pH-Sensitive Acetalated Dextran/PLGA-Based Double-Layered Microparticles and Their Application in Food Preservation

Abstract

Double-layered microparticles (150–190 μm) composed of biodegradable poly­(lactic-co-glycolic acid) (PLGA) and pH-responsive acetalated dextran were fabricated using a one-step emulsion solvent evaporation technique. Nearly 80% dextran was released from the microparticles after 20 days of incubation in pH ∼ 5 medium, and the complete disappearance of shell (Ac-dextran) layer was also evident from scanning electron microscopy (SEM) images after 20 days under the same condition. However, the Ac-dextran shell was found to remain unchanged in neutral pH. Dual actives such as antibacterial (benzoic acid) and antioxidant (tocopherol) were incorporated in the shell and core of the microparticles to exploit their applications as food-preserving materials. An accelerated release of antibacterial and a controlled release of antioxidant were found to be useful for prolonging the shelf life of a low-pH food such as pork broth (pH ∼ 5) over 20 days by providing complete bacterial growth inhibition and high radical scavenging efficiency (70–90%).

Segregation of Benzoic Acid in Polymer Crystalline Cavities

“…These low toxicity compounds are widely used in medicine and can be found in various cosmetic products, medications and food as additives and preservatives to certain approved concentrations [ 22 , 23 ]. In fact, many studies report on the release of BA and derivatives [ 24 , 25 , 26 , 27 , 28 , 29 ].…”

Integration of benzoic acid‐loaded nanocellulose fibers on biodegradable poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) matrix and its application into food preservation

“…The antibacterial behavior of the bare corona-treated PHBV and BZ-NFC-coated PHBV film was assessed against Escherichia coli (E. coli), gram-negative bacteria, and Staphylococcus aureus (S. aureus), gram-positive bacteria, by using the plate count method. 21,25 Freshly prepared bacterial cultures of S. aureus, and E. coli, were made ready by using $10 μL of the bacterial culture (stored in glycerol solution at around À70 C to À80 C) into $10 mL Luria broth solution (LB), which was later reserved for $24 h at $37 C and 200 rpm at one position in the incubator. About $100 μL of E. coli and S. aureus solutions with a fixed concentration of $130 cells per mL were inoculated in the PBS 7 for attaining a static concentration of $4.898 Â 10 6 CFU/mL and $ 5.11 Â 10 6 CFU/mL for E. coli and S. aureus.…”

“…Several methods for incorporating antimicrobial agents into polymer-based packaging films, including direct entrapment through noncovalent interaction, and surface immobilization, have been developed to control the active release rate. 19,[21][22][23][24][25][26] Although these methods have demonstrated their potency in prolonging the food shelf life, they suffer from scalability issues, thus making them industrially less viable. Conversely, scalable techniques using high-temperature mixing methods aimed at encapsulating antimicrobial actives in polymer films during film formation stage 24 often compromise the active's performance due to thermal decomposition of actives.…”

“…Enhancing the robust interaction between the packaging film, that is, polymer matrix and antimicrobial agent is essential for controlling the active release, thereby availing prolonged food shelf life by suppressing the burst release of actives. Several methods for incorporating antimicrobial agents into polymer‐based packaging films, including direct entrapment through noncovalent interaction, and surface immobilization, have been developed to control the active release rate 19,21–26 . Although these methods have demonstrated their potency in prolonging the food shelf life, they suffer from scalability issues, thus making them industrially less viable.…”

Engineering Carbohydrate-Based Particles for Biomedical Applications: Strategies to Construct and Modify

“…Acetal modification of hydroxyl groups of dextran results in organic soluble acetalated dextran (Ac-DEX). , Its degradability and molecular weight can be tuned by switching the pH of the medium. The ratio of cyclic acetal groups to acyclic acetal groups can be varied depending on the reaction time of the acetal modification step, thus controlling the degradation rate of the polymer as cyclic acetals degrade at a slower rate than that of acyclic acetals .…”