Development and Investigation of Zein and Cellulose Acetate Polymer Blends Incorporated with Garlic Essential Oil and β-Cyclodextrin for Potential Food Packaging Application

Abstract

The obtainment of new materials with distinct properties by mixing two or more polymers is a potential strategy in sustainable packaging research. In the present work, a blend of cellulose acetate (CA) and zein (60:40 wt/wt CA:zein) was manufactured by adding glycerol or tributyrin as plasticizers (30% wt/wt), and garlic essential oil (GEO), complexed (IC) or not with β-cyclodextrin (βCD), to produce active packaging. Blends plasticized with tributyrin exhibited a more homogeneous surface than those containing glycerol, which showed major defects. The blends underperformed compared with the CA films regarding mechanical properties and water vapor permeability. The presence of IC also impaired the films’ performance. However, the blends were more flexible than zein brittle films. The films added with GEO presented in vitro activity against Listeria innocua and Staphylococcus aureus. The IC addition into films, however, did not ensure antibacterial action, albeit that IC, when tested alone, showed activity against both bacteria. These findings suggest that the mixture of CA and plasticizers could increase the range of application of zein as a sustainable packaging component, while essential oils act as a natural bioactive to produce active packaging.

Development, characterization, application, and degradation of sustainable active packaging: cellulose acetate and zein films incorporated with garlic essential oil

“…As stated before, an initial screening showed that the GEO did not affect the tested bacteria equally. While the Gram-positive bacteria, such as L. innocua, had their growth impaired by the EO, none of the Gram-negative bacteria investigated appeared to be affected by it (Marques et al, 2022). In this sense, it is possible that part of the diverse microbial population in cheese was not impacted by the active films, and was able to grow normally during the storage time.…”

“…Selected colonies were taken from the plate and suspended in 0.85% (wt/v) saline solution until obtaining a visual suspension density similar to 0.5 McFarland turbidity standard (approximately 10 7 CFU•mL −1 ) and diluted 1:10. Then, we proceeded with the agar dilution method, with modifications, to investigate the MIC of GEO (CLSI, 2012;Marques et al, 2022). Samples were dispersed in 10 mL of liquefied BHI agar (around 45 °C), resulting in GEO final concentrations ranging from 39.75 µg•mL −1 to 2650 µg•mL −1 , and subsequently poured into Petri dishes with a diameter of 60 mm.…”

“…The films were prepared according to Marques et al (2022). Three grams of cellulose acetate were added to 30 mL of acetone (ratio of 1:10 wt/v) and let disperse for 24 h. After that, 0.9 g of glycerol was added into dispersions (30% wt/wt based on polymer mass).…”

“…with modifications (Marques et al, 2022). The films (Ø = 83 mm) were placed on poly(methyl methacrylate) cups containing a saturated solution of lithium chloride (12 ± 5%…”

“…Garlic compounds have been recognized as natural antimicrobial agents with a broad spectrum of action, showing activity against Gram-positive and Gram-negative bacteria (Ezeorba et al, 2022). However, an initial screening was done against different bacteria, and it was verified activity against only the Gram-positive ones (Marques et al, 2022). This result may be due to the EO composition, since the antimicrobial property of GEO depends on the type and ratio of the organosulfur compounds present Arbach et al, 2019).…”