Edible thermochromic beads from flavonoid, fatty acid, and lecithin for smart packaging.

Enzymatic browning and microbial growth are two natural phenomena that occur when fruits and vegetables are exposed to abnormal conditions, i.e., temperatures in the range of 12-22 °C, leading to their spoilage. Controlling the temperatures during the supply chain aims to optimize the product's shelf life. Irreversible thermochromic beads were fabricated using a simple extrusion technique containing fatty acid, lecithin, and anthocyanin solution-alginate. The pigmentation durability was adjusted based on electrostatic interactions, as evidenced by the reduction in dye leaching in the case of the produced bead at pH = 6 to less than 0.007 after 45 min. Characterization shows that the chosen combination of fatty acids and the quinonoid molecule is useful for producing thermochromic beads, with a color change at 12 °C-22 °C, from blue to purple. Using the prepared thermochromic beads in the supply chain of fresh-cut salad and brussels sprouts showed a great result for monitoring their freshness after 21 ± 1 min.

Development of shelf life-extending packaging for vitamin C syrup based on high-density polyethylene and extracted lignin argan shells.

Biobased packaging is an essential parameter in the pharmaceutical industry. In the present work, bio-composites consisting of high-density polyethylene (HDPE) as a matrix and lignin recovered from argan nut shells as filler were developed to investigate their potential use as packaging materials for vitamin C drugs. The lignin was extracted via alkali and klason processes, and the effects of the extraction method as well as the lignin content on the thermal, morphological, mechanical, and rheological properties of the produced composites, as well as their application for vitamin C packaging, were investigated. Among all the prepared packaging materials, the one with desirable results in pH, color stability, hardness, and mechanical characteristics was based on alkali lignin. It achieved its highest Young's modulus enhancement, 10.12 %, at 10 % alkali lignin loading, while the highest yield strain enhancement (4.65 %) was obtained with 2 % loading. When compared to neat HDPE and HDPE/klason lignin packaging materials, vitamin C solutions packed with this composite showed a lower oxidation rate, attributed to the extremely low pH variation and high color stability of the material, which decreased the rate of vitamin C degradation. According to these findings, HDPE/alkali lignin composite is a promising vitamin C syrup packaging material.

Stable smart packaging betalain-based from red prickly pear covalently linked into cellulose/alginate blend films.

Smart materials based on biomaterials have been shown growing interest by researchers. This paper investigated pH-indicator film with less leaching containing betalain molecule extracted from red prickly pear fixed in the cellulose-alginate blend as a matrix. Herein, the film was manufactured from a blend containing covalently bounded cellulose with betalain via the creation of a Fischer esterification (FE) to solve the leaching problem of dyes in contact with food. The structural, thermal, morphological optical, and mechanical properties and the pH-sensitive properties of films were examined. The FTIR and color analysis confirmed the fisher esterification. The fisher esterification led to a pH-indicator film with less leaching with significant color stability against UV light. The smart film changes colors with the pH values, where it goes from purple at a pH below 10 to yellow color at a pH above 10. All those proprieties with contact angles helped this film to be used as an intelligent film for monitoring salmon spoilage.

Intelligent food packaging film containing lignin and cellulose nanocrystals for shelf life extension of food.

The UV-protection films based on renewable materials extracted from natural sources are being one of the most interesting targets for the packaging industry. In this paper, the UV-protection films were produced based on modified lignin and cellulose nanocrystals, both were extracted from the Argania nutshell. The lignin was extracted via the alkylation process followed by chemical modification using epichlorohydrin. The chemical modification and the in-use temperature range of the films were investigated via FTIR and TGA, where the chemical modification of lignin improves the thermal property which is an essential parameter during the thermo-sealing of food packaging. On the other hand, the CNCs were extracted via acid hydrolysis treatment with the smallest size around 300 nm generating smooth texture of films. Finally, the produced films were shown a maximum absorption of the UV light in the range of 450-200 nm and great results in food packaging.

Effects of bleaching and functionalization of kaolinite on the mechanical and thermal properties of polyamide 6 nanocomposites.

Polyamide 6 nanocomposites (PA6)/kaolinite were prepared by melt compounding. First, kaolinite was bleached via a solvothermal reaction using oxalic acid as a bleaching agent; then, the bleached product was modified using dimethylsulfoxide (DMSO) and subsequently methanol (MeOH) via a displacement method. Thus, cetyltrimethyl ammonium bromide (CTAB) and triethoxy(octyl)silane (TEOS) molecules were intercalated into kaolinite nano-platelets. Seven types of nanocomposites were prepared using pristine, bleached or intercalated kaolinite. The kaolinite powder and the nanocomposite specimens were characterized by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), thermal analysis, scanning electronic microscopy (SEM), whiteness index and tensile tests. The influence of the bleaching process of kaolinite and the intercalation methods on the whiteness index of the nanocomposites was also observed, in which the whiteness index of the functionalized kaolinite nanocomposites was enhanced by up to 10.65% when compared to neat PA6. The thermal results revealed that the intercalation and functionalization greatly affect the thermal stability of the virgin polymer. On the other hand, the intercalation of kaolinite enhances the dispersion/distribution, improves the interfacial adhesion, and increases the aspect ratio of the kaolinite nanoparticles; this affords remarkable nanocomposite property enhancements, represented by a high Young's modulus value of 4.68 GPa and a maximum percentage growth of 80.6% for silane-grafted kaolinite nanoparticles at just 8 wt%.

Bio-composites based on polylactic acid and argan nut shell: Production and properties.

The aim of this work is to develop a new bio-composite based on polylactic acid (PLA) reinforced with argan nut shells (ANS). In this study, the effect of ANS chemical surface treatments on the morphological, mechanical, thermal, and rheological properties of PLA was investigated. In particular, a comparison between three chemical treatments (alkali, bleaching, and silane) is made for two filler concentrations (8 and 15% wt.). Scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, dynamic mechanical analysis, and tensile measurements were used to determine the morphology (particle distribution/dispersion/adhesion), thermal stability, mechanical behavior and rheological properties of the bio-composites compared with neat PLA. The results showed that the highest Young's modulus improvement (16%) was obtained with 15% of bleached ANS particles, while the highest tensile strength (1%) and strain at yield (8.5%) improvements were obtained with a silane treatment. These results were associated with good ANS-PLA interfacial adhesion and distribution in the matrix. Nevertheless, lower thermal stability (onset degradation temperature) for all the bio-composites was observed when compared to neat PLA. To complete the characterizations, water absorption and water contact angle were determined indicating better resistance of the bio-composites when ANS surface treatment was applied.