Robust, Flexible, and High-Barrier Films from Bacterial Cellulose Modified by Long-Chain Alkenyl Succinic Anhydrides

Abstract

This paper describes a simple and low-pollution surface modification strategy for fabricating flexible, semi-transparent, and robust bacterial cellulose (BC)/Kombucha tea-based BC films that are effectively resistant to water, water vapor, oxygen, ultraviolet light, and foodborne pathogenic bacteria. The strategy uses dimethyl sulfoxide as the pre-swelling solvent and long-chain alkenyl succinic anhydrides with different chain lengths as the esterifying agents. The proof of esterification, crystallinity index, film microstructure, and degree of surface substitution were systematically investigated. Our result showed that acylation with 2-octenylsuccinic anhydride for 8 h conferred the BC films with the highest water-vapor/oxygen resistance and optimal mechanical/thermal properties. In addition, the modified BC film has good antimicrobial properties and is capable of wrapping strawberries, increasing their longevity. Biodegradation and alkaline hydrolysis tests demonstrated that compostability of the film and recycling of the BC pulp are possible, revealing that such high-performance biofilm-based food packaging could have a green life cycle.

Development of strong and high-barrier food packaging films from cyclic-anhydride modified bacterial cellulose

“…BC films were fabricated by solvent casting according to our reported method. 16 The resulting dry BC films were carefully peeled from the dishes and stored in sealed LDPE bags at room temperature (RT) under natural light. The thickness of each film was measured at 10 random points using a digital micrometer accurate to 0.001 mm, which revealed that the average film thickness was approximately 40 μm.…”

“…The WS ratio of the modified BC films was calculated using eqn (4), according to our reported method: 16 WS = ( M 1 − M 2 )/ M 2 where M 1 is the weight of a sample after wiping, and M 2 is the weight of a sample after preconditioning in an oven at 60 °C for 5 h. These measurements were performed in triplicate, and the averages ± standard deviations are reported.…”

“…The biodegradation capacity of the lms was tested by burying them in natural soil at a depth of 10 cm for 10-30 d. 16,38 Aer 10 d, the lm fragments were removed from the soil, rinsed with water, and dried in an oven, and the weight loss ratio was determined using the gravimetric method and characterized by FTIR spectroscopy. Then the tested lms were re-buried in soil at a depth of 10 cm for 20 d to observe the biodegradation situation.…”

“…These changes can sharply reduce the shelf-lives of oxygen-sensitive packaged foods such as strawberries and meats due to the accelerated loss of moisture and proliferation of microorganisms. 16,17 However, these –OHs also enable chemical functionalization of cellulose ( e.g. , esterification, silylation, etherification, amidation), which confers new properties upon the BC films and thus paves the way for multiple practical applications in areas such as food and biomedicine.…”

Water-resistance chitosan film through enzymatic treatment and layer-by-layer assembly with bacterial cellulose for food packaging materials

“…Antimicrobial properties analysis was performed as previous with some modification. 32 S. aureus and E. coli strains were used. All samples were sterilized under ultraviolet light for 45 min.…”