Search

Blending chitosan and gelatin, two biodegradable and non-toxic polymers, is a recurrent choice in food coating or biomaterials development. The incorporation of vegetal extracts into chitosan/gelatin films can improve or introduce some properties to these materials. Jatobá resin is a product of Hymenaea genus trees with antimicrobial and anti-inflammatory activities, interesting properties for films applied in several areas. The chitosan degree of acetylation (DA) influences the inter and intramolecular interactions of this polymer and, therefore, also implicates in changes of its properties. This research aims to study the influence of jatobá resin inclusion and chitosan DA modification on chitosan/gelatin films properties. Both jatobá resin and chitosan DA affected physicochemical, antimicrobial and barrier properties of the films, allowing the control of these properties by changes in these parameters. Jatobá resin incorporation and the decrease in chitosan DA significantly improved antimicrobial activity and water vapor permeability of films with the reduction of water solubility and swelling., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this study, chitosan and gelatin materials incorporated with grape seed (Vitis vinifera L.) (VSE) and jabuticaba peel (Plinia cauliflora) (PPE) extracts were developed with potential application as food coatings. It was evaluated how the concentration of the extracts and their addition order in the polymeric matrix affect its properties. Samples with VSE presented a higher total phenolic content and also a more elastic behavior than samples with PPE. The addition order effect over viscosity was the opposite for the extracts, and for the samples with VSE a lower viscosity was obtained when the extract was added before gelatin. All samples were hydrophilic, a good result for application as coatings. Films with PPE were less soluble than chitosan/gelatin film, and CG5P sample was chosen as the most suitable for the desired application, due to its lower water vapor permeation value. The microbial permeation test showed that all samples avoid microorganism growth, extending shelf life of food. The results of this study revealed the extracts concentration was the main factor which influenced the studied parameters; however, their addition order had significant importance on rheological and barrier properties, the ones most influenced by the availability of extract compounds in the polymeric system., Competing Interests: Declaration of competing interest The authors declare they have no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The physicochemical properties of nanoparticles (NPs) directly influence the colloidal stability and bio‐nano interface, which makes the study of these factors extremely important for NPs applicability. Here, we report the influence of pH and ionic strength in the size, surface charge, and antimicrobial activity of chitosan/rhamnolipid nanoparticles (C/RL‐NPs), synthesized by mixing C and RL in the proportion of 1:1, with the dropwise addition of TPP (sodium tripolyphosphate) in the molar ratio of 1:2.5:1.3, respectively. The obtained NPs were resuspended in different solvents to investigate the ionic strength effect on their stability and antimicrobial activity. By decreasing pH and ionic strength, NPs size was reduced while their surface charge increased. Chitosan nanoparticles (C‐NPs) remained stable in the presence of TPP at acidic pH and low ionic strength, indicating that the modulation of physicochemical conditions for the crosslinking between the two ionic components was an efficient approach to enhance C/RL‐NPs colloidal stability. Thermogravimetric analysis confirmed the interaction between rhamnolipid and chitosan in C/RL‐NPs. The antibacterial activity of C/RL‐NPs against Staphylococcus aureus increased significantly, demonstrating the importance of investigating size and surface charge to dictate the bioactivity properties of such hybrid natural‐based nanomaterial. [ABSTRACT FROM AUTHOR]

Food safety denotes a major concern for the society, industries, and policymakers. Among the incipient strategies to recognize products that are unfit for consumption is smart packaging that can respond to changes in composition or storage conditions throughout spoilage and communicate this to consumers. Herein, we report on a halochromic packaging that switches colors in response to changes in pH and ammonia concentration upon fish decay. Different lignin and grape seed and peel extract contents are shown to play a role on the physicochemical, morphological, mechanical, and biological features of the packaging, which are then easily tailored by simply varrying composition. Lignin was shown to improve the water barrier properties (water vapor permeability of 0.19 ± 0.01 g mm kPa−1 h−1 m−2 and water contact angle of 89 ± 3°) of chitosan-based films, but hindered its swelling (over three times) and mechanical resistance with decreased elongation at break and Young's modulus, which was tuned by the extracts. The antioxidant activity was increased to 47% by adding only 0.50 wt% of grape seed extract, and its antimicrobial activity against Staphylococcus aureus surpassed that of extract-free samples. The capacity for real-time detecting NH 3 vapor was validated for naked eye, as per an evident color change from yellow to orange. Finally, a film comprising chitosan/lignin/grape seed extract was successfully applied as a sticker indicator to monitor the spoilage of fish over time. Importantly, besides ensuring and tracking food freshness in a real-time fashion, this study is set out to mitigate food waste generation, approach that is boosted when we valorize agri-food residual streams to fabricate triple-action materials. Overall, our waste-only materials integrate the three roles (i.e., antimicrobial, antioxidant, and intelligent) to prevent further waste, plus burdens related to food spoilage. [Display omitted] • Triple-action packaging films were developed using agri-food side streams. • Antioxidant, antibacterial, and halochromic roles were integrated. • Real-time tracking of food freshness was enabled. • Food waste can prevent further food waste, plus burdens related to food spoilage. [ABSTRACT FROM AUTHOR]