Performance-enhanced regenerated cellulose film by adding grape seed extract.

Eco-friendly packaging material with intelligent colorimetric performance has been a requirement for food safety and quality. This work focused on a food packaging material from regenerated cellulose films that added the grape seed extract (GSE) and polyethylene glycol 200 (PEG). FTIR and SEM techniques were employed to prove the compatibility of GSE with cellulose matrix. The composite film showed an enhanced elongation at break (16.61 %) and tensile strength (33.09 MPa). The addition of PEG and GSE also improved the water contact angle of regenerated-cellulose film from 53.8° to 83.8°. Moreover, the composite films exhibited UV-blocking properties while maintaining adequate transparency. The GSE induced the regenerated films with a macroscopic change in color under different pH conditions. Furthermore, the loading of GSE slowed down the decomposition of strawberries and delayed the self-biodegradation compared with the control for more than 3 days and 18 days. The present study showed a regenerated cellulose film with acceptable mechanical and hydrophilia properties, pH-responsiveness, anti-decomposition, and delayed biodegradation performances, indicating a potential color sensor in food packaging.

The role of surface functional groups of pectin and pectin-based materials on the adsorption of heavy metal ions and dyes.

Natural macromolecules have been used to adsorb pollutants including heavy metal ions and organic dyes due to low-cost, accessible, biodegradable, and eco-friendly advantages. Pectin, an important natural polymer, possesses abundant carboxyl and hydroxyl functional groups that can interact with the metal and organic cations via electrostatic interaction; as well as be modified by other chemicals for preparing hybrid and composite materials. The resultant materials have been employed to remove pollutants from aqueous solution; the importance of chemical composition was unlocked. Here, we reviewed contaminant removal by pectin, and pectin-based hybrid and composite materials, and highlighted the role of functional groups on pollutant removal. The removal of heavy metal ions was mainly due to surface coordination, while that of organic cations to electrostatic interactions of the functional groups. Moreover, the influence of initial contaminant concentration was critically discussed. The comprehensive review can provide valuable information on pectin and its application in contaminant removal.