Preparation and Characterization of Novel Green Seaweed Films from Ulva rigida.

Ulva rigida green seaweed is an abundant biomass consisting of polysaccharides and protein mixtures and a potential bioresource for bioplastic food packaging. This research prepared and characterized novel biodegradable films from Ulva rigida extracts. The water-soluble fraction of Ulva rigida was extracted and prepared into bioplastic films. 1H nuclear magnetic resonance indicated the presence of rhamnose, glucuronic and sulfate polysaccharides, while major amino acid components determined via high-performance liquid chromatography (HPLC) were aspartic acid, glutamic acid, alanine and glycine. Seaweed extracts were formulated with glycerol and triethyl citrate (20% and 30%) and prepared into films. Ulva rigida films showed non-homogeneous microstructures, as determined via scanning electron microscopy, due to immiscible crystalline component mixtures. X-ray diffraction also indicated modified crystalline morphology due to different plasticizers, while infrared spectra suggested interaction between plasticizers and Ulva rigida polymers via hydrogen bonding. The addition of glycerol decreased the glass transition temperature of the films from -36 °C for control films to -62 °C for films with 30% glycerol, indicating better plasticization. Water vapor and oxygen permeability were retained at up to 20% plasticizer content, and further addition of plasticizers increased the water permeability up to 6.5 g·mm/m2·day·KPa, while oxygen permeability decreased below 20 mL·mm/m2·day·atm when blending plasticizers at 30%. Adding glycerol efficiently improved tensile stress and strain by up to 4- and 3-fold, respectively. Glycerol-plasticized Ulva rigida extract films were produced as novel bio-based materials that supported sustainable food packaging.

Maltol-Incorporated Acetylated Cassava Starch Films for Shelf-Life-Extension Packaging of Bakery Products.

Maltol is widely used as a flavor enhancer in baked goods and has an antimicrobial function. Maltol can also be incorporated into biopolymer films to produce active biodegradable packaging for bakery products. This research investigated the incorporation of 1-10% maltol into acetylated cassava starch films as functional packaging for shelf-life extension of butter cake. Films were determined for morphology, chemical interaction and packaging properties. Infrared absorption indicated H-bonding between starch and maltol, while plasticization effects decreased mechanical relaxation temperature. Microstructures showed enhanced smoothness at up to 3% maltol, while maltol crystallization occurred at higher concentrations, giving non-homogeneous matrices. Tensile strength and elongation at break reduced by 37% and 34%, respectively, with the addition of maltol up to 10%. Maltol concentration modified the hydrophilicity and molecular mobility of the matrices, impacting water vapor and oxygen permeability. Films incorporated with maltol were used as packaging for preservative-free butter cake and delayed visible mold growth at room temperature. Starch films with maltol at 1-5% delayed fungal growth by up to 2.7-times, while films containing 10% maltol inhibited mold growth by 6-times (up to 19 days of storage). Incorporating maltol into starch films produced bioactive materials, extending shelf-life while maintaining the aroma of bakery products.

Polyesters Incorporating Gallic Acid as Oxygen Scavenger in Biodegradable Packaging.

Biodegradable polyesters polybutylene succinate (PBS) and polybutylene adipate-co-terephthalate (PBAT) were blended with gallic acid (GA) via cast extrusion to produce oxygen scavenging polymers. The effects of polyesters and GA contents (5 to 15%) on polymer/package properties were investigated. Increasing GA formed non-homogeneous microstructures and surface roughness due to immiscibility. GA had favorable interaction with PBAT than PBS, giving more homogeneous microstructures, reduced mechanical relaxation temperature, and modified X-ray diffraction and crystalline morphology of PBAT polymers. Non-homogenous dispersion of GA reduced mechanical properties and increased water vapor and oxygen permeability by two and seven folds, respectively. Increasing amounts of GA and higher humidity enhanced oxygen absorption capacity, which also depended on the dispersion characteristics of GA in the matrices. PBAT gave higher oxygen absorption than PBS due to better dispersion and higher reactive surface area. GA blended with PBAT and PBS increased oxygen scavenging activity as sustainable active food packaging using functional biodegradable polymers.

Functional Polymer and Packaging Technology for Bakery Products.

Polymeric materials including plastic and paper are commonly used as packaging for bakery products. The incorporation of active substances produces functional polymers that can effectively retain the quality and safety of packaged products. Polymeric materials can be used to produce a variety of package forms such as film, tray, pouch, rigid container and multilayer film. This review summarizes recent findings and developments of functional polymeric packaging for bakery products. Functional polymerics are mainly produced by the incorporation of non-volatile and volatile active substances that effectively retain the quality of packaged bakery products. Antimicrobial agents (either synthetic or natural substances) have been intensively investigated, whereas advances in coating technology with functional materials either as edible coatings or non-edible coatings have also preserved the quality of packaged bakery products. Recent patents demonstrate novel structural packaging designs combined with active functions to extend the shelf life of bakery products. Other forms of active packaging technology for bakery products include oxygen absorbers and ethanol emitters. The latest research progress of functional polymeric packaging for bakery products, which provides important reference value for reducing the waste and improving the quality of packaged products, is demonstrated. Moreover, the review systematically analyzed the spoilage factors of baked products from physicochemical, chemical and microbiological perspectives. Functional packaging using polymeric materials can be used to preserve the quality of packaged bakery products.