Starch films loaded with tannin: the study of rheological and physical properties

Olga Mileti; Domenico Mammolenti; Noemi Baldino; Francesca Romana Lupi; Domenico Gabriele

doi:10.1016/j.ijbiomac.2023.127973

Starch films loaded with tannin: the study of rheological and physical properties

Int J Biol Macromol. 2024 Jan;254(Pt 3):127973. doi: 10.1016/j.ijbiomac.2023.127973. Epub 2023 Nov 8.

Authors

Olga Mileti¹, Domenico Mammolenti¹, Noemi Baldino¹, Francesca Romana Lupi², Domenico Gabriele¹

Affiliations

¹ Department of Information, Modeling, Electronics and Systems (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036 Rende, CS, Italy.
² Department of Information, Modeling, Electronics and Systems (D.I.M.E.S.), University of Calabria, Via P. Bucci, Cubo 39C, I-87036 Rende, CS, Italy. Electronic address: francesca.lupi@unical.it.

PMID: 37944713
DOI: 10.1016/j.ijbiomac.2023.127973

Abstract

Recently, the research on innovative food packaging has been oriented toward biodegradable materials to lower the environmental impact generated by conventional plastics. The films often carry functional additives interacting with the matrix and modifying its physical properties. In this work tannin, a scarcely exploited active additive, was used to obtain potato starch-based films, and its content was optimized on the basis of mechanical and microscopic tests. Rheological measurements were adopted to evaluate the tannin-starch interaction and the microstructure of the film forming solutions (FFSs). Their thickness, color, thermal conductivity, elastic modulus (E_el), elongation at break (EAB), surface wettability and water solubility were evaluated. Furthermore, microstructure was investigated through Fourier-transform infrared spectroscopy (FTIR), polarized light (POM) and scanning electron microscopy (SEM). It was observed that all FFSs behave as weak gels and tannin addition weakens the gel structure and decreases the gelatinization temperature from about 60 °C to 57 °C. Plastic and deformable films (E_el = 1.96 MPa and EAB = 189 %) were obtained at low tannin fractions, whereas, at a higher concentration, stiffer films (E_el = 12 MPa and EAB = 10 %), with hydrophobic behavior were produced. Among the tested tannin fractions, an intermediate value of 1.7 % (w/w) was found to be promising for industrial purposes.

Keywords: Gelatinization; Microstructure; Polyphenols; Rheological properties; Tape casting.

MeSH terms

Food Packaging
Permeability
Starch* / chemistry
Tannins*
Tensile Strength

Substances

Tannins
Starch