among the treated films, film treated with acetone showed much thermal stability. Moreover, the film treated with methanol had shown two different temperatures of maximum degradation. It is concluded that in addition to β-sheet content, various other factors such as various processing conditions and structural organization of protein may influence the stability of the films.
authors.affiliation: Insect Physiology and Biochemistry Laboratory, Department of Zoology, University of Calicut, Kerala, India 673 635.
authors.forename: Sajitha
authors.initials: S
authors.lastname: Narayanan
authors.affiliation: Insect Physiology and Biochemistry Laboratory, Department of Zoology, University of Calicut, Kerala, India 673 635.
authors.forename: Mankadath
authors.initials: M
authors.lastname: Gokuldas
keywords: FTIR; Orthaga exvinacea; Silk film; Silk protein; Silken web; TG-DTA