Preparation and partial characterization of films made with dual-modified (acetylation and crosslinking) potato starch

Intelligent films based on dual-modified starch and microencapsulated Aronia melanocarpa anthocyanins: Functionality, stability and application

This study aims to enhance the physical properties and color stability of anthocyanin-based intelligent starch films. Three dual-modified starches, namely crosslinked-oxidized starch (COS), acetylated distarch phosphate (ADSP), and hydroxypropyl distarch phosphate (HDSP), were utilized as film matrices. Aronia melanocarpa anthocyanins were incorporated through three different pre-treatments (free, spray-drying microencapsulation, and freeze-drying microencapsulation) to assess the prepared films' functionality, stability, and applicability. The results indicate that the ADSP film exhibited an approximately two-fold increase in elongation at break (EAB) compared to native starch film. Specifically, the ADSP film's water contact angle (WCA) reached 90°, demonstrating excellent flexibility and hydrophobicity. Scanning electron microscopy (SEM) revealed stronger interactions between anthocyanins and the film matrix after microencapsulation. Furthermore, after 30 days of exposure to 37 °C heat and light radiation, the freeze-dried anthocyanin-based intelligent film (FDA film) exhibited minimal fading, displaying the highest stability among the tested films. Notably, during beef freshness monitoring, the intelligent films underwent significant color changes as the beef deteriorated. In conclusion, the developed FDA film, with its outstanding stability and responsive pH characteristics, holds immense potential as a novel packaging material for food applications.

Influence of acetylation and chemical interaction on edible film properties and different processing methods for food application

This study developed sweet potato starch (SPS) based edible films and investigated several methods (acetylation, amidated pectin (AP), and CaCl₂ use) to improve the edibility and different processing methods (casting and extruding) to package food possible in commercial use. Starch acetylation was conducted with up to 8 mL of acetic acid (A8) and improved the stretchability and solubility of the film. The AP addition [∼30 wt% (P3)] enhanced the film strength, further increasing solubility. CaCl₂ addition [∼150 mg/g of AP (C3)] also positively influenced the film solubility and water barrier properties of the films. The SPS-A8P3C3 film showed 3.41 times higher solubility than the native SPS film. Both casted and extruded SPS-A8P3C3 films drastically dissolved in high-temperature water. When applied to oil packaging, two films could delay the lipid oxidation of the packaged samples. These results demonstrate the usability of edible packaging and extruded film for commercial use.

Toward a Circular Bioeconomy: Development of Pineapple Stem Starch Composite as a Plastic-Sheet Substitute for Single-Use Applications

Plastic waste poses a significant challenge for the environment, particularly smaller plastic products that are often difficult to recycle or collect. In this study, we developed a fully biodegradable composite material from pineapple field waste that is suitable for small-sized plastic products that are difficult to recycle, such as bread clips. We utilized starch from waste pineapple stems, which is high in amylose content, as the matrix, and added glycerol and calcium carbonate as the plasticizer and filler, respectively, to improve the material's moldability and hardness. We varied the amounts of glycerol (20-50% by weight) and calcium carbonate (0-30 wt.%) to produce composite samples with a wide range of mechanical properties. The tensile moduli were in the range of 45-1100 MPa, with tensile strengths of 2-17 MPa and an elongation at break of 10-50%. The resulting materials exhibited good water resistance and had lower water absorption (~30-60%) than other types of starch-based materials. Soil burial tests showed that the material completely disintegrated into particles smaller than 1 mm within 14 days. We also created a bread clip prototype to test the material's ability to hold a filled bag tightly. The obtained results demonstrate the potential of using pineapple stem starch as a sustainable alternative to petroleum-based and biobased synthetic materials in small-sized plastic products while promoting a circular bioeconomy.

