Influence of Starch Composition and Molecular Weight on Physicochemical Properties of Biodegradable Films

Abstract

Thermoplastic starch (TPS) films are considered one of the most promising alternatives for replacing synthetic polymers in the packaging field due to the starch biodegradability, low cost, and abundant availability. However, starch granule composition, expressed in terms of amylose content and phosphate monoesters, and molecular weight of starch clearly affects some film properties. In this contribution, biodegradable TPS films made from potato, corn, wheat, and rice starch were prepared using the casting technique. The effect of the grain structure of each starch on microstructure, transparency, hydration properties, crystallinity, and mechanical properties of the films, was evaluated. Potato starch films were the most transparent and corn starch films the most opaque. All the films had homogeneous internal structures—highly amorphous and with no pores, both of which point to a good starch gelatinization process. The maximum tensile strength (4.48–8.14 MPa), elongation at break (35.41–100.34%), and Young’s modulus (116.42–294.98 MPa) of the TPS films were clearly influenced by the amylose content, molecular weight, and crystallinity of the film. In this respect, wheat and corn starch films, are the most resistant and least stretchable, while rice starch films are the most extensible but least resistant. These findings show that all the studied starches can be considered suitable for manufacturing resistant and flexible films with similar properties to those of synthetic low-density polyethylene (LDPE), by a simple and environmentally-friendly process.

Synthesis of Modified Starch/Polyvinyl Alcohol Composite for Treating Textile Wastewater

“…Therefore, in order to remove dye, polyvinyl alcohol, and starch from textile wastewater simultaneously, it is necessary to develop an efficient and low-cost fixed-bed adsorbent alternative. Starch and its derivatives are of increasing interest because of their higher biodegradability and renewability [30,31]. Cationic starch derivatives with quaternary ammonium groups are commonly prepared through the reaction of starch with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) [32,33].…”

Recent advances in starch‐based films toward food packaging applications: Physicochemical, mechanical, and functional properties

“…These histograms display the breadth in reported mechanical properties for simple film formulations. In the presentation of starch film data, 42 references were compiled giving n = 86 for both tensile strength and elongation at break statistics (Emblem & Emblem 2012;Matweb) Characteristic peaks for the V-type crystal structure can be observed at 2θ values of 19.6 to 19.8 and 22.1 to 22.7 and are typically quite broad (Domene-Lopez et al, 2019;Dries et al, 2016). Most of the research on starch has been conducted with starch from various cereal grains, potatoes, and cassava because of their ubiquitous production around the world.…”

“…Continued widespread use of petrochemically sourced plastics has resulted in relentless plastics pollution and pervasive environmental microplastics (Chen, Feng, & Wang, 2020; Rhodes, 2018). In the context of the current review, the widespread use of plastics in food packaging, of which ∼40% is made from petrochemical plastics, is a particular concern (Domene‐Lopez, Garcia‐Quesada, Martin‐Gullon, & Montalban, 2019). Of the plastics used in food packaging, polyethylene (PE), a highly biodegradation‐resistant and difficult to recycle plastic, is the most commonly used (Brooks Amy, Wang, & Jambeck Jenna, 2018; Gewert, Plassmann, & MacLeod, 2015; Sivan, 2011).…”

“…Based on the diffraction pattern of the granules, starch can further be divided into its crystal types, primarily so‐called “A‐type” or “B‐type” crystal structures. A‐type diffraction patterns show characteristic peaks at 2θ values of ∼12, 18, 20, and 23, whereas B‐type crystallinity produces peaks at 2θ values of ∼5, 11, 20, 22, and 24 (Domene‐Lopez et al., 2019; Luchese, Benelli, Spada, & Tessaro, 2018; Maniglia, Tessaro, Ramos, & Tapia‐Blacido, 2019). Starch from cereal grains typically produces a more A‐type diffraction pattern, whereas starch from root tubers has a more B‐type diffraction pattern.…”

“…Starch from cereal grains typically produces a more A‐type diffraction pattern, whereas starch from root tubers has a more B‐type diffraction pattern. The occurrence of peaks for both A‐ and B‐type diffraction patterns is typically referred to as a “C‐type” crystal structure (Domene‐Lopez et al., 2019; Dries, Gomand, Delcour, & Goderis, 2016; El Halal et al., 2019). A‐type crystal structure arises from double helices arranged in a monoclinic unit cell containing four water molecules, whereas B‐type diffraction peaks arise from double helices in a hexagonal unit cell containing a central channel with 36 water molecules.…”