Development and application of mathematical modeling of thymol release from environmental-responsive potato starch active packaging films

Traditional active packaging materials are easily affected by the environment, resulting in their inability to release active substances in specified quantities at specified times and locations. In this study, MCM-41 was used as a thymol (THY) carrier and added to the potato starch (PS) matrix to design an intelligent release active packaging film based on storage microenvironment. MCM-41 encapsulation improved thermal stability of THY. THY-MCM-41 addition significantly improved the tensile strength (TS, 7.18 MPa) of the film (P < 0.05) and endowed the film excellent gas and water barrier protection. THY release was responsive to temperature and relative humidity (RH), and the First-order model better explained the THY release pattern (R2 > 0.980). The THY-MCM-41/PS film exhibited long-term antibacterial effect during 10-day storage due to the sustained release of THY. Additionally, strawberries packaged in the THY-MCM-41/PS film exhibited the best sensory characteristics during 5-day storage (25 °C and 50 % RH). Overall, the present THY-MCM-41/PS film provides a novel alternative for the sustained release of active substances in order to achieve the excellent preservation of goods such as fruits and vegetables.

Pectin/sodium alginate-based active film integrated with microcrystalline cellulose and geraniol for food packaging applications

Biopolymer-based packaging films were prepared from pectin (PEC) and sodium alginate (SA), with the incorporation of 10 % MCC and different concentrations of geraniol (GER at 2.5, 5.0, 7.5, and 10.0 %). Rheological properties suggested that film-forming solutions and film-forming emulsions exhibited a shear-thinning or pseudo-plastic non-Newtonian behaviour. The dried films were crosslinked with 2.0 % CaCl2. The addition of MCC into PEC/SA film enhanced the TS but reduced it with the impregnation of GER without influencing the EAB and toughness of the film. The water solubility of the films significantly reduced with the rise in the GER levels but enhanced the water vapor and oxygen barrier attributes. TGA demonstrated that incorporating MCC reduced the film's thermal degradation (44.92 % to 28.81 %), but GER had an insignificant influence on the thermal stability. FTIR spectra revealed that hydrogen bond formation was positively linked with the GER addition in the film formulation. X-ray diffractograms showed that prepared films were predominantly amorphous. Antimicrobial studies showed a complete reduction of Escherichia coli and Bacillus cereus in 24 h. Overall, the composite film displayed excellent physical and active properties and PEC/SA/MCC/5.0 %GER/CaCl2 film was considered the best formulation for food packaging applications.

Gelatin-sodium alginate packaging film with date pits extract: An eco-friendly packaging for extending raw minced beef shelf life

Gelatin-sodium alginate-based active packaging films were formulated by including date pits extracts (DPE), as bioactive compound, in raw minced beef meat packaging. The DPE effects at 0.37, 0.75 and 1.5% (w/w, DPE/ gelatin-sodium alginate) on physical, optical, antioxidant and antibacterial properties of established films were assessed. Findings showed that film lightness decreased with the incorporation of DPE. Physical, antioxidant and anti-food-borne pathogens capacities were enhanced by increasing DPE concentration in the films. For 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), the films with 1.5% DPE had the greatest levels (94 and 88%, respectively). DPE films (1.5%) also exhibited the highest anti-Listeria moncytogenes activity, with an inhibition zone of 25 mm. Moreover, during 14 days at 4 °C, the bio-preservative impact of gelatin-sodium alginate film impregnated with DPE at three levels on microbial, chemical, and sensory characteristics of meat beef samples was evaluated. By the end of the storage, DPE at 1.5% enhanced the instrumental color, delayed chemical oxidation and improved sensory traits. By chemometric techniques (principal component analysis (PCA) and heat maps), all data allowed to obtain helpful information by segregating all the samples at each storage time. PCA and heat maps could connect oxidative chemical changes, instrumental color parameters, and microbiological properties to sensory attributes. These data offer an approach to well interpreting the sensory quality and how they are affected by chemical and microbiological changes in the studied meat samples. Our findings indicated the potential of the gelatin-sodium alginate film incorporated with DPE for enhancing meat safety and quality.

Novel active starch films incorporating tea polyphenols-loaded porous starch as food packaging materials

A novel active food packaging film was developed by casting a corn starch/tea polyphenol (TP)-loaded porous starch (PS, obtained by enzymatic hydrolysis) film forming solution, with the latter helping to regulate the slow release of TP. Results showed that PS had a favorable TP adsorption capacity, and the casted films had a homogeneous distribution of the formulation components. Likewise, the active films had good mechanical properties, UV barrier properties, thermal stability, and excellent antioxidant properties. The slow release of TP from the films was sustained, which is a desired characteristic for extending the protection afforded by the active film to the food under consideration.

Carrageenan/agar-based functional film integrated with zinc sulfide nanoparticles and Pickering emulsion of tea tree essential oil for active packaging applications

A functional carrageenan/agar-based film was prepared by combining tea tree oil Pickering emulsion (PET) and zinc sulfide nanoparticles (ZnSNP). PET was formulated using tea tree essential oil stabilized with nanocellulose fibers. PET and ZnSNPs were uniformly dispersed in the binary polymer matrix and formed compatible films. The incorporation of ZnSNPs improved the mechanical strength, whereas PET slightly decreased the strength, but the combined addition of ZnSNP and PET maintained the mechanical strength with slightly improved flexibility. The addition of ZnSNP and PET, alone or in combination, slightly improved the water vapor barrier, water resistance, and thermal stability of the film. In addition, the carrageenan/agar-based composite membrane showed distinct antioxidant and antibacterial activity. The ZnSNP and PET incorporated binary composite films with enhanced physical and functional properties are likely to be used in active food packaging applications.

Advances in the application of chitosan as a sustainable bioactive material in food preservation

Chitosan is obtained from chitin and considered to be one of the most abundant natural polysaccharides. Due to its functional activity, chitosan has received intense and growing interest in terms of applications for food preservation over the last half-century. Compared with earlier studies, recent research has increasingly focused on the exploration of preservation mechanism as well as the targeted inhibition with higher efficiency, which is fueled by availability of more active composite ingredients and integration of more technologies, and gradually perceived as "chitosan-based biofilm preservation." In this Review, we comprehensively summarize the potential antimicrobial mechanisms or hypotheses of chitosan and its widely compounded ingredients, as well as their impacts on endogenous enzymes, oxidation and/or gas barriers. The strategies used for enhancing active function of the film-forming system and subsequent film fabrication processes including direct coating, bioactive packaging film and layer-by-layer assembly are introduced. Finally, future development of chitosan-based bioactive film is also proposed to broaden its application boundaries. Generally, our goal is that this Review is easily accessible and instructive for whose new to the field, as well as hope to advance to the filed forward.