ABSTRACT
Utilization of food-waste-derived bioactive compounds with biodegradable polymers is an attractive strategy leading innovation in the food packaging sector and contributing to reduce the environmental concerns of plastic packaging disposal. In this field, this work is aimed to use hazelnut perisperm as an antioxidant agent in the production of biodegradable polymeric films for active packaging applications. For this purpose, hazelnut perisperm of a selected particle size (<250 µm) at different percentages (0%, 5% and 10% by weight) was added to a bioderived and compostable polymer suitable for food contact, known as Ecovio®. The blends were produced by a twin-screw extrusion process, while active films were prepared with a pilot lab-scale film blowing plant. The films were characterized in terms of physical−mechanical properties (thermal, tensile, oxygen barrier, optical, sealing ability) and antioxidant activity (DPPH), to investigate their potential use as active packaging. The results showed that the presence of the hazelnut perisperm confers significant antioxidant activity to the films, which is useful in counteracting lipid oxidation and preserve the quality of lipophilic foods, e.g., nut-dried fruits. An extension of the sealability temperature range of the films without compromising their strength was also highlighted. Moreover, the hazelnut perisperm causes a gradual decrease in the stiffness and mechanical strength of the films and an increase in the ductility of the system.
ABSTRACT
Heat-shrinkable films, largely made of polyolefins and widely employed in the packaging sector as collation or barrier films, due to their short service life, are held responsible for high environmental impact. One possible strategy for reduction in their carbon footprint can be the use of biodegradable polymers. Thus, this work aimed to develop novel, heat-shrinkable, fully biodegradable films for green packaging applications and to analyze their functional performance. Films were obtained from blends of amorphous polylactic acid (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT) at different mass ratios and compatibilized with a chain extender. They were produced by means of a lab-scale film blowing extrusion apparatus and characterized in terms of physical-mechanical properties and shrinkability. The influence of the processing parameters during the extrusion blowing process on the films' behavior was investigated, highlighting the effects of blend composition and stretching drawing conditions. Shrinkage tests demonstrated that the produced films have shrinkability values in the typical range of mono-oriented films (ca. 60-80% in machine direction and ca. 10-20% in transverse direction). Moreover, the shrinkage in machine direction increases both with the mass flow rate, the take-up ratio to blow-up ratio and the bubble cooling of the film blowing process, and with the PLA content into the blend. In particular, films at higher PLA content also exhibit higher transparency and stiffness.
ABSTRACT
Increasing consumer demand for foods with high nutritional quality, prolonged shelf life and low environmental impact of the package, is driving innovation towards the development of new packaging. Multifunctional food packaging films, biodegradable, heat-sealable and antimicrobial, were developed. A PLA coating layer incorporating either sodium benzoate, potassium sorbate, or a combination of them was deposited onto a poly(lactic) acid/poly(butylene adipate-co-terephthalate) substrate film. The effectiveness of the developed systems to preserve the quality of foods was tested in shelf-life experiments performed on shredded carrots and pineapple juice, selected as model processed raw foods. The best performance was observed for the active film containing potassium sorbate: microbial populations increased less rapidly and were 0.7-1.8 log CFU/g lower at the end of storage period in this film than in control packs. Of the two model foods, the pineapple juice was better preserved: after 7 days in active packaging, color change and microbial counts of juice were below that of control, observed after one day and after 3 days of storage respectively. Moreover, the incorporation of the active phases did not significantly affect the mechanical, barrier and optical properties of the films, opening new ways to prolong shelf-life of minimally processed foods. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05435-y.
ABSTRACT
This study focuses on the upgrading strategies to make Fil-s (acronym for film-small), a polyolefin-based material coming from the mechanical recycling of post-consumer flexible packaging, fit for re-use in the piping sector. The effects of washing treatments (at cold and hot conditions) and the addition of an experimental compatibilizer on the chemical-physical properties of Fil-s were first assessed. The measurements of some key properties (density, melt flow index, flexural modulus, yield strength), for both Fil-s as such and the different developed Fil-s based systems, was also conducted in order to evaluate the suitability of this complex and challenging waste stream to replace virgin PE-based pipe and fitting products, in compliance to ASTM D3350 standard. The outcomes of the present work contributed to define a code, for each Fil-s system investigated, useful for identifying the level of their performance in piping applications. All the recyclates were extruded as pipes by using a pilot scale plant, but the process resulted more stable and continuous with the compatibilized Fil-s, as it was deducible from its flow properties. Moreover, the best mechanical performances were exhibited by the hot-washed Fil-s pipes, with an increase in pipe stiffness equal to 65% respect to the unwashed sample.
ABSTRACT
In this work, eco-sustainable blown films with improved performance, suitable for flexible packaging applications requiring high ductility, were developed and characterized. Films were made by blending two bioplastics with complementary properties-the ductile and flexible poly(butylene-adipate-co-terephthalate) (PBAT) and the rigid and brittle poly(lactic acid) (PLA)-at a 60/40 mass ratio. With the aim of improving the blends' performance, the effects of two types of PLA, differing for viscosity and stereoregularity, and the addition of a commercial polymer chain extender (Joncryl®), were analyzed. The use of the PLA with a viscosity ratio closer to PBAT and lower stereoregularity led to a finer morphology and better interfacial adhesion between the phases, and the addition of the chain extender further reduced the size of the dispersed phase domains, with beneficial effects on the mechanical response of the produced films. The best system composition, made by the blend of PBAT, amorphous PLA, and the compatibilizer, proved to have improved mechanical properties, with a good balance between stiffness and ductility and also good transparency and sealability, which are desirable features for flexible packaging applications.
ABSTRACT
The use of biopolymers can reduce the environmental impact generated by plastic materials. Among biopolymers, blends made of poly(lactide) (PLA) and poly(butylene-adipate-co-terephthalate) (PBAT) prove to have adequate performances for food packaging applications. Therefore, the present work deals with the production and the characterization of blown films based on PLA and PBAT blends in a wide range of compositions, in order to evaluate their suitability as chilled and frozen food packaging materials, thus extending their range of applications. The blends were fully characterized: they showed the typical two-phase structure, with a morphology varying from fibrillar to globular in accordance with their viscosity ratio. The increase of PBAT content in the blends led to a decrease of the barrier properties to oxygen and water vapor, and to an increase of the toughness of the films. The mechanical properties of the most ductile blends were also evaluated at 4 °C and -25 °C. The decrease in temperature caused an increase of the stiffness and a decrease of the ductility of the films to a different extent, depending upon the blend composition. The blend with 40% of PLA revealed to be a good candidate for chilled food packaging applications, while the blend with a PLA content of 20% revealed to be the best composition as frozen food packaging material.
