Development and characterization of antimicrobial and antioxidant whey protein-based films functionalized with Pecan (Carya illinoinensis) nut shell extract

Condensed Tannins, a Viable Solution To Meet the Need for Sustainable and Effective Multifunctionality in Food Packaging: Structure, Sources, and Properties

“…Incorporation of CT is generally achieved through extrusion, , solvent casting, , or vacuum filtration, followed by dehydration, , without the need for chemicals to covalently link the antioxidant to the polymer, although in some cases, the use of plasticizers, such as glycerol, has been reported. − Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are routinely employed for the morphological characterization of the functionalized polymeric material, ,,,, whereas the optical transmittance profiles and color of the films can be recorded and defined by use of an ultraviolet–visible (UV–vis) spectrophotometer and colorimeter, respectively. ,,, On the basis of the UV absorption properties of CT, UV–vis spectroscopy, possibly coupled with gravimetric tests, , can also be used to monitor the release of the additive from the film when in contact with the food matrix or reference solvents. , As far as the effects of CT on the mechanical properties of the polymeric films are concerned, tensile tests are generally performed, ,− along with dynamic mechanical analysis . Other characterizations of the functionalized films generally involve gas (e.g., oxygen, water vapor, air, and carbon dioxide) permeability, ,,− water contact angle, and water uptake/swelling measurement. , The effective incorporation of CT and the kind of interactions between the polymer and the additive can be easily determined by attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopy and/or thermogravimetric analysis (TGA). ,− ,, TGA is also used to characterize the thermal stability of the films, , whereas the photo-oxidative stability can be determined by ATR–FTIR spectroscopy and tensile tests further to light exposure . The antioxidant properties acquired by the functionalized films can be straightforwardly evaluated by means of the widely used antioxidant assays 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and oxygen radical abs...…”

“…Other characterizations of the functionalized films generally involve gas (e.g., oxygen, water vapor, air, and carbon dioxide) permeability, ,,− water contact angle, and water uptake/swelling measurement. , The effective incorporation of CT and the kind of interactions between the polymer and the additive can be easily determined by attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopy and/or thermogravimetric analysis (TGA). ,− ,, TGA is also used to characterize the thermal stability of the films, , whereas the photo-oxidative stability can be determined by ATR–FTIR spectroscopy and tensile tests further to light exposure . The antioxidant properties acquired by the functionalized films can be straightforwardly evaluated by means of the widely used antioxidant assays 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) assays, ,− ,, whereas for the determination of the antimicrobial activity, the agar plate diffusion method ,, or optical density measurement are generally applied. Biofilm formation inhibition activity can also be determined using the microplate assay or confocal laser scanning microscopy …”

“…As a remarkable example of the multifunctionality that may be imparted by CT to food packaging materials, PLA films incorporating CT from pecan nut shell exhibited improved mechanical properties and thermal and photo-oxidative stability, along with antioxidant and enzymatic browning inhibition activities. , The same tannins have also been exploited for the implementation of antimicrobial and antioxidant whey protein-based edible films with excellent gas barrier properties . Cross-linking interactions between CT from pine bark and proteins have been demonstrated in soy protein isolate films, resulting in improved thermal stability, tensile strength, and antioxidant activity and decreased water vapor and oxygen permeability .…”

“…42,44,45,48 On the basis of the UV absorption properties of CT, UV−vis spectroscopy, possibly coupled with gravimetric tests, 49,50 can also be used to monitor the release of the additive from the film when in contact with the food matrix or reference solvents. 19,47 As far as the effects of CT on the mechanical properties of the polymeric films are concerned, tensile tests are generally performed, 19,44−50 along with dynamic mechanical analysis. 46 Other characterizations of the functionalized films generally involve gas (e.g., oxygen, water vapor, air, and carbon dioxide) permeability, 19,44,47−49 water contact angle, 44 and water uptake/swelling measurement.…”

Physicochemical and Antimicrobial Properties of Whey Protein-Based Films Functionalized with Palestinian Satureja capitata Essential Oil

“…Figure 6 shows the antimicrobial activity of the WP-based films, prepared in the ab sence or presence of TEO1, towards S. enteriditis 706 RIVM, S. enterica ATCC ® 14028, aureus ATCC 29213, and E. faecalis ATCC 29212 strains, observed by placing small square (1.5 cm × 1.5 cm) of each film on a confluent bacterial plate in full contact with the aga surface [34,35]. After 24 h at 37 °C, it was observed that the WP-based film itself was unable to inhib bacterial growth (Figure 6).…”