Mechanical, Barrier, Antioxidant and Antimicrobial Properties of Alginate Films: Effect of Seaweed Powder and Plasma-Activated Water

Abstract

The incorporation of natural fillers such as seaweed may potentially enhance the properties of biopolymer films. In this study, we investigated the effect of seaweed powder as a bio-filler in alginate-based films at different concentrations (10, 30, and 50%, w/w alginate) and particle sizes (100 and 200 μm) on the mechanical, barrier, antioxidant, and antimicrobial properties of alginate which are essential for food packaging applications. Initially, mechanical properties of the alginate films prepared at different temperatures were evaluated to find the optimal temperature for preparing alginate solution. The addition of seaweed powder did not have any positive effect on the mechanical properties of the alginate films. However, the barrier (water vapor transmission rate) and antioxidant properties were improved with the addition of seaweed filler regardless of concentration. In addition, selected films were prepared in plasma-activated water (PAW). The mechanical properties (tensile strength, but not elongation at break) of the films prepared with PAW improved compared to the films prepared in distilled water, while a significant decrease was observed when incorporated with the seaweed filler. The films prepared in PAW also showed improved barrier properties compared to those prepared in distilled water. The antimicrobial activity of the alginate-seaweed film-forming solution was in general more pronounced when prepared with PAW and stored at 10 °C, particularly at the highest concentration of the film-forming solution (83.3% v/v). A more pronounced inhibitory effect was observed on the Gram-positive S. aureus than on the Gram-negative E. coli, which has been attributed to the different composition and structure of the respective cell walls. This study has demonstrated the potential of seaweed filler in combination with PAW towards enhanced functionality and bioactivity of alginate films for potential food packaging applications.

Combined Effect of Citric Acid and Polyphenol-Rich Grape Seed Extract towards Bioactive Smart Food Packaging Systems

“…DPPH radical scavenging activity was measured as described by Dysjaland et al (2022) [ 37 ], with some modifications. The film was dissolved in DW to a concentration range of 0.01–3.00 mg/mL sodium alginate.…”

“…The evaluation of antimicrobial properties of the film-forming solutions was conducted according to the modified method described by Dysjaland et al (2022) [ 37 ] and Sharmin et al (2021) [ 38 ]. The antimicrobial studies focused on Escherichia coli CCUG 10979 (Gram-negative) and Staphylococcus aureus CCUG 1828 (Gram-positive) reference strains, obtained from the Culture Collection of the University of Gothenburg (Sweden).…”

Food packaging based on biodegradable polymers from seaweeds: a systematic review

“…In the context of food packaging, polymer films that possess the appropriate mechanical properties include elongation at break, elastic modulus, and tensile strength. The tests demonstrate that the film can withstand a range of stresses, including those encountered in the preparation, handling, and storage of food, without experiencing any degradation in its integrity [65]. Intermolecular interactions between polymer chains, as well as the integrity and solubility of the constituents, have a substantial impact on the mechanical properties of composite films produced by combining.…”

Application of duck bone gelatin and sodium alginate-based edible coating materials on beef sausage quality during chilled storage

“…Sodium alginate can be a barrier against air and light. The combination of these two materials is known to form a layer that has a strong and dense matrix so that it will minimize the contact between food ingredients and oxygen [30].…”

“…An edible coating of gelatin can bind water when applied to food [7]. [30] state that the use of alginate as a basic material for making edible coatings can also be a cause of decreased moisture content. This is because alginate has the property of being able to immobilize water, which causes the amount of absorbed water and free water in food to decrease.…”