As biodegradable and eco-friendly bio-resources, polysaccharides from a wide range of sources show steadily increasing interest. The increasing fossil-based production of materials are heavily associated with environmental and climate concerns, these biopolymers are addressing such concerns in important areas such as food and biomedical applications. Among polysaccharides, high amylose starch (HAS) has made major progress to marketable products due to its unique properties and enhanced nutritional values in food applications. While high amylose-maize, wheat, barley and potato are commercially available, HAS variants of other crops have been developed recently and is expected to be commercially available in the near future. This review edifies various forms and processing techniques used to produce HAS-based polymers and composites addressing their favorable properties as compared to normal starch. Low toxic and high compatibility natural plasticizers are of great concern in the processing of HAS. Further emphasis, is also given to some essential film properties such as mechanical and barrier properties for HAS-based materials. The functionality of HAS-based functionality can be improved by using different fillers as well as by modulating the inherent structures of HAS. We also identify specific opportunities for HAS-based food and biomedical fabrications aiming to produce cheaper, better, and more eco-friendly materials. We acknowledge that a multidisciplinary approach is required to achieve further improvement of HAS-based products providing entirely new types of sustainable materials.

Starch-based bioplastics offer a promising alternative to conventional plastics. However, they exhibit certain limitations, notably in terms of mechanical strength and barrier properties. These challenges could potentially be addressed through the incorporation of nanocellulose as a reinforcing agent. In this study, we fabricated bioplastic films using a casting and blending approach, employing highly linear pure amylose (AM) in combination with cellulose nanofibers (CNF) or cellulose nanocrystals (CNC) at various ratios. This allowed for a direct comparison of CNF and CNC functionality within the AM matrix. We systematically assessed mechanical properties and water barrier characteristics, encompassing parameters such as water permeability, moisture content, swelling, solubility, crystallinity, thermal stability, transmittance, and opacity. Additionally, we investigated water vapor and oxygen permeability. Furthermore, we delved into distinctions between CNC and CNF biocomposites. Incorporation of either type of nanocellulose yielded enhancements in film properties, with CNF exerting a more pronounced positive influence compared to CNC. Particularly noteworthy were the mechanical properties, wherein CNF composite films demonstrated markedly higher tensile strength and Young’s modulus compared to their CNC counterparts. For instance, the inclusion of 1% CNF led to a substantial increase in AM tensile strength from 66.1 MPa to 144.8 MPa. Conversely, water vapor permeability exhibited a converse behavior, as the addition of 1% CNF resulted in a significant reduction of water barrier properties from 8.7 to 1.32 g mm m⁻² 24 h⁻¹kPa⁻¹. Intriguingly, CNC films displayed greater elongation at the point of rupture in comparison to CNF films. This can be attributed to the larger surface area of the CNC and the favorable interfacial interaction between AM and CNC. Notably, the introduction of nanocellulose led to reduced film opacity and improved thermal stability. In summary, nanocellulose interacted synergistically with the AM matrix, establishing a robust hydrogen-bonded network that greatly enhanced the performance of the biocomposite films.

Fresh meat and fish are widely consumed foods with short and very short shelf lives, respectively. Efficient supply chains and the judicious use of food packaging are the most effective means of extending shelf life and thus reducing food waste and improving food safety. Food packaging that allows for the use of a modified atmosphere (MAP) is effective in extending the period where the food is both palatable and safe. However, monitoring the state of aging and the onset of spoilage of the product poses challenges. Microbial counts, pH measurements, and sensory evaluations are all informative but destructive and are therefore only useful for monitoring quality via sampling. More attractive would be a technology that can follow the progress of ageing in an individual product while leaving the food packaging intact. Here, we present a pH indicator to be placed inside each package that may be read by the naked eye. It is a colorimetric indicator with a matrix made of pure amylose (AM; 99% linear α-glucans) and cellulose nanofibers (CNFs). Suitable mechanical properties of films cast of the two polysaccharides were achieved via the optimization of the blending ratio. The films were loaded with either of two pH indicators: anthocyanin extracts from red cabbage (RCA) and the synthetic dye neutral red (NR). Mechanical, thermal, permeability, microstructural, and physical properties were tested for all composite films. Films with 35% CNF (35AC-RCA) and (35AC-NR) were selected for further study. Minced meat was packaged under MAP conditions (70% O₂ + 30% CO₂), while minced fish was packaged under MAP (70% N₂ + 30% CO₂) and stored at 5 °C for 20 days. Microbial growth, pH, and sensory scores of the minced meat systems differentiated between fresh (0–6 days) and medium-fresh (7–10 days), and minced fish between fresh (0–10 days) and medium-fresh (11–20 days). The total color difference showed that the RCA indicator was able to differentiate between fresh (red) and medium-fresh (pink-red) minced meat, while for minced fish, this indicator discriminated between three stages: fresh (red), medium-fresh (pink-red), and spoiled (pink-blue). The NR indicator failed to discriminate the freshness of either meat or fish under the effect of MAP. Pearson correlation statistical models showed a correlation between color change of the indicator, pH, content of gases, and gas content. In summary, RCA immobilized in an AM + 35% CNF nanocomposite film can monitor the freshness of packaged minced meat/fish under the effect of MAP via color change that may be evaluated with the naked eye.

Binary and ternary blends of amylose (AM), polylactic acid (PLA), and glycerol were prepared using a Pickering emulsion approach. Various formulations of AM/PLA with low PLA contents ranging from 3% to 12% were mixed with AM matrix and reinforced with 25% cellulose nanofibers (CNF), and PLA-grafted cellulose nanofibers (g-CNF), the latter to enhance miscibility. Polymeric films were fabricated through solvent casting and characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Wide-Angle X-ray Scattering (WAXS), and the evaluations of physical, mechanical properties, and wettability were performed using contact angle measurements. The binary blends of AM and PLA produced films suitable for packaging, pharmaceutical, or biomedical applications with excellent water barrier properties. The ternary blends of AM/CNF/PLA and AM/g-CNF/PLA nanocomposite films demonstrated enhanced tensile strength and reduced water permeability compared to AM/PLA films. Adding g-CNF resulted in better homogeneity and increased relative crystallinity from 33% to 35% compared to unmodified CNF. The application of Pickering emulsion in creating AM-based CNF/ PLA composites resulted in a notable enhancement in tensile strength by 47%. This study presents an effective approach for producing biodegradable and reinforced PLA-based nanocomposite films, which show promise as bio-nanocomposite materials for food packaging applications.