Toward a Circular Bioeconomy: Exploring Pineapple Stem Starch Film as a Plastic Substitute in Single Use Applications

In this study, biodegradable starch film was developed from pineapple stem waste as a substitute for non-biodegradable petroleum-based films for single-use applications where strength is not too demanding. High amylose starch from a pineapple stem was used as the matrix. Glycerol and citric acid were used as additives to adjust the ductility of the material. Glycerol content was fixed at 25% while that of citric acid varied from 0 to 15% by weight of starch. Films with a wide range of mechanical properties can be prepared. As more citric acid is added, the film becomes softer and weaker, and has greater elongation at the break. Properties range from a strength of about 21.5 MPa and 2.9% elongation to a strength of about 6.8 MPa and 35.7% elongation. An X-ray diffraction study showed that the films were semi-crystalline. The films were also found to be water-resistant and can be heat-sealed. An example of a single-use package was demonstrated. A soil burial test confirmed that the material was biodegradable and completely disintegrated into sizes smaller than 1 mm within one month.

Biopolymers as green-based food packaging materials: A focus on modified and unmodified starch-based films

The ideal food packaging materials are recyclable, biodegradable, and compostable. Starch from plant sources, such as tubers, legumes, cereals, and agro-industrial plant residues, is considered one of the most suitable biopolymers for producing biodegradable films due to its natural abundance and low cost. The chemical modification of starch makes it possible to produce films with better technological properties by changing the functional groups into starch. Using biopolymers extracted from agro-industrial waste can add value to a raw material that would otherwise be discarded. The recent COVID-19 pandemic has driven a rise in demand for single-use plastics, intensifying pressure on this already out-of-control issue. This review provides an overview of biopolymers, with a particular focus on starch, to develop sustainable materials for food packaging. This study summarizes the methods and provides a potential approach to starch modification for improving the mechanical and barrier properties of starch-based films. This review also updates some trends pointed out by the food packaging sector in the last years, considering the impacts of the COVID-19 pandemic. Perspectives to achieve more sustainable food packaging toward a more circular economy are drawn.

Physical, Chemical and Biochemical Modification Approaches of Potato (Peel) Constituents for Bio-Based Food Packaging Concepts: A Review

Potatoes are grown in large quantities and are mainly used as food or animal feed. Potato processing generates a large amount of side streams, which are currently low value by-products of the potato processing industry. The utilization of the potato peel side stream and other potato residues is also becoming increasingly important from a sustainability point of view. Individual constituents of potato peel or complete potato tubers can for instance be used for application in other products such as bio-based food packaging. Prior using constituents for specific applications, their properties and characteristics need to be known and understood. This article extensively reviews the scientific literature about physical, chemical, and biochemical modification of potato constituents. Besides short explanations about the modification techniques, extensive summaries of the results from scientific articles are outlined focusing on the main constituents of potatoes, namely potato starch and potato protein. The effects of the different modification techniques are qualitatively interpreted in tables to obtain a condensed overview about the influence of different modification techniques on the potato constituents. Overall, this article provides an up-to-date and comprehensive overview of the possibilities and implications of modifying potato components for potential further valorization in, e.g., bio-based food packaging.

New insights into moisture sorption characteristics, nutritional composition, and antioxidant and morphological properties of dried duckweed [Wolffia arrhiza (L.) Wimm]

BACKGROUND

Duckweed has been considered as an alternative future food material as a result of its high nutritional values, although it also has a high moisture content resulting in a short shelf life. Moisture sorption isotherms are used to design dehydration and storage conditions to prolong the shelf life food products. To date, information regarding the sorption isotherm of duckweed has not been reported. Scanning electron microscopy (SEM) is frequently used to study food microstructure. However, this technique has to be performed under high-vacuum conditions and takes a long time. In the present study, two-photon imaging microscopy was selected to investigate the microstructure of dried duckweed instead of SEM.

RESULTS

Among five sorption isotherm models, the Peleg model gave the highest goodness of fit. The monolayer moisture content (M₀ ) of duckweed was in the range 7.43-7.92% dry basis (d.b.) and 8.87-8.86% d.b. for the GAB and BET multilayer kinetic models, respectively. The moisture changing behavior at each relative humidity step could be described by two exponential and reaction order kinetics. A clear cell structure (hexagonal shape) and stomata, as well as structural images (both 2D and 3D), were obtained using the two-photon microscopy technique.

CONCLUSION

The Peleg model best described the moisture sorption behaviors of dried duckweed and the shape of sorption isotherms were classified as type III isotherm. The M₀ of dried duckweed ranged from 7.43 to 8.86% d.b. Two-photon microscopy was a potent tool for investigating the microstructure and composition of dried duckweed. © 2021 Society of Chemical Industry.

Preparation and Properties of Pea Starch/ε-Polylysine Composite Films

The composite films comprising pea starch (St) and ε-polylysine (PL) as the matrix and glycerol and sodium alginate as the plasticizers were investigated. The rheological properties, mechanical properties, Fourier transformed infrared spectroscopy, water vapor permeability (WVP), oil permeability, microstructure, thermogravimetry (TGA), and antimicrobial properties of the composite films were analyzed. The properties of the composite films with different mass ratios of St/PL varied significantly. First, the five film solutions were different pseudoplastic fluids. Additionally, as the mass ratio of PL increased, the tensile strength of the blends decreased from 9.49 to 0.14 MPa, the fracture elongation increased from 38.41 to 174.03%, the WVP increased, and the oil resistance decreased substantially. The films with a broad range of St/PL ratios were highly soluble; however, the solubility of the film with a St/PL ratio of 2:8 was reduced. Lastly, the inhibition of E. coli, B.subtilis, and yeast by the films increased with increasing mass ratios of PL, and the inhibition of B.subtilis was the strongest.

Development and characterization of dual-modified yam (Dioscorea rotundata) starch-based films

The current consumer demand for fresh food and the interest in caring for the environment have driven the development of biodegradable film packaging to replace synthetic films to preserve the integrity of food. The objective of this work was to evaluate the effects of starch modifications (oxidized, cross-linked, and dual: oxidized/cross-linked), starch concentration (1 and 2%), and glycerol concentration (5 and 15%) on water vapor permeability (WVP), mechanical properties (tensile strength and elongation), optical, and structural properties of films based on “hawthorn” yam starch. The WVP of the films was 4.4 × 10⁻¹⁰ to 1.5 × 10⁻⁹ g/m∗s∗Pa, where the films with oxidized yam starch showed a 58.04% reduction concerning the native starch. The tensile strength of oxidized yam starch films showed a decrease of 17.51% with an increase in glycerol concentration. For the 1% starch concentration, elongation increased by 17.03% when the glycerol concentration was increased from 5 to 15%. Modification of starch, starch concentration, and glycerol have a significant effect on the barrier, mechanical, physical, and structural properties of films made with yam starch, where films made with oxidized yam starches at a concentration of 1% starch and 5% glycerol showed the best responses of the properties evaluated.

Dual modification of various starches: Synthesis, properties and applications

The problems associated with native starches (NSs) and single modified starches were stated in order to justify dual modification of various starches. Broadly, there are two types of dual modification, i.e., homogeneous dual modification and heterogeneous dual modification. The combination of two physical modifications, e.g., (extrusion/annealing); two chemical modifications, e.g., (succinylation/cross-linking) and two enzymes modification (α-amylase/pullulanase) falls under the former classification and the latter classification is the combination of two of each of the differently stated modifications, e.g., acetylation/annealing, extrusion/succinylation, and microwave-assisted phosphorylation, etc. The classification, synthesis, properties and applications of dually modified starches were discussed. There is an attempt to elucidate the problems of each of the single modification in order to justify dual modifications. In dual modifications, the order of reactions, the reaction conditions, the medium of reaction, and the botanical sources of the various starches are very important parameters.

Fabrication and characterization of one high-hygroscopicity liquid starch-based mulching materials for facilitating the growth of plant

One high-performance liquid starch-based mulching materials (LSMM) was successfully fabricated by grafting polyacrylic acid (PAA) onto starch then crosslinking with N,N'-methylene-bisacrylamide (MBA). The effects of the dosage of acrylic acid on the performances of LSMM film had been explored. The LSMM was characterized by FTIR, solid state ¹³C NMR, XRD and SEM. Their application performances by spraying the LSMM on the soil surface also had been discussed. The PAA grafted onto starch significantly improved the properties of LSMM film (tensile strength 20.89 MPa, elongation at break 59.19 %, water absorbency 68.58 g/g and solubility in water 4.5 %). The PAA broke the hydrogen bonds and reduced the crystallinity of starch molecule, which can form the compact structure in LSSM film. As a result, the LSMM showed excellent relative hygroscopicity, water retention, degradability (weight loss 72.61 %) and the effect of facilitating the growth and germination ratio (84.00 %) of lettuce